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DEPARTMENT  OF  THE  INTERIOR 

UNITED  STATES  GEOLOGICAL  SURVEY 

GEORGE  OTIS  SMITH,  Director 


Bulletin  615 


RHODE  ISLAND  COAL 


GEORGE  H.  ASHLEY 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 

1915 


X 


CONTENTS. 


55  7 

HMV ' 

Xo.  (d  /•S  — \k 

Page. 


Introduction 5 

History  of  development  and  use  of  Rhode  Island  coal 7 

Early  history 7 

Development  from  1840  to  1880 9 

Recent  history 11 

Development  in  1913 14 

Conditions  affecting  method  and  cost  of  mining 14 

Character  of  the  coal 17 

General  features 17 

Field  conditions 17 

Physical  appearance 20 

Specific  gravity 21 

Chemical  character 23 

Reason  for  low  heat  value  of  Rhode  Island  coal 33 

Behavior  of  Rhode  Island  coal  toward  moisturo 37 

Utilization  of  Rhode  Island  coal 38 

Kinds  of  use 38 

Household  use 39 

Use  in  steam  raising 41 

Use  in  metallurgy 46 

Briquetting  tests 47 

Brick  burning  and  similar  work 48 

Indirect  use  as  water  gas  or  producer  gas 49 

Use  for  foundry  facings  and  furnace  linings 57 

Conclusions 57 

Papers  and  reports 58 

Index 60 


ILLUSTRATIONS. 


Page. 


Plate  I.  Sketch  map  of  the  Rhode  Island  coal  field 6 

II.  Views  at  Budlong  mine,  Cranston,  R.  I.:  A,  Open  cut  in  mine,  look- 
ing north;  B,  Face  of  bed  a little  north  of  the  mouth  of  the  slope, 
showing  the  characteristic  schistose  or  squeezed-lens  appearance 
of  the  coal 12 

III.  A,  Surface  plant  at  Budlong  mine,  Cranston,  R.  I.;  B,  Surface  plant 

at  South  mine  of  Portsmouth  Coal  Co.,  Portsmouth,  R.  1 13 

IV.  A,  View  in  graphite  mine  at  Fenners'  Ledge,  near  Providence,  R.  I.; 

B,  Diagram  showing  distortion  of  the  bed  represented  in  A 18 

V.  A,  View  at  north  end  of  Budlong  pit,  Cranston,  R.  I.;  B,  Diagram 
showing  variations  in  thickness  of  anthracite  at  north  end  of  Bud- 
long pit,  represented  in  A 19 

Figure  1.  Crushed  structure  of  coal 19 

2.  Chart  showing  composition  and  theoretic  heating  power  of  Rhode 

Island  coal  in  comparison  with  other  coals  with  which  it  must 
compete  in  New  England 24 

3.  Chart  showing  relation  of  carbon  in  Rhode  Island  coal  to  fuel  value . . 36 


589  63 


3 


RHODE  ISLAND  COAL. 


By  George  H.  Ashley. 


INTRODUCTION. 

Rhode  Island  coal  has  had  a perennial  interest  for  the  people  of  that 
State  and  for  outside  coal  and  iron  men  and  promoters.  Its  situation, 
directly  on  the  seaboard  and  in  the  center  of  a region  of  dense  popu- 
lation and  large  manufactures  (see  PL  I),  gives  it  a great  advantage 
in  the  New  England  markets  over  other  coals  through  reduced  cost  of 
transportation,  an  item  that  adds  largely  to  the  cost  of  the  coals  with 
which  New  England  is  now  supplied.  Lured  by  this  apparent  ad- 
vantage, company  after  company  has  sought  to  exploit  the  coal  or  to 
utilize  it  in  metallurgic  enterprises  in  which  they  were  interested; 
but  the  fact  remains  that  Rhode  Island  anthracite  is  still  unused  com- 
mercially and  the  impression  has  become  general  that,  considered  as  a 
source  of  heat,  it  is  more  of  a will-o’-the-wisp  than  a reality. 

On  the  one  hand,  it  is  contended  that  in  the  final  great  conflagra- 
tion Rhode  Island  coal  will  be  the  last  thing  to  take  fire.  On  the 
other  hand,  it  is  said  that  for  more  than  20  years  the  Taunton  Copper 
Co.  used  this  coal  exclusively  and  successfully  for  fuel.  Both  these 
statements  can  not  be  correct,  so  to  meet  the  demand  arising  from 
ipany  inquiries  made  of  the  Survey  for  some  definite  statement  of 
facts  in  regard  to  Rhode  Island  coal,  the  author  spent  a few  days  in 
the  first  part  of  October,  1913,  in  Rhode  Island  studying  the  mining 
and  use  of  the  coal,  and  by  means  of  the  results  of  those  studies  and 
other  data,  already  published,  has  prepared  the  following  brief  paper 
describing  the  coal,  its  use,  and  its  mining.  The  geology  of  the  Rhode 
Island  coal  field,  at  least  of  that  part  of  it  which  is  in  Rhode  Island, 
will  he  described  in  a detailed  State  report,  now  in  preparation  by 
Charles  W.  Brown,  State  geologist  of  Rhode  Island. 

The  facts  ascertained  and  here  reported  may  he  briefly  summed  up 
as  follows: 

The  coal  of  Rhode  Island  is  extremely  variable  in  character  and  qual- 
ity, ranging  from  anthracite  to  graphite,  and  containing  moderately 
high  ash  to  very  high  ash,  and  usually  a high  percentage  of  moisture 
when  first  mined.  Because  of  its  peculiar  characteristics,  all  the  coal 
requires  peculiar  handling  to  be  used  successfully,  and  the  extremely 

5 


6 


RHODE  ISLAND  COAL. 


graphitic  portions  can  hardly  be  used  as  fuel.  The  attempt  to  burn  it 
or  to  treat  it  as  other  coals  have  been  treated  has  usually  been  unsuc- 
cessful, but  if  properly  prepared  and  properly  used,  it  appears  to  have 
possible  uses.  Its  high  content  of  water  requires  that  it  be  seasoned 
under  cover  before  it  is  used,  and  its  commonly  high  content  of  ash 
is  adverse  to  its  shipment  for  use  at  distant  points.  Its  greatest  future 
use,  therefore,  appears  to  be  at  the  mines  in  the  manner  indicated  in 
this  report. 

The  coal  beds  appear  to  have  been  originally  of  moderate  thickness, 
but  they  have  been  folded,  compressed,  and  squeezed  by  pressure 
until  the  coal  has  been  forced  into  great  pockets  in  places  and  nearly 
or  quite  squeezed  out  elsewhere,  the  beds  as  a whole  dipping  into  the 
earth  irregularly  and  at  high  angles.  On  account  of  this  folding  and 
internal  movement  the  coal  has  itself  been  broken,  compressed, 
twisted,  and  squeezed,  as  putty  may  be  squeezed  through  the  fingers, 
and  in  places  there  have  been  introduced  into  it  large  quantities  of 
quartz  and  other  rock  impurities.  Mining  will  be  cheap  in  the  pockets 
and  expensive  where  the  coal  is  thin,  the  net  cost  of  mining  probably 
running  considerably  higher  than  in  the  anthracite  field  of  Pennsyl- 
vania. The  possibility  of  using  the  associated  clay  rock  for  making 
paving  brick,  tile,  and  like  products  suggests  itself,  and  such  use  may 
materially  offset  a part  of  the  cost  of  mining  in  certain  localities. 

The  apparent  failures  to  mine  the  coal  profitably  appear  to  be  due 
to  four  causes — :first,  improper  preparation  of  the  coal  at  the  mines; 
second,  attempted  use  in  and  with  furnaces  and  with  apparatus  built 
for  use  of  dissimilar  coals;  third,  relatively  low  duty  obtainable  from 
the  coal  in  comparison  with  competing  coals  per  dollar  of  cost,  and 
the  special  and  particular  handling  required;  and,  fourth,  stock  job- 
bing. The  attempt,  for  example,  to  burn  Cranston  coal  in  large 
sizes,  fresh  from  the  mine,  in  an  ordinary  furnace  is  doomed  to  dis- 
appointment. The  attempt  to  pay  dividends  on  a capitalization  of 
several  million  dollars  from  the  profits  on  a daily  output  of  a few 
hundred  tons  of  coal,  improperly  prepared  and  improperly  used,  can 
have  but  one  end. 

Rhode  Island  coal  needs  investigation  rather  than  investment. 
Though  it  presents  a field  of  peculiar  interest  to  the  practical  coal 
operator  who  commands  sufficient  funds,  with  the  possibility  of  suc- 
cessful use  on  the  spot  in  making  power  by  modern  methods  with 
financial  reward,  its  use  as  a basis  of  general  stock  selling  is  open  to 
the  gravest  suspicion,  and  such  stock  should  be  avoided  by  non- 
technical investors  until  the  property  represented  has  been  examined 
for  them  by  competent  experts. 

The  attempt  to  sell  Rhode  Island  coal  in  the  open  market  under 
present  conditions  is  almost  certain  to  result  in  failure.  The  public 
at  large  has  lost  faith  in  this  coal  as  compared  with  other  coals  used 


SKETCH  MAP  OF  THE  RHODE  ISLAND  COAL  FIELD. 


).  S.  GEOLOGICAL  SURVEY 


BULLETIN  615  PLATE  I 


SKETCH  MAP  OF  THE  RHODE  ISLAND  COAL  FIELD. 


DEVELOPMENT  AND  USE  OF  THE  COAL.  7 

in  New  England,  partly  because  of  its  weight,  making  it  appear  small 
in  bulk  when  delivered,  partly  because  of  the  excessive  amount  of 
ash  carried  by  most  of  it,  but  mainly  because  of  the  lower  duty  it 
usually  renders  when  burned  in  the  ordinary  way.  On  the  other 
hand,  the  sale  of  Rhode  Island  coal  as  electricity,  ready  for  use  by 
the  turn  of  a switch,  will  avoid  any  possible  prejudice  or  any  failure 
because  of  improper  use,  and  will  avoid  freight  charges  on  the  ash. 
Such  use,  therefore,  possibly  through  the  medium  of  the  gas  pro- 
ducer and  gas  engine,  seems  to  be  the  proper  aim  of  future  successful 
exploitation.  This  use  means  a few  plants  specially  built  and  spe- 
cially manned.  So  utilized,  it  is  believed  that  Rhode  Island  coal 
may  afford  a large  field  of  profitable  investment. 

HISTORY  OF  DEVELOPMENT  AND  USE  OF  RHODE 
ISLAND  COAL.1 

EARLY  HISTORY. 

In  studying  the  utilization  of  Rhode  Island  coal  it  is  well  to  review 
the  successes  and  failures  of  the  past  and  then  to  learn,  by  experi- 
mental tests,  possible  methods  of  using  not  yet  tried  commercially. 

The  “front”  bed  of  coal  at  Portsmouth  outcrops  in  plain  sight  in 
the  low  cliffs  bordering  Narragansett  Bay  on  the  west  side  of  the 
island  of  Rhode  Island,  and  beds  of  coal  or  carbonaceous  shale  have 
been  encountered  in  digging  wells  in  many  places  in  Rhode  Island 
and  the  adjoining  part  of  Massachusetts,  so  that  the  presence  of  coal 
in  the  State  has  been  known  from  a very  early  time.  The  coal  at 
Portsmouth  seems  to  have  been  known  at  least  as  early  as  1760.  In 
February,  1768,  patent  was  granted  to  parties  who  “were  about  to 
dig  after  pit  coal  or  sea  coal”  in  the  hill  at  the  back  of  the  town  of 
Providence,  as  shown  by  the  acts  and  resolves  of  the  Rhode  Island 
General  Assembly. 

It  is  said  that  during  the  Revolutionary  War  the  British  soldiers 
in  Newport  used  the  coal  from  the  island  for  heating.  In  an  address 
in  June,  1887,  former  Gov.  Lippett  said  that  his  grandfather  had 
attempted  to  mine  Rhode  Island  coal  more  than  a century  before — 
that  is,  prior  to  1787. 

In  1808  the  General  Assembly  of  Rhode  Island  granted  a lottery 
to  raise  $10,000  in  search  of  coal,  and  in  that  year  two  mines  appear 
to  have  been  opened  on  Butts  Hill,  in  Portsmouth,  one  known  first 
as  the  Aquidneck  mine  and  later  as  the  New  England  mine,  and  the 
other,  on  the  east  side  of  the  hill,  known  as  the  Case  mine.  These 
mines  were  opened  by  Purton  Nichols,  who  bought  the  land  but  was 
to  give  the  old  owner  1 bushel  of  coal  for  each  100  bushels  mined. 


1 This  history  has  been  culled  from  all  available  sources,  especially  the  earlier  geologic  reports  elsewhere 
referred  to  and  the  files  of  the  Providence  Journal. 


8 


RHODE  ISLAND  COAL. 


In  1809  the  Rhode  Island  Coal  Co.  and  the  Aquidneck  Coal  Co.  were 
incorporated,  and  from  $12,000  to  $15,000  was  then  expended  in 
exploiting  the  coal.  In  1812  the  general  assembly  granted  a lottery 
of  $40,000  to  the  Rhode  Island  Coal  Co.,  one  of  $30,000  to  the  Aquid- 
neck  Coal  Co.,  and  one  of  $12,000  “for  the  search  for  coal  in  Cumber- 
land.” Little  money  appears  to  have  been  raised  by  the  granting  of 
these  lotteries,  as  Massachusetts  refused  to  permit  the  sale  of  tickets 
in  that  State.  According  to  a letter  of  Mr.  Clowes  (1828),  these 
companies  failed  for  want  of  practical  skill  and  proper  preparation 
of  the  coal,  the  effort  being  made  to  market  it  in  large  lumps.  In 
the  early  history  of  the  mines  “round”  coal  is  reported  to  have  sold 
for  $5  a ton  and  slack  for  $2.50.  Prices  were  soon  reduced  to  $3  for 
round  and  50  cents  to  $1  for  slack  coal. 

Coal  was  found  in  Cumberland  in  1808  in  digging  a well  near  the 
house  of  Timothy  Dexter,  between  Blackstone  River  and  Abbotts 
Run,  a little  north  of  Pawtucket.  Some  drilling  was  done  and  a pit 
was  sunk  80  feet  to  a bed  said  to  have  been  15  feet  thick.  Several 
hundred  tons  of  coal  were  raised. 

Some  was  given  away,  some  was  sold,  and  some  used  on  the  premises  and  in  Provi- 
dence and  other  towns.  * * * But  few  people  knew  how  to  use  this  anthracite. 
They  would  take  it  and  place  it  on  a common  fire  and,  though  it  would  burn  in  this 
way,  yet  it  could  not  be  so  used  to  much  advantage.  Wood  * * * was  then 
abundant,  and  there  was  no  encouragement  to  working  mines  when  other  fuel  was 
plentiful,  * * * so  we  did  not  consider  it  worth  our  while  to  continue  the  work- 
ing of  the  beds.1 

In  1828  interest  revived  and  a new  opening  60  feet  deep  was  made 
to  the  coal.  About  50  tons  had*  been  taken  out  when  a fall  of  the 
roof  killed  the  son  of  the  proprietor  and  led  to  the  abandonment  of 
the  mine. 

In  1835  J.  Alexander  and  Seth  Mason  & Bros,  became  interested 
at  this  locality  and  sunk  a shaft  to  a depth  of  40  feet,  when,  after  a 
heavy  rain,  the  shaft  caved  in.  They  then  sunk  a second  slope  to  a 
depth  of  45  or  50  feet,  when  their  funds  ran  out  and  they  found  it 
necessary  to  incorporate;  so  in  1836  they  incorporated  as  the  New 
England  Coal  Mining  Co.  The  slope  was  then  continued  down  the 
coal  bed  to  78  feet,  and  machinery  was  set  up.  Drifts  were  then 
driven  300  feet  on  the  coal  and  600  tons  of  coal  was  raised,  “ the  last 
of  which  sold  readily  for  $6  cash  at  the  mine.”  The  coal  did  not  find 
favor,  because,  it  is  thought,  it  came  from  too  near  the  outcrop  and 
was  not  properly  cleaned.  About  $1,500  worth  of  coal  was  sold. 
About  this  time  the  surface  buildings  were  burned. 

In  1837  more  money  was  raised  by  assessment  and  a 150-foot  verti- 
cal shaft  was  started.  At  60  feet  the  shaft  was  abandoned  and,  as  a 

1 Hearing  on  the  memorial  of  the  New  England  Coal  Mining  Co.  before  the  select  special  committee  of 
the  General  Assembly  of  Rhode  Island  and  Providence  Plantations,  together  with  the  report  of  the 
committee,  1838. 


DEVELOPMENT  AND  USE  OF  THE  COAL. 


9 


last  resort,  the  company,  having  expended  about  $20,000,  petitioned 
the  legislature  for  financial  aid.  The  mine  was  worked  under  a 
25-year  lease,  with  a ground  rental  of  $1,500  a year  and  a royalty  of 
50  cents  a ton.  The  memorial  made  to  the  legislature  is  filled  with 
certificates  as  to  the  good  quality  of  the  coal,  but  the  legislature  made 
no  appropriation. 

After  the  failure  of  the  two  companies  at  Portsmouth  others  tried 
to  work  the  mines  without  success.  In  1827  it  is  reported  that  2,200 
tons  were  raised  by  20  men  and  5 boys,  and  sold  at  $4.50  a ton. 

Coal  was  known  in  Mansfield,  Mass.,  in  1810.  In  1835  three  com- 
panies, advised  and  assisted  by  Dr.  C.  T.  Jackson,  were  formed  for 
mining  the  coal  in  Mansfield,  namely,  the  Massachusetts  Mining  Co., 
at  the  Harden  farm,  2 miles  southwest  of  Mansfield;  the  Mansfield 
Mining  Co.;  and  the  Mansfield  Coal  Co.  The  Massachusetts  Mining 
Co.  expended  somewhat  less  than  $15,000  and  raised  1,200  to  1,500 
tons  of  coal,  worth  from  $5,000  to  $6,000.  All  these  mines  had 
stopped  work  in  1838.  One  of  the  companies  is  said  to  have  raised 
about  2,000  tons  of  coal.  The  mine  on  the  Alfred  Harden  place  is 
described  by  Jackson  as  64  feet  deep,  with  a gallery  40  feet  long  ex- 
tending southeastward.  Another,  on  the  Otis  Skinner  place,  half 
a mile  to  the  northwest,  was  85  feet  deep  and  was  equipped  with  a 
good  engine.  The  third  mine,  on  the  Harris  estate,  was  sunk  to  a 
depth  of  100  feet  and  drifts  were  cut  north-northwest  and  south-south- 
east. Jackson  reports  that  the  coal  cost  about  $1  a ton  to  extract, 
the  mines  raising  10  tons  of  coal  on  some  days  and  hardly  any  on 
other  days. 

In  1840  it  was  estimated  that  about  $40,000  had  been  expended  at 
Portsmouth. 

Perpendicular  shafts  and  horizontal  galleries  were  excavated  and 
a steam  engine  with  an  endless  chain  was  used  in  getting  out  the 
water,  the  extra  power  being  used  to  raise  the  coal. 

DEVELOPMENT  FROM  1840  TO  1880. 

In  1840  the  Rhode  Island  Coal  Co.  took  over  the  Portsmouth 
property  after  some  preliminary  drilling  had  been  done  by  a Mr. 
Spiker.  Mr.  Otis  Peters  was  connected  with  this  company.  His 
mine  was  deepened  from  100  to  400  or  500  feet.  Three  years  later 
the  property  passed  to  a Hartford  company,  which,  in  turn,  failed 
to  make  it  successful. 

In  1847  the  Portsmouth  Coal  Co.  reopened  the  old  Case  mine,  on 
the  east  side  of  Butts  Hill,  but  soon  abandoned  the  enterprise.  At 
that  time  the  mine  on  the  west  side  of  the  hill  was  being  run  by  the 
Aquidneck  Coal  Co.  In  the  last  half  of  1850  this  mine  yielded  3,100 
tons  of  coal. 


10 


RHODE  ISLAND  COAL. 


In  1850  the  Mount  Hope  Mining  Co.  took  the  old  Case  mine,  giving 
it  the  name  Mount  Hope  mine.  Dr.  Hartshorn,  of  Providence,  and 
Gov.  Jackson,  of  Rhode  Island,  were  among  the  owners.  About  the 
same  time  a mine  was  opened  in  Bristol.  The  Aquidneck  Coal  Co., 
working  on  the  west  side  of  the  hill,  deepened  their  mine  from  150 
feet  down  the  slope  to  625  feet.  In  1852  they  were  employing  55 
men  and  raising  75  to  100  tons  a day,  using  two  40-horsepower  steam 
engines  for  pumping,  hoisting,  screening,  and  assorting  the  coal  for 
market.  The  cost  of  mining  was  then  estimated  to  be  $1  a ton. 

This  company  tried  hard  to  induce  the  use  of  the  coal  by  large 
manufacturing  plants,  going  so  far  as  to  send  a man,  John  Corrigan, 
to  manufacturers  to  show  them  how  to  use  it.  For  a time,  apparently, 
a considerable  trade  was  built  up,  but  it  was  found  that  when  the  coal 
was  used  by  the  regular  firemen  the  furnace  walls  were  melted,  and, 
as  a whole,  the  great  care  required  in  its  use  was  too  much  of  a burden, 
so  people  refused  to  use  it.  The  company  lasted  three  years,  and 
the  mines  were  then  taken  over  by  a Worcester  company,  which  ran 
for  a few  years  and  sold  out  to  the  Taunton  Copper  Co. 

The  Taunton  Copper  Co.  is  the  one  shining  example  of  continued 
successful  use  of  Rhode  Island  coal.  This  company  opened  the 
North  mine  before  1860  and  continued  operating  until  1883,  building 
a dock  and  railroad  connections.  Though  most  of  the  coal  used  came 
from  the  North  mine,  the  South  mine  was  extended  from  700  or  800 
feet  to  1,600  feet.  A copper  smelter  was  built  and  copper  ore  was 
brought  in  from  Cuba  and  South  America  and  smelted.  This  com- 
pany, of  which  Mr.  S.  L.  Crocker,  of  Taunton,  was  president,  mined 
about  10,000  tons  of  coal  a year.  The  coal  was  also  used  to  some 
extent  for  domestic  purposes  and  at  least  “several  cargoes”  were 
shipped  to  Poughkeepsie,  where  they  were  used  successfully  in  the 
furnaces  of  the  Poughkeepsie  Iron  Co.  The  imposition  of  a high 
protective  tariff  on  copper  ores  and  the  death  of  the  principal  owner 
of  the  plant  resulted  in  its  closing. 

Meanwhile,  the  Pocasset  Coal  Co.  had  opened  up  the  Cranston  coal. 
In  1866  Heald,  Britton  & Ford,  of  Worcester,  wrote  that  they  had 
used  some  of  the  Cranston  coal;  that  they  were  satisfied  with  it  and 
thought  it  improved  the  strength  of  the  iron.  In  1868  the  agent  for 
the  Pocasset  Coal  & Iron  Co.  stated  that  during  his  agency  3,600  tons 
of  coal  had  been  mined  and  teamed  from  Cranston  to  Providence.1 
In  order  to  introduce  it,  it  was  sold  under  the  price  of  Pennsylvania 
coal  and  is  said  to  have  been  used  largely  by  the  Mount  Hope  Iron 
Works,  G.  G.  Hicks  Boiler  Works,  and  other  establishments. 

In  1874  a careful  test  of  Cranston  coal  was  made  at  the  Sockanos- 
set  pumping  station  of  the  Providence  Waterworks.  (See  pp.  42-43.) 

# 1 Memorial  of  T.  S.  Ri.lgway  in  relation  to  the  coal  field  of  Rhode  Island,  presented  to  the  General 

Assembly,  1870. 


DEVELOPMENT  AND  USE  OF  THE  COAL. 


11 


The  test  does  not  seem  to  have  led  to  the  use  of  Cranston  coal  by  the 
city  and  apparently  mining  was  abandoned  except  in  a very  small 
way.  A Mr.  Moore  at  this  time  used  the  product  of  a small  mine  in 
his  facing  works  at  Elmwood. 

During  this  period  both  the  Valley  Falls  mine  and  the  Roger 
Williams  mine,  a mile  to  the  north,  were  in  operation  part  of  the 
time.  In  1853,  according  to  Mr.  E.  T.  Hitchcock,  the  Roger  Williams 
mine,  which  had  been  worked  at  an  earlier  date,  had  been  recently 
reopened  by  a 300-foot  vertical  shaft.  From  this  a drift  260  feet 
long  had  been  run,  striking  a bed  from  15  to  25  feet  thick.  It  was 
thought  by  Mr.  Hitchcock  that  this  bed  was  probably  a pocket,  and 
the  fact  that  it  was  not  worked  very  long  sustained  that  impression. 

The  Valley  Falls  mine  was  at  that  time  being  worked  by  the 
Blackstone  Coal  Co.  The  mine  consisted  of  an  incline  500  feet  long, 
reaching  to  a depth  of  375  feet  and  working  on  a coal  bed  6 to  8 feet 
thick.  It  is  said  that  four  other  beds  were  found  at  that  point. 
Hitchcock  said  that  the  coal  burned  well,  though  in  its  most  recent 
history  the  Valley  Falls  mine  is  reported  to  have  mined  chiefly 
material  for  furnace  linings. 

RECENT  HISTORY. 

In  1885  the  New  York  Carbon  Iron  Co.,  of  Pittsburgh,  became  inter- 
ested in  Cranston  coal.  They  were  then  using  a patent  process, 
invented  by  Dr.  C.  J.  Eames,  for  making  billets  for  blooms.  In  1886 
their  metallurgist,  Richard  Eames,  was  sent  to  Cranston  to  supervise 
the  opening  of  a mine  and  the  shipment  of  coal.  He  found  that  the 
mine  on  the  Harris  place  consisted  of  an  open  cut  with  a slope  225 
feet  long  and  40  feet  deep.  He  opened  a shaft  75  feet  deep  and 
equipped  it  with  buckets  capable  of  raising  30  tons  a day.  From  the 
bottom  of  the  shaft  five  chambers  were  opened,  four  of  them  being  40 
feet  square  and  the  fifth  95  feet  long,  15  feet  wide,  and  20  feet  high. 
They  employed  30  men,  and  for  a time  in  1887  shipped  to  Pittsburgh 
250  to  300  tons  of  coal  a week.  This  was  certainly  “ shipping  coals  to 
Newcastle,”  but  the  company  seems  to  have  found  its  use  successful 
and  economical.  No  record  was  found  showing  how  long  this  use 
of  the  coal  continued,  but  apparently  it  did  not  last  long. 

In  1887  W.  F.  Durfee,  of  New  York,  became  interested  in  the  estab- 
lishment of  a blast  furnace  at  Portsmouth  for  working  the  Cumberland 
iron  ore.  For  a time  he  stirred  up  considerable  public  interest.  In 
an  address  before  the  board  of  trade,  June  7,  1887,  Mr.  Durfee  quoted 
Prof.  R.  H.  Thurston  as  approving  the  use  of  Rhode  Island  coal  in  the 
smelting  of  copper  ore  and  in  modern  high  smelting  furnaces.  He 
cited  the  successful  use  at  Pittsburgh,  and  in  the  past  at  Pough- 
keepsie, quoted  favorable  extracts  from  letters  from  other  users,  and 
suggested  its  possible  future  use  in  the  manufacture  of  fuel  (water) 


12 


RHODE  ISLAND  COAL. 


gas.  Possibly  as  a result  of  this  agitation,  in  1889  the  Worcester 
Steel  Works,  of  Worcester,  Mass.,  reopened  the  three  mines  at  Ports- 
mouth, which  had  been  idle  since  1883  and  which  had  filled  with 
water.  This  included  not  only  the  South  and  the  North,  or  Crocker, 
mines,  but  also  the  Mitchell  mine  on  the  west  side  of  Butts  Hill,  which 
had  been  opened  by  Thomas  Mitchell  in  1871-72  and  sunk  to  a depth 
of  80  feet.  At  the  same  time  Miles  Standish,  of  New  York,  leased  the 
Hazard  or  Case  mine  and  adjoining  property.  In  May,  1889,  70 
miners  were  employed,  though  the  mine  was  still  being  pumped  out. 
At  that  time  the  company  expected  to  employ  300  men  as  soon  as  the 
mine  had  been  completely  unwatered.  It  was  also  the  intention  to 
erect  a blast  furnace  and  foundry  at  Portsmouth  and  mine  Cumber- 
land iron  ore.  The  project  was  not  successful  and  the  property 
reverted  to  the  Rice  heirs,  of  Boston,  and  remained  idle  for  20  years, 
or  until  1909. 

Meanwhile,  attempts  were  made  to  mine  the  coal  at  Cranston, 
usually  by  stock  companies.  It  is  reported  that  not  less  than  seven 
companies  were  so  formed  during  recent  years.  These  companies  may 
be  typified  by  the  Cranston  Coal  Co.,  which  was  active  two  or  three 
years  ago.  This  company  was  organized  with  a capital  of  1,000,000 
shares,  having  a par  value  of  $5,  and  the  coal  was  offered  at  $5  a 
ton,  as  against  $6.50  to  $7.50  for  Pennsylvania  anthracite.  Half- 
tone photographs  in  their  advertisements  show  work  being  carried  on 
in  an  open  cut,,  which  has  much  the  same  appearance  as  the  cut  has 
to-day.  A rough  estimate  indicates  that  in  all  of  the  years  this  mine 
has  been  opened  not  more  than  10,000  to  15,000  tons  could  have  been 
removed,  so  apparently  a very  small  amount  of  coal  could  have  been 
mined  and  sold  by  this  company. 

When  visited  by  the  writer  in  October,  1913,  the  Cranston  mines 
consisted  still  of  an  open  cut  about  300  feet  long  and  a slope,  then  full 
of  water,  less  than  100  feet  long,  from  which  rooms  had  been  turned 
off.  A dozen  men  were  getting  out  about  60  tons  of  coal,  which  was 
being  hand  screened  after  crushing  into  small  sizes  for  domestic  use 
by  Mr.  Budlong  and  families  in  neighboring  houses.  The  coal  was 
being  mined  by  drilling  and  blasting,  as  rubble  is  quarried;  it  was 
then  loaded  into  buckets  and  placed  on  cars,  which  were  pushed  by 
hand  a short  distance,  then  raised  from  the  cut  by  a derrick.  The 
coal  next  went  to  a crusher  and  was  then  screened.  When  the  mine 
was  visited  the  coal  was  being  rescreened  by  hand  and  bagged. 
Plate  II,  A,  shows  the  open  cut  and  Plate  II,  B,  a closer  view  of  part 
of  the  face  of  the  coal  at  Budlong  mine,  Cranston,  R.  I.;  Plate  III,  A , 
shows  the  surface  plant;  and  Plate  V,  A (p.  19),  shows  the  north  end 
of  the  mine  accompanied  by  a diagram,  Plate  Y,  B,  that  indicates 
the  coal  and  its  variations  in  thickness  within  a few  feet.  / 


U.  S.  GEOLOGICAL  SURVEY 


BULLETIN  615  PLATE  II 


A.  OPEN  CUT  IN  MINE,  LOOKING  NORTH. 

Mouth  of  slope  with  part  of  incline  track  in  center.  Blast  going  off  just  to  the  right.  Dip  of  bed  is  shown  by 
base  of  overlying  rock  in  lower  right  corner. 


B.  FACE  OF  BED  A LITTLE  NORTH  OF  THE  MOUTH  OF  THE  SLOPE,  SHOWING  THE  CHARAC- 
TERISTIC SCHISTOSE  OR  SQUEEZED-LENS  APPEARANCE  OF  THE  COAL. 

VIEWS  AT  BUDLONG  MINE,  CRANSTON,  R.  I. 


U.  S.  GEOLOGICAL  SURVEY 


BULLETIN  615  PLATE  III 


A.  SURFACE  PLANT  AT  BUDLONG  MINE,  CRANSTON,  R.  I. 


A pile  of  hand-screened  coal  is  seen  in  the  foreground. 


B.  SURFACE  PLANT  AT  SOUTH  MINE  OF  PORTSMOUTH  COAL  CO.,  PORTSMOUTH,  R.  I. 


DEVELOPMENT  AND  USE  OF  THE  COAL. 


13 


In  1898  Boston  parties,  under  the  title  “Compressed  Coal  Co.,” 
took  hold  of  the  Portsmouth  mine  and  put  in  a briquetting  plant. 
The  plant,  part  of  which  had  been  moved  from  Arkansas,  made  egg 
briquets,  using  the  Zwoyer  process.  Most  of  the  material  briquetted 
was  taken  from  the  old  culm  pile  at  the  North  mine  and  consequently 
was  high  in  ash.  The  briquets  did  not  find  a ready  market,  the 
attempt  appears  to  have  shared  the  common  fate,  and  the  mines 
were  again  allowed  to  fill  with  water. 

While  this  small  development  was  going  on  at  Cranston  a new  and 
much  larger  development  was  taking  place  at  Portsmouth.  Some- 
time previous  to  1909  Mr.  J.  W.  Dennis  became  interested  in  a process 
of  briquetting  that  was  patented  by  N.  W.  Bloss,  by  which  Chile 
saltpeter  is  used  to  aid  in  the  burning  of  the  coal.  Dennis  experi- 
mented with  this  process  and  afterward  with  a process  patented  by 
H.  J.  Williams,  of  Boston.  In  the  Williams  process  crude  calcium 
chloride  is  used,  as  it  cost  only  1 J cents  a ton  for  the  treatment,  as 
against  12  cents  for  the  saltpeter.  The  coal  was  treated  by  immer- 
sion in  a solution  of  calcium  chloride.  It  was  contended  by  Mr. 
Williams  that,  whereas  the  raw  coal  kindled  with  difficulty  and  gave 
a flame  only  5 to  8 inches  long,  which  soon  disappeared,  the  treated 
coal  gave  a flame  36  inches  long  for  an  hour  and  a half,  after  which 
it  gradually  decreased  but  remained  long  for  several  hours;  that  it 
kindled  more  rapidly  and  gave  a hotter  fire.  It  is  said  that  after 
three  years  of  practical  tests  and  demonstration  the  method  was 
submitted  to  H.  M.  Whitney,  resulting  in  the  formation,  in  Feb- 
ruary, 1909,  of  the  Rhode  Island  Coal  Co.,  with  a capitalization  of 
$5,000,000,  the  company  being  incorporated  in  Maine.  The  com- 
pany purchased  400  acres  and  obtained  control  of  the  coal  rights  of 
4,000  additional  acres.  During  the  spring  and  summer  of  1909  the 
mine  was  pumped  out,  the  slope  entrance  was  enlarged  and  straight- 
ened, and  the  mine  was  cleaned  up.  Ultimately  the  South  mine  was 
equipped  with  a breaker,  air  compressors,  large  hoisting  engines,  a 
briquetting  machine,  and  other  appliances.  (See  PI.  Ill,  B.)  The 
coal  dust  was  briquetted  by  the  R.  A.  Zwoyer  process,  Mr.  Zwoyer  being 
employed  as  the  briquetting  engineer.  The  slope  was  extended  to 
2,100  feet,  on  the  same  average  dip  of  31°,  to  the  bottom,  though  the 
dip  became  steeper  toward  the  bottom  rather  than  flatter.  Pumps 
were  put  in,  the  walls  at  the  mouth  of  the  mine  were  cemented  up, 
and  the  whole  mine  apparently  was  put  in  good  condition  for  work. 
Additional  core  drilling  was  done  and  the  success  and  future  of  the 
new  enterprise  was  told  in  glowing  terms  in  full-page  descriptions  in 
the  daily  papers.  Estimates  were  made  that  the  output  would  be 
4,000  to  5,000  tons  a day,  at  a net  profit  of  $2.50  to  $3  a ton.  This 
would  have  yielded  from  $200,000  to  $300,000  net  profit  each  month. 
By  December,  1911,  the  gross  receipts  are  reported  to  have  reached 


14 


RHODE  ISLAND  COAL. 


$12,175  for  the  month.  In  February,  1912,  the  company  went  into 
the  hands  of  a receiver.  At  the  time  the  mine  was  visited  by  dele- 
gates of  the  Providence  Association  of  Mechanical  Engineers,  May  20, 
1911,  there  were  reported  to  be  82  miners  employed,  earning  from  $6 
to  $7  per  week,  at  the  rate  of  $1.50  a car.  The  mine  was  then  using 
14  mules  underground.  Later  the  company  was  reorganized  as  the 
Portsmouth  Coal  Co.  On  December  31,  1912,  the  published  report 
of  the  company’s  finances  showed  accounts  and  notes  payable 
exceeding  the  cash  and  other  assets  by  more  than  $75,000,  and  in 
January,  1913,  after  the  receipt  of  the  experts’  report,  the  directors 
of  the  company  advised  the  stockholders  that  the  mine  had  been 
abandoned.  The  pumps  were  kept  going  until  July,  1913,  but  when 
visited  in  October  the  mine  had  filled  up  to  the  1,400-foot  level  and 
the  water  was  gradually  submerging  the  pumps  and  other  machinery. 

DEVELOPMENT  IN  1913. 

In  October,  1913,  the  conditions  in  Rhode  Island  with  reference 
to  mining  may  be  briefly  summed  up  as  follows : 

Three  mines  were  open,  two  of  which  were  running.  At  the 
Fenner  Ledge,  near  Providence,  3 men,  working  under  Mr.  Fenner, 
were  getting  out  about  3 cars  of  graphite  a month,  which  was  selling 
at  more  than  $7  a ton.  At  the  Cranston  mine,  on  the  Harris  place, 
near  the  Sockanosset  Reservoir  and  the  Reform  School,  about  a 
dozen  men  were  getting  out  a few  tons  of  coal  from  an  open  cut  for 
household  use.  This  coal  was  being  hand-screened  and  bagged. 
Bituminous  coal  was  being  used  under  the  boilers  at  the  mine.  The 
slope  was  full  of  water.  At  Mr.  Budlong’s  nursery  a considerable 
quantity  of  small  coal  was  stored  in  the  open  for  use  during  the 
summer,  when  the  duty  required  of  the  engines  was  smaller.  During 
the  winter  soft  coal  was  used  exclusively.  At  Portsmouth  both 
mines  were  equipped  for  raising  coal.  The  South  mine  was  also 
equipped  with  briquetting  machinery,  air  compressors,  and  other 
appliances.  The  mines  were  well  supplied  with  pumps,  mine  tele- 
phones, and  other  equipment,  but  were  gradually  filling  with  water. 
The  graphite  mine  near  Central  Falls  had  not  been  active  for  several 
years  and  was  fallen  shut.  The  graphite  deposit  near  Tiverton  was 
not  visited  and  its  condition  is  not  known.  In  January,  1914,  it 
was  reported  to  the  writer  that  the  mines  at  Portsmouth  were  being 
dismantled. 

CONDITIONS  AFFECTING  METHOD  AND  COST  OF 

MINING. 

As  already  stated,  the  coal  beds  and  the  associated  rocks  have 
been  subjected  to  intense  horizontal  pressure,  so  that  not  only  has 
the  internal  structure  of  the  coal  been  affected,  but  the  coal  beds 


METHOD  AND  COST  OF  MINING. 


15 


and  other  rocks  have  been  compressed  into  great  folds.  Unfortu- 
nately for  mining,  the  folding  is  in  many  places  very  complicated. 
The  coal,  which  is  relatively  soft,  has  yielded  more  than  the  sur- 
rounding rocks,  so  that  the  beds  have  lost  their  original  regularity 
and  now  occur  in  pockets,  irregular  in  size  and  shape,  separated  by 
more  or  less  extensive  areas  of  thin  coal  or  areas  from  which  the 
coal  has  been  entirely  squeezed  out.  Furthermore,  the  varying  inten- 
sity of  the  pressure  from  place  to  place  has  also  resulted  in  consider- 
able differences  in  the  quality  of  the  coal;  in  some  areas  it  has  been 
converted  entirely  to  graphite  with  a large  admixture  of  ash;  in 
others,  where  the  pressure  was  less,  the  percentages  of  graphite  and 
ash  are  much  less  or  very  low. 

In  view  of  these  conditions  it  must  be  recognized  that  Rhode 
Island  coal  can  not  be  mined  on  a large  scale  according  to  a regular 
plan,  as  most  coal  may  be.  Such  mining,  like  most  metal  mining, 
will  face  uncertainties  as  to  the  position,  the  quantity,  and  the 
quality  of  the  mineral  sought.  These  uncertainties  will  probably  be 
greater  in  some  parts  of  the  field  than  in  others.  In  flat-lying  regular 
beds  of  coal  5 to  8 feet  thick  practically  all  the  digging  is  in  coal 
and  all  the  product  may  be  sold.  The  mine  may  be  laid  out  in 
regular  entries  at  regular  distances  apart,  from  which  rooms  of  equal 
length  are  turned  off  at  regular  intervals  and  the  intervening  pillars 
so  mined  out  that,  ideally,  no  coal  is  left  in  the  mine.  Furthermore, 
haulage  is  a simple  matter,  as  the  motors  may  be  taken  into  the 
rooms  or  shifted  to  any  part  of  the  mine  without  difficulty. 

By  contrast,  in  the  Rhode  Island  coal  field  extensive  prospecting 
will  be  necessary  to  determine  the  location  of  the  lenses  of  workable 
coal.  The  mine  must  be  developed  along  the  irregular  lines  deter- 
mined by  the  lenses,  and  a considerable  portion  of  the  digging  will 
be  in  rock,  as  where  the  coal  is  thin,  or  where  it  may  be  necessary  to 
diverge  from  the  bed  in  order  to  keep  the  haulage  ways  on  fairly  even 
grade.  This  rock  digging  costs  as  much  as  or  more  than  the  dig- 
ging in  the  coal  and  does  not  yield  a salable  product.  As  the  shape 
and  position  of  the  lenses  of  thicker  coal  can  not  be  known  until  the 
coal  is  mined  out,  it  will  not  be  possible  to  plan  entries  and  rooms 
so  as  to  remove  the  coal  at  the  least  possible  cost. 

To  these  special  costs,  due  to  the  irregularity  of  the  beds,  must  be 
added  the  usual  higher  cost  of  mining  by  slope  or  shaft  as  compared 
with  drift  mining  and  the  higher  cost  of  mining  and  haulage  in 
highly  pitching  beds  as  compared  with  flat-lying  beds.  These  and 
many  other  elements  of  cost  may  not  differ  greatly  from  similar 
costs  in  the  anthracite  fields  of  Pennsylvania  or  in  small  areas  in 
other  fields  of  the  United  States,  provided  that  the  coal  at  any  place 
maintains  a fairly  uniform  dip,  as  it  does  at  Portsmouth,  and  fairly 
uniform  thickness,  which  will  probably  not  be  found  in  any  part  of 


16 


RHODE  ISLAND  COAL. 


this  field.  If,  however,  the  coal  bed  is  crumpled  into  S-shaped 
curves,  or  other  curves  of  fantastic  shape,  as  the  surface  indications 
in  some  areas  suggest,  the  cost  of  removing  the  coal  may  be  greatly 
increased. 

The  cheapest  coal  bed  to  mine  has  a thickness  of  6 to  8 feet.  Where 
the  beds  run  under  6 feet,  the  cost  begins  to  rise,  at  first  slowly,  hut 
more  and  more  rapidly  as  the  thickness  decreases.  For  equal  areas, 
a 3-foot  bed  yields  only  half  the  tonnage  of  a 6-foot  bed,  but  involves 
for  the  same  tonnage  of  yield  the  care  of  double  the  amount  of  roof 
and  the  laying  of  double  trackage,  besides  the  additional  cost  of 
supervision  and  many  other  items.  The  mining  rate  usually  begins 
to  increase  rapidly  as  the  thickness  of  the  coal  goes  below  3 feet, 
and  as  the  decrease  continues  the  proportion  of  rock  that  must  be 
mined  and  paid  for  without  return  steadily  increases,  so  that  for 
beds  from  1 foot  to  18  inches  in  thickness  the  cost  per  ton  may  be 
two  or  three  times  the  cost  of  a bed  from  3 to  6 feet  thick.  On  the 
other  hand,  experience  has  shown  that  under  usual  conditions  the 
cost  of  mining  per  unit  of  output  does  not  continue  to  decrease  as 
the  bed  increases  in  thickness  beyond  the  zone  of  minimum  cost, 
for  what  is  saved  in  trackage  and  other  items  is  more  than  made  up 
in  the  increased  cost  of  timbering  or  decrease  in  percentage  of 
recovery. 

If  the  shale  or  clay  lying  next  to  the  bed  of  coal  can  be  used  com- 
mercially it  may  be  mined  with  the  coal  and  thus  the  cost  per  ton  for 
mining  the  coal  may  be  greatly  reduced.  In  studying  this  field, 
therefore,  attention  should  be  given  to  the  character  of  the  shale  or 
clay  adjoining  the  coal.  The  writer  would  suggest  that  the  shale 
accompanying  the  coal  at  Portsmouth  be  tested  for  use  in  the  manu- 
facture of  paving  brick  and  drain  tile. 

Another  element  to  be  considered  is  the  uncertainty  of  the  extent 
of  the  beds  or  of  their  persistence  in  character.  This  field  has  not 
yet  been  sufficiently  explored  to  show  whether  the  beds  are  extensive 
or  whether  they  were  originally  laid  down  in  small  basins.  As  this 
matter  is  being  studied  by  the  State  survey,  under  Mr.  Brown,  the 
writer  did  not  make  a detailed  examination  of  the  coal  beds,  such  as 
would  be  necessary  to  discriminate  between  differences  of  thickness 
due  to  pressure  from  those  due  to  the  differences  of  original  deposition 
of  the  bed.  The  mining  at  Portsmouth  strengthens  the  belief  that 
the  beds  there  may  at  first  have  been  very  regular,  though  mining 
and  prospecting  have  not  yet  been  extensive  enough  to  indicate 
whether  the  Portsmouth  area  is  more  than  a local  basin.  On  the 
other  hand,  a comparison  of  the  sections  at  the  Sockanosset  mine 
with  those  at  Fenners  Ledge  suggests  variability  in  quality  if  not  in 
extent. 


CHARACTER  OF  THE  COAL. 


17 


In  view  of  the  conditions  mentioned,  it  is  evident  that  mining  on 
an  extensive  scale  in  Rhode  Island  should  not  he  undertaken  until 
the  field  to  be  mined  has  been  thoroughly  and  completely  tested  by 
the  diamond  or  core  drill.  A hole  should  be  drilled  in  each  10  acres 
or  smaller  area  and  the  coal  cores  analyzed.  The  fact  that  once  or 
twice  extensive  drilling  of  this  kind  has  been  carried  on  in  this  field 
and  was  not  followed  by  an  attempt  at  development  indicates  that 
the  results  were  not  all  that  might  have  been  hoped  for.  Thus  the 
Portsmouth  field  was  drilled  across  by  Mr.  A.  B.  Emmons  in  1883-84, 
but  the  results  did  not  lead  to  development. 

At  present  the  only  mine  that  might  furnish  data  as  to  cost  is  that 
at  Portsmouth.  The  coal  at  Sockanosset  has  been  mined  either  in 
open  cut  by  ordinary  quarry  methods  or  by  shallow  slopes,  neither  of 
which  can  afford  data  for  computing  the  cost  of  mining  on  a large 
scale  under  existing  conditions.  Evidence  from  several  sources  indi- 
cates that  the  cost  will  average  not  less  than  $2.50  a ton,  a figure 
given  by  Shaler  in  discussing  the  subject  in  1899  and  quoted  by  the 
superintendent  of  recent  mining  operations  at  Portsmouth.  As  the 
cost  of  mining  coal  tends  to  increase  as  the  mine  workings  increase  in 
extent,  the  actual  cost  of  extensive  miniug  will  probably  exceed  $2.50 
unless  it  is  possible  to  utilize  the  shale  that  lies  next  to  the  coal. 

CHARACTER  OF  THE  COAL. 

GENERAL  FEATURES. 

Physically  and  chemically  the  coal  varies  greatly  from  place  to 
place,  both  in  the  field  as  a whole  and  within  any  one  mine.  Coal  is 
an  indefinite  mixture  of  carbon,  hydrogen,  oxygen,  nitrogen,  and 
sulphur,  and  of  other  materials  which  do  not  burn  and  which  are 
grouped  together  as  ash.  Carbon  is  the  principal  element.  In  part  it 
appears  to  occur  as  uncombined  carbon,  or,  as  it  is  commonly  called, 
u fixed  carbon,”  and  in  part  it  is  combined  with  hydrogen  and  possibly 
oxygen  in  different  combinations.  The  oxygen  is  so  combined  with 
hydrogen  that  in  the  combustion  of  the  coal  the  oxygen  and  one- 
eighth  of  its  weight  of  hydrogen,  if  so  much  is  present,  passes  off  as 
moisture  without  adding  to  the  heating  value  of  the  coal.  Small 
quantities  of  nitrogen,  sulphur,  and  other  substances  are  usually  found 
in  the  coal,  besides  the  ash,  which  is  mainly  material  that  has  been 
added  to  the  original  vegetable  matter  and  which  may  range  from  1 
or  2 per  cent  to  50  per  cent  or  more. 

FIELD  CONDITIONS. 

Coal  has  been  derived  from  vegetable  matter  which,  when  buried  in 
quantity  in  the  earth  and  subjected  to  pressure  and  heat,  undergoes 
changes  and  gradually  loses  part  of  the  hydrogen  combined  with 
97887°— Bull.  615—15 2 


18 


RHODE  ISLAND  COAL. 


carbon,  so  that  there  is  a consequent  proportional  increase  in  the  per- 
centage of  uncombined  carbon.  In  the  lower  grades  of  bituminous 
coal  the  uncombined  or  fixed  carbon  ranges  from  40  to  55  per  cent  of 
the  coal.  Where  the  coal  has  been  subjected  to  greater  pressure  or 
heat,  the  fixed  carbon  may  increase  to  65  or  even  to  75  per  cent  as  in 
semibituminous  coals.  Where  the  coal  has  been  subjected  not  only 
to  the  pressure  of  the  overlying  rocks  but  has  been  strongly  com- 
pressed from  the  side,  so  that  the  beds  are  folded  into  great  folds,  as 
in  the  anthracite  field  of  Pennsylvania,  the  fixed  carbon  may  form 
80  or  90  per  cent  or  more  of  the  coal. 

In  the  Rhode  Island  field  the  pressure  on  the  sides  appears  to  have 
been  still  more  intense,  not  only  folding  the  rocks  in  great  folds  but 
crushing,  squeezing,  and  shearing  them  with  accompanying  heat  so 
high  that  in  some  places  they  have  been  changed  chemically  and 
physically.  As  a result  of  this  intense  pressure  and  heat  the  coal  of 
Rhode  Island  has  been  changed  to  anthracite  containing  a high  per- 
centage of  fixed  carbon,  and  in  places  the  material  of  the  beds  has 
flowed,  like  so  much  putty  squeezed  in  the  hand,  until  the  original 
structure  is  practically  all  lost  and  all  or  nearly  all  traces  of  the  com- 
bined carbon  and  hydrogen  have  been  driven  off,  so  that  there  the 
material  has  reached  the  last  stage  and  become  graphite. 

In  many  regions  of  intense  pressure  and  folding  though  the  harder 
beds  of  rock  may  maintain  their  thickness  and  character  with  little 
change,  any  softer  rocks,  such  as  clays  or  coal,  tend  to  yield,  flowing 
away  from  the  points  of  greatest  pressure  and  accumulating  in  areas 
of  less  pressure.  In  these  areas  the  intensity  of  pressure  varies  with 
some  degree  of  regularity,  appearing  to  be  greatest  at  intervals  or 
nodes  along  certain  lines  and  least  in  other  lines,  somewhat  after  the 
manner  of  waves  of  water  or  air.  The  position  of  these  lines  with 
their  nodes  in  any  area  must  be  worked  out  in  the  field,  as  the 
causes  of  this  variation  are  not  yet  well  understood. 

In  the  Rhode  Island  coal  field  the  coal  beds  are  associated  with 
clay  rocks  that  have  yielded  with  the  coal  beds,  though  apparently 
not  to  the  same  extent.  This  has  allowed  a greater  variation  in  the 
position  of  the  coal  beds  than  would  otherwise  have  occurred.  As  a 
result,  the  coal  instead  of  forming  a string  of  regular  lenses  connected 
by  areas  of  thin  coal  may  in  places  occur  in  lenses  that  are  extremely 
irregular.  Plates  IV  and  V show  in  outline  the  type  of  lenses  being 
mined  at  two  points  near  Cranston. 

An  examination  of  the  coal  at  different  points  in  one  of  these  lenses 
shows  a considerable  difference  in  the  character  of  the  coal.  Wher- 
ever there  has  been  a plane  or  surface  in  the  coal  along  which  con- 
siderable sliding  has  taken  place,  the  coal  in  that  surface  appears  to 
have  been  more  heated  and  metamorphosed  than  the  rest,  and  has 


U.  S.  GFOLOGICAL  SURVEY 


BULLETIN  615  PLATE  IV 


A.  VIEW  IN  GRAPHITE  MINE  AT  FENNERS  LEDGE,  NEAR  PROVIDENCE,  R.  I. 


B.  DIAGRAM  SHOWING  DISTORTION  OF  THE  BED  REPRESENTED  IN  A. 

The  bed  nearly  pinches  out  above  the  present  workings.  The  best  graphite  being  mined  was  found  at  the  right, 
in  a sort  of  tongue  squeezed  out  in  the  folding  of  the  rocks. 


U.  S.  GEOLOGICAL  SURVEY 


BULLETIN  615  PLATE  V 


A.  VIEW  AT  NORTH  END  OF  BUDLONG  PIT,  CRANSTON,  R.  I. 


B.  DIAGRAM  TO  SHOW  VARIATIONS  IN  THICKNESS  OF  ANTHRACITE  AT  NORTH  END  OF 
BUDLONG  PIT,  SHOWN  IN  A. 


CHARACTER  OF  THE  COAL. 


19 


become  graphitic.  In  places  the  whole  bed  has  been  squeezed  until 
it  was  forced  to  flow  to  areas  where  the  pressure  was  less,  and  to  such 
an  extent  that  all  the  coal  appears  to  be  graphitic.  In  general,  the 
thinner  the  coal  is  at  any  point  the  larger  the  percentage  of  graphite 
it  contains,  as  though  internal  movement  had  been  greater  at  those 
points. 

It  is  clear  that  this  compression  and  movement  in  the  coal  has 
been  slow,  at  times  breaking  the  coal  so  as  to  leave  open  crevices 
and  then  compressing  and  recementing  it.  In  places  where  such 
open  crevices  have  been  formed  temporarily  water  containing  quartz 
in  solution  has  flowed  into  the  crevices  and  the  quartz  has  been 
deposited  in  some  places  as  a network  through  the  coal.  Where  the 
beds  are  much  metamorphosed,  as  at  Fenners  Ledge,  a considerable 
quantity  of  asbestos  is  associated  with  the  carbonaceous  material. 
The  crushed  structure  of  the  coal  is  shown  in  figure  1 . The  structure 
is  well  brought  out  by  the  minute  lenses  of 
quartz  and  pyrite. 

The  breaking  open  and  recementing  of  the 
coal  appears  to  have  permitted  the  injection 
into  it  of  more  or  less  of  the  adjoining  shale 
rock,  so  that,  in  general,  where  the  coal  is 
thin  from  having  been  squeezed  out  it  is 
much  higher  in  ash  than  elsewhere,  the  high 
ash  appearing  to  increase  with  the  increase  of 
graphite.  The  coal  in  the  same  mine  may 
therefore  vary  greatly  from  place  to  place,  being  high  in  graphite  and 
ash  in  places  where  as  a rule  it  is  thin,  and  being  freer  of  both  ash 
and  graphite  in  the  pockets. 

The  field  as  a whole  appears  to  have  been  subjected  to  large 
regional  differences  in  pressure  and  there  are  corresponding  regional 
differences  in  the  character  of  the  coal.  For  example,  a comparison 
of  the  coal  at  the  Portsmouth  mine,  which  is  toward  the  middle  of 
the  basin,  with  the  coal  and  other  rocks  at  places  along  the  edge  of 
the  basin  suggests  that  in  general  the  coal  beds  and  accompanying 
clay  rocks  have  undergone  greater  distortion  and  change  at  the 
edges  of  the  basin  than  at  points  in  the  center.  The  pressure  in  the 
center  of  the  basin  appears  to  have  been  relieved  to  some  extent  by 
the  yielding  and  crushing  of  the  rooks  on  the  edge  of  the  basin,  where 
they  were  compressed  against  the  older,  harder  rocks. 

Unfortunately  the  coals  in  most  of  the  interior  part  of  the  basin 
appear  to  be  buried  too  deep  for  mining.  Future  prospecting  may 
reveal  increased  areas  of  coal  on  the  arches  of  anticlines,  or  in  blocks 
brought  up  by  faulting,  that  will  be  within  mining  distance  of  the 
surface  and  yet  have  the  advantage  of  being  less  disturbed  and 
changed  than  the  beds  now  known  around  the  edges  of  the  basin. 


Figure  1. — Crushed  structure 
of  coal. 


20 


RHODE  ISLAND  COAL. 


PHYSICAL  APPEARANCE. 

The  best  coal  seen  approaches  Pennsylvania  anthracite  in  color, 
fracture,  and  luster.  The  fracture,  however,  is  less  conchoidal  and 
the  color  invariably  tends  to  be  more  of  a steel  gray,  none  of  the 
coals  seen  showing  the  bright  jetlike  luster  of  freshly  broken  Penn- 
sylvania anthracite.  But  little  difference  was  noted  in  the  color  of 
the  best  coal  from  Portsmouth  and  the  best  from  Cranston,  though 
the  average  coal  at  Portsmouth  differs  considerably  from  that  at 
Cranston.  In  fracture  the  best  coal  at  Portsmouth  tends  to  break 
down  in  rhombs  with  short,  irregular  faces  instead  of  with  the  rounded 
conchoidal  surfaces  of  broken  anthracite.  In  some  specimens  the 
rhombs  are  closely  diamond-shaped  in  cross  section  with  parallel 
faces.  Other  specimens  of  the  coal  appear  to  consist  of  a series  of 
irregular  plates,  as  though  it  had  been  cleaved  by  transverse  pressure 
and  the  plates  then  pushed  over  each  other  but  finally  cemented 
together*  into  a coherent  mass.  In  still  other  specimens  the  coal 
appears  to  have  been  broken  into  minute  fragments  of  all  shapes, 
which  were  later  recemented  and  consolidated  like  a conglomerate 
or  breccia.  The  color  of  such  pieces  ranges  from  steel  gray,  locally 
slightly  bronzed,  to  a dull  black,  like  the  color  of  manganese.  Much 
of  this  coal,  in  fact,  is  dull  bluish  gray  to  black,  with  bright  luster  in 
spots,  grading  into  black  without  luster.  Though  hard,  thisxoal  as 
a rule  is  friable  and  requires  careful  handling  in  shipping  to  prevent 
slacking. 

In  the  Cranston  district  the  coal  everywhere  seen  differs  both  in 
appearance  and  fracture  from  the  Portsmouth  coal,  the  closest  re- 
semblance noted,  both  in  color  and  fracture,  being  in  coal  said  to 
have  come  from  the  foot  of  the  incline  at  the  Budlong  mine.  As  a 
rule  the  Portsmouth  coal  appears  to  have  been  broken  into  minute 
fragments  by  a close  network  of  fracture  planes,  but  the  coal  at 
Cranston  has  more  of  a flow  structure,  the  original  rhombic  frag- 
ments, if  there  were  such  fragments,  having  been  pressed  and  drawn 
into  scales  or  flakes.  Pieces  of  the  coal,  large  or  small,  everywhere 
present  smooth,  rounded  surfaces,  rubbed  and  polished  or  glistening. 
These  surfaces  appear  in  many  specimens  to  consist  of  at  least  a 
film  of  graphite.  Exceptionally,  the  entire  piece  appears  to  be  com- 
posed of  thin  scales  or  flakes  of  graphite,  held  together  more  or  less 
imperfectly.  Such  pieces  will  make  a mark  as  readily  as  a pencil, 
and  have  an  oily  feeling  when  rubbed  with  the  fingers.  Much  of  the 
gray  appearance  appears  to  be  due  to  films  of  a grayish  or  bluish- 
white  substance,  apparently  quartz  that  has  been  carried  into  the 
coal  in  solution  in  water;  and  the  same  solutions  also  carried  in  more 
or  less  pyrite  or  iron  sulphide,  the  “sulphur”  of  the  miners.  In 
places  the  quartz  forms  veins  or  irregular  plates  an  inch  or  two  thick, 
commonly  with  a lens  of  pyrite  running  through  the  center. 


CHARACTER  OF  THE  COAL. 


21 


The  best  of  the  Cranston  ooal  shows  almost  no  quartz  or  only  in 
minute  scattered  flakes  or  films.  The  poorer  coal  looks  as  if  it  had 
been  dipped  into  some  gray  solution  and  then  dried.  The  poorest 
coal  is  full  of  distinctly  visible  quartz  veins  of  considerable  thickness 
and  extent  and,  where  mined  near  the  surface,  is  commonly  stained 
rusty  red  from  the  oxidation  of  the  pyrite.  In  fact,  much  of  the  coal 
at  Cranston,  if  picked  up  beside  the  road,  would  not  seem  to  be  coal 
nor  to  have  any  of  the  qualities  of  a fuel.  It  shows  a bluish-gray  to 
ashen-gray  color,  changing  in  places  to  a dull  or  glistening  black,  and 
has  the  structure  of  a foliated  schist.  Much  of  this  coal  would  be 
defined  by  a geologist  as  a carbonaceous  schist. 

SPECIFIC  GRAVITY. 

The  weight  or  specific  gravity  of  Rhode  Island  coal  has  operated 
against  its  use.  Pennsylvania  anthracite,  as  delivered,  has  a volume 
of  35  to  40  cubic  feet  per  short  ton,  according  as  the  coal  is  broken 
large  or  small.  Much  of  the  Rhode  Island  anthracite  in  the  same 
sizes  has  a volume  of  only  25  to  30  cubic  feet  per  ton.  The  house- 
holder who  has  been  accustomed  to  the  ordinary-sized  load  of  Penn- 
sylvania anthracite  is  inclined  to  think  when  he  receives  a load  of 
Rhode  Island  anthracite  that  he  is  getting  short  measure  or  to 
believe  that  the  smaller  volume  of  the  Rhode  Island  coal  can  not  give 
as  much  heat  as  the  larger  volume  of  the  Pennsylvania  coal.  He  thus 
at  once  becomes  prejudiced  against  the  coal  or  the  use  of  it. 

The  writer  had  the  specific  gravity  determined  of  five  samples  of 
Rhode  Island  anthracite  and  one  of  Pennsylvania  anthracite  in  the 
chemical  laboratory  of  the  United  States  Geological  Survey.  In 
order  to  learn  to  what  extent  ash  affected  the  specific  gravity,  C.  E. 
Lesher  later  determined  the  ash  from  the  same  samples.  The  results 
obtained  are  as  follows: 

Specific  gravity  and  ash  of  Rhode  Island  coal. 


No. 

Sample. 

Specific 

gravity.^ 

Ash.& 

Air-dry- 
ing loss 
at  60°  C.  5 

1 

Portsmouth  mine,  best  appearing 

1.65 

13 

17 

2 

Portsmouth  mine 

1.96 

13 

3.5 

3 

Cranston,  from  slope 

2.20 

18 

1 

4 

Cranston,  open  cut,  selected  coal 

2.06 

6 

.5 

5 

Fenners  Ledge  (graphite  mine) 

2.45 

65 

1 

Pennsylvania  anthracite,  for  comparison 

1.43 

5 

.5 

a Examined  by  George  Steiger.  Specimens  were  first  coated  with  paraffin  so  that  the  specific  gravity 
obtained  would  be  independent  of  pore  space. 

b Determined  by  C.  E.  Lesher.  Specimens  had  had  ample  opportunity  to  dry  out,  so  that,  with  one 
exception,  there  was  but  slight  air-drying  loss  at  60°  C. 

A comparison  of  the  figures  shows  but  a slight  relation  between 
weight  and  ash.  The  figures  suggest  a distinct  difference  in  the 
weight  of  Cranston  coal  as  compared  with  that  of  Portsmouth  coal. 


22 


RHODE  ISLAND  COAL. 


Sample  4,  from  Cranston,  has  a higher  specific  gravity  than  sample  2, 
from  Portsmouth,  though  it  contains  less  ash.  Sample  3 has  a 
higher  percentage  of  ash  and  also  higher  specific  gravity  than  sample 
4.  But  samples  1 and  2,  with  the  same  percentage  of  ash,  show  a 
marked  difference  in  specific  gravity.  In  fact,  if  the  specific  gravity 
of  sample  1 was  obtained  while  it  contained  17  per  cent  of  moisture, 
as  it  seems  to  have  been,  the  air-dried  sample  would  have  had  a 
specific  gravity  of  only  1.36,  making  the  difference  still  more  striking. 

The  sampling  and  testing  were  not  complete  enough  to  permit 
general  conclusions  to  be  formed  with  certainty,  but  the  figures  sug- 
gest, at  least,  that  there  may  be  differences  in  the  specific  gravity  of 
the  coal  regardless  of  the  ash.  Sample  1 indicates  that  some  of  this 
coal  when  air-dried  is  of  no  higher  specific  gravity  than  other 
anthracite  coals. 

These  figures  for  specific  gravity  may  be  supplemented  by  the 
following  figures  obtained  by  Jackson:1 


Specific  gravity  and  ash  of  coal  from  Rhode  Island  and  Massachusetts , according  to  C.  T. 

Jackson. 


Specific 

gravity. 

Ash. 

Portsmouth,  R.  I.,  rusty  coal,  “best  quality” 

1.85 

1.7704 

1.69 

1.71 

1.73 

3.235 
9. 50 
6.4 
2.0 
4.0 

Portsmouth,  R.  I.,  coal,  good,  solid,  grayish  black,  not  graphitic 

Skinner  coal  at  Mansfield,  Mass 

Hardon  coal  at  Mansfield,  Mass 

Do 

A.  B.  Emmons  2 obtained  2.209  as  the  specific  gravity  of  coal  from 
the  Cranston  shaft,  and  the  ash  ran  13.07  per  cent.  The  corre- 
spondence with  the  figure  2.20,  obtained  by  Steiger,  may  be  acci- 
dental, but  it  confirms  in  a measure  the  recent  determination. 

In  general,  it  appears  that  Rhode  Island  coal  is  heavier  for  a given 
volume  than  the  coals  with  which  it  competes;  that  the  coal  on  the 
edges  of  the  basin,  where  most  compressed,  is  heavier  than  out  in  the 
basin,  as  at  Portsmouth  or  Mansfield;  and  that,  though  these  differ- 
ences may  be  in  part  due  to  differences  of  percentage  of  ash,  they 
appear  also  to  be  due  to  differences  in  the  weight  of  the  coal  matter. 

Some  idea  of  the  bearing  of  the  specific  gravity  of  the  coal  on  its 
burning  qualities  may  be  gained  from  a quotation  from  a recent  work 
by  Porter  and  Durley:  3 

It  is  probable  that  few,  if  any,  coals  which  have  a specific  gravity  over  1.6  are  worth 
burning  and,  excepting  the  anthracites  and  possibly  one  or  two  other  special  coals, 
a specific  gravity  of  1.52  may  be  taken  as  the  approximate  density  of  the  most  impure 
coals  that  can  be  profitably  burned  for  commercial  purposes. 

1 Jackson,  C.  T.,  Report  on  the  geologic  and  agricultural  survey  of  the  State  of  Rhode  Island,  Provi- 
dence, 1840. 

2 Emmons,  A.  B.,  Notes  on  the  Rhode  Island  and  Massachusetts  coals:  Am.  Inst.  Min.  Eng.  Trans., 
vol.  13,  pp.  510-517,  1885. 

3 Porter,  J.  B.,  and  Durley,  R.  J.;  An  investigation  of  the  coals  of  Canada:  Canada  Dept.  Mines,  Mines 
Branch,  vol.  1,  p.  194, 1912. 


CHARACTER  OP  THE  COAL. 


23 


CHEMICAL  CHARACTER. 

The  chemical  composition  of  a coal  determines  its  heat-giving 
capacity.  The  principal  heat-giving  elements  of  any  coal  are  the 
uncombined  or  fixed  carbon  and  the  combined  hydrogen  and  carbon, 
known  as  “ volatile  matter”  or  “ volatile  combustible.”  If  Rhode 
Island  coal  contained  only  those  substances  it  would  contain  about 
95  per  cent  of  fixed  carbon  and  5 per  cent  of  volatile  matter,  or  in 
the  ratio  of  19  to  1.  Pennsylvania  anthracite,  as  shown  by  an  aver- 
age analysis  of  a large  number  of  commercial  samples  made  by  the 
Second  Geological  Survey  of  that  State,1  shows  an  average  ratio  of 
22  to  1,  so  that  Rhode  Island  anthracite,  when  freed  of  water  and  ash, 
contains  a little  more  volatile  matter  and  a little  less  fixed  carbon 
than  Pennsylvania  anthracite.  Unfortunately,  the  percentage  of 
moisture  and  ash  in  Rhode  Island  coal  greatly  exceeds  that  in  Penn- 
sylvania anthracite,  with  which  it  comes  into  competition,  and, 
further,  as  discussed  beyond,  it  is  found  that  the  volatile  matter  of 
Rhode  Island  coal  is  entirely  noncombustible,  consisting  probably 
of  water  and  carbon  dioxide,  so  that  it  should,  as  a source  of  heat, 
be  excluded  from  the  coal  and  be  grouped  with  the  ash  and  moisture. 

The  average  analysis  of  Pennsylvania  anthracite  referred  to  gives 
the  average  percentage  of  moisture  in  the  commercial  coal  as  3.30. 
The  average  of  recent  analyses  of  mining  samples  of  Rhode  Island 
coals,  made  by  the  United  States  Bureau  of  Mines,  is  16  per  cent 
for  samples  from  Portsmouth,  where  the  coal  is  mined  underground, 
and  6.5  per  cent  from  the  open  cut  at  Cranston.  The  ash  in  the 
average  Pennsylvania  anthracite  analysis  is  8.40;  in  the  recent 
analyses  of  Rhode  Island  coal  by  the  Bureau  of  Mines  it  ranges  from 
13.76  to  33.90,  the  average  being  22.91.  In  general,  it  would  appear 
that  the  moisture  in  fresh  Rhode  Island  coal  is  from  two  to  six  times 
as  high  as  in  Pennsylvania  anthracite  and  the  ash  between  two  and 
three  times  as  high.  The  possibility  of  reducing  the  moisture  by 
drying  and  the  ash  by  washing  will  be  considered  below. 

As  compared  with  the  bituminous  coals  that  are  shipped  into  New 
England,  Rhode  Island  coal  is  proportionately  lower  in  “pure  coal,” 
that  is,  coal  without  water  or  ash,  for,  though  water  and  ash  form 
from  one-fourth  to  one-half  of  Rhode  Island  coal  as  mined,  they 
form  only  one-tenth  to  one- twentieth  of  the  bituminous  coals  from 
the  eastern  edge  of  the  Appalachian  coal  field.  These  are  the  coals 
that  are  shipped  into  New  England,  but  they  are  the  highest  grades 
of  bituminous  coals  and  do  not  represent  bituminous  coals  in  gen- 
eral. Considered  commercially,  however,  Rhode  Island  coal  should 
necessarily  be  compared  with  the  coals  with  which  it  must  compete. 

The  table  on  pages  26-27  gives  a set  of  recent  analyses  by  the  Bureau 
of  Mines  of  samples  of  Rhode  Island  coal  taken  in  the  mine,  in  accord- 


1 Second  Geol.  Survey  Pennsylvania  Summary  Rept.,  vol.  3,  pt.  1,  1895. 


24 


RHODE  ISLAND  COAL. 


ance  with,  the  modern  practice  of  cutting  the  full  width  of  the  worked 
portion  of  the  bed,  quartering  down  to  a 2-pound  sample,  which  is 
then  hermetically  sealed  so  that  the  moisture  content  is  preserved 


Coal  and 

laboratory  number 


HEAT-YIELDING  ELEMENTS  OF  COAL 


British 

thermal 

units 

found 


Fixed  carbon  56.4% 


Composition 

Average 

Portsmouth,  R.  I. « 
coal 

Heat  value 


Composition 
Average 
Cranston,  R.  I.  < 
coal 

Heat  value 


Composition 


Composition 

;e 5953-5956  < 
3a.  anthracite 

Heat  value 


Composition 

8488 

Clearfield,  Pa.  • 
coal 

Heat  value 


Composition 

2156 

Cambria  Co.,  Pa. 
coal 

Heat  value 


Composition 

5456 

Pocahontas,  Va. 
coal 

Heat  value 


Composition 

8112 

New  River,  W Va. 
coal 

Heat  value 
Composition,  per  cent 
B.  L u.,  thousands 


'Vol. 

mat 

2.8% 


Ash  23.5% 


Moisture  17.1% 


Combustible  matter  55.6%^ 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  8,060  -^ 


Fixed  carbon  68.3% 


Carbon;  in  volatile  0 % ? 
Available  hydrogen  0%? 
-Sulphur  .34% 

Vol. 
"imat 
2.6% 


Total  55.6% 


Total  8,070  8,103 


Combustible  matter  67%-*N 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  9,710  V 


Fixed  carbon  71 .7  % 


Carbon  in  volatile  0%  ? 
Available  hydrogen  0%  ? 
10-*— Sulphur  .38% 


' Total  67% 

Total  9,720  9,673 


Vol.  mat  Moisture 

i7.%  Ashl5.7%  5.4% 


Combustible  matter  71.7%^ 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  10,390 


, Carbon  in  volatile  — **  <^**1 
i Available  hydrogen  J 

^^>T280  30— Sulphur  .74% 


Total  74.7%. 

Total  1 1.820  12,040 


Fixed  Carbon  84.3% 


Combustible  matter  80.9 

Fixed  carbon 

Theoretic  yield,  B.  t u:  1 1,730 


m 


1?';  Moisture 

2.8% 

2-1 Ash  10.7% 


Fixed  carbon  72.% 


1l'.7%  Total  82.6% 
Carbon  in  volatile  0%*<l 
^-Available  hydrogen^  | 

,1120,  30«-Sulphur.77%  I Total  12.880  12.970 

BBSS)  N .is*;  ^ 

\ Moisture 
I Ash  2-9% 

Vol.  mat  20.5%  4.6% 


Combustible  matter  72.  %» 

Fixed'  carbon 

Theoretic  yield,  B.  t u:  10,440 
Fixed  carbon  73.% 


r 

, 1,550 


10.7%  43%  Total  87% 
Carbon  in  volatile. J | 


^Available  hydrogen 
2,670  | 3Q«-Sulphur  i Total  14.690  14,510 


.77%  ) 


Vol.  mat  16.8%6.6% 


Combustible  matter  73.%^ 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  10,580  v1 


Fixed  carbon75.3% 


7.6%  3.8%  Total  844%. 
^Carbon  in  volatile-^  )i  - 
, *,  „ Available  hydrogen  ' i 
1,100  2,360  ,30-Sulohurl  Total  14.070  14.279 

[?m  imMHrBZSI  .94%'  \-  . *4 

\ Moisture 
Ash  1-6% 

Vol.  matil7.1%5.8% 


Combustible  matter  75.3%^ 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  10,910-^ 


7.8%  4%  Total  87.1% 
^Carbon  in  volatile  — » t 1 

i f i 


Fixed  carbon  76.4% 


•f  r Available  hydrogen 

30— Sulphur  '(Total  14,440  ,14,672 

• Moisture 
! .Msh  3.2% 

Vol.  mat  18.5  %2.7%  ' 


Combustible  matter  76.4%^ 

Fixed  carbon 

Theoretic  yield,  B.  t u.:  1 1,086 


7.6%  4.2%Total  88.2% 

.-  Carbon  in  volatile  k 

* Available  hydrogen  7 

1,102  2,653  , 30-SulDhur  Total  14.848  14.760 

■m&Baassssaa  .64% 

IOC- 


60 


70 


90 


10  11  12  13  14  15  16 


Horizontal  scales. 


Figure  2. — Chart  showing  composition  and  theoretic  heating  power  of  Rhode  Island  coal  in  comparison 
with  other  coals  with  which  it  must  compete  in  New  England. 

without  change  until  analyzed.  The  second  table  gives  analyses  of 
Rhode  Island  coal  made  by  the  Bureau  of  Mines  from  samples  taken 
from  carload  lots  or  from  large  quantities,  which  were  tested  at 
the  laboratories  of  the  Bureau  of  Mines  in  different  ways.  These 


CHARACTER  OF  THE  COAL. 


25 


samples  have  had  opportunity  to  dry  out  and  so  show  a much 
smaller  percentage  of  moisture.  The  sample  taken  at  Portsmouth 
consisted  of  about  20  tons  of  “the  best  that  the  mine  can  produce.” 
In  the  third  table  are  given  some  analyses  of  samples  taken  across 
the  bed,  or  from  lots  of  several  tons  each,  by  A.  B.  Emmons, 
and  analyzed  by  F.  A.  Gooch  and  B.  T.  Putnam.1  These  anal- 
yses differ  from  those  in  the  first  table  in  that  the  samples  have 
more  or  less  dried  out  according  to  the  weather  at  the  time  the 
analysis  was  made.  The  Bureau  of  Mines  analyses  are  all  made  on 
the  air-dried  sample.  The  fourth  table  includes  some  old  analyses 
by  Jackson.2  They  are  of  interest  in  that  they  give  analyses  of  coal 
from  the  part  of  the  field  near  Mansfield.  The  analyses  from  Ports- 
mouth form  a basis  for  comparison.  The  fifth  table  gives  a few  anal- 
yses made  by  the  Bureau  of  Mines  from  samples  in  the  anthracite 
field;  the  fields  of  Jefferson  County,  Clearfield  County,  and  Cambria 
County  of  Pennsylvania;  the  Pocahontas  field  of  Virginia;  and  the 
New  River  field  of  West  Virginia. 

The  chart  given  in  figure  2 shows  the  relative  character  of  Rhode 
Island  coal  in  contrast  with  the  coals  just  mentioned,  both  as  to 
composition  and  heating  power. 

In  the  following  tables,  under  “Kind,”  A represents  a mine  sample 
collected  by  an  inspector  of  the  technologic  branch  of  the  United 
States  Geological  Survey;  B,  a mine  sample  collected  by  a geologist 
of  the  Survey;  and  C,  a car  sample  taken  at  the  fuel-testing  plant. 
The  form  of  analysis  is  denoted  by  number  as  follows:  1 represents 
the  sample  as  received;  2,  the  sample  dried  at  a temperature  of  105° 
C.;  and  3,  the  sample  free  from  moisture  and  ash  according  to  calcu- 
lation. 


1 Emmons,  A.  B..  op.  cit. 


2 Jackson,  C.  T.,  op.  cit, 


Analyses  of  Rhode  Island  anthracite  by  the  Bureau  of  Mines  from  mine  samples .< 

Newport  County. 


26 


RHODE  ISLAND  COAL. 


Heating  value. 

British 

thermal 

units. 

9,230 

11,093 

13,858 

9,313 
10, 737 
13, 723 

5,976 

7,830 
13, 120 

8,528 

11,063 

13,946 

7,300 

8,675 
13, 930 

6,545 

7,840 

13,200 

8,895 

10,360 

13,490 

9,040 

10,510 

13,770 

Calories. 

5, 128 
6,163 
7,699 

5, 174 
5,965 
7,624 
3,320 
4,350 
7,289 

4,738 

6,146 

7,748 

4,055 
4,820 
7, 740 

3,635 

4,355 

7,335 

4,945 
5, 755 
7,495 

5,025 

5,835 

7,650 

Air-dry- 
ing loss. 

14.0 

9.6’ 

23.1 

21.0 

14.8 
15.5 

13.8 
11.4 

Ultimate. 

Oxygen. 

17. 92 
3.60 

14.49 
3.11 
3. 97 

23.59 
3. 33 
5. 59 

22.49 

2.  74 
3.45 

17.63. 
4. 30 
6. 86 
18.  20 
4.  21 
7. 08 
15. 45 

3.  40 
4. 39 

14. 14 
2. 06 
2.  71 

Nitrogen. 

0. 27 
.32 

CXI  iO  CXI  O 00  CXJ  OOCOO  00  t-H  CO  OCXIO  00OCXI  OCXJCT. 

CXI  CXI  CO  H H CX|  rH  CXI  CXI  t-H  CXI  CO  t-H  r-H  <M  O O t-H  t-H  C* 

Carbon. 

62.  63 
75. 27 

64.  23 
74.  05 
94.  66 

42.  36 
55.  50 
93. 00 
58. 46 
75. 85 
95. 62 

47. 88 
56. 90 
91.39 

45.  54 
54. 57 

91.88 

62.53 
72. 78 
94. 80 

62. 09 
72. 13 

94.53 

Hydro-  j 
gen. 

2. 12 
.30 

1. 88 
.47 
.60 

3. 15 
.68 
1.14 

2. 84 
.38 
.48 

2.39 
. 75 
1.20 

2. 11 

.32 

.54 

1.93 

.43 

.56 

1.84 
.33 
.43 

Sulphur. 

0>t-h*0  0*0  10  co-**o  O CO  O <N^<M  lOOOO  O O CXI 

lOhH  CO  CO  ^ OOO  HHH  hh(N  HHCO  OHH  co*oo 

o 1-H  T-H  0 4 

Proximate. 

Ash. 

16. 47 
19. 80 

18.88 

21. 77 

30. 77 
40. 32 

15. 93 
20. 67 

31.8 
37.7 

33.9 

40.6 

20.0 

23.2 

20.4 

23.7 

Fixed 

carbon. 

64. 43 

77. 44 
97.74 

65. 30 
75.  28 
96.  22 

42.  54 
55.  74 
93. 40 

58. 37 
75.  72 

95. 45 

49.8 

59.3 

95.0 

46.0 
55.  4 

93.0 

61.9 

72.3 

94.0 

63.2 

73.8 

96.5 

Volatile 

matter. 

OOO  0*000  i-H  ^ O 00  r—l  *o  _ 

CO  t'-  CX|  *00  1''-  ooo  t^-o*o  *000  *COO  0*00  *0*0*0 

<M*c^ci  cxi c4 co  cocoo  cxi  co  ^ c4  co  *o  ^ ^ o cxi  c4  co 

Moisture. 

16.80 

13.26 
23. 68 
22. 92 

15.9 
16.6 
14.1 

13.9 

Sample. 

Condi- 

tion. 

HNM  r-KNCO  H(NM  HNM  HN«  HNM  i-IWeO  .-H  IN  00 

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B 

B 

B 

B 

B 

B 

B 

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CHARACTER  OF  THE  COAL. 


27 


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28 


RHODE  ISLAND  COAL. 


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CHARACTER  OF  THE  COAL. 


29 


Analyses  of  coals  from  Portsmouth , II.  I.,  and  Mansfield,  Mass.,  by  Jackson.a 


Water 

and 

volatile 

matter. 

Fixed 

carbon. 

Ash. 

Portsmouth,  R.  I.,  coal,  clean,  free  from  rust 

10.0 

84.5 

77.0 

5.5 

Portsmouth,  R.  I.,  rusty  coal 

7.0 

16.0 

3.66 

Portsmouth,  R.  I.,  rusty  coal,  “best  quality*’ 

• 10.5 

85.84 

Portsmouth,  R.  I.,  coal,  solid,  grayish-black,  and  glossy  but  not  graphitic. . 
Mansfield,  Mass.,  Skinner  mine 

13.0 

6.2 

77.5 

87.4 

9.5 

6.4 

Mansfield,  Mass.,  Hardon  mine ' 

6.0 

92.0 

2.0 

Do 

6.0 

90.0 

4.0 

a Jackson,  C.  T.,  op.  cit. 


These  analyses  of  Mansfield  coal  must  be  interpreted  in  the  light 
of  recent  analyses  of  Portsmouth  coal.  They  suggest  that  the  coal 
at  Mansfield  has  a little  higher  percentage  of  fixed  carbon  than  that 
at  Portsmouth  and  possibly  is  more  graphitic. 

Jackson  reports  a comparative  test  for  ash  of  Portsmouth  and 
Lackawanna  coal  by  Christopher  Rhodes,  jr.  In  the  first  test  33,477 
pounds  of  Lackawanna  coal  yielded  2,566  pounds  of  ash,  or  7.66 
per  cent;  in  the  second  test  32,344  pounds  of  the  same  coal  yielded 
2,489  pounds  of  ash,  or  7.69  per  cent.  On  the  other  hand,  8,705 
pounds  of  Portsmouth  coal  yielded  1,332  pounds  of  ash,  or  15.3  per 
cent. 


Analyses  of  anthracite  and  bituminous  or  semibituminous  coals  from  Pennsylvania , Virginia , and  West  Virginia .< 

Pennsylvania. 


30 


RHODE  ISLAND  COAL. 


Heating  value. 

British 

thermal 

units. 

12,047 
12, 737 
15,287 
15,390 

12,577 

12,933 

14,873 

13,298 
13,682 
14, 882 

12, 523 
12, 818 
14, 855 

13,351 
13,810 
15,248 
14,465 
14,999 
15,660 
14,510 
14, 850 
15,690 

14,279 

14,800 

15,890 

16,013 

Calories. 

6,693 
7,076 
8,493 
8, 550 

6,987 

7,185 

8,263 

7,388 
7,601 
8, 268 

6,957 

7,121 

8,253 

7,417 

7,672 

8,471 

8,036 
8,333 
8,700 
8,060 
8,305 
8, 715 

7,933 

8,222 

8,828 

8,896 

Air-dry- 
ing loss. 

3.4 

1.6 

1.5 

1.5 

2.6 

! 2-4 

2.1 

2.9 

Ultimate. 

Oxygen. 

cOt^CMcO  ^ICOO  OCOCO  HHO  CO  00  r- < 
CiMt^t'-  CO  <M  iO  O l-H  00  00  H CHrf( 

co  ei  ei  oi  ci  oi  ^ h ci  cd  th  ci  id  ci  ci 

5.49 
2. 93 
3.11 

5.91 

2.89 

3.11 

3.14 

Nitrogen. 

NHNOJ  OOOH  CO  lO  rH  CO  00  Oi  Oi  Cl  t-H 
00  Oi  Oi  cOt^OO  COCON  COON  !>.  00  Oi 

© 

1.37 

1.41 
1.48 

1.26 

1.31 

1.40 

1.42 

Carbon. 

72. 65 

76. 81 
92.19 
93.05 
79. 22 
81.47 
93.70 
84.36 
86.78 
94.39 

78. 96 

80.82 
93.68 

81.35 
84.15 
92. 91 

82.  79 
85.30 
89.53 

80.70 
83.64 
89.80 
90. 75 

Hydro- 

gen. 

3.10 

2.64 

3.17 

3.20 
2.23 
1.97 
2. 27 

1.89 

1.63 

1.77 

2. 13 
1.91 

2.21 

3.08 
2.  80 

3.09 

OHIO  CO  CM  ^ Ci 
O 00  o lO  CO  co  co 

id  ^ id  '"tf  T*  Tji* 

Sulphur. 

0.74 

.79 

.95 

tHCOt*  Oi  o »ON^  o <M  00  CM  lO  Oi  Oi  CO  iO 

lOOcO  00  Oi  O O O <M  COCO  00  00  00  r-t^OO  Oi  Oi  o 

Proximate. 

Ash. 

15. 78 
16.68 

12. 69 
13.05 

7.83 
8. 06 

13.39 

13.71 

9.12 

9.43 

4.07 

4.22 

4.6 

4.7 

6.63 

6.87 



frixed 

carbon. 

71.79 
75. 90 
91.09 

82.07 
84.40 

97.07 
88.21 
90.  75 
98.  71 

82.  77 
84.71 

98.17 

84.28 

87.19 

96. 27 

65.18 
67.59 
70.57 

72.0 

73.8 
77.5 
73.04 
75.  70 

81.28 

Volatile 

matter. 

7.02 
7. 42 
8. 91 

2.48 
2. 55 
2.93 
1.16 
1.19 
1.29 

1.54 

1.58 

1.83 

3.27 

3.38 

3.73 

27.19 

28.19 

29.43 

20.5 

21.5 

22.5 

16.82 

17.43 
18.  72 

Moisture. 

5.41 

2.76 

2.80 



2.30 

3.33 

3.56 

2.9 

3.51 

Sample. 

Con- 

dition. 

rH  03  CO  H(NM  t— t CO  H(NM  HN«  rH  <N  CO  HNM'J 

Kind. 

c 

A 

A 

A 

A 

A 

! 

B 

C 

Labo- 

ratory 

No. 

1245.. . 

5956.. . 

5954.. . 

5955.. . 

5953.. . 

5219.. . 

8488.. . 

2152.. . 

County. 

Lackawanna 

Schuylkill 

Do 

Do 

Do 

Clearfield 

Cambria 

I § | 


• - .CO 
p4+a  O 

2 S ® 


o-S 

boo 


® CM 


<N 

b 

© Pi 


-§ 

bO*o 


£ 


'Sg^° 

S' 


I O 

jUS  . 

i^oS  ■§ 

a.S 

J S Jis 

> g §33 

-a  o t“,a) 
■ 32  ? © 


. t 

> O .92 
; <D  A Xi 

i£  ® 3 
•TVS  ® 

!SS| 

iSsS 


a 


h> 


38  3 

O*  05  Ci 
l-H  lO  to 


»o 


West  Virginia, 


CHARACTER  OF  THE  COAL. 


31 


C ^ CO 

oo'oo'oo' 


o>  o 

OH 

<N  d 


CO  CO  to 
HIOH 

t-H  CO*  to 


1C  CO  C» 

CO  H 
05  <M  05 


X}  tf 
<u  3 
rO  o 

^-,,3 

II 

© A 
cc  o 


M,3 

55  ** 

'<3  o 

^ a 
is 


§£ 

.a  a 


a ~ 

O 2 

•sl 

o| 

fM  O 
2 3 

Irt 


-3  3 
3 « 

2^ 

35  o 

g.a 

OJ, 


O O 

PM 


32 


RHODE  ISLAND  COAL. 


The  fact  that  Rhode  Island  coal  will  part  with  or  take  up  moisture, 
according  as  the  air  is  dry  or  moist,  is  discussed  below.  (See  p.  37.) 
The  coal  takes  up  as  much  as  15  per  cent  of  moisture  if  it  is  exposed 
to  dampness  or  loses  most  of  its  moisture  if  it  is  exposed  to  a dry  wind 
when  broken  up  fine.  The  heating  value  of  the  coal  may  therefore 
be  said  to  range  between  the  values  given  for  the  coal  as  mined  and 
as  air-dried. 

As  shown  by  the  analyses,  Rhode  Island  coal  as  mined  ranges  from 
less  than  6,000  to  more  than  9,000  British  thermal  units  where  mined 
underground,  and  from  less  than  8,500  to  more  than  10,000  British 
thermal  units  if  mined  in  open  cuts,  where  it  is  possible  that  the  coal 
may  have  dried  out  in  part.  The  anthracite  culm  yields  more  than 
12,000  British  thermal  units,  and  three  other  samples  of  anthracite 
as  mined  yield  from  12,500  to  13,350  British  thermal  units.  In 
other  words,  the  anthracite  culm  shows  a theoretic  heating  power 
double  that  of  the  poorest  of  the  Rhode  Island  samples  and  one-third 
better  than  the  best  from  underground,  or  about  one-fifth  better  than 
the  best  of  the  open-cut  samples.  It  would  appear  that  in  general 
Rhode  Island  coal  as  mined  has  from  60  to  70  per  cent  of  the  heating 
power  of  the  bituminous  coals  cited,  though  it  ranges  both  above  and 
below  these  figures.  This  comparison  makes  it  clear  that  Rhode 
Island  coal,  if  used  as  fresh  mined  in  large  lumps  (which  can  not  dry 
out  quickly),  will  not  compare  well  with  other  coals,  regardless  of  the 
furnace  or  other  apparatus  used.  But  if  comparison  is  made  between 
Rhode  Island  coal  and  other  coals  on  the  air-dried  basis  the  result 
is  not  quite  so  one-sided.  The  other  coals  cited  carry,  as  a rule,  so 
low  a percentage  of  moisture  as  mined  that  drying  in  air  increases 
their  heating  qualities  only  a very  few  hundred  British  thermal  units 
at  the  outside,  whereas  the  drying  out  of  Rhode  Island  coal  may 
result  in  an  increase  of  heating  capacity  of  10  to  20  per  cent  in  the 
coals  high  in  moisture  and  2 to  10  per  cent  in  the  coal  from  Cranston. 

The  average  of  the  British  thermal  unit  determinations  1 on  air- 
dried  samples  of  Rhode  Island  coal  is  9,908.  If  sample  9330,  which 
is  labeled  as  “ weathered, ” is  left  out  of  account  the  average  is  10,068. 
It  may  therefore  be  taken  as  a fair  assumption  that,  on  the  air-dried 
basis,  Rhode  Island  coal  has  a value  of  10,000  British  thermal  units. 
On  this  basis  it  may  be  noted  that  thoroughly  dried  Rhode  Island 
coal  has  theoretically  about  75  per  cent  of  the  heating  power  of  anthra- 
cite coal  and  about  70  per  cent  of  the  heating  power  of  the  high-grade 
bituminous  coals  that  are  brought  into  New  England. 

The  analyses  of  Rhode  Island  coal  given  above  are  from  samples 
of  beds  that  are  mined  for  coal  and,  as  a rule,  are  from  the  better 
parts  of  these  beds.  The  carbonaceous  matter  of  the  coal  measures  of 
Rhode  Island  grades  from  the  best  of  these  samples  to  carbonaceous 

i Bur.  Mines  Bull.  22,  pt.  1,  pp.  184-185. 1913. 


CHARACTER  OF  THE  COAL. 


33 


shale  containing  only  a very  small  percentage  of  carbonaceous  matter. 
As  already  explained,  where  the  beds  have  been  squeezed  thin,  the 
coal  has  generally  been  changed  to  graphite  and  is  accompanied  by  a 
high  percentage  of  ash,  which  consists  mainly  of  quartz,  apparently 
deposited  by  water  carrying  silica  in  solution.  No  analyses  of  prop- 
erly averaged  samples  of  the  more  graphitic  portions  of  the  coal  beds 
are  at  hand.  The  following  analyses,  however,  of  samples  from  Fen- 
ners Ledge,  at  Arlington,  will  give  a fair  idea  of  the  composition  of 
the  graphite  beds: 


Analyses  of  graphite  of  Fenners  Ledge , at  Cranston , R.  I.a 


1 b 

2b 

3 b 

46 

5 

6 

Graphitic  carbon 

Silica  

47.68 

46.32 

55.04 

41.65 

2.66 

.65 

57.17 
39. 63 
2.63 
.57 

64.21 

34.08 

1.31 

.40 

25.27 

40.  76 

Sulphur 

Moisture 

6.00 

Volatile 

7.86 
66. 87 

5.92 

53.32 

Ash 

100.00 

100. 00 

100.00 

100.00 

100. 00 

100. 00 

a Preliminary  report  of  the  Natural  Resources  Survey  of  Rhode  Island:  Rhode  Island  Bur.  Industrial 
Statistics  Bull.  1 (Ann.  Rept.  1909,  pt.  3),  p.  115,  1910. 

b Furnished  by  G.  L.  Gross. 

1.  By  Prof.  Sharpies,  of  Boston. 

2.  By  State  Assayer  Perkins,  of  Rhode  Island. 

3.  By  same  analyst  as  2,  from  later  sample. 

4.  Latest  analysis,  by  English. 

5 and  6.  By  Chase  Palmer,  of  the  U.  S.  Geological  Survey,  from  samples  obtained  by  E.  S.  Bastin  and 
C.  W.  Brown. 

This  material  can  hardly  be  considered  a fuel  and  in  fact  is  pre- 
pared and  sold  for  foundry  facings.  Though  the  analyses  given 
are  supposed  to  be  from  a continuation  of  the  same  bed  or  carbona- 
ceous zone  as  that  which  is  being  mined  at  Cranston  for  coal,  the 
material  at  the  Fenners  Ledge  appears  to  have  been  much  more 
squeezed  than  that  at  the  Budlong  mine,  which  doubtless  accounts 
for  its  more  graphitic  character  as  well  as  its  higher  percentage 
of  ash.  At  this  point,  as  shown  in  figure  1 (p.  19)  and  Plate  IV 
(p.  18),  the  bed  is  as  irregular  as  most  metalliferous  ore  bodies. 
At  the  G.  L.  Gross  mine,  to  the  south,  the  bed  appears  to  be  more 
regular,  and  mining  has  been  extended  about  200  feet  underground. 

REASON  FOR  LOW  HEAT  VALUE  OF  RHODE  ISLAND  COAL. 

Attention  has  already  been  called  to  the  high  ash  and  high  moisture 
content  of  Rhode  Island  coal.  In  safriple  9328,  as  given  in  the 
table  on  page  26,  the  ash  and  moisture  together  amount  to  33.27 
per  cent  of  the  coal,  practically  one- third  of  it.  In  sample  9329 
they  amount  to  33.14  per  cent;  in  sample  3330  to  54.45  per  cent, 
or  more  than  one-half,  and  so  on.  In  contrast  with  these  figures, 
the  Pocahontas  coal  shown  in  analysis  5456  (p.  31)  has  only  6.49 
97887°— Bull.  615—15 3 


34 


RHODE  ISLAND  COAL. 


per  cent  of  ash  and  moisture  together,  and  the  New  River  coal 
(analysis  5467,  p.  31)  has  only  5.31  per  cent.  Since  the  ash  and 
moisture  are  almost  if  not  entirely  inert  matter,  it  is  evident  that  if 
the  coal  is  made  up  of  two- thirds  coal  and  one- third  ash  and  moisture, 
it  can  have  only  two-thirds  the  heating  value  it  would  have  if  ail  coal. 

But  there  is  still  another  factor  involved.  If  comparison  is  made 
between  Rhode  Island  coal  and  other  coals  on  the  ash-free  and 
moisture-free  basis,  it  is  evident  that  there  is  still  a marked  difference. 
For  example,  none  of  the  Rhode  Island  coals  on  this  basis  reach  a 
heat  yield  of  14,000  British  thermal  units,  whereas,  of  the  competing 
coals  listed  none  go  under  14,800  and  the  best  average  16,000  British 
thermal  units.  In  other  words,  there  is  a difference  of  1,000  to  2,000 
British  thermal  units  in  the  heat  value  of  the  coaly  matter  or  pure 
coal.  The  cause  of  this  is  fairly  apparent  from  a further  study  of 
the  analyses.  It  was  noted  above  that  if  the  moisture  and  ash  are 
left  out  of  consideration,  Rhode  Island  coal  has  almost  exactly  the 
same  composition  as  Pennsylvania  anthracite;  that  is,  about  95  per 
cent  of  fixed  carbon  and  5 per  cent  of  volatile  matter.  Why,  then, 
do  they  not  have  the  same  relative  heating  power  ? 

If  a study  is  made  of  the  analysis  of  Pocahontas  coal  shown  in  the 
table  on  page  31,  sample  5456,  it  maybe  noted  that,  on  the  ash  and 
moisture  free  basis  the  fixed  carbon  is  81.44  per  cent  and  the  total 
carbon  89.88  per  cent.  Therefore,  8.44  per  cent  of  the  carbon  occurs 
in  combination  with  the  other  elements  of  the  coal.  When  Poca- 
hontas coal  is  heated  to  500°  C.,  about  two-thirds  of  the  gas  that  is 
given  off  (water  and  tar  having  been  separated  out)  is  composed  of 
carbon  and  hydrogen  compounds — about  one-sixth  is  hydrogen  and 
the  other  one-sixth  is  carbon  dioxide,  carbon  monoxide,  and  illumi- 
nants.  If  the  temperature  is  raised  to  1,000°  C.,  the  gas  is  two- 
thirds  hydrogen,  one-fourth  carbon  and  hydrogen  compounds,  and 
the  rest  carbon  dioxide,  carbon  monoxide,  and  illuminants.1  The 
hydrogen,  carbon  and  hydrogen  compounds,  carbon  monoxide,  and 
illuminants  are  combustible.  The  carbon  dioxide  is  not.  In  the 
specific  tests  to  which  reference  has  been  made  the  carbon  dioxide, 
ammonia,  and  water  of  constitution  which,  added  together,  make  up 
the  “ inert  volatile  matter,”  come  to  only  0.7  per  cent. 

Now,  1 pound  of  carbon  in  burning  to  carbon  dioxide  will  yield 
about  14,400  British  thermal  units.  If  81.44  per  cent  of  the  coal  is 
fixed  carbon,  the  fixed  carbon  in  a pound  of  Pocahontas  coal  like 
sample  5456  should  yield  11,727  British  thermal  units.  But  the  coaly 
matter  or  “pure  coal”  of  that  sample  is  credited  with  15,860  British 
thermal  units.  Evidently  the  remainder  must  come  from  the 
burning  of  the  volatile  matter.  As  we  have  seen,  the  volatile  matter 
consists  almost  entirely  of  carbon  and  hydrogen  in  combustible  form. 


Bur.  Mines  Bull.  1,  p.  39, 1910. 


CHARACTER  OF  THE  COAL. 


35 


So  much  of  the  hydrogen  as  will  come  off  in  combination  with  oxygen 
in  the  form  of  water — that  is,  an  amount  equal  to  one-eighth  of  the 
oxygen — is  deducted.  As  the  oxygen  amounts  to  3.45  per  cent, 
one-eighth  of  that  or  0.43  per  cent  may  be  subtracted  from  4.75  per 
cent  of  hydrogen,  leaving  4.32  per  cent  of  “available”  hydrogen, 
as  it  is  called.  Now,  0.0844  of  a pound  of  carbon,  the  amount  of 
carbon  in  the  volatile  matter  of  a pound  of  coal  under  consideration, 
will  yield  14,400  X 0.0844  or  1,215  British  thermal  units.  But 
1 pound  of  hydrogen  when  burned  to  water  yields  62,048  British 
thermal  units  and  0.0432  of  a pound  of  hydrogen,  the  amount  in  a 
pound  of  this  coal,  would  therefore  yield  2,680  British  thermal  units. 
The  2,680  and  the  1,215  British  thermal  units  added  to  the  11,727 
British  thermal  units  from  the  fixed  carbon  give  15,622  British 
thermal  units,  as  compared  with  15,860  obtained  in  the  calorimeter 
test.  As  a matter  of  fact,  certain  elements  affecting  the  result  have 
not  been  taken  into  consideration  in  the  above  computation. 

Similarly  the  analyses  of  anthracite  coal  from  Lackawanna  and 
Schuylkill  counties,  Pa.  (analyses  1245  and  5953  to  5956,  p.  30), 
show  that  apparently,  though  not  probably,  all  the  carbon  is  in  the 
form  of  fixed  carbon,  and  an  analysis  of  the  volatile  matter  may 
fail  to  show  any  hydrocarbons;  but  from  the  percentage  of  hydrogen 
and  oxygen  it  is  evident  that  there  is  still  a considerable  amount 
of  “available”  hydrogen  left.  For  example,  in  the  ash-free  and 
moisture-free  sample  of  anthracite  culm  from  Lackawanna  County 
(analysis  1245  (condition  3),  p.  30),  there  are  3.17  per  cent  of  hydrogen 
and  2.72  per  cent  of  oxygen.  As  one-eighth  of  2.72  per  cent  or  0.34 
per  cent  of  hydrogen  will  satisfy  the  oxygen,  2.38  per  cent  of  hydrogen 
is  left  for  burning.  But  0.0238  of  a pound,  the  amount  of  available 
hydrogen  in  a pound  of  that  coal,  will  yield  1,376  British  thermal 
units,  so  that  the  coal  shows  a heat  value  at  least  that  much  higher 
than  that  obtained  from  the  fixed  carbon  alone. 

In  Rhode  Island  coal,  as  shown  in  the  analyses  (pp.  26-28),  not  only 
is  all  the  carbon  apparently  in  the  form  of  fixed  carbon  but  all  the 
hydrogen  is  required  to  satisfy  the  oxygen,  leaving  none  “available” 
for  burning.  In  other  words,  on  the  face  of  it,  the  volatile  matter 
of  Rhode  Island  coal  does  not  appear  to  contain  any  combustible 
matter.  In  fact,  in  most  of  the  samples  there  is  not  enough  hydrogen 
to  satisfy  the  oxygen,  so  that  some  of  the  oxygen  may  be  united 
with  some  of  the  carbon  in  the  form  of  carbon  dioxide.  As  the 
fixed  carbon  is  determined  by  subtracting  from  100  the  ash,  moisture, 
and  volatile  matter,  and  is  therefore  liable  to  include  more  than 
the  carbon  (for  in  some  of  these  analyses  it  exceeds  in  amount  the 
total  carbon  in  the  coal),  it  is  probable  that  the  volatile  matter 
consists  mainly  of  water  and  carbon  dioxide  and  possibly  some  carbon 
monoxide. 


36 


RHODE  ISLAND  COAL. 


If  all  the  fixed  carbon  in  Rhode  Island  coal  were  burned  it  would 
yield  a higher  calorific  value  for  the  coal  than  is  actually  obtained, 
which  indicates  that  the  volatile  matter  of  that  coal  adds  nothing 
to  its  heat  value,  and  that  the  “ fixed  carbon”  contains  a small 
amount  of  noncombustible  matter  or  loses  some  heat  in  the  evapora- 
tion of  the  contained  water. 

In  brief,  though  the  small  amount  of  volatile  matter  in  Pocahontas 
coal  is  calculated  to  yield  about  one-fourth  the  heat  value  and  the 
volatile  matter  in  Pennsylvania  anthracite  is  calculated  to  yield 
about  one-tenth  the  heat  value,  the  volatile  matter  in  the  Rhode 
Island  coal  appears  to  add  little  or  nothing  to  the  heat  value,  which 


90 


c 

0) 

o 

i. 

© 

Cl. 

C 

O 

JO 

L 


80 


1 

•3  38-j 
>329 

/ 

-9328 

933! 

x = As  received 
o = Air  dried 
. • -Ash  and  moisture  free 

Numbers  are  those  of 
laboratory  samples 

933< 

1 v/4 

/93; 

6X9 

9335 

771 

337 

7771 

o/ 

o: 

932S 

(3fK 

’"771'i 

®932 

'72 

8 

77 

7Z£ 

3337 

77< 

j9p/ 

9379 

7 

77 

-7-7-rr» 

7700 , 

-fyr 

>337 

6 

93 

30  nJ( 

/ / / Ux 

fO  93 
9331 

>5 

336 

9336 

/ xg 

335 

9 

330* 

60 


50 


40 


6,000  7,000  8,000  9,000  10,000  11,000  12,000  13,000  14,000 

Heat  value  in  British  thermal  units 
Figure  3.— Chart  showing  relation  of  carbon  in  Rhode  Island  coal  to  fuel  value. 


seems  to  be  derived  entirely  from  the  fixed  carbon.  As  a matter 
of  fact,  the  calorific  value  of  Rhode  Island  coal  can  be  readily  com- 
puted within  probably  1 per  cent  by  multiplying  the  percentage  of 
fixed  carbon  by  144.  Thus,  if  the  percentage  in  one  one-hundredth 
of  a pound  be  multiplied  by  14,400,  it  will  be  found  to  be  generally 
a little  higher  than  the  actual  figure  obtained  in  the  calorimeter. 
Thus  in  sample  9328  (p.  26)  the  fixed  carbon  is  64.43,  and  0.6443  X 
14,400  gives  9,278  British  thermal  units,  as  compared  with  9,230 
obtained  in  the  calorimeter.  In  sample  9330  (p.  26)  the  fixed 
carbon  in  a pound,  0.4254,  multiplied  by  14,400  gives  6,025  British 
thermal  units,  as  compared  with  5,976  obtained  in  the  test.  In 
sample  9331  (p.  26)  the  fixed  carbon  should  yield,  by  the  above 
method  of  computation,  8,405  British  thermal  units,  whereas  the 
test  gave  8,528;  here  the  actual  value  is  slightly  above  the  value 


CHARACTER  OP  THE  COAL. 


37 


as  computed.  Figure  3 shows  the  relation  between  the  fixed  carbon 
and  the  British  thermal  unit  value  as  determined.  The  chart  shows 
first  that  the  fixed  carbon  of  the  coal,  whether  from  Portsmouth 
or  Cranston,  has  an  almost  uniform  heat  value  and  that  the  heat 
value  is  expressed  as  stated  above  by  a little  below  144  British 
thermal  units  for  each  per  cent  of  fixed  carbon  in  the  coal.  The 
line  expressing  the  average  ratio  as  drawn  has  the  ratio  1:143. 

BEHAVIOR  OF  RHODE  ISLAND  COAL  TOWARD  MOISTURE. 

The  presence  of  such  a high  percentage  of  moisture  in  so  hard  a 
coal  has  always  excited  a peculiar  interest.  In  this  connection  it 
was  pointed  out  by  Emmons  in  1884  that  the  Portsmouth  coal,  at 
least,  possessed  the  striking  peculiarity  of  quickly  taking  up  a large 
percentage  of  water  under  a moist  condition  of  the  atmosphere 
and  as  readily  parting  with  it  under  a drier  condition  of  the  atmos- 
phere. Emmons  describes  the  following  interesting  experiments 
conducted  by  Gooch : 1 

A sample  of  Portsmouth  coal,  * * * powdered  and  exposed  for  24  hours  in 
the  balance  room  during  the  prevalence  of  a northwest  wind,  contained  after  exposure 
water  amounting  to  0.65  per  cent  of  its  weight  when  dried  at  115°. 

Water 
(per  cent). 

The  dried  (at  115°  C.)  coal  took  up  during  24  hours’  exposure  in  the 
balance  room,  while  the  same  wind  was  blowing,  of  its  own 


weight 0. 15 

After  16  hours’  exposure  over  water  it  had  taken  up 8. 46 

After  24  hours’  exposure  over  water  it  had  taken  up 9.  72 

After  61  hours’  exposure  over  water  it  had  taken  up 12.  64 

After  85  hours’  exposure  over  water  it  had  taken  up 12.  67 

The  percentage  of  water  fell: 

After  24  hours’  exposure  over  H2S04  to 1.  38 

After  48  hours’  exposure  over  H2S04  to 54 

After  138  hours’  exposure  over  H2S04  to .64 


A similar  sample  was  wet  thoroughly,  dried  with  filter  paper,  and  exposed  24 
hours  in  the  balance  room  during  a northwest  wind.  Its  content  of  water  in  terms  of 
coal  dried  at  115°  C.  amounted  to  0.75  per  cent. 

Water 
(per  cent). 

A sample  of  the  drill  core  from  Portsmouth  (see  analyses  5,6,  and 
7,  p.  28),  moistened  thoroughly,  dried  with  paper,  and  exposed 
24  hours  during  a northwest  wind,  contained,  in  terms  of  mate- 


rial dried  at  115°  C 0.  81 

The  dried  coal  took  up  during  24  hours’  exposure  in  balance  room. . . 22 

It  took  up  over  water,  in  16  hours 8.  96 

It  took  up  over  water,  in  24  hours 10. 32 

It  took  up  over  water,  in  61  hours 12.  88 

It  took  up  over  water,  in  85  hours 13.  80 


1 Emmons,  A.  B.,  Notes  on  the  Rhode  Island  and  Massachusetts  coals:  Am.  Inst.  Min.  Eng.  Trans., 
vol.  13,  pp.  512-513,  1885. 


38  RHODE  ISLAND  COAL. 

The  coal  contained  of  water,  expressed  in  terms  of  itself  dried  at  115°  C.: 

Water 
(per  cent). 


After  24  hours’  exposure  over  0. 85 

After  48  hours’  exposure  over  H2S04 53 

After  138  hours’  exposure  over  H2S04 46 


A sample  of  the  same  piece,  exposed  in  the  balance  room  without  wetting,  contained 
of  water  0.72  per  cent  of  the  weight  of  the  coal  dried  at  115°  C. 

A sample  of  the  same  piece,  exposed  in  the  balance  room  without  wetting  or  drying 
in  the  air  bath,  contained  of  water,  expressed  in  terms  of  itself  dried  at  115°  C.: 

Water 
(per  cent). 


After  16  hours’  exposure  over  water 11.  45 

After  21  hours’  exposure  over  water 13. 26 

After  37  hours’  exposure  over  water 16.  77 

After  61  hours’  exposure  over  water 16.  91 

After  85  hours’  exposure  over  water 16.  87 

After  109  hours’  exposure  over  water 16. 85 

The  content  of  water  expressed  in  percentage  of  coal  dried  at  115°  C. : 

After  24  hours’  exposure  over  H2S04,  fell  to 1. 84 

After  48  hours’  exposure  over  H2S04,  fell  to 83 

After  138  hours’  exposure  over  H2S04,  fell  to 71 


For  the  sake  of  comparison,  a piece  of  Pennsylvania  anthracite  was  taken  from  the 
cellar  and  similarly  treated. 

As  it  came  from  the  bin  it  contained  of  water  4.69  per  cent  of  the  weight  of  the  coal 
dried  at  115°  C.: 

Water 
(per  cent) . 


Powdered  and  dried  at  115°  C.,  it  contained 4.  42 

After  26  hours’  exposure  over  water 5.  91 

After  75  hours’  exposure  over  water 6.  34 

After  144  hours’  exposure  over  water 5. 10 


A similar  piece  (i.  e.,  not  powdered),  exposed  over  water  without  previous  drying 
in  air  bath,  contained,  in  terms  of  weight  of  coal  dried  at  115°  C.: 

Water 
(per  cent.) 


After  30  hours’  exposure  over  water 5.  38 

After  80  hours’  exposure  over  water 5.  67 

After  150  hours’  exposure  over  water 5.  69 

After  23  days’  exposure  over  water 5. 38 

A piece  of  Cumberland  bituminous  coal  contained,  as  it  came  from 
the  bin  (the.  sample  was  powdered),  in  terms  of  the  coal  dried  at 

115°  C 1.38 

After  26  hours’  exposure  over  water 1.  98 

After  75  hours’  exposure  over  water 2.  06 

After  144  hours’  exposure  over  water 1.  95 


UTILIZATION  OF  RHODE  ISLAND  COAL. 

KINDS  OF  USE. 

Rhode  Island  anthracite  may  be  employed  for  household  use, 
steam  production,  metallurgic  work,  briquetting,  brick  burning,  arid 
similar  work,  the  manufacture  of  water  gas  or  producer  gas  for  use 
directly  or  for  power  production  to  be  transmitted  electrically  to 


UTILIZATION  OF  THE  COAL. 


39 


centers  of  distribution.  The  graphitic  portions  of  the  beds  may  be 
used  for  foundry  facings  and  furnace  linings. 

Its  suitability  for  building  chimneys  and  other  uses  had  been 
suggested  at  an  early  date,  as  indicated  in  Bryant’s  poem  “ A medi- 
tation on  Rhode  Island  coal.”  Its  successful  household  use  at  that 
time  (before  1832)  is  indicated  by  the  beginning  of  the  poem: 

I sat  beside  the  glowing  grate,  fresh  heaped  with  Newport  coal. 

That  the  difficulties  of  its  burning  had  been  fully  appreciated  are 
also  indicated  toward  the  end  of  the  poem,  where  he  says: 

Thou  shalt  be  coals  of  fire  to  those  that  hate  thee, 

And  warm  the  shins  of  all  that  underrate  thee; 

Yea,  they  did  wrong  thee  foully — they  who  mocked 
Thy  honest  face,  and  said  thou  wouldst  not  burn; 

Of  hewing  thee  to  chimney  pieces  talked, 

And  grew  profane,  and  swore,  in  bitter  scorn, 

That  men  might  to  thy  inner  caves  retire, 

And  there,  unsinged,  abide  the  day  of  fire. 

HOUSEHOLD  USE. 

Rhode  Island  coal  has  always  been  used  in  a small  way  for  house- 
hold heating  and  some  householders  are  said  to  have  used  it  for  40 
years  or  more.  Samuel  Sanford,  who  was  well  acquainted  with  the 
Portsmouth  mines  in  the  seventies,  says  that  Portsmouth  coal  was 
then  selling  at  the  mine  at  $3.50  a ton  and  that  a small  amount  was 
purchased  and  hauled  away  for  household  use,  but  that  90  per  cent 
of  the  people  living  in  the  neighborhood  preferred  to  burn  Pennsyl- 
vania anthracite,  costing  at  that  time  from  $5.50  to  $7.50  a ton.  This 
condition  has  apparently  prevailed  during  the  whole  history  of  the 
field. 

In  burning  the  coal  is  said  to  ignite  very  slowly  and  to  snap  vio- 
lently and  explode,  tending  to  throw  pieces  of  the  coal  out  of  the  fire, 
but  when  once  well  ignited  it  burns  very  much  like  anthracite  and 
gives  an  intense  heat.  The  ash  is  said  to  have  almost  the  same  bulk 
as  the  coal  and  as  a rule  to  fuse  and  clinker  badly.  The  intense  heat 
is  said  to  be  destructive  to  stoves  and  utensils  and  the  clinkering 
tends  to  destroy  the  grate  bars.  Probably  as  a result  of  this  rapid 
burning  it  is  said  to  burn  itself  out  quickly  and  to  require  much  more 
attention  in  firing  and  in  keeping  overnight  than  other  coals. 

It  is  said  that  by  breaking  the  coal  down  fine  and  carefully  screen- 
ing it  to  remove  dust  it  ignites  more  easily,  as  it  will  after  thoroughly 
drying,  which  also  prevents  the  snapping  of  the  coal  when  first 
heated. 

The  existence  of  films  of  graphite  in  the  coal  along  planes  of  slip- 
ping has  been  thought  to  be  partly  the  cause  of  the  slow  ignition  of 
the  more  graphitic  coal.  The  breaking  up  of  this  coal  aids  in  its 
ignition,  it  is  supposed,  by  allowing  freer  passage  of  the  heat. 


40 


RHODE  ISLAND  COAL. 


In  general,  as  compared  with  other  anthracites  and  bituminous 
coals,  as  shown  both  by  the  tests  in  the  laboratory  and  under  the 
furnace,  Rhode  Island  coal  has  only  from  70  to  80  per  cent  of  the  heat- 
ing power  of  other  anthracites  and  from  60  to  70  per  cent  of  the  heat- 
ing power  of  bituminous  coals  shipped  into  New  England.  Indeed, 
the  poorer  samples  of  Rhode  Island  coal  show  only  about  40  per  cent 
of  the  heating  efficiency  of  competing  coals.  This  fact,  together  with 
its  slower  ignition,  its  destructively  hot  fire,  and  the  fact  that  it 
yields  a maximum  of  eight  times  as  much  ash  as  competing  coals  and 
requires  more  frequent  attention,  fully  explains  its  unsuccessful  use 
for  household  heating  in  the  past.  It  is  the  misfortune  of  Rhode 
Island  coal  that  it  must  compete  with  the  best  coals  of  the  United 
States,  which  are  brought  into  its  market  by  boat  at  very  low  rates. 

At  least  two  attempts  have  been  made  to  briquet  Rhode  Island 
coal  commercially,  both  of  them  by  the  Zwoyer  process.  Appar- 
ently neither  attempt  proved  successful.  Whether  the  process  or  the 
binder  had  anything  to  do  with  the  lack  of  success  is  not  known.  It 
is  claimed  that  the  briquets  first  made,  in  1898,  fell  to  pieces,  owing 
to  the  binder  burning  out  before  the  coal  became  ignited,  and  the 
briquets  made  recently  are  said  to  have  yielded  dense  volumes  of 
smoke  and  soot  that  soon  clogged  the  flues  and  chimneys.  It  may 
be  doubted  whether  any  of  the  binders  in  common  use  to-day  will 
prove  satisfactory  in  the  household  stove,  in  which  the  temperature 
is  relatively  low  as  compared  with  that  of  the  furnaces  under  steam 
boilers  for  power.  Experiments  have  since  been  made  at  Ports- 
mouth, and  the  results  of  tests  by  the  Bureau  of  Mines  indicate  that 
it  will  be  possible  to  make  briquets  that  will  be  practically  smokeless 
and  that  will  stand  handling.  It  appears  possible  that  experiments 
will  develop  a process  of  making  briquets,  probably  with  some  admix- 
ture of  a high  gas  coal,  that  will  give  at  least  fairly  successful  results 
in  household  use. 

The  experiments  published  by  the  Bureau  of  Mines  were  made  at 
St.  Louis  in  1906  by  what  was  then  the  technologic  branch  of  the 
United  States  Geological  Survey.  No  test  was  made  of  Rhode 
Island  coal  alone,  but  two  tests  were  made  of  that  coal  mixed  with 
two  different  bituminous  coals  from  Pennsylvania  in  the  form  of 
briquets.  The  manufacture  and  character  of  the  briquets  is  described 
under  the  heading  “Briquetting  tests”  (pp.  .46-48).  The  tests  were 
made  on  a sectional  steam  boiler,  such  as  is  in  common  use  for  house 
heating.  The  detailed  results  of  these  tests  are  given  in  Bulletin  27  of 
the  Bureau  of  Mines.  The  economic  results  only  are  repeated  here. 
For  the  sake  of  comparison  there  are  also  given  the  results  obtained 
by  similar  tests  made  in  the  engineering  laboratory  of  the  University 
of  Illinois,  at  Urbana,  111.,  on  anthracite,  coke,  and  Pocahontas  coal. 


UTILIZATION  OF  THE  COAL 


41 


Results  of  tests  of  briquetted  fuels  in  home-heating  boilers  at  St.  Louis,  Mo.,  and 

TJrbana,  III. 


Test  number. 

Designation  of  fuel. 

Economic  resi 

Equivalent  evapo- 
ration from  and 
at  212°  F.  per 
pound  of  fuel. 

alts  (pounds). 

Fuel  per  hour  per 
100  square  feet  of 
radiating  surface 
(mean  load  car- 
ried during  test). 

As  fired. 

Dry. 

As  fired. 

Dry. 

St.  L.  47 

Pennsylvania  No.  15  (one-half)  and 

6.55 

6.94 

4.57 

4.57 

Rhode  Island  No.  1 (one-half). 

St.  L.  35 

Pennsylvania  No.  18  (one-half)  and 

7.13 

7.34 

4.19 

4.14 

Rhode  Island  No.  1 (one-half). 

Urb. 163  

Anthracite  

7.22 

7.88 

4.15 

3.99 

Urb.  185 

Coke  

7.98 

8.37 

3.75 

3.61 

Urb.  173  . 

Pocahontas 

8. 24 

8.98 

3.65 

3.58 

Efficiency  (per  cent). 

Fuel  at  $1  per  2,000 
pounds. 

Test 

number. 

Designation  of  fuel. 

Boiler  and 
furnace 
(dry-fuel 
basis). 

Plant 
(fuel  as 
fired 
basis). 

Cost  in 
cents  per 
100  square 
feet  of 
radiating 
surface 
per  hour 
(mean  load 
carried 
during 
test). 

Cost  (in 
cents)  of 
evaporating 
1,000 

pounds  of 
water  from 
and  at 
212°  F. 

St.  L.  47.... 

Pennsylvania  No.  15  (one-half)  and 
Rhode  Island  No.  1 (one-half). 

52.01 

49. 44 

0.2290 

7.64 

St.  L.  35.... 

Pennsylvania  No.  18  (one-half)  and 
Rhode  Island  No.  1 (one-half). 

52.24 

51.43 

.2100 

7.01 

Urb.  163.... 

Anthracite 

57.58 

54.91 

.208 

6.92 

Urb.  185.... 

Coke 

62.50 

61.44 

.188 

6.27 

Urb.  173.... 

Pocahontas 

57.60 

53.92 

.183 

6.07 

As  far  as  the  experiments  were  conducted  it  was — 

shown  that  the  pitch  binders  used  are  not  suitable  for  the  furnace  working  at  the  low 
temperatures  common  in  the  household  boiler,  as  they  volatilize  and  in  most  cases 
escape  unburned  or  were  deposited  on  the  surface  of  the  boiler.  This  coating  generally 
burned  off  once  or  twice  a day,  causing  a high  temperature  in  the  flue  and,  as  a con- 
sequence, danger  of  fire. 1 

A test  of  “treated  Rhode  Island  coal”  by  the  Bureau  of  Mines, 
though  not  conclusive,  failed,  it  is  said,  to  show  improvement  in  the 
burning  or  heating  qualities  of  the  coal. 

USE  IN  STEAM  RAISING. 

The  same  qualities  of  the  coal  that  are  shown  by  household  use 
are  evident  in  its  use  in  steam  raising.  (See  description  of  action  on 
grate  in  test  401,  p.  45.)  In  this  use  its  heat-giving  value  is  of  prime 
importance.  The  tests  of  the  calorimeter  show  Rhode  Island  coal  to 


1 Snodgrass,  J.  M.,  Fuel  tests  of  house-heating  boilers:  Univ.  Illinois  Bull.  31,  1909. 


42 


RHODE  ISLAND  COAL. 


have  from  40  to  80  per  cent  of  the  heating  value  of  competing  coals. 
A number  of  careful  commercial  tests  have  been  made,  for  one  of 
which  the  general  results  are  available. 

In  1874  a test  of  the  Cranston  coal  was  made  at  the  pumping 
station  of  the  Providence  Waterworks.  Unfortunately  a table  giving 
the  detailed  figures  for  the  run  has  been  lost,  but  the  report  which 
accompanied  the  table  is  still  available.  The  following  extracts 
from  the  report,  a copy  of  which  was  furnished  by  the  city  engi- 
neer’s office,  give  the  most  complete  and  satisfactory  demonstration 
of  the  steaming  qualities  of  the  coal  that  has  been  found.  The 
report  in  part  is  as  follows : 

CRANSTON  COAL. 

The  Cranston  coal  used  at  Pettaconset  is  a lusterless  anthracite,  containing  graphite, 
quartz,  and  traces  of  asbestos  and  sulphur  among  its  impurities.  It  yields  about  26 
per  cent  of  ash.  Its  specific  gravity  is  2.30  and  weight  64.75  pounds  (?  133.75  pounds) 
to  the  cubic  foot.  Its  evaporation  power  is  about  7.76  pounds  of  water  from  and  at 
212°  per  pound  of  coal,  which  is  the  same  as  6.6  pounds  of  water  from  60°  to  steam  at 
60  pounds. 

The  Lackawanna  coal  is  a brilliant  anthracite,  containing  about  18  per  cent  of  ash. 
Its  specific  gravity  is  1.60  and  weighs  52.82  pounds  (?  99.8  pounds)  to  the  cubic  foot. 
Its  evaporative  power  is  about  10.74  pounds  of  water  from  and  at  212°  per  pound  of 
coal,  which  is  the  same  as  9.10  pounds  of  water  from  60°  to  steam  at  60  pounds. 

The  evaporative  power  of  the  Cranston  coal  is  therefore  about  72  per  cent  of  the 
Lackawanna. 

The  following  explanation  of  the  lost  table  is  given: 

Line  7.  Rate  of  delivery  is  based  upon  the  number  of  strokes  during  the  run  or 
experiment,  length  of  stroke  as  observed,  and  a deduction  of  2J  per  cent  from  the 
theoretical  discharge  of  the  pump.  This  percentage  of  loss  is  established  by  repeated 
weir  measurements  during  former  experiments.  * * * 

Line  22.  The  rate  of  combustion  is  based  on  the  coal  used  during  the  experiment. 

Line  23.  In  making  up  the  total  amount  of  fuel  used  during  the  day  a small  amount 
of  coke  was  charged  as  Lackawanna  coal,  and  the  wood  as  equal  to  one-half  its  weight 
of  coal. 

Lines  24  and  25  are  placed  in  juxtaposition  to  show  the  large  amount  of  coal  used 
in  banking. 

Line  26.  The  percentage  of  ash  is  made  up  from  the  total  fuel  used  during  the  day. 
It  was  dampened  and  weighed  wet  and  so  given  in  the  table.  The  Lackawanna  ash 
was  found  to  weigh  78  per  cent  of  the  recorded  weight  when  dry.  The  Cranston  ash 
95£  per  cent. 

Lines  27  and  28.  The  water  evaporated  per  pound  of  coal  or  combustible  is  based 
on  the  fuel  recorded  during  the  run  or  experiment,  and  is  probably  too  large  by  so 
much  as  the  coal  charged  to  the  run  is  too  little. 

The  figures  previously  given  as  the  evaporative  power,  viz,  7.76  and  10.74,  are  a 
mean  of  the  quantity  evaporated  during  the  run  and  during  the  day  per  pound  of 
combustible.  The  water  was  measured  with  a meter,  said  meter  being  tested  before 
and  after  the  experiment  and  proper  correction  made. 

Line  29  is  added  as  a check  upon  the  quantity  of  water  used  during  the  different 
days.  It  will  be  observed  that  it  was  nearly  uniform. 

Line  30.  The  length  of  stroke  is  a mean  of  quarter-hourly  observations. 


UTILIZATION  OP  THE  COAL. 


43 


Line  31 . The  duty  is  based  upon  the  theoretical  discharge  of  the  pump  and  the 
static  head.  While  this  does  not  give  the  engine  full  credit  for  its  work  for  this 
trial,  it  was  considered  the  least  liable  to  error.  It  may  be  added , however,  that  other 
experiments  have  shown  the  friction  head  for  pump,  main,  and  check  valves  to  be 
about  3.9  per  cent  of  static  head.  * * * 

Line  35  is  given  to  show  the  relative  duty  based  upon  the  coal  used  during  the 
day  or  week,  which  is  probably  the  truest  criterion  of  the  value  of  the  coal.  Line 
32,  on  column  R,  is  taken  as  unity  as  a fair  standard  of  comparison. 

It  will  be  observed  that  columns  M and  N show  the  value  of  the  Cranston  coal 
about  72  per  cent  of  the  Lackawanna. 

Line  36  makes  the  basis  of  comparison  with  the  water  evaporated  daily,  but  a 
mean  was  obtained  as  previously  explained,  viz,  72  per  cent,  which  seems  to  agree 
with  the  duty,  as  it  should. 

About  10  per  cent  of  Lackawanna  coal  and  a small  portion  of  coke  was  used  with 
the  Cranston  coal,  to  aid  the  fire  when  burning  irregularly  on  the  grate.  Less  of 
this  was  used  as  experience  was  gained  in  its  use.  It  is  probable  that  with  care  and 
skill  no  other  coal  need  be  used  in  connection  with  it.  A large  loss  was  due  to  the 
small  coal,  partially  burned,  falling  through  the  grate;  although  an  occasional  effort 
was  made  to  sift  it  and  reuse  it,  no  practical  gain  was  made. 

It  was  thought  that  a slower  rate  of  combustion  would  be  favorable  to  the  coal, 
and  permission  was  given  to  the  agent  for  the  coal  to  burn  it  slower.  January  28th 
and  29th,  it  will  be  observed,  it  was  reduced  a little,  and  a slight  increase  of  duty 
obtained;  but  it  seems  that  this  diminished  rate  of  combustion  as  recorded  is  prob- 
ably in  part  due  to  screenings  of  small  coal  deducted  from  the  coal  charged  and  also 
deducted  from  the  ash,  thus  reducing  the  ash  very  much  for  those  two  days,  but 
increasing  it  proportionately  the  next  day.  However,  a slight  increase  of  duty  is  seen 
for  the  10-days’  run,  where  the  rate  of  combustion  is  10.16  pounds  of  coal  per  square 
foot  of  grate  per  hour  over  the  first  week’s  run,  where  it  was  10.56  pounds. 

As  it  was  the  effort  of  the  agent  to  keep  the  engine  up  to  the  usual  speed,  and  with 
very  good  result,  it  was  necessary  to  increase  the  rate  of  combustion  over  the  usual 
rate,  viz,  7.30  pounds,  in  order  to  effect  it.  It  seems  very  probable  that  a slower 
rate  than  was  used  would  be  advantageous. 

Steaming  tests  of  Rhode  Island  coal  from  Cranston  have  been 
made  by  the  United  States  Geological  Survey  and  the  Bureau  of 
Mines  on  the  coal  alone  and  briquetted  with  other  high  volatile  coals. 
Results  of  these  tests  are  as  follows: 

RHODE  ISLAND  NO.  I.1 

Anthracite  graphitic  coal  from  Cranston,  Providence  County  (near  Providence), 
was  designated  Rhode  Island  No.  1.  This  sample  was  mined  from  surface  workings 
at  Cranston  and  commercially  would  be  classed  as  run-of-mine  coal.  It  was  shipped 
under  the  inspection  of  J.  S.  Burrows  and  was  used  in  making  steaming  test  401; 
also  mixed  with  Utah  No.  1 in  steam  tests  (on  briquets)  414  and  415,  coking  tests 
141  and  157,  and  briquetting  test  127;  mixed  with  Utah  No.  2 in  steaming  test  416 
(on  briquets)  and  briquetting  test  133;  mixed  with  Pennsylvania  No.  15  in  briquet- 
ting test  184;  and  mixed  with  Pennsylvania  No.  18  in  briquetting  test  243. 

i Holmes,  J.  A.,  in  charge,  Report  of  the  United  States  fuel-testing  plant  at  St.  Louis,  Mo.:  U.  S. 
Geol.  Survey  Bull.  332,  pp.  223-224,  1908. 


44 


RHODE  ISLAND  COAL. 


Chemical  analyses  of  Rhode  Island  No.  1. 


Car  sam- 

Steaming tests.** 

ple.® 

401 

414 

415 

416 

Laboratory  No 

3216 

Air-drying  loss 

2.00 

Proximate: 

Moisture 

2. 41 

2.33 

2.45 

2.27 

5.85 

Volatile  matter 

4.92 

2. 47 

24.21 

22. 20 

25.20 

Fixed  carbon 

73. 61 

78. 72 

62.60 

65.29 

59. 56 

Ash 

19. 06 

16.48 

10.74 

10. 24 

9. 39 

Sulphur 

.07 

.08 

.41 

.41 

.85 

Ultimate: 

Hydrogen 

.90 

.67 

2.95 

3. 13 

2. 94 

Carbon 

75. 10 

79. 49 

78.63 

77.64 

76.42 

Nitrogen 

.17 

.18 

.74 

.74 

.73 

Oxygen 

4.70 

2. 71 

6.25 

7.59 

9.04 

Ash 

16. 87 

11.01 

10.48 

9. 97 

Sulphur 

.08 

.42 

.42 

.90 

Calorific  value  (as  received): 

Determined- 

Calories  

6,109 
10, 996 

British  thermal  units 

Calculated  from  ultimate  analysis — 

Calories 

6, 176 
11,117 

British  thermal  units 

a Sample  from  producer-gas  test  113  (failure)  treated  as  car  sample. 

b Proximate  analysis  of  fuel  as  fired;  ultimate  analysis  of  dry  fuel  figured  from  car  sample. 


Steaming  tests  of  Rhode  Island  No.  1 {briquets). 


Test  401. 

Test  414. 

Test  415. 

Test  416. 

Duration  of  test 

...hours.. 

8.05 

5. 0 

5.0 

10.02 

Heating  value  of  fuel B.  t.  u.  per  pound  dry  fuel. .. 

11,639 

12,845 

12,823 

12,244 

Force  of  draft: 

Under  stack  damper inch  water. . 

0.54 

0.67 

0.62 

0.58 

Above  fire...! : 

.18 

.21 

.06 

.20 

Furnace  temperature 

°F. . 

(®) 

2,119 

2.053 

Dry  fuel  used  per  square  foot  of  grate  surface,  per  hour . 

. .pounds.. 

20.22 

18.42 

19.01 

21.51 

Equivalent  water  evaporated  per  square  foot  of  water-heatmg 

surface  per  hour 

1.99 

2. 96 

3.25 

2.78 

Percentage  of  rated  horsepower  of  boiler  developed . . 

55.8 

83.0 

91.0 

78.0 

W ater  apparently  evaporated  per  pound  of  fuel  as  fired . pounds . . 

4. 19 

6.75 

7. 17 

4.26 

AVater  evaporated  from  and  at  212°  F.: 

Per  pound  of  fuel  as  fired 

..pounds.. 

4.81 

7.86 

8.36 

4.95 

Per  pound  of  dry  fuel 

....do.... 

4.93 

8.05 

8. 55 

5.26 

Per  pound  of  combustible 

do 

7. 70 

9.35 

9.75 

7.70 

Efficiency  of  boiler,  including  grate 

.per  cent. . 

40.91 

60.52 

64.39 

41.49 

Fuel  as  fired: 

Per  indicated  horsepower  hour 

5.88 

3.60 

3.38 

5.71 

Per  electrical  horsepower  hour 

....do.... 

7.26 

4.44 

4.18 

7.05 

Dry  fuel: 

Per  indicated  horsepower  hour 

....do.... 

5.74 

3.51 

3.31 

5.38 

Per  electrical  horsepower  hour 

1 

do 

7.08 

4.34 

4.08 

6.64 

® Too  low  to  be  read  with  Wanner  optical  pyrometer.  Forced  draft  used  on  this  test. 


Remarks:  Tests  414  and  415  on  briquets  made  from  Rhode  Island  No.  1 and  Utah 
No.  1 mixed.  The  briquets  burned  freely,  with  short,  yellow  flame;  did  not  crack 
open,  but  coked  throughout  and  held  together  well.  No  smoke;  burned  very  much 
like  anthracite,  except  for  color  of  flame.  These  comparative  tests  on  Rhode  Island 
coal  No.  1 gave  only  55.8  per  cent  capacity  and  were  unsatisfactory.  (See  test  401 
above.)  Heavy  clinker,  which  was  tough  and  plastic  when  hot  and  brittle  when 
cold,  but  did  not  stick  to  the  grate. 

Test  416  on  briquets  from  test  133,  made  from  Rhode  Island  No.  1 and  Utah  No. 
2 mixed.  With  natural  draft  the  briquets  burned  with  a very  short  flame;  with 
forced  draft  they  burned  with  a longer  flame,  giving  a hotter  fire.  Briquets  did  not 
coke  or  hold  together  well  in  the  fire.  No  smoke;  see  briquetting  test  127  for  com- 
parative data.  No  clinker;  a large  amount  of  ash  resulted,  due  to  the  crumbling 
of  the  briquets  and  the  falling  of  the  loose  particles  through  the  grate. 


UTILIZATION  OF  THE  COAL. 


45 


In  Bulletin  23  of  the  Bureau  of  Mines  the  following  additional 
data  are  given  on  page  179  for  test  401  and  on  page  191  for  tests 
414  to  416: 

Test  No.  401  (No.  1). — The  coal  burned  slowly,  with  a short,  bluish  flame.  It 
became  hot  and  fused  together,  cutting  off  the  air  supply  through  the  grate.  Hooking 
the  fire  helped  slightly.  Small  pieces  of  coal  burned  more  completely  than  large 
ones.  About  three-fourths  inch  coal  would  be  the  best  size  for  steaming  purposes. 
Large  pieces  burn  only  on  the  surface,  because  the  ash  fuses  and  adheres  to  the  coal, 
thus  insulating  the  inner  portion.  Low  capacity  was  developed,  owing  to  the  fact 
that  high  enough  draft  could  not  be  obtained  with  the  fan  blower.  In  order  to  develop 
the  rated  capacity,  a draft  of  3 to  4 inches  of  water  would  be  necessary.  A rocking 
grate  would  be  preferable  to  a flat  grate.  Pressure  was  used  in  the  ash  pit.  Auto- 
matic air  admission  was  not  operated.  The  furnace  temperature  was  too  low  to  be 
read  by  the  Wanner  optical  pyrometer. 

Test  No.  414  (briquets). — One-quarter  of  the  observations  of  furnace  temperature 
were  too  low  to  be  read  by  the  Wanner  optical  pyrometer.  The  average  is  not  repre- 
sentative of  the  test.  The  briquets  did  not  crumble  in  the  fire  and  burned  with  a 
short  flame.  Automatic  air  admission  was  not  operated.  A heavy  layer  of  plastic 
clinker  formed  on  the  grate.  It  was  broken  with  some  difficulty. 

Test  No.  415  (briquets). — The  briquets  did  not  crumble  in  the  fire  and  burned  with 
a short  flame.  Automatic  air  admission  was  not  operated.  A heavy  layer  of  plastic 
clinker  formed  on  the  grate.  It  was  broken  with  some  difficulty.  Forced  draft  was 
used. 

Test  No.  410  (briquets). — The  briquets  crumbled  in  the  fire,  did  not  cake,  and 
burned  with  a long  flame.  Automatic  air  admission  was  not  operated.  A large 
amount  of  free  ash  formed  on  the  grate.  It  was  easily  removed.  Forced  draft  was 
used. 

For  the  sake  of  comparison  there  are  given  below  figures  from 
the  tests  by  the  Bureau  of  Mines  at  St.  Louis,  Mo.,  and  at  Norfolk, 
Va.,  showing,  first,  the  horsepower  developed  and,  second,  the  pounds 
of  water  evaporated  per  pound  of  fuel  of  Rhode  Island  coal  on  the 
one  hand  and  of  some  of  the  competing  coals  on  the  other. 

Results  of  steaming  tests  by  the  Bureau  of  Mines  on  Rhode  Island  coal  and  other  coals  that 
are  shipped  into  New  England. 


Bureau  of  Mines 
designation. 

Coal. 

Location. 

Kind  of 
sample. 

Horse- 
power 
developed 
on  test. 

Pounds  of 
water 
evaporated 
per  pound 
of  fuel 
equivalent 
from  and 
at  212°  F. 

490  Md.  No.  2 

Georges  Creek 

Frostburg 

Rim  of  mine . . 

239.2 

9. 87 

237  Pa.  No.  8 

Cambria  County. . 
Anthracite  culm . . 

Ehrenfeld 

do 

174.2 

9.85 

36  Pa.  No.  3 

Scranton 

Culm 

184.5 

8. 01 

401  R.  I.  No.  1 

do 

Cranston 

117. 1 

4. 81 

46  W.  Va.  No.  12 

Pocahontas  No.  8. . 

Big  Sandy 

Rim  of  mine . . 

206.1 

9.  74 

56W.Va.  No.  11 

Pocahontas  No.  3. . 

Zenith 

do 

213.7 

9.54 

39  W.  Va.  No.  6 

New  River 

Rush  Run 

do 

213.2 

9. 88 

296  W.  Va.  No.  21 

Kanawha 

Winifrede 

do 

213.8 

9.69 

414  Utah  No.  1 and  R.  I. 

Mixed 

Briquets 

174.3 

7.86 

No.  1. 

415  Utah  No.  1 and  R.  I. 

do 

do 

191.2 

8.36 

No.  1. 

416  Utah  No.  2 and  R.  I. 

do 

do 

163.7 

4.95 

No.  1. 

46 


RHODE  ISLAND  COAL. 


According  to  these  figures,  Rhode  Island  coal  alone  yields  from  54 
to  68  per  cent  as  much  horsepower  as  the  other  coals  listed  and  from 
48  to  60  per  cent  as  many  pounds  of  water  evaporated  per  pound  of 
fuel.  Lest  it  be  thought  that  the  highest  figures  have  been  selected 
for  the  competing  coals,  it  may  he  mentioned  that  in  other  tests 
Pocahontas  coal  developed  horsepower  as  high  as  268  and  New  River 
coal  as  high  as  367.  As  20  tons  of  coal  was  used  and  every  effort  was 
made  that  the  coal  should  be  representative  of  that  being  regularly 
mined,  the  results  may  be  accepted  as  accurate.  As  the  car  sample 
analysis  of  this  coal  (p.  44)  shows  it  to  have  been  above  rather  than 
below  the  average,  it  may  be  safely  stated  that,  judged  by  analyses, 
calorimeter  tests,  and  tests  in  actual  practice,  Rhode  Island  coal  in 
making  steam  will  yield  from  40  to  80  per  cent  as  many  heat  units  as 
the  coals  with  which  it  must  compete  to-day. 

USE  IN  METALLURGY. 

Rhode  Island  coal  has  been  used  successfully  in  the  reduction  of 
copper  ore  and  in  the  metallurgy  of  iron,  as  already  stated  under  the 
heading  “ History  of  development.”  At  the  time  of  its  successful 
use  anthracite  coal  was  used  in  the  blast  furnace  and  the  furnaces 
were  much  smaller  than  at  present.  To-day  coke  has  been  substi- 
tuted for  anthracite  and  is  being  used  exclusively.  The  furnaces 
have  been  enlarged  both  in  size  and  output.  No  figures  are  at  hand 
which  would  form  the  basis  for  a comparison  of  the  availability  of 
Rhode  Island  anthracite  as  compared  with  coke  in  the  modern  fur- 
nace, but  a general  consideration  of  the  reasons  for  the  use  of  coke 
in  the  modern  furnace  and  its  cost  would  suggest  that  Rhode  Island 
coal  could  not  compete  with  coke  either  in  cost  or  availability.  It 
is  quite  possible  that  for  foundry  use  and  in  small  reheating  furnaces, 
under  certain  conditions,  it  might  be  still  possible  to  use  Rhode  Island 
coal  in  spite  of  the  cost. 

BRIQUETTING  TESTS. 

In  addition  to  the  actual  commercial  tests  of  Rhode  Island  coal 
when  made  into  briquets,  the  Bureau  of  Mines  has  made  a number 
of  briquetting  tests  with  that  coal.1  The  analyses  of  the  coal  used, 
both  alone  and  mixed,  will  be  given  first,  as  none  of  the  tests 
were  made  on  the  Rhode  Island  coal  alone.  Rhode  Island  No.  1 
was  from  Cranston;  Pennsylvania  No.  15  was  B or  Miller  coal  from 
Wehrum,  Indiana  County;  Pennsylvania  No.  18  was  the  same  coal 
from  Lloydell,  Cambria  County;  Utah  No.  1 was  from  Huntington 
Creek,  Carbon  County;  Utah  No.  2 was  from  Coalville,  Summit 
County. 


Holmes,  J.  A.,  op.  cit.,  pp.  201  et  seq. 


UTILIZATION  OF  THE  COAL. 


47 


Analyses  of  coals  used  in  briquetting  tests. 


R.I. 
No.  1, 
car 
sam- 
ple. 

Pa. 

No.  15, 
car 
sam- 
ple. 

Pa. 

No.  18, 
car 
sam- 
ple. 

Utah 
No.  1, 
car 
sam- 
ple. 

Utah 
No.  2, 
car 
sam- 
ple. 

Half 
R.I. 
No.  1, 
half 
Pa. 

No.  15. 

Half 
R.  I. 
No.  1, 
half 
Pa. 

No.  18. 

Half 
R.  I. 
No.  1, 
half 
Utah 
No.  1. 

Half 
R.I. 
No.  1, 
half 
Utah 
No.  2. 

3216 

4082 

4509 

3199 

3259 

4913 

2.00 

2. 80 

4.10 

3.80 

2.30 

Proximate: 

Moisture 

2.41 

3.13 

4.46 

6. 05 

12.66 

0.74 

1.34 

2.45 

5. 85 

Volatile  matter 

4.92 

17. 61 

15.44 

42.02 

38.30 

15.96 

16.39 

24.21 

25.20 

Fixed  carbon 

73.61 

69.45 

71.63 

47.06 

43.19 

69. 71 

70.34 

62. 60 

59.56 

Ash 

19.06 

9.81 

8.47 

4.87 

5.85 

13.59 

11.93 

10.74 

9.39 

Su  phur 

.07 

3.77 

1.49 

.55 

1.39 

2. 61 

1.37 

.41 

.85 

Ultimate: 

Hydrogen 

.90 

4.62 

4.80 

5. 76 

3.05 

3.46 

2.95 

2.94 

Carbon 

75. 10 

76.41 

77.43 

72. 32 

77.48 

77.79 

78.63 

76.42 

Nitrogen 

.17 

1.14 

11.28 

1.38 

.49 

.53 

.74 

.73 

Oxygen 

4.70 

4.25 

6. 53 

15. 12 

2.C5 

4.74 

6.25 

9.04 

Ash 

13.  70 

12. 09 

11.01 

9.97 

Sulphur 

2. 63 

1.39 

.42 

.90 

Calorific  value  (as  received) : 

Determined- 

Calories 

6,109 

7,664 

7,601 

7, 306 

British  thermal  units 

10,996 

13, 795 

13,682 

13, 151 

Calculated  from  ultimate 

analyses — 

Calories 

6,176 

7,189 

British  thermal  units 

11,117 

12,940 

The  briquets  are  thus  described.  (See  also  pp.  43-44.) 

Test  184- — Pennsylvania  No.  15  was  mixed  with  an  equal  portion  of  Rhode  Island 
No.  1 (run  of  mine)  in  this  test.  Excellent  briquets  were  made  with  6.25  per  cent 
binder  on  the  Renfrow  machine.  Although  the  pitch  used  had  a low  melting  point, 
the  briquets  handled  well  from  the  machine,  and  piled  without  sticking.  The  outer 
surface  was  very  hard  and  smooth,  and  broke  without  crumbling,  giving  a smooth 
fracture  and  sharp  edges. 

Test  243. — Equal  parts  of  Pennsylvania  No.  18  and  Rhode  Island  No.  1,  both  run 
of  mine.  An  effort  was  made  to  improve  the  burning  qualities  by  increasing  the 
melting  point  of  the  binder,  but  owing  to  the  hardness  of  the  pitch  used  and  insuffi- 
cient pressure,  these  briquets  were  not  satisfactory.  They  could  not  be  handled  when 
warm  without  many  being  broken,  but  when  cold  were  brittle,  producing  considerable 
slack  in  handling.  No  physical  tests  were  made. 

Test  127  (Utah  No.  1 with  Rhode  Island  coal  No.  1). — This  test  was  made  to  prove 
the  value  of  briquetting  a good  fuel  with  one  that  is  commercially  worthless.  A high- 
volatile  coal,  low  in  ash,  was  chosen  to  mix  with  the  graphitic  coal.  Various  percent- 
ages were  tried,  but  47  per  cent  of  each  coal  and  6 per  cent  binder  made  an  entirely 
satisfactory  briquet.  Six  per  cent  binder  made  excellent  briquets;  outer  surface 
smooth  and  polished  and  very  hard;  briquets  broke  without  crumbling,  and  broken 
surfaces  were  smooth  and  hard. 

Test  133  (Utah  No.  1 and  Rhode  Island  No.  1). — In  this  test  Rhode  Island  No.  1, 
the  only  available  high- volatile  (carbon?)  coal,  was  chosen  in  order  to  supplement  the 
data  of  test  127.  Test  133  was  not  successful,  as  coal  showed  characteristics  of  lignite, 
both  in  briquetting  and  burning.  The  mixture  contained  47  per  cent  of  each  coal. 
Briquets  with  6 per  cent  binder  were  tough  and  hard ; outer  surface  smooth  and  very 
hard;  the  fracture  rough  but  clean  and  firm.  No  drop  tests  were  made. 


48 


RHODE  ISLAND  COAL. 


The  tests  of  the  briquets  gave  the  following  results: 

Results  of  tests  of  briquets. 


Size  as  used: 

Over  one-fourth  inch 

One-tenth  to  one-fourth  inch 

One-twentieth  to  one-tenth  inch. . 
One-fortieth  to  one-twentieth  inch 

Under  one-fortieth  inch 

Details  of  manufacture: 

Machine  used 

Temperature  of  briquets 

Binder — 

Kind 

Laboratory  No 

Amount 

Weight  of— 

Fuel  briquetted 

Briquets,  average 

Ileat  value  per  pound — 

Fuel  as  received 

Fuel  as  fired 

Binder 

Drop  test  (1-inch  screen): 

Held 

Passed 

Tumbler  test  (1-inch  screen): 

Held 

Passed  (fines) 

Fines  through  10-mesh  sieve 

Weathering  test: 

Time  exposed 

Condition 


a Pennsylvania  No.  15. 


per  cent 

do.. 

do.. 

do.. 

do.. 


°F 


.per  cent 

.pounds 
— do.. 


.per  cent 
— do.. 

.per  cent 
do.. 


.days 


Test  184. 

Test  243. 

Test  127. 

Test  133. 

0.8 

1.0 

1.0 

1.2 

7.0 

6.8 

5.8 

6.0 

15.0 

17.6 

9.4 

19.2 

22.2 

25.2 

26.4 

25.6 

55.0 

49.4 

57.4 

48.0 

Renf. 

Renf. 

Renf. 

Renf. 

185 

185 

149 

149 

w.  g.  p. 

w.  g.  p. 

w.  g.  p. 

w.  g.  p. 

4543 

4625 

3410 

3410 

6.25 

8.0 

6 

6 

10,000 

2,000 

16,000 

37,000 

0.5 

0.5 

0.52 

fa  13, 712 

b 13,682 

\c  10,996 

c 10,996 

12,259 

11,032 

12, 793 

13,387 

12,532 

11,527 

16,969 

16,576 

16,478 

16,478 

68.5 

31.5 

93.0 

7.0 

91.4 

11 

214 

190 

A 

B 

C 

b Pennsylvania  No.  18.  c Rhode  Island  No.  1. 


In  these  descriptions  Renf.  refers  to  the  Renfrow  machine;  w.  g.  p. 
is  water-gas  pitch;  the  drop  test  consisted  in  dropping  50  pounds 
of  the  briquets  in  a box  a distance  of  6J  feet  onto  an  iron  plate, 
screening  each  time  what  would  go  through  a 17-mesh  wire  screen. 
In  the  tumbler  test  50  pounds  were  revolved  in  the  Opermayer  tum- 
bler 56  times  and  then  screened  through  1-inch  and  -^inch  mesh 
screens.  Under  “ Weathering  test/’  A means  unchanged;  B,  shape 
unchanged,  surface  pitted  or  dulled  or  edges  worn;  C,  outside 
briquets  weathered,  fracture  not  sharp. 

House-heating  tests  were  made  for  briquets  described  in  tests  184 
and  243  and  steaming  tests  from  briquets  made  in  tests  127  and  133. 
These  have  been  described  under  the  headings  “House  heating”  and 
“Steam  raising.” 

BRICK  BURNING  AND  SIMILAR  WORK. 


The  use  of  this  coal  for  brick  burning  or  the  burning  of  limestone 
for  fertilizers  has  been  suggested.  In  this  work  the  broken  or  fine 
coal  is  placed  between  layers  of  brick  in  a kiln  or  between  layers  of 
limestone  when  burned  in  piles  in  the  fields.  The  writer  does  not 
know  of  such  use  having  been  made  of  the  coal  and  is  not  prepared 
to  predict  how  successful  it  would  be.  The  ash  apparently  would 


UTILIZATION  OF  THE  COAL. 


49 


not  be  a serious  detriment  in  such  use.  The  coal  might  also  be  used 
for  the  roasting  of  ores  and  in  other  work  where  the  ash  is  not  a serious 
detriment  and  high  heat  rather  than  long-continued  heat  is  desired. 

INDIRECT  USE  AS  WATER  GAS  OR  PRODUCER  GAS. 

There  has  been  a widespread  feeling  for  many  years  that  Rhode 
Island  coal  would  some  day  come  to  its  own  through  its  use  in  the 
production  of  water  gas  or  producer  gas  for  metallurgic  work,  or 
more  especially  for  use  in  the  gas  engine  in  the  production  of  electric 
power  to  be  used  for  manufacturing  near  the  mines  or  to  be  trans- 
mitted to  the  cities.  Its  possible  use  in  the  manufacture  of  water 
gas  was  mentioned  by  Shaler  in  1899,  who  says  “that  a test  of  a few 
tons  of  the  coal  had  been  made  in  the  manufacture  of  water  gas  and 
that  it  was  well  suited  to  the  purpose.”  1 It  has  been  thought 
that  a few  plants  situated  at  the  mines,  by  being  specially  designed 
and  specially  manned,  would  be  able  to  deal  with  the  peculiar  char- 
acteristics of  the  coal  satisfactorily  and  thus  take  advantage  of  its 
location  in  saving  transportation  costs. 

In  principle  producer  gas  is  made  by  forcing  air  through  a mass 
of  incandescent  coal  so  controlled  that  the  oxygen  of  the  air  finds 
a surplus  of  carbon  and  unites  to  form  carbon  monoxide  which  is 
combustible  and  passed  off  with  the  nitrogen,  which  is  inert,  the 
product  being  known  as  producer  gas.  In  the  manufacture  of  water 
gas  superheated  steam  is  used  in  place  of  the  air,  and  the  product 
consists  of  hydrogen  with  carbon  monoxide  instead  of  the  inert 
nitrogen.  Water  gas,  therefore,  yields  about  twice  as  many  heat 
units  as  the  same  quantity  of  producer  gas  or,  if  enriched,  from  four 
to  five  times  as  many.  Modern  practice  has  tended  toward  the  pro- 
ducer-gas plant  as  the  most  efficient  method  of  transforming  the 
power  of  the  coal  immediately  into  electric  power,  though  with  Rhode 
Island  coal  water  gas  may  prove  the  better  of  the  two. 

A number  of  tests  have  been  made  by  the  Bureau  of  Mines  on 
Rhode  Island  coal  in  the  producer-gas  plant.  Though  it  may  be 
conceded  that  future  tests  may,  and  doubtless  will,  lead  to  changes 
in  the  construction  of  the  producer-gas  plant  that  will  more  fully 
adapt  it  to  the  peculiar  behavior  of  Rhode  Island  coal  and  that  with 
such  an  improved  and  specially  devised  plant  better  results  would  be 
obtained,  yet  the  figures  here  quoted  may  be  accepted  as  fairly  indic- 
ative of  the  results  obtainable  with  present  forms  of  the  producer. 

The  results  of  the  producer-gas  tests  are  described  in  Bulletin  13 
of  the  Bureau  of  Mines,  and  because  of  the  interest  in  this  phase  of 
the  problem  the  results  of  the  tests  are  given  in  full. 

i Shaler,  N.  S.,  Woodworth,  J.  B.,  Foerste,  A.  F.,  Geology  of  the  Narragansett  Basin:  U.  S.  Geol. 
Survey  Mon.  33,  p.  84,  1899. 

97887°— Bull.  615—15 4 


50 


RHODE  ISLAND  COAL. 


The  coal  used  in  test  113  was  mined  from  the  Budlong  pit,  at 
Cranston,  under  the  supervision  of  J.  S.  Burrows. 

The  coal  for  tests  190  and  191  was  later  shipped  from  the  same 
pit  by  Budlong  & Son.  It  consisted  principally  of  small  lumps, 

1 or  2 inches  in  size,  and  a few  larger  lumps  were  broken  up  by  the 
hammer  before  firing  and  the  fine  material  was  screened  out.  Before 
making  this  test  a little  of  it  was  tried  in  the  blacksmith  forge  with 
the  following  result,  as  described  in  a preliminary  report:1 

Before  the  testing  was  started  a small  quantity  of  this  fuel  was  burned  in  a black- 
smith’s forge  in  order  to  note  any  special  characteristics  that  it  might  exhibit  while 
burning,  and  thus  aid  in  the  operation  of  the  producer  during  the  test.  On  the 
blacksmith’s  forge  it  was  very  slow  to  ignite,  but  when  well  ignited  it  burnt  very  much 
like  anthracite  and  gave  an  intense  heat.  When  first  fired,  it  snapped  violently  and 
frequently  small  lumps  of  coal  were  thrown  forcibly  from  the  fire.  After  burning  for 
about  half  an  hour  in  the  forge  there  was  a considerable  amount  of  slag  or  clinker 
about  the  consistency  of  thick  tar.  Upon  examination  this  slag  did  not  appear  to 
consist  entirely  of  fused  ash,  but  to  contain  quite  a portion  of  the  unburnt  fuel  in  the 
fused  state.  Although  the  conditions  in  the  blacksmith  forge  of  heavy  forced  draft 
were  unlike  the  conditions  that  would  exist  in  the  producer,  it  was  expected  that  the 
tendency  of  the  fuel  to  fuse  would  prevent  to  some  extent  its  more  successful  use  in 
the  producer. 

The  coal  for  test  194,  amounting  to  about  20  tons,  was  obtained 
from  the  Portsmouth  mine  under  the  supervision  of  C.  A.  Fisher,  of 
the  United  States  Geological  Survey.  It  was  taken  in  the  heading 
at  the  800-foot  level,  about *1,200  feet  south  of  the  slope.  At  this 
point  the  coal  was  being  mined  and  mining  had  extended  about  50 
feet  beyond  the  face  of  the  heading,  which  had  been  left  when  the 
mine  was  previously  abandoned.  The  coal  at  this  point,  as  described 
by  Mr.  Brown  2 — 

is  some  65  inches  thick,  showing  in  the  upper  and  lower  portions  of  the  coal  bed  some 

2 or  3 inches  of  graphitic  shaly  material,  which  probably  results  from  shear.  The  coal 
shows  a considerable  degree  of  purity,  excepting  near  the  middle  of  the  bed  where 
1^  or  2 inches  of  “bone”  with  quartz  and  later  pyrite  occur.  The  bedding  is  rather 
thin,  probably  one-half  inch,  but  in  some  cases  there  is  a thick  bed  of  some  8 inches 
of  massive  coal.  Throughout  the  bed,  increasing  toward  the  edges  of  the  roll,  there  occur 
numerous  offset  veins  of  quartz,  sometimes  reaching  a thickness  of  2 or  3 inches,  but 
penetrating,  in  a large  number  of  cases,  in  mere  shreds  and  veinlets  of  silica.  * * * 
No  run-of-mine  coal  could  be  taken  and  the  tests  therefore  are  made  upon  the  best 
coal  that  the  mine  can  produce. 

The  tests  are  described  as  follows : 3 

Rhode  Island  No.  1,  test  113. — Rhode  Island  No.  1 was  a graphitic  coal  having  a 
gray,  metallic  appearance.  Some  of  the  lumps  were  extremely  hard,  but  others  were 
soft.  This  material  was  charged  on  top  of  a good  fuel  bed  of  Tennessee  coal  capable 
of  making  a gas  of  average  quality.  As  the  charging  continued,  the  heat  value  of  the 

1 Preliminary  report  of  the  natural  resources  survey  of  Rhode  Island:  Rhode  Island  Bur.  Industrial 
Statistics  Bull.  1 (Ann.  Rept.  1909,  pt.  3),  p.  105, 1910. 

2 Idem,  pp.  95-96. 

a Bur.  Mines  Bull.  13,  pp.  199,  342-346,  349,  1911, 


UTILIZATION  OF  THE  COAL. 


51 


gas  steadily  decreased,  whereas  the  temperature  of  the  fuel  bed  increased.  After 
15  hours  the  calorimeter  would  not  work  because  of  the  low-heat  value  of  the  gas, 
which,  at  that  time,  was  about  55  British  thermal  units  per  cubic  foot.  Three  hours 
later  the  engine  stopped  and  subsequent  attempts  to  start  it  again  were  unsuccessful. 
* * ***** 

Pittsburgh  No.  19 A,  test  190. — The  fuel  used  during  this  test  was  a Rhode  Island 
graphitic  anthracite.  It  was  heavy  and  hard  and  a freshly  broken  surface  presented 
a glossy  appearance;  it  contained  a large  percentage  of  graphite  and  one  could  mark 
with  pieces  of  the  coal  as  readily  as  with  a pencil. 

Because  this  fuel  ignited  slowly  the  coke  bed  was  allowed  to  become  thoroughly 
incandescent  before  any  of  the  graphitic  coal  was  charged,  and  while  the  fuel  bed 
was  being  built  up  a maximum  draft  was  maintained.  About  an  hour  after  the  first 
charge  of  coal  was  made  the  gas  burned  steadily  at  the  test  cock,  and  although  it  was 
low  in  heat  value  the  engine  was  started.  After  running  about  30  minutes,  however, 
on  no  load  it  stopped,  due  to  the  poor  quality  of  the  gas.  After  the  engine  was  started 
the  draft  in  the  producer  decreased  considerably  on  account  of  the  small  amount  of 
gas  consumed  by  the  engine.  With  this  reduced  draft  the  fire  died  down  and  the  gas 
decreased  rapidly  in  heat  value.  Soon  after  the  engine  stopped  the  gas  was  discharged 
into  the  atmosphere,  and  with  a good  draft  the  fire  soon  began  to  improve;  the  gas, 
however,  was  of  unsatisfactory  quality  for  some  time.  The  engine  was  finally  started 
again,  and  in  order  to  maintain  a sufficient  draft  to  produce  combustible  gas  a portion 
of  the  gas  was  allowed  to  escape  through  the  purge  pipe.  During  the  remainder  of 
the  day  (about  hours)  the  producer  gave  no  trouble  and  a little  over  half  of  full  load 
was  maintained  at  the  engine.  At  the  close  of  the  day’s  run  the  producer  was  seem- 
ingly in  good  condition  for  the  night’s  shutdown.  The  fire,  however,  did  not  keep 
and  the  next  morning  it  was  necessary  to  rekindle  it  with  wood.  As  is  shown  by 
the  graphic  log,  the  results  obtained  were  more  satisfactory  after  the  first  day’s 
trial.  From  one  to  two  hours  each  morning  were  required  to  get  the  producer  in 
condition  to  generate  gas  of  sufficient  heat  value  to  start  the  engine,  and  at  the  close 
of  each  day ’s  run  the  fire  was  banked  with  a good  grade  of  coal  in  order  to  hold  it  over- 
night. Throughout  the  greater  part  of  the  test  also  a considerable  portion  of  the  gas 
was  necessarily  allowed  to  escape  to  the  atmosphere  in  order  to  maintain  the  required 
draft.  The  quantity  of  gas  thus  wasted  was  difficult  to  estimate,  and  for  this  reason 
little  value  can  be  attached  to  the  figures  given  in  the  table  on  page  357  [p.  53  of  this 
paper]  for  fuel  consumed  per  horsepower  hour,  since  no  allowance  for  this  waste  was 
made. 

Throughout  the  test  the  fuel  bed  increased  rapidly  in  thickness,  and  at  the  end  of 
the  fourth  day  the  producer  was  completely  filled  with  fuel  and  refuse.  One  of  the 
characteristics  of  this  graphitic  coal  is  that  its  ash  occupies  nearly  the  same  volume 
as  the  original  fuel.  The  resistance  of  the  fuel  bed  was  not  excessive  at  any  time  and 
few  shots  were  made.  Throughout  the  run  little  trouble  was  experienced  from  clinker, 
although  a considerable  quantity  formed  and  adhered  firmly  to  the  producer  walls. 

Pittsburgh  No.  19 A,  test  191. — A second  test  was  made  on  Pittsburgh  No.  19A  in  an 
attempt  to  reduce  the  waste  of  gas  and  thus  obtain  results  that  would  be  of  more  value 
than  those  obtained  from  test  190.  Instead  of  kindling  a fire  on  the  coke  bed,  as  in  the 
preceding  tests,  1,000  pounds  of  the  graphitic  coal,  making  a layer  1 foot  thick,  were 
first  charged  on  top  of  the  coke  in  the  producer,  and  then  the  fire  was  started  on  top  of 
this.  The  result  of  this  change  of  procedure  was  satisfactory;  gas  of  sufficient  heat 
value  to  run  the  engine  was  generated  in  about  an  hour  and  a quarter  from  the  time 
of  starting  the  fire,  and  at  the  end  of  the  test  practically  all  of  the  coke  was  recovered. 
During  the  first  three  hours  of  the  test  no  gas  was  discharged  into  the  atmosphere,  and 
consequently  there  was  no  waste;  but  at  the  end  of  this  period  the  fire  began  to  die 
out  and  the  gas  diminished  in  heat  value.  It  was  evident  that  the  draft  in  the 


52 


RHODE  ISLAND  COAL. 


producer  was  too  low;  consequently  a portion  of  the  gas  was  allowed  to  escape,  and 
soon  afterwards  the  fuel  bed  was  in  much  better  condition  and  the  heat  value  of  the 
gas  was  considerably  higher. 

Throughout  the  test  it  was  frequently  necessary  to  resort  to  this  method  of  increasing 
the  draft  in  order  to  generate  gas  of  sufficient  heat  value  to  run  the  engine.  Never- 
theless the  quantity  of  gas  thus  wasted  was  much  less  than  in  the  preceding  test, 
and  from  the  results  given  in  the  table  it  may  be  seen  that  the  fuel  consumption 
was  also  much  less.  On  the  other  hand,  the  effort  to  operate  with  a minimum  waste  of 
gas  resulted  in  a much  lower  average  draft  than  in  the  preceding  test,  and  the  effect 
of  this  was  to  lower  the  heat  value  of  the  gas,  and  consequently  to  diminish  the 
average  load  which  could  be  carried  at  the  engine. 

The  thickness  of  the  fuel  bed  increased  rapidly,  as  in  the  preceding  test,  but  during 
the  last  part  of  the  run  there  was  much  more  clinker  formed  than  at  any  time  during 
test  190. 

******* 

Pittsburgh  No.  62,  test  194 • — Pittsburgh  No.  62  was  a graphitic  anthracite  from 
Rhode  Island,  having  the  same  characteristics  as  Pittsburgh  No.  19A.  It  behaved  in 
a similar  manner  in  the  producer,  being  slow  to  ignite  and  requiring  a good  draft  to 
generate  a gas  of  fair  quality.  As  in  previous  tests  with  this  fuel,  a part  of  the  gas  was 
wasted  during  much  of  the  time,  and  for  this  reason  little  value  can  be  attached  to 
the  figures  for  fuel  consumption  per  brake  horsepower-hour  given  in  the  table  on 
page  357  [p.  53  of  this  paper].  This  graphitic  coal  would  not  hold  fire  overnight  in 
the  producer,  and  in  order  to  avoid  rekindling  each  morning  the  fire  was  banked  at 
the  end  of  each  day’s  run  with  a good  grade  of  bituminous  coal,  which  held  the  fire 
satisfactorily.  The  coal  thus  used  was  reduced  to  its  equivalent  weight  of  graphitic 
coal  and  charged  against  the  test.  From  to  2 hours  each  morning,  after  starting  the 
producer,  was  required  before  a gas  capable  of  running  the  engine  was  generated. 
Throughout  the  test  the  gas  was  rather  variable  in  quality  and  the  load  carried  was 
somewhat  irregular,  as  is  shown  by  the  graphic  log.  A comparatively  small  amount  of 
clinker  formed  during  this  run. 

Results  of  producer-gas  tests  made  at  Pittsburgh,  Pa. 


Duration  of  test 

Proximate  analysis  of  fuel  (per  cent): 

Moisture 

Volatile  matter 

Fixed  carbon 

Ash 

Sulphur,  separately  determined ' 

Fuel  charged  in  producer  (pounds): a 
Total— 

As  fired 

Dry 

Combustible 

Per  hour — 

As  fired 

Dry 

Combustible 

Per  square  foot  of  fuel-bed  area  per  hour— 

As  fired 

Dry 

Combustible — . 

Refuse: 

Total  (determined  by  weight) 

Combustible  in  refuse— 

Total 

Per  cent 


hours. 


pounds. . 


No.  19A, 
Auburn, 
R.  I. 


22.33 

3.70 
2.11 
71.45 
22. 74 
.06 


11, 335 
10,916 
8,339 

507.6 

488.8 

373.4 

39.2 

37.7 

28.8 

3,000 

1,648 

55.0 


No.  19A, 
Auburn, 
R.  I. 


29.00 

4.80 

2.50 

69.90 

22.80 

.10 


9, 454 

9.000 
6,844 

326.0 
310.3 

236.0 

25.2 
24.0 

18.2 

2,138 

845 

39.5 


No.  62, 
Ports- 
mouth, 
R.  I. 


32. 17 

11.50 
3.41 

63.59 

21.50 
.59 


11,334 

10,031 

7,594 

352.3 

311.8 

236.1 

27.2 

24.1 

18.2 

2,815 

551 

55.1 


a Figures  given  include  the  fuel  equivalent  of  coke  consumed  during  test. 


UTILIZATION  OF  THE  COAL. 


53 


Results  of  producer-gas  tests  made  at  Pittsburgh , Pa. — Continued. 


No.  19A, 
Auburn, 
R.I. 

No.  19A, 
Auburn, 
R.  I. 

No.  62, 
Ports- 
mouth, 
R.I. 

Combustible  consumed: 

Total pounds.. 

6,691 

80.2 

5,999 

87.7 

6,043 

79.6 

Coke  in  fixing  bed  (pounds): 

813 

1,017 

989 

1,435 

673 

166 

647 

28 

762 

Calorific  value  (British  thermal  units): 
Fuel  per  pound— 

10, 121 

10,090 
10, 590 

10,440 

10,523 

13,898 

3,777 

4,262 

101.0 

10, 510 

13, 759 

13,930 

3,996 

4,205 

94.7 

Standard  gas— 

From  1 pound  of  fuel — 

2,587 

2,696 

99.1 

Dry 

Consumed  per  horsepower  hour— 

9,296 

11,258 

10,076 

12,548 

15,010 

8,989 
10,757 
12, 625 

Electrical 

13,319 

21,919 

5,993 

4,950 

4,187 

Equivalent  to  stated  horsepower  per  minute — 

Gas 

21,737 

22,161 

6,269 

5,489 

4,407 

5, 238 
4,462 

3,682 

399,379 

13,772 

42.2 

Standard  gas  produced  (cubic  feet) — 

Total 

296,348 

13,271 

26.1 

423,526 

13,165 

37.4 

Per  pound  of  fuel  charged — 

As  fired 

Dry 

27.2 

44.4 

42.2 

Combustible 

35.5 

58.4 

55.8 

Standard  gas  consumed  by  engine  (cubic  feet): 

Per  hour 

13,261 

93.8 

13,762 

106.4 

13,155 

Per  horsepower  hour — 

Indicated 

Brake 

113.6 

132.5 

106!  5 

Electrical 

134.4 

158.5 

125.0 

Composition  of  gas  (per  cent  of  volume): 

6.98 

7.24 

5. 08 

02.2. 

.13 

.06 

.08 

C2H4 

.00 

.00 

.00 

CO 

23.25 

22.74 

24. 91 

h2 

6.33 

5. 28 

4.  66 

CH* 

.38 

.34 

.43 

N2 

62.93 

1,015 

45.5 

64.34 

1,054 

36.3 

64.84 

Water  used: 

Vaporizer  (pounds)— 

Total 

ol53 

Per  hour 

Per  pound  of  fuel  fired 

.09 

.11 

Wet  scrubber  (cubic  feet) — 

Total 

6,296 

282 

4,503 

155 

5,371 

167 

Per  hour 

Per  1,000  cubic  feet  standard  gas 

21.3 

11.3 

12.7 

Engine  jackets  (cubic  feet) — 

Total 

2, 557 

3,382 

121 

2,866 

89 

Per  hour 

115 

Per  brake-horsepower  hour 

.98 

1.16 

.72 

Entire  plant  (cubic  feet)— 

Total 

8,869 

397 

7,902 

273 

8,239 

256 

Per  hour 

Per  brake-horsepower  hour 

3. 40 

2.62 

2.07 

Average  barometric  pressure  (inches  of  mercury) 

29.18 

29. 12 

29.20 

Average  pressure  (inches  of  water): 

Gas  leaving  producer 

— 6.21 

— 6.99 

—4. 77 

Gas  leaving  economizer 

— 6.57 

— 7.24 

—5. 09 

Gas  leaving  wet  scrubber 

-10. 68 

—10. 04 

—7.59 

Gas  entering  dry  scrubber 

+ 5.55 
+ 2.97 
+ .62 

+ 6.04 
+ 2.93 
+ .39 

103 

+6.14 
+3. 37 
+1.85 

64 

Gas  entering  meter 

Gas  leaving  meter 

Average  temperatures  (°F.): 

Air  entering  economizer 

110 

Air  and  vapor  entering  producer 

391 

363 

400 

Gas  leaving  producer 

1,214 

1,048 

1,180 

Gas  leaving  economizer 

616 

543 

516 

54 


RHODE  ISLAND  COAL, 


Results  of  producer-gas  tests  made  at  Pittsburgh , Pa. — Continued. 


Average  temperatures  (°F.) — Continued. 

Gas  leaving  wet  scrubber 

Gas  entering  meter 

Jacket  water: 

Entering 

Leaving 

Gas  horsepower 

Revolutions  per  minute  of  gas  engine 

Explosions  per  minute  per  cylinder 

Indicated  horsepower,  total 

Brake  horsepower: 

Developed  at  engine 

Commercially  available 

Electrical  horsepower: 

Developed  at  switchboard 

Commercially  available 

Average  electrical  horsepower  required  to  run  auxiliary  machinery 

Economic  results:  Fuel  charged  in  producer  per  horsepower  hour  (pounds): 
Per  indicated  horsepower  developed — 

As  fired 

Dry 

Combustible 

Per  brake  horsepower— 

Developed  at  engine— 

As  fired 

Dry 

Combustible 

Commercially  available — 

As  fired 

Dry 

Combustible 

Per  electrical  horsepower — 

Developed  at  switchboard — 

As  fired.. 

Dry 

Combustible 

Commercially  available— 

As  fired 

Dry 

Combustible 

Efficiency  (per  cent): 

Of  conversion  and  cleaning  gas 

Of  producer  plant 

Thermal,  based  on  stated  horsepower  and  gas  horsepower- 

indicated 

Brake 

Electrical 

Of  entire  plant,  based  on  fuel  charged  per  stated  horsepower  per  hour— 

Brake  horsepower  developed  at  engine 

Brake  horsepower  commercially  available 

Electrical  horsepower  developed  at  switchboard 

Electrical  horsepower  commercially  available 


No.  19A, 
Auburn, 
R.I. 

No.  19A, 
Auburn, 
R.I. 

No.  62, 
Ports- 
mouth, 
R.I. 

81 

80 

47 

85 

85 

43 

72 

76 

39 

137 

135 

119 

516.  8 

512.5 

522.5 

261.2 

260.7 

268.8 

130. 6 

130.4 

134.4 

141.3 

129.4 

147.8 

116. 7 

103.9 

123.5 

113.4 

100.7 

120.1 

98.7 

86.8 

105.2 

95.9 

84.1 

102.3 

2.8 

2.7 

2.9 

3.59 

2.52 

2.38 

3.46 

2.40 

2.11 

2.64 

1.82 

1.60 

4.35 

3.14 

2.85 

4.19 

2.99 

2.52 

3.20 

2.27 

1.91 

4.48 

3.24 

2.93 

4.31 

3. 08 

2.60 

3.29 

2.34 

1.97 

5.14 

3.76 

3.35 

4.95 

3.57 

2.96 

3.78 

2.72 

2.24 

5.29 

3.88 

3. 44 

■ 5. 10 

3.69 

3.05 

3189 

2.81 

2.31 

•25.6 

39.7 

36.2 

25.5 

39.4 

36.0 

27.3 

25.3 

28.3 

22.6 

20.3 

23.6 

19.1 

16.9 

20.1 

5.8 

8.0 

8.6 

5.6 

7.8 

8.3 

4.9 

6.7 

7.3 

4.8 

6. 5 

7.1 

In  order  that  comparison  may  be  made  with  the  results  of  tests  of 
other  coals  there  is  given  a supplementary  table/  showing  the  pounds 
of  fuel  of  Rhode  Island  and  some  other  coals  charged  in  the  producer 
per  commercial  brake  horsepower  and  electric  horsepower,  as  that 
forms  the  best  basis  for  comparison. 


1 Bur.  Mines  Bull.  13,  p.  357, 1911. 


Economic  results  of  Rhode  Island  coals  as  compared  with  certain  other  coals  of  the  United  States  when  used  in  producer-gas  plant. 


UTILIZATION  OF  THE  COAL, 


55 


Fuel  charged  in  producer  per  horsepower-hour  (pounds). 

Per  electric  horsepower. 

Commercially  available. 

Com- 

bus- 

tible. 

HHrtlNHHrHHrtHHrtlNINNHNINWNHciN 

Dry. 

s&gssgsgggg&sssssssggss 

^^^co^^i-H*-t^T--iffqc^c4eceo<riir4coidc<5<NC^co 

As 

fired. 

r4rH^M^^r-ic<i'-<c<i«c^eO'^e«5c«5ece<5oe<3C^c<ico 

Developed  at  switch- 
board. 

Com- 

bus- 

tible. 

88$3£22S£8SS82g2SS3£££gg3 

Dry. 

^^^corH^i-Hi-HrHrtMc4<Ne4e<5C>ipieo'<i’coci<NC^ 

As 

fired. 

TH^^ec^i-HrH^r-ic4Mc4eO'9’eoeocoec»oe«scipieo 

Per  brake  horsepower. 

Commercially  available. 

Com- 

bus- 

tible. 

jHHHHHHHHHHHHHHHHNeOWHHrt 

Dry. 

8S3gS3S8&k£8gS2S83£3g£gg 

rH  tH  rH  N rH  rH  rH  rH  rH  rH  rH  C$  C$  Cl  iH  C$  ci  rtf  W rH  <N  c4 

As 

fired. 

THrn^eorHT-;rtiHrHc^c4c4eo'sIpiN«ci'a’eoc>ic4pi 

• 

Developed  at  engine. 

Com- 

bus- 

tible. 

3S8gg£g£3k3kggSSgS;gS;S£o: 

^ r4  ,-i  r-^  -HHHHHHHHHHHHMNHHH 

Dry. 

1.23 

1.58 

1.41 

2.81 

1.57 

1.17 

1.13 

1.49 

1.31 

1.62 

1.72 
2.28 
2.01 
2.47 
2.70 
1.84 
2.37 
2.63 
4.19 

2.99 

1.73 

1.99 
2.52 

As 

fired. 

8S$£222S88gSSg£S;S  §833888 

^^^eorH-^HJrt^NcideoMNNNci^eorH-cqw 

Per  indicated  horse- 
power developed. 

Com- 

bus- 

tible. 

83gS3S888S5£283kS&2§g;S8SSg 

OHHHH  * • • ‘.J^iH.HrHrHrH.HeirHrH.-irH 

Dry. 

HHHNHH  ,HrHiH,HiH,HCsic<iiHrHCSCOC^rH.HC<i 

As 

fired. 

gS8£3S82Sg2Sg88828SSSg8 

hhhmhh  .H,Hcsc^TH<^coc^cic^oico<ri>Hoics 

Location  of  mine  or  deposit. 

Marianna,  Pa 

do 

Madison,  Pa 

Elizabeth  City,  N.  C 

Madison,  Pa 

Pocahontas,  Va 

do 

do 

do 

Rockdale,  Tex 

Lytle,  Tex 

Walston,  Pa 

Lehigh,  N.  Dak 

lone,  Cal 

Walston,  Pa 

Scranton,  N.  Dak 

lone,  Cal 

Sherrard,  111 

Auburn,  R.  I 

do 

Coalville,  U tah 

Tono,  Wash 

Portsmouth,  R.  I 

Designation 
of  fuel. 

§ Ji  d 3 S3  d a d d 2 2 2 $ 8 s' 

5 o'  o*  « oa  6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 
-g  fc  fc  53  5 £ 5 fc  fc  £ fc  % £ fc  £ £ & £ £ fc  fc  & fc  £ 

S 

Test 

No. 

g5SSSSgSSS|HS3|gg||s|85 

56 


RHODE  ISLAND  COAL. 


In  general,  a study  of  the  full  tables  as  published  in  Bulletin  13  of 
the  Bureau  of  Mines  shows  that  it  requires  from  1 to  2 pounds  of 
Pocahontas  coal  or  bituminous  coal  from  central  Pennsylvania  to 
produce  1 available  electric  horsepower-hour  as  compared  with 
2.85  to  5.29  pounds  of  Rhode  Island  coal.  This  may  be  stated  differ- 
ently as  follows:  One  ton  of  Pocahontas  coal  or  central  Pennsylvania 
bituminous  coal  will  yield  1,000  to  2,000  available  horsepower-hours, 
whereas  Rhode  Island  coal,  according  to  the  tests  made,  will  yield 
from  375  to  700  horsepower-hours.  Generally,  the  yield  from  Rhode 
Island  coal  appears  to  have  been  about  one-third  of  that  from  the 
other  coals  named.  If  account  be  taken  of  the  cost  and  interest  for 
transmission  lines  from  the  field  to  centers  of  distribution,  as  from 
Portsmouth  to  Providence,  and  the  added  cost  of  handling  the  larger 
quantity  of  coal  necessary  and  the  very  much  larger  quantity  of  ash, 
it  appears  that  Rhode  Island  coal  at  the  mouth  of  the  mine  for  use 
in  the  producer-gas  plant,  is  worth  only  one-fourth  to  one-third  the 
value  of  competing  coals  delivered  at  Providence  or  Boston.  If  it 
be  assumed,  however,  that  specially  designed  apparatus  would  prevent 
the  loss  of  gas  noted  in  the  experiments  it  seems  possible  that  from 
2 to  3 pounds  of  Rhode  Island  coal  could  be  made  to  produce  1 
electric  horsepower-hour,  averaging  say  2J  pounds,  against  an  aver- 
age of,  say,  li  pounds  for  competing  steam  coals.  With  the  added 
costs  referred  to  above,  it  seems  that  a ton  of  average  selected  Rhode 
Island  coal  should  deliver  in  Providence  or  Boston  electric  power 
equivalent  to  that  obtained  from  one-half  ton  of  average  competing 
coals. 

In  November,  1913,  Pocahontas  coal  was  selling  at  wholesale  in 
Providence  and  Boston  at  a little  under  $4  a ton.  In  order  to  com- 
pete with  power  produced  by  that  coal,  Rhode  Island  coal  of  the 
best  grade  must  be  mined  and  delivered  at  the  mouth  of  the  mine 
to  a producer-gas  plant  for  not  over  half  that  price,  or  $2  a ton. 

In  using  Rhode  Island  coal  in  the  producer-gas  plant,  the  cost 
of  mining  might  be  reduced  sufficiently  to  allow  competition  by  put- 
ting the  producer-gas  plant  in  the  mine,  as  low  in  the  basin  as  pos- 
sible. As  the  coal  carries  no  combustible  volatile  matter,  neither 
the  coal  nor  the  dust  should  offer  any  danger  of  fire  or  explosion  and, 
as  the  rocks  adjacent  to  the  coal  are  very  firm,  the  cost  of  preparing 
rooms  should  be  little  more  than  the  cost  of  excavation.  Such 
rooms  are  now  used  for  pumps  in  the  Portsmouth  mine.  By  plac- 
ing the  plant  low  the  coal  can  be  lowered  by  gravity  from  the  higher 
levels.  The  plant  could  also  be  installed  in  small  movable  units, 
including  a gas  producer  and  gas  engine,  the  power  to  be  taken  out 
of  the  mine  as  electricity.  By  this  method  it  might  prove  feasible 
to  move  the  unit  plants  from  one  of  these  large  lenses  to  another. 
As  these  lenses  in  the  Portsmouth  mine  and  at  Cranston  appear  to 


CONCLUSIONS. 


57 


have,  in  places,  a length  of  1,000  feet  or  more  and  a width  of  100 
or  200  feet  or  more  and,  at  Portsmouth,  an  average  thickness  of  4J 
feet,  it  seems  that  one  of  them  should  yield  sufficient  tonnage  to 
cover  the  cost  of  moving  and  installation  of  a small  unit.  Whether 
such  a mine  installation,  by  eliminating  the  cost  of  the  lift  out  of  the 
mine,  would  reduce  the  total  cost  sufficiently  to  render  competition 
possible  would  have  to  be  demonstrated. 

USE  FOR  FOUNDRY  FACINGS  AND  FURNACE  LININGS. 

In  the  preceding  sections  the  utilization  of  Rhode  Island  anthra- 
cite has  been  discussed.  This  has  been  the  specific  purpose  of  this 
bulletin.  A little  may,  however,  be  said  in  regard  to  the  use  of  the 
more  graphitic  portions  of  the  beds.  Though  all  the  anthracite  con- 
tains more  or  less  graphite,  portions  of  the  beds  have  been  changed 
entirely  to  what  appears  to  be  graphite.  Such  a bed  at  Fenners 
Ledge  is  being  mined  at  present  in  an  open  cut  by  Mr.  Fenner  and 
sold  for  foundry  facings,  for  which  it  appears  to  be  well  adapted  after 
the  proper  preparation.  At  the  old  Gross  mine,  to  the  south,  an 
attempt  was  made  to  prepare  the  graphite  for  market.  Buildings 
were  erected  and  machinery  installed.  The  graphite  was  crushed 
and  screened,  using  expensive  brass  sieves.  The  process  adopted  did 
not  prove  successful,  apparently  owing  to  the  difficulty  of  separating 
the  fine  quartz. 

Graphite  has  also  been  mined  at  Bridgeton,  Valley  Falls,  and 
Tiverton,  at  the  first  and  last  places  from  open  cuts,  but  at  Valley 
Falls  the  workings  were  extended  underground.  The  material  was 
used  for  foundry  facings  and  some  of  it  for  furnace  linings. 

CONCLUSIONS. 

A review  of  the  physical  and  chemical  character  of  Rhode  Island 
coal,  the  history  of  its  past  exploitation  and  use,  and  past  and  recent 
tests  of  its  use  leads  to  the  following  general  conclusions: 

Rhode  Island  coal  is  a high-ash,  high-moisture,  graphitic  anthra- 
cite coal  of  high  specific  gravity. 

Calorimeter  tests  show  it  to  yield  from  6,000  to  11,000  British 
thermal  units,  averaging,  as  taken  from  the  mine,  about  9,000  Brit- 
ish thermal  units,  or  about  10,000  after  air  drying.  As  compared 
with  coals  shipped  to  New  England,  with  which  it  must  compete, 
which  range  from  12,000  British  thermal  units  for  Pennsyl- 
vania anthracite  culm  to  nearly  15,000  British  thermal  units,  and 
average  13,000  for  anthracite  and  about  14,500  for  bituminous  as 
mined,  Rhode  "Island  coal  yields  on  the  average  from  60  to  70  per 
cent  of  the  heat  value  of  these  competing  coals.  The  best  of  the 
Rhode  Island  coal  may  reach  90  per  cent  of  the  heat  value  of  the 
poorest  competing  coal  and  80  per  cent  of  the  better  grade. 


58 


RHODE  TSLAND  COAL. 


A careful  test  in  actual  practice  showed  Rhode  Island  coal  to  have 
72  percent  of  the  efficiency  of  Lackawanna  coal. 

In  experimental  tests  by  the  Bureau  of  Mines,  Rhode  Island  coal 
yielded  from  54  to  68  per  cent  as  much  horsepower  as  the  other  coals 
listed  and  from  48  to  60  per  cent  as  many  pounds  of  water  evaporated 
per  pound  of  fuel. 

In  household  and  steam  use  it  is  found  to  ignite  slowly  and  with 
difficulty  and  to  make  so  hot  a fire  as  to  destroy  stove  tops,  melt 
vessels  and  boilers  placed  on  it,  and  destroy  furnace  linings,  so  that 
the  fire  is  difficult  to  maintain  and  control.  Its  ignition  and  burning 
are  improved  by  breaking  down  to  small  sizes  and  careful  screening. 

Rhode  Island  coal  has  been  successfully  used  in  the  metallurgy  of 
copper  and  iron.  Evidence  is  lacking  to  show  that  it  could  compete 
with  coke  in  the  modern  furnace. 

Rhode  Island  coal  has  been  briquetted,  but  without  commercial 
success.  It  is  believed  that  future  tests  may  make  possible  the  pro- 
duction of  briquets  that  hold  together  and  do  not  smoke. 

The  high  specific  gravity  renders  washing  o»f  this  coal  with  present 
methods  difficult  if  not  impossible. 

In  producer-gas  tests  by  the  Bureau  of  Mines,  Rhode  Island  coal 
yielded  from  375  to  700  horsepower-hours  per  ton  of  coal,  as  compared 
with  1,000  to  2,000  available  horsepower-hours  for  competing  coals. 
Specially  designed  plants,  it  seems  reasonable  to  suppose,  might  be 
made  to  yield  at  least  one-half  as  much  power  with  Rhode  Island 
coal  as  with  competing  coals. 

In  general,  it  appears  that  at  the  present  time  the  best  outlook 
for  Rhode  Island  coal  is  in  the  production  of  electric  power  at  the 
mines,  either  in  steam  engines  or  by  means  of  specially  devised 
producer-gas  or  water-gas  plants.  It  appears  further,  however,  that 
this  can  not  be  done  with  financial  success  until  it  can  be  shown 
that  Rhode  Island  coal  can  be  mined  and  delivered  at  the  fur- 
nace for  less  than  one-half  the  wholesale  price  of  competing  coals  in 
Providence  and  Boston. 

PAPERS  AND  REPORTS. 

Papers  and  reports  to  which  reference  is  made  or  which  are  of  value 
in  connection  with  this  subject  are  listed  below  in  chronologic  order: 

1.  Providence  Journal.  Through  the  kindness  of  officials  of  the  Providence  Public 

Library,  the  writer  had  access  to  the  old  files  of  the  Journal  and  to  a large 
number  of  clippings  on  the  subject  of  Rhode  Island  coal.  These  have  formed 
the  basis  of  much  of  the  section  on  the  history  of  development  (pp.  7-14). 

2.  Hearing  on  the  memorial  of  the  New  England  Coal  Mining  Co.  before  the  select 

special  committee  of  the  General  Assembly  of  Rhode  Island  and  Providence 
Plantations,  together  with  the  report  of  the  committee,  1838. 

3.  Report  and  bill  to  the  Commonwealth  of  Massachusetts  relating  to  the  coal  mines 

of  the  State,  1839. 


PAPERS  AND  REPORTS. 


59 


4.  Jackson,  C.  T.,  Report  on  the  geologic  and  agricultural  survey  of  the  State  of 

Rhode  Island,  Providence,  1840. 

5.  Hitchcock,  E.  T.,  Final  report  on  the  geology  of  Massachusetts,  Northampton, 

1841. 

6.  Mount  Hope  Coal  Co.,  The  coal  beds  of  Rhode  Island,  1852. 

7.  Hitchcock,  E.  T.,  The  coal  field  of  Bristol  County  and  of  Rhode  Island:  Am. 

Jour.  Sci.,  2d  ser.,  vol.  16,  pp.  227-336,  1853. 

8.  Hitchcock,  E.  T.,  Geology  of  the  Island  of  Aquidneck:  Proc.  Am.  Assoc.  Adv.  Sci., 

vol.  14,  pp.  112-137,  1860. 

9.  Rhode  Island  Society  for  the  Encouragement  of  Domestic  Industry,  Providence, 

1869. 

10.  Memorial  of  T.  S.  Ridgway,  in  relation  to  the  coal  field  of  Rhode  Island,  pre- 

sented to  the  General  Assembly,  1870. 

11.  Emmons,  A.  B.,  Notes  on  the  Rhode  Island  and  Massachusetts  coals:  Am.  Inst. 

Min.  Eng.  Trans.,  vol.  13,  pp.  510-517,  1885. 

12.  Adams,  W.  H.,  Eng.  and  Min.  Jour.,  1886.  (Referred  to  as  having  described 

some  tests  on  Rhode  Island  coal;  could  not  be  located.) 

13.  Providence  Franklin  Society.  Report  on  the  geology  of  Rhode  Island,  Provi- 

dence, 1887.  (Gives  a complete  list  of  papers  on  the  geology  of  Rhode  Island 
up  to  the  time  of  publication.) 

14.  Shaler,  N.  S.,  Woodworth,  J.  B.,  Foerste,  A.  F.,  Geology  of  the  Narragansett  Basin: 

U.  S.  Geol.  Survey  Mon.  33,  1899.  (This  is  a complete  comprehensive  report 
on  the  geology  of  the  coal  basin  containing  the  Rhode  Island  coal.  It  does  not 
deal  at  great  length  with  the  coal  from  either  the  stratigraphic  or  the  commercial 
standpoint.) 

15.  Second  Geol.  Survey  Pennsylvania  Summary  Rept.,  vol.  3,  pt.  1,  1895. 

16.  Lord,  N.  W.,  Experimental  work  conducted  in  the  chemical  laboratory  of  the 

United  States  fuel-testing  plant  at  St.  Louis,  Mo.:  U.  S.  Geol.  Survey  Bull.  323, 
1907. 

17.  Breckenridge,  L.  P.,  A study  of  four  hundred  steaming  tests,  made  at  the  fuel- 

testing plant,  St.  Louis,  Mo.:  U.  S.  Geol.  Survey  Bull.  325,  1907. 

18.  Holmes,  J.  A.,  in  charge,  Report  of  the  United  States  fuel-testing  plant  at  St. 

Louis,  Mo.:  U.  S.  Geol.  Survey  Bull.  332,  1908. 

19.  Bin-rows,  J.  S.,  Mine  sampling  and  chemical  analyses  of  coals  tested  at  the  United 

States  fuel-testing  plant,  Norfolk,  Va.:  U.  S.  Geol.  Survey  Bull.  362,  1908. 

20.  Randall,  D.  T.,  Tests  of  coal  and  briquets  as  fuel  for  house-heating  boilers:  U.  S. 

Geol.  Survey  Bull.  366,  1908. 

21.  Snodgrass,  J.  M.,  Fuel  tests  of  house-heating  boilers:  University  of  Illinois  Bull. 

31,  1909. 

22.  Preliminary  report  of  the  natural  resources  survey  of  Rhode  Island:  Rhode 

Island  Bur.  Industrial  Statistics  Bull.  1 (Ann.  Rept.  1909,  pt.  3),  1910. 

23.  Fernald,  R.  H.,  and  Smith,  C.  D.,  Resume  of  producer-gas  investigations:  Bur. 

Mines  Bull.  13,  1911. 

24.  Lord,  N.  W.,  and  others,  Analyses  of  coal  in  the  United  States:  Bur.  Mines 

Bull.  22,  1913. 

Brief  references  were  made  in  the  Engineering  and  Mining  Journal 
and  other  journals  and  papers  given  in  the  list  published  in  item  13. 


INDEX. 


Analyses  of  coals  used  in  briquets 47 

of  Rhode  Island  anthracite 20-29, 44 

Aquidneck  Coal  Co.,  operations  of 8, 9, 10 

Ash,  cause  of  high  content  of 19 

determinations  of 21-22 

percentage  of 23-33 

B. 

Bibliography 58-59 

Blackstone  Coal  Co.,  operations  of 11 

Brick  burning,  possible  use  of  the  coal  for 48-49 

Briquets,  attempts  to  make 13 

tests  of 40-41,43-45,46-48 

Bryant,  W.  C.,  cited 39 

Budlong  mine,  anthracite  in,  diagram  show- 
ing thickness  of 19 

face  of  bed  north  of  mouth  of  slope,  plate 

showing 12 

north  end  of,  plate  showing 19 

open  cut  in,  plate  showing 12 

operation  of 12 

surface  plant  at,  plate  showing 13 

Bureau  of  Mines,  briquetting  tests  by 46-48 

steaming  tests  of  various  coals  by 45-46 

tests  of  the  coal  in  a producer-gas  plant  by  49-57 

C. 

Chemical  character  of  the  coal 17, 23-33 

Clay,  test  of,  desirable 16 

Compressed  Coal  Co.,  operations  of 13 

Cranston  coal,  briquetting  tests  of 43-45,46-48 

mining  of 14 

producer-gas  tests  of 50-57 

steam  test  of 42-43 

Cranston  Coal  Co.,  operations  of 12 

Cumberland,  coal  found  in 8 

D. 

Drilling,  results  of 17 

Durfee,  W.  F.,  interest  revived  by 11-12 

E. 

Electricity,  use  of  coal  for 7 

Emmons,  A.  B.,  cited 37-38 

F. 

Fenner  Ledge , mining  at 14 

graphite  mine  at,  view  in 16 

Foundry  facings,  use  of  graphite  for 57 

Furnace  linings,  use  of  graphite  for 57 

G. 

Gas  producer,  advantage  of  placing,  in  mine.  56-57 

Graphite,  content  of 20 

Fenner  Ledge,  analyses  of. 33 

produced  from  coal  by  heat 18-19 

uses  of 57 


H. 

Page. 

Heat  value,  low,  reason  for 33-37 

Heating  power,  chart  showing 24 

comparison  of 32 

Household  use  of  the  coal 39-41 

L. 

Lackawanna  coal,  ash  in 29 

comparison  of,  with  Cranston  coal 42-43 

heating  power  of 35 

Lenses,  irregular,  formed  by  pressure 18 

Lime  burning,  possible  use  of  the  coal  for 48-49 

Lotteries  granted  to  aid  in  mining  coal 7, 8 

M. 

Mansfield,  Mass.,  analyses  of  coals  from 29 

coal  mining  at 9 

Mansfield  Coal  Co.,  operations  of : 9 

Mansfield  Mining  Co.,  operations  of 9 

Massachusetts  Mining  Co.,  operations  of 9 

Metallurgy,  use  of  the  coal  in 10, 11, 46 

Mining,  cost  of,  conditions  affecting 14-17 

Mitchell,  Thomas,  operations  of 12 

Moisture,  behavior  of  coal  toward 32,37-38 

percentage  of 23-33 

Mount  Hope  Mining  Co.,  operations  of 10 

N. 

New  England  Coal  Mining  Co.,  operations  of.  8-9 

New  York  Carbon  Iron  Co.,  operations  of 11 

Newport  County  coals,  analyses  of 26 

Nichols,  Purton,  mines  opened  by 7 

P. 

Pennsylvania,  analyses  of  coals  from 30 

Physical  character  of  the  coal 20-21 

Pocahontas  coal,  heating  power  of 34-35 

Pocasset  Coal  Co.,  operations  of 10 

Porter,  J.  B.,  and  Durley,  R.  J.,  cited 22 

Portsmouth  coal,  analyses  of 28, 29 

behavior  of,  toward  moisture 37-38 

producer-gas  test  of 50-57 

Portsmouth  Coal  Co.  of  1847,  operations  of . . . 9 

Portsmouth  Coal  Co.  of  1912,  North  and  South 

mines  of,  equipment  of 14 

operations  of 14 

South  mine  of,  plate  showing  surface  plant 

at 13 

Pressure,  effects  of,  on  the  coal 6, 14-15, 17-19 

regional  differences  of 19 

Producer  gas,  tests  of  the  coal  for 49-57 

Providence  County  coals,  analyses  of 27 

Providence  Waterworks,  test  of  coal  at 10-11 

Pyrite,  content  of 20, 21 

Q. 

Quartz,  content  of 20, 21 

Quartz  veins,  formation  of 19 


61 


62 


INDEX, 


R. 

Page. 

Revolutionary  War,  use  of  coal  during 7 

Rhode  Island  coal,  character  of 5-6,57-58 

compared  with  other  coals  when  used  in 

a producer-gas  plant 55-56 

history  of 7-9,9-14 

proper  and  improper  modes  of  using 6-7, 10 

Rhode  Island  Coal  Co.  of  1809,  operations  of.  8 
Rhode  Island  Coal  Co.  of  1840,  operations  of.  9 
Rhode  Island  Coal  Co.  of  1909,  operations  of.  13-14 

Rhode  Island  coal  field,  sketch  map  of • 6 

Roger  Williams  mine,  working  of 11 

S. 

Snodgrass,  J.  M.,  cited 41 

Specific  gravity,  determinations  of 21-22 

Standish,  Miles,  operations  of 12 

Steam  raising,  use  of  the  coal  in 41-46 


T. 

Page. 


Taunton  Copper  Co.,  operations  of 10 

use  of  coal  by 5, 10 

U. 

Uses,  practicable,  of  Rhode  Island  coal 38-39 

V. 

Virginia,  analyses  of  coals  from 31 

W. 

Water  gas,  possible  use  of  the  coal  for 49 

W est  Virginia,  analyses  of  coals  from 31 

Worcester  Steel  Works,  operations  of 12 


O 


DEPARTMENT  OF  THE  INTERIOR 

Franklin  K.  Lane,  Secretary 


United  States  Geological  Survey 

George  Otis  Smith,  Director 


Bulletin  616 


THE 

DATA  OF  GEOCHEMISTRY 


THIRD  EDITION 


FRANK  WIGGLESWORTH  CLARKE 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 

1916 


' ^ 


5T7 

2:  Y £> 

f't-t-'fT  bib 


CONTENTS. 


Introduction PagGg 

Chapter  I.  The  chemical  elements 

Nature  of  the  elements ^2 

Distribution  of  the  elements 2.3 

Relative  abundance  of  the  elements 22 

The  periodic  classification g^ 

Meteorites gg 

Chapter  II.  The  atmosphere 42 

Composition  of  the  atmosphere 

The  relations  of  carbon  dioxide  to  climate 47 

Rainfall * * 4g 

The  primitive  atmosphere 5g 

Chapter  III.  Lakes  and  rivers 5g 

ori8in 58 

Statement  of  analyses ^g 

The  interpretation  of  analyses 

Springs " ' . 63 

Changes  of  composition 04 

Analyses  of  river  waters gg 

The  St.  Lawrence  basin gg 

The  Atlantic  slope 72 

The  Mississippi  basin 

Southwestern  rivers g2 

Rivers  of  California gg 

The  Columbia  River  basin 84 

Other  northwestern  rivers gg 

The  Saskatchewan  system 87 

Summary  for  North  America gg 

Rivers  of  South  America g0 

Lakes  and  rivers  of  Europe gg 

Rivers  of  India  and  Java 205 

The  Nile 206 

Organic  matter  in  waters 207 

Contamination  by  human  agencies ]0g 

Gains  and  losses  in  waters 2 10 

Chemical  denudation 2H 

Chapter  IV.  The  ocean 119 

Elements  in  the  ocean 219 

Composition  of  oceanic  salts 222 

Carbonates  in  sea  water 228 

Oceanic  sediments 230 

Potassium  and  sulphates 238 

The  chlorine  of  sea  water 239 

The  dissolved  gases 242 

Influence  of  living  organisms  on  the  ocean 247 

Age  of  the  ocean 4S 


3 


4 


CONTENTS. 


Chapter  V.  The  waters  of  closed  basins 

Preliminary  statement 

The  Bonneville  basin 

The  Lahontan  basin 

Lakes  of  California 

Northern  lakes 

Central  and  South  America 

Caspian  Sea  and  Sea  of  Aral 

The  Dead  Sea 

Other  Russian  agad  Asiatic  lakes 

Miscellaneous  lakes 

Summary 

Chapter  VI.  Mineral  wells  and  springs 

Definition 

Classification 

Chloride  waters 

Sulphate  waters 

Carbonate  waters 

Waters  of  mixed  type 

Siliceous  waters 

Nitrate,  phosphate,  and  borate  waters 

Acid  waters 

Summary  of  waters 

Changes  in  waters 

Calcareous  sinter 

Ocherous  deposits 

Siliceous  deposits 

Reactions  with  adjacent  material 

Yadose  and  juvenile  waters 

Thermal  springs  and  volcanism 

Bibliographic  note 

Chapter  VII.  Saline  residues 

Deposition  of  salts 

Concentration  of  sea  water 

The  Stassfurt  salts 

Other  salt  beds 

Analyses  of  salt-. 

Analyses  of  gypsum 

Bitterns 

Sodium  sulphate 

Miscellaneous  desert  salts 

Alkaline  carbonates 

Borates 

Nitrates 

The  alums 

Chapter  VIII.  Volcanic  gases  and  sublimates 

Gaseous  emanations 

Sublimates 

Occluded  gases 

Volcanic  explosions 

Summary 


Page. 

154 

154 

154 

157 

160 

161 

164 

165 
167 
169 

172 

173 
179 

179 

180 
181 
187 
190 

193 

194 
196 
198 
201 
202 

203 

204 

205 
209 

213 

214 

215 
217 

217 

218 
221 
228 
230 
232 

232 

233 

236 

237 
243 
253 

259 

260 
260 
269 
274 
285 
289 


CONTENTS. 


5 


Page. 

Chapter  IX.  The  molten  magma 291 

Temperature 291 

Influence  of  water 297 

Magmatic  solutions 298 

Eutectics i 301 

Separation  of  minerals 304 

Differentiation 307 

Radioactivity 313 

Chapter  X.  Rock-forming  minerals 321 

Preliminary  statement 321 

Diamond  and  graphite 322 

Native  metals 328 

Sulphides 332 

Fluorides 335 

Corundum 336 

The  spinels 341 

Hematite 346 

Titanium  minerals 348 

Cassiterite  and  zircon 352 

Phosphates 354 

The  silica  minerals 356 

The  feldspars 363 

Leucite  and  analcite 368 

The  nephelite  group 371 

The  cancrinite-sodalite  group 373 

The  pyroxenes : 376 

The  amphiboles 383 

The  olivine  group 389 

The  micas 391 

The  chlorites 396 

The  melilite  group 398 

The  garnets 400 

Yesuvianite 403 

The  scapolites 403 

Iolite 405 

The  zoisite  group 406 

Topaz 408 

The  andalusite  group 409 

Staurolite 411 

Lawsonite 411 

Dumortierite 412 

Tourmaline 412 

Beryl 413 

Serpentine,  talc,  and  kaolinite 414 

The  zeolites 416 

The  carbonates 417 

Chapter  XI.  Igneous  rocks 419 

Preliminary  considerations 419 

Classification 420 

Composition  of  rocks 433 

The  rhyolite-granite  group 433 

The  trachyte-syenite  group! 438 


6 CONTENTS. 

Chapter  XI.  Igneous  rocks — Continued. 

Composition  of  rocks — Continued.  Page. 

Nephelite  rocks 443 

Leucite  rocks 447 

Analcite  rocks 449 

The  monzonite  group 451 

The  andesite-diorite  series 453 

The  basalts 457 

Diabase 460 

The  gabbros 462 

Femic  rocks 463 

Basic  rocks 466 

Limiting  conditions 469 

Proximate  calculations 473 

Chapter  XII.  The  decomposition  of  rocks 476 

The  general  process 476 

Solubility  of  minerals 478 

Effects  of  vegetation 483 

Influence  of  bacteria 485 

Influence  of  animal  life 485 

Products  of  decomposition 486 

Rate  of  decomposition 490 

Kaolin 491 

Laterite  and  bauxite 493 

Absorption 501 

Sand 502 

Silt 504 

Glacial  and  residual  clays 507 

Loess 509 

Marine  sediments 511 

Glauconite 516 

Phosphate  rock 519 

Ferric  hydroxides 528 

Manganese  ores 533 

Chapter  XIII.  Sedimentary  and  detrital  rocks 537 

Sandstones 537 

Flint  and  chert 542 

Shale  and  slate 545 

Limestone 548 

Dolomite .- 559 

Iron  carbonate 571 

Silicated  iron  ores 573 

Gypsum 576 

Native  sulphur 576 

Celestite 578 

Barite 579 

Fluorite 582 

Chapter  XI Y.  Metamorphic  rocks 583 

Metamorphic  processes 583 

Classification 588 

Uralitization 589 

Glaucophane  schists 591 

Sericitization 593 


CONTENTS. 


7 


Chapter  XIV.  Metamorphic  rocks — Continued.  Page. 

Other  alterations  of  feldspar 594 

Chloritization 600 

Constitutional  formulas 600 

Talc  and  serpentine 602 

Quartzite 606 

Metamorphosed  shales 608 

Ferruginous  schists 609 

Dehydration  of  clays 610 

Mica  schist 614 

Gneiss 618 

Metamorphic  limestones 620 

Diagnostic  criteria 624 

Chapter  XV.  Metallic  ores 626 

Definition 626 

Source  of  metals 627 

Gold 641 

Silver 648 

Copper 655 

Mercury 664 

Zinc  and  cadmium 669 

Lead 676 

Tin 683 

Arsenic,  antimony,  and  bismuth 687 

Nickel  and  cobalt 691 

Chromium 696 

Molybdenum  and  tungsten 698 

The  platinum  metals 700 

Vanadium  and  uranium 705 

Columbium,  tantalum,  and  the  rare  earths 710 

Chapter  XVI.  The  natural  hydrocarbons 713 

Composition 713 

Syntheses  of  petroleum 722 

Origin  of  petroleum 726 

Chapter  XVII.  Coal 738 

Origin  of  coal 738 

Peat 742 

Lignite 745 

Bituminous  coal 750 

Anthracite 752 

The  variations  of  coal 755 

The  gases  in  coal 757 

Artificial  coals 760 

The  constitution  of  coal 763 

Index 767 


THE  DATA  OF  GEOCHEMISTRY.1 


By  F.  W.  Clarke. 


INTRODUCTION. 

In  the  crust  of  the  earth,  with  its  liquid  and  gaseous  envelopes,  the 
ocean  and  the  atmosphere,  about  eighty  chemical  elements  are  now 
recognized.  These  elements,  the  primary  units  of  chemical  analysis, 
are  widely  different  as  regards  frequency;  some  are  extremely  rare, 
others  are  exceedingly  abundant.  A few  occur  in  nature  uncombined ; 
but  most  of  them  are  found  only  in  combination.  The  compounds 
thus  generated,  the  secondary  units  of  geochemistry,  are  known 
as  mineral  species;  and  of  these,  excluding  substances  of  organic 
origin,  only  about  a thousand  have  yet  been  identified.  By  artificial 
means  innumerable  compounds  can  be  formed;  but  in  the  chemistry 
of  the  earth’s  crust  the  range  of  possibility  seems  to  be  extremely 
limited.  From  time  to  time  new  elements  and  new  mineral  species 
are  discovered;  but  it  is  highly  probable  that  all  of  them  which  have 
any  large  importance  in  the  economy  of  nature  are  already  known. 
The  rarest  substances,  however,  whether  elementary  or  compound, 
supply  data  for  the  solution  of  chemical  problems;  they  can  not, 
therefore,  be  ignored  or  set  to  one  side  as  having  no  significance.  In 
scientific  investigation  aU  evidence  is  of  value. 

By  the  aggregation  of  mineral  species  into  large  masses  rocks  are 
produced;  and  these  are  the  fundamental  units  of  geology.  Some 
rocks,  such  as  quartzite  or  limestone,  consist  of  one  mineral  only,  more 
or  less  impure;  but  most  rocks  are  mixtures  of  species,  in  which, 
either  by  the  microscope  or  by  the  naked  eye,  the  individual  compo- 
nents can  be  clearly  distinguished.  Being  mixtures,  rocks  are  widely 
variable  in  composition;  and  yet  certain  types  are  of  common  occur- 
rence, whHe  others  are  small  in  quantity  and  rare.  The  commonest 
rock-forming  minerals  are  naturally  the  more  stable  compounds  of 
the  most  abundant  elements ; and  the  rocks  themselves  represent  the 
outcome  of  relatively  simple  rather  than  of  complex  reactions.  Sim- 
plicity of  constitution  seems  to  be  the  prevaHing  rule.  An  eruptive 

1 The  first  edition  of  this  volume  was  published  in  1908  as  Bulletin  330  of  the  United  States  Geological 
Survey.  A second  edition  appeared  in  1911  as  Bulletin  491.  The  work  has  been  revised  and  enlarged 
for  the  present  edition. 


9 


10 


THE  DATA  OF  GEOCHEMISTRY. 


rock,  for  example,  may  be  composed  mainly  of  eight  chemical  ele- 
ments, namely,  oxygen,  silicon,  aluminum,  iron,  calcium,  magnesium, 
sodium,  and  potassium.  These  elements  are  capable  of  combining  so 
as  to  form  some  hundreds  of  mineral  species ; and  yet  only  a few  of  the 
latter  appear  in  the  rock  mass.  The  less  stable  species  rarely  occur; 
the  more  stable  always  predominate.  The  reactions  which  took  place 
during  the  formation  of  the  rock  were  strivings  toward  chemical 
equilibrium,  and  a maximum  of  stability  under  the  existing  condi- 
tions was  the  necessary  result.  The  rarer  rocks,  like  many  of  the 
rarer  minerals,  are  the  products  of  exceptional  conditions;  but  the 
tendency  toward  stable  equilibrium  is  always  the  same.  Each  rock 
may  be  regarded,  for  present  purposes,  as  a chemical  system,  in 
which,  by  various  agencies,  chemical  changes  can  be  brought  about. 
Every  such  change  implies  a disturbance  of  equilibrium,  with  the 
ultimate  formation  of  a new  system,  which,  under  the  new  conditions, 
is  itself  stable  in  turn.  The  study  of  these  changes  is  the  province 
of  geochemistry.  To  determine  what  changes  are  possible,  how  and 
when  they  occur,  to  observe  the  phenomena  which  attend  them,  and 
to  note  their  final  results  are  the  functions  of  the  geochemist.  Analy- 
sis and  synthesis  are  his  two  chief  instruments  of  research,  but  they 
become  effective  only  when  guided  by  a broad  knowledge  of  chemical 
principles,  which  correlate  the  data  obtained  and  extract  from  the 
evidence  its  full  meaning.  From  a geological  point  of  view  the  solid 
crust  of  the  earth  is  the  main  object  of  study;  and  the  reactions  which 
take  place  in  it  may  be  conveniently  classified  under  three  heads — 
first,  reactions  between  the  essential  constituents  of  the  crust  itself; 
second,  reactions  due  to  its  aqueous  envelope;  and  third,  reactions 
produced  by  the  agency  of  the  atmosphere.  That  the  three  classes 
of  reactions  shade  into  one  another,  that  they  are  not  sharply  defined, 
must  be  admitted ; but  the  distinction  between  them  is  valid  enough 
to  serve  a good  purpose  in  the  arrangement  and  discussion  of  the 
data.  Under  the  first  heading  the  reactions  which  occur  in  volcanic 
magmas  and  during  their  contact  with  rock  masses  are  studied  • 
under  the  second  we  find  the  changes  due  to  percolating  waters  and 
the  chemistry  of  natural  waters  in  general;  the  essentially  surficial 
action  of  the  atmosphere  forms  the  subject  matter  of  the  third. 

Furthermore,  for  convenience  of  study,  the  solid  crust  of  the  earth 
may  be  regarded  as  made  up  of  three  shells  or  layers,  which  inter- 
penetrate one  another  to  some  extent,  but  which  are,  nevertheless, 
definite  enough  to  consider  separately.  First  and  innermost  there 
is  a shell  of  crystalline  or  plutonic  rocks,  of  unknown  thickness, 
which  forms  the  nearest  approach  to  the  original  material  of  which 
the  crust  was  composed.  Next,  overlying  this  layer,  is  a shell  of 
sedimentary  and  fragmental  rocks;  and  above  this  is  the  third  layer 
of  soils,  clays,  gravels,  and  the  like  unconsolidated  material.  The 


INTRODUCTION. 


11 


second  and  third  shells  are  relatively  thin,  and  consist  of  material 
derived  chiefly  from  the  first,  in  great  part  through  the  transforming 
agency  of  waters  and  of  the  atmosphere,  although  organic  life  has 
had  some  share  in  bringing  about  certain  of  the  changes.  In  addi- 
tion to  the  substances  which  the  two  derived  layers  have  received 
from  the  original  plutonic  mass  they  contain  carbon  and  oxygen  taken 
up  from  the  atmosphere,  and  also  a considerable  proportion  of  water 
which  has  become  fixed  in  the  clays  and  shales.  Along  with  this  gain 
of  material,  there  has  been  a loss  of  salts  leached  out  into  the  ocean, 
but  the  factor  of  increase  is  the  larger.  When  igneous  rocks  are 
transformed  into  sedimentary  rocks,  there  is  an  average  net  gain  of 
weight  of  8 or  9 per  cent,  as  roughly  estimated  from  the  composition 
of  the  various  kinds  of  rock  under  consideration.  To  some  extent, 
then,  the  ocean  and  the  atmosphere  are  being  slowly  absorbed  by  and 
fixed  in  the  solid  crust  of  the  earth;  although  under  certain  condi- 
tions this  tendency  is  reversed,  with  liberation  of  water  and  of  gases. 
A perfect  balance  of  this  sort,  however,  can  not  be  assumed;  and  how 
far  the  main  absorptive  process  may  go,  it  is  hardly  worth  while  to 
conjecture.  The  data  available  for  the  solution  of  the  problem  are 
too  uncertain. 

Upon  the  subject  of  geochemistry  a vast  literature  exists,  hut  it  is 
widely  scattered  and  portions  of  it  are  difficult  of  access.  The 
general  treatises,  like  the  classical  works  of  Bischof  and  of  Roth, 
are  not  recent,  and  great  masses  of  modern  data  are  as  yet  uncor- 
related. The  American  material  alone  is  singularly  rich,  but  most 
of  it  has  been  accumulated  since  Roth’s  treatise  was  published. 
The  science  of  chemistry,  moreover,  has  undergone  great  changes 
during  the  last  25  years,  and  many  subjects  now  appear  under  new 
and  generally  unfamiliar  aspects.  The  methods  and  principles  of 
physical  chemistry  are  being  more  and  more  applied  to  the  solution 
of  geochemical  problems,1  as  is  shown  by  the  well-known  researches 
of  Van’t  Hoff  upon  the  Stassfurt  salts  and  the  magmatic  studies  of 
Vogt,  Doelter,  and  others.  The  great  work  in  progress  at  the  geo- 
physical laboratory  of  the  Carnegie  Institution  is  another  illustration 
of  the  change  now  taking  place  in  geochemical  investigation.  To 
bring  some  of  the  data  together,  to  formulate  a few  of  the  problems, 
and  to  present  certain  general  conclusions  in  their  modern  form  are 
the  purposes  of  this  memoir.  It  is  not  an  exhaustive  monograph 
upon  geochemistry,  but  rather  a critical  summary  of  what  is  now 
known  and  a guide  to  the  more  important  literature  of  the  subject. 
If  it  does  no  more  than  to  make  existing  data  available  to  the  reader, 
its  preparation  will  be  justified. 


1 Principles  of  chemical  geology,  by  J.  V.  Elsden  (London,  1910),  is  an  excellent  though  brief  treatise  on 
this  aspect  of  geochemistry.  It  covers,  however,  only  a small  portion  of  the  field. 


CHAPTER  I. 

THE  CHEMICAL  ELEMENTS. 

NATURE  OF  THE  ELEMENTS. 

Although  many  thousands  of  compounds  are  known  to  chemists, 
and  an  almost  infinite  number  are  possible,  they  reduce  on  analysis 
to  a small  group  of  substances  which  are  called  elements.  It  is  not 
necessary  for  the  geologist  to  speculate  on  the  ultimate  nature  of 
these  bodies;  it  is  enough  for  him  to  recognize  the  fact  that  all  the 
compounds  found  in  the  -earth  are  formed  by  their  union  with  one 
another  and  that  they  are  not  to  any  considerable  extent  reducible 
to  simpler  forms  of  matter  by  any  means  now  within  our  control. 
To  the  geochemist,  generally  speaking,  they  are  the  final  results  of 
analysis,  beyond  which  it  is  rarely  necessary  to  go.  This  statement, 
however,  must  not  be  taken  without  qualification.  It  is  probable, 
as  shown  by  the  writer  many  years  ago,1  that  the  elements  were 
originally  developed  by  a process  of  evolution  from  much  simpler 
forms  of  matter,  as  is  indicated  by  the  progressive  chemical  com- 
plexity observed  in  passing  from  the  nebulae  through  the  hotter 
stars  to  the  cold  planets.  Changes  in  the  opposite  direction  have 
been  discovered  through  recent  investigations  upon  radioactivity,2 
by  which  an  actual  breaking  down  of  some  elements  is  proved. 
Uranium  undergoes  a slow  metamorphosis  to  radium,  and  radium 
in  turn  passes  through  a series  of  changes  which  ends  in  the  produc- 
tion of  helium.  Thorium  also  exhibits  a similar  instability,  but 
thoiium,  radium,  and  uranium  are  elements  of  high  atomic  weight, 
and  therefore,  in  all  probability,  of  maximum  complexity.  It  is 
conceivable  that  all  the  elements  may  be  similarly  unstable,  but  in 
so  slight  a degree  that  their  transmutations  have  not  yet  been 
detected.  Speculations  of  this  order,  however,  can  be  left  out  of 
consideration  now.  For  present  purposes  the  recognized  elements 
are  our  fundamental  chemical  units,  and  the  questions  of  their 
origin  and  transmutability  may  be  neglected. 

At  present  the  elements  enumerated  in  the  subjoined  table  are 
known,  all  doubtful  substances  being  omitted.  The  radio activ^le- 
ments,  polonium,  actinium,  radio  thorium,  ionium,  etc.,  are  also  dis- 

1 F.  W.  Clarke,  Pop.  Sci.  Monthly,  January,  1873.  See  also  the  later  well-known  speculations  of  J.  Nor- 
man Lockyer. 

2 This  subject  will  be  discussed  at  length  later. 


12 


THE  CHEMICAL  ELEMENTS. 


13 


regarded  for  the  reasons  that  they  are  imperfectly  known  and 
geologically  unimportant.  The  recently  discovered  celtium  is  also 
too  little  known  to  be  included  here. 

The  chemical  elements. 


Symbol. 

Atomic 

weight. 

Aluminum 

A1 

27.  1 

Antimony 

Sb 

120.2 

Argon 

A 

39.  88 

Arsenic 

As 

74.  96 

Barium 

Ba 

137.  37 

Bismuth 

Bi 

208.0 

Boron t . 

B 

11.0 

Bromine 

Br 

79.  92 

Cadmium 

Cd 

112.  40 

Caesium 

Cs 

132.  81 

Calcium 

Ca 

40.  09 

Carbon 

C 

12.  005 

Cerium 

Ce 

140.  25 

Chlorine 

Cl 

35.  46 

Chromium 

Cr 

52.0 

Cobalt 

Co 

58.  97 

Columbium 

Cb 

93.5 

Copper 

Cu 

63.  57 

Dysprosium 

Dy 

162.5 

Erbium 

Er 

167.4 

Europium 

Eu 

152.0 

Fluorine 

F 

19.0 

Gadolinium 

Gd 

157.3 

Gallium 

Ga 

69.9 

Germanium 

Ge 

72.5 

Glucinum 

G1 

9.1 

Gold 

Au 

197.2 

Helium 

He 

4.  00 

Hydrogen 

H 

1.  008 

Indium 

In 

114.8 

Iodine 

I 

126.  92 

Iridium 

Ir 

193. 1 

Iron 

Fe 

55.  85 

Krypton 

Kr 

82.9 

Lanthanum 

La 

139.0 

Lead 

Pb 

207.  20 

Lithium 

Li 

6.94 

Lutecium 

Lu 

175.0 

Magnesium 

Mg 

24.  32 

Manganese 

Mn 

54.  93 

Mercury 

Hg 

200.  6 

Molybdenum 

Mo 

96.0 

Symbol. 

Atomic 

weight. 

Neodymium 

Nd 

144.3 

Neon 

Ne 

20.0 

Nickel 

Ni 

58.  68 

Niton 

Nt 

222.4 

Nitrogen 

N 

14.  01 

Osmium 

Os 

190.  9 

Oxygen 

O 

16.  00 

Palladium 

Pd 

106.  7 

Phosphorus 

P 

31.  04 

Platinum 

Pt 

195.2 

Potassium 

K 

39. 10 

Praseodymium 

Pr 

140.9 

Radium 

Ra 

226.  0 

Rhodium 

Rh 

102.9 

Rubidium 

Rb 

85.  45 

Ruthenium 

Ru 

101.7 

Samarium 

Sa 

150.4 

Scandium 

Sc 

44. 1 

Selenium 

Se 

79.2 

Silicon 

Si 

28.3 

Silver 

Ag 

107.  88 

Sodium 

Na 

23.  00 

Strontium 

Sr 

87.  63 

Sulphur 

S 

32.  06 

Tantalum 

Ta 

181.5 

Tellurium 

Te 

127.5 

Terbium 

Tb 

159.2 

Thallium 

T1 

204.0 

Thorium 

Th 

232.4 

Thulium 

Tm 

168.5 

Tin 

Sn 

118.7 

Titanium 

Ti 

48. 1 

Tungsten 

W 

184.0 

Uranium 

U 

238.2 

Vanadium 

V 

51.  06 

Xenon 

Xe 

130.2 

Ytterbium  (Neoyt- 

terbium)   

Yb 

173.5 

Yttrium 

Yt 

88.7 

Zinc 

Zn 

65.  37 

Zirconium 

Zr 

90.6 

DISTRIBUTION  OF  THE  ELEMENTS.1 

The  elements  differ  widely  in  their  abundance  and  in  their  mode  of 
distribution  in  nature.  Under  the  latter  heading  the  more  important 
data  may  be  summarized  as  follows: 

Aluminum. — The  most  abundant  of  all  the  metals.  An  essential 
constituent  of  all  important  rocks  except  the  sandstones  and  lime- 

1 For  an  early  table  showing  distribution,  see  Elie  de  Beaumont,  Bull.  Soc.  g£ol.  France,  2d  ser.,  vol.  4, 
1846-47,  p.  1333. 


14 


THE  DATA  OF  GEOCHEMISTRY. 


stones,  and  even  in  these  its  compounds  are  common  impurities. 
Being  easily  oxidized,  it  nowhere  occurs  native.  Found  chiefly  in 
silicates,  such  as  the  feldspars,  micas,  clays,  etc.;  but  also  as  the 
oxide,  corundum;  the  hydroxide,  bauxite;  as  fluoride  in  cryolite;  and 
in  various  phosphates  and  sulphates.  With  the  exception  of  the 
fluorides,  only  oxidized  compounds  of  aluminum  are  known  to  exist 
in  nature. 

Antimony. — Common,  but  neither  abundant  nor  widely  diffused. 
Found  native,  more  frequently  as  the  sulphide,  stibnite,  also  in  vari- 
ous antimonides  and  sulphantimonides  of  the  heavy  metals,  and  as 
oxide  of  secondary  origin.  The  minerals  of  antimony  are  generally 
found  in  metalliferous  veins,  but  the  amorphous  sulphide  has  been 
observed  as  a deposit  upon  sinter  at  Steamboat  Springs,  Nevada. 

Argon. — An  inert  gas  that  forms  nearly  1 per  cent  of  the  atmos- 
phere, and  is  also  found  in  some  mineral  springs.  No  compounds  of 
argon  are  known. 

Arsenic. — Found  native,  in  two  sulphides,  in  various  arsenides  and 
sulpharsenides  of  the  heavy  metals,  as  oxide,  and  in  a considerable 
number  of  arsenates.  Axsenopyrite  is  the  commonest  arsenical  min- 
eral. Arsenic  is  very  widely  diffused  and  traces  of  it  exist  normally 
even  in  organic  matter.  It  is  not  an  uncommon  ingredient  in  min- 
eral, especially  thermal,  springs.  In  its  chemical  relations  it  is 
regarded  as  nonmetallic  and  closely  allied  to  phosphorus. 

Barium. — Widely  distributed  in  small  quantities  throughout  the 
igneous  rocks,  probably  as  a minor  constituent  of  the  feldspars  and 
micas,  although  other  silicates  containing  barium  are  known.  Com- 
monly found  concentrated  as  the  sulphate,  barite,  or  as  the  carbonate, 
witherite.  This  element  occurs  only  in  oxidized  compounds.1 

Bismuth. — Resembles  antimony  in  its  modes  of  occurrence,  but  is 
less  common.  Native  bismuth  and  the  sulphide,  bismuthinite,  are  its 
chief  ores.  Two  silicates  of  bismuth,  several  sulphobismuthides,  and 
the  telluride,  oxide,  carbonate,  vanadate,  and  arsenate  exist  as  rela- 
tively rare  mineral  species. 

Boron. — An  essential  constituent  of  several  silicates,  notably  of 
tourmaline  and  datolite.  Its  compounds  are  obtained  commercially 
from  borates,  such  as  borax,  ulexite,  and  colemanite,  or  from  native 
orthoboric  acid,  sassolite,  which  is  foimd  in  the  waters  of  certain 
volcanic  springs.  Some  alkaline  lakes  or  lagoons,  especially  in  Cali- 
fornia and  Tibet,  yield  borax  in  large  quantities. 

Bromine. — Found  in  natural  waters  in  the  form  of  bromides.  Sea 
water  contains  it  in  appreciable  quantities,  and  much  bromine  has 
been  extracted  from  the  brine  wells  of  West  Virginia  and  Michigan. 
The  bromide  and  chlorobromide  of  silver  are  well-known  ores. 


1 On  barium  in  soils,  see  G.  H.  Failyer,  Bull.  Bur.  Soils  No.  72,  U.  S.  Dept  Agr.,  1910. 


THE  CHEMICAL  ELEMENTS. 


15 


Cadmium. — A relatively  rare  metal  found  in  association  with  zinc, 
which  it  resembles.  Occurs  usually  as  the  sulphide,  greenockite. 

Cxsium. — A rare  metal  of  the  alkaline  group,  allied  to  potassium. 
Often  found  in  lepidolite,  and  in  the  waters  of  some  mineral  springs. 
The  very  rare  mineral  pollucite  is  a silicate  of  aluminum  and  caesium. 

Calcium. — One  of  the  most  abundant  metals,  but  never  found  in 
nature  uncombined.  An  essential  constituent  of  many  rock-forming 
minerals,  especially  of  anorthite,  garnet,  epidote,  the  amphiboles, 
the  pyroxenes,  and  scapolite.  Limestone  is  the  carbonate,  fluorspar 
is  the  fluoride,  and  gypsum  is  the  sulphate  of  calcium.  Apatite  is 
the  fluophosphate  or  chlorophosphate  of  this  metal.  Many  other 
mineral  species  also  contain  calcium,  and  it  is  found  in  nearly  all 
natural  waters  and  in  connection  with  organized  life,  as  in  bones 
and  shells.  Calcium  sulphide  has  been  identified  in  meteorites. 

Carbon. — The  characteristic  element  of  organic  matter.  In  the 
mineral  kingdom  carbon  is  found  crystallized  as  graphite  and  dia- 
mond and  also  amorphous  in  coal.  Carbon  dioxide  is  a normal 
constituent  of  atmospheric  air.  Natural  gas,  petroleum,  and  bitumen 
are  essentially  hydrocarbons.  Carbonic  acid  and  carbonates  exist 
in  most  natural  waters,  and  great  rock  masses  are  composed  of  carbon- 
ates of  calcium,  magnesium,  and  iron.  A few  silicates  contain  car- 
bon, but  of  these,  cancrinite  is  the  only  species  having  petrographic 
importance. 

Cerium. — One  of  the  group  of  elements  known  as  the  metals  of  the 
rare  earths.  These  substances  are  generally  found  in  granites  or 
elseolite  syenites,  or  in  gravels  derived  therefrom.  Cerium  exists 
in  a considerable  number  of  mineral  species,  but  the  phosphate, 
monazite,  and  the  silicates,  cerite  and  allanite,  are  all  that  need  be 
mentioned  here. 

Chlorine. — The  most  abundant  element  of  the  halogen  group. 
Commonly  found  as  sodium  chloride,  as  in  sea  water  and  rock  salt. 
Also  in  certain  rock-forming  minerals,  such  as  sodalite  and  the 
scapolites,  and  in  a variety  of  other  minerals  of  greater  or  less  im- 
portance. Silver  chloride,  for  example,  is  a well-known  ore,  and 
carnallite  is  valuable  for  the  potassium  which  it  contains. 

Chromium. — Very  widely  diffused,  generally  in  the  form  of  chro- 
mite, and  most  commonly  in  magnesian  rocks.  A few  chromates  and 
several  silicates  containing  chromium  are  also  known,  but  as  rela- 
tively rare  minerals. 

Cobalt. — Less  abundant  than  nickel,  with  which  it  is  generally 
associated.  Usually  found  as  sulphide  or  arsenide,  or  in  oxidized 
salts  derived  from  those  compounds. 

Columbium.1 — A rare  acid-forming  element  resembling  and  associ- 
ated with  tantalum.  Both  form  salts  with  iron,  manganese,  calcium, 


Also  known  as  "niobium.”  The  name  columbium  has  more  than  40  years’  priority. 


16 


THE  DATA  OF  GEOCHEMISTRY. 


uranium,  and  the  rare-earth  metals,  the  minerals  columbite,  tantalite, 
and  samarskite  being  typical  examples.  All  these  minerals  are 
most  abundant  in  pegmatite  veins. 

Copper.— Minute  traces  of  this  metal  are  often  detected  in  igneous 
rocks,  although  they  are  rarely  determined  quantitatively.  Also 
present  in  sea  water  in  very  small  amounts.  Its  chief  ores  are 
native  copper,  several  sulphides,  two  oxides,  and  two  carbonates. 
The  arsenides,  arsenates,  antimonides,  phosphates,  sulphates,  and 
silicates  also  exist  in  nature,  but  are  less  important.  In  chalco- 
pyrite  and  bornite,  copper  is  associated  with  iron. 

Dysprosium. — A little-known  metal  of  the  rare  earths. 

Erbium. — One  of  the  rare-earth  metals  of  the  yttrium  group.  See 
“ Yttrium.’ ’ 

Europium. — Another  metal  of  the  rare  earths,  of  slight  importance. 

Fluorine. — The  most  characteristic  minerals  of  fluorine  are  cal- 
cium fluoride  (fluor  spar)  and  cryolite,  a fluoride  of  aluminum  and 
sodium.  Apatite  is  a phosphate  containing  fluorine,  and  the  element 
is  also  found  in  a goodly  number  of  silicates,  such  as  topaz,  tourma- 
line, the  micas,  etc.  Fluorine,  therefore,  is  commonly  present  in 
igneous  rocks,  although  in  small  quantities. 

Gadolinium. — One  of  the  metals  of  the  rare  earths.  See  “Cerium” 
and  “Yttrium  ” 

Gallium. — A very  rare  metal  whose  salts  resemble  those  of  alu- 
minum. Found  in  traces  in  many  zinc  blendes.  Always  present 
in  spectroscopic  traces  in  bauxite  and  in  nearly  all  aluminous 
minerals. 

Germanium. — A very  rare  metal  allied  to  tin.  The  mineral  argy- 
rodite  is  a sulphide  of  germanium  and  silver. 

Glucinum. — A relatively  rare  metal,  first  discovered  in  beryl,  from 
which  the  alternative  name  beryllium  is  derived.  Found  also  in  the 
aluminate,  chrysoberyl;  in  several  rare  silicates  and  phosphates; 
and  in  a borate,  hambergite.  As  a rule  the  minerals  of  glucinum 
occur  in  granitic  rocks. 

Gold. — Found  in  nature  as  the  free  metal  and  in  tellurides.  Very 
widely  distributed  and  under  a great  variety  of  conditions,  but 
almost  invariably  associated  with  quartz  or  pyrite.  Gold  has  been 
observed  in  process  of  deposition,  probably  from  solution  in  alkaline 
sulphides,  at  Steamboat  Springs,  Nevada.  It  is  also  present,  in  very 
small  traces,  in  sea  water. 

Helium. — An  inert  gas  obtained  from  uraninite.  The  largest 
quantities  are  derived  from  the  Ceylonese  thorianite  and  the  highly 
crystalline  uraninite  found  in  pegmatite.  The  massive  mineral  from 
metalliferous  veins  contains  little  or  no  helium.  Traces  of  helium 
also  exist  in  the  atmosphere,  in  spring  waters,  and  in  some  samples 
of  natural  gas. 


THE  CHEMICAL  ELEMENTS. 


17 


Holmium. — One  of  the  rare-earth  metals.  Little  known. 

Hydrogen. — This  element  forms  about  one-ninth  part  by  weight 
of  water,  and  therefore  it  occurs  almost  everywhere  in  nature.  In 
a majority  of  all  mineral  species,  and  therefore  in  practically  all 
rocks,  it  is  found,  either  as  occluded  moisture,  as  water  of  crystal- 
lization, or  combined  as  hydroxyl.  All  organic  matter  contains 
hydrogen,  and  hence  it  is  an  essential  constituent  of  such  derived 
substances  as  natural  gas,  petroleum,  asphaltum,  and  coal.  The 
free  gas  has  been  detected  in  the  atmosphere,  but  in  very  minute 
quantities. 

Indium. — A rare  metal,  found  in  very  small  quantities  in  certain 
zinc  blendes.  Spectroscopic  traces  of  it  can  be  detected  in  many 
minerals,  especially  in  iron  ores. 

Iodine.— The  least  abundant  element  of  the  halogen  group.  Found 
in  sea  water,  in  certain  mineral  springs,  and  in  a few  rare  minerals; 
especially  the  iodides  of  silver,  copper,  and  lead.  Calcium  iodate, 
lautarite,  exists  in  the  Chilean  nitrate  beds. 

Iridium. — A metal  of  the  platinum  group.  See  “Platinum.” 

Iron. — Next  to  aluminum,  the  most  abundant  metal,  although 
native  iron  is  rare.  Found  in  greater  or  less  amount  in  practically 
all  rocks,  especially  in  those  which  contain  amphiboles,  pyroxenes, 
micas,  or  olivine.  Magnetite  and  hematite  are  oxides  of  iron,  limon- 
ite  is  a hydroxide,  pyrite  and  marcasite  are  sulphides,  siderite  is 
the  carbonate,  and  there  are  also  many  silicates,  phosphates,  arse- 
nates, etc.,  which  contain  this  element.  The  mineral  species  of  which 
iron  is  a normal  constituent  are  numbered  by  hundreds. 

Krypton. — An  inert  gas  of  the  argon  group,  found  in  small  quanti- 
ties in  the  atmosphere. 

Lanthanum. — A metal  of  the  rare-earth  group,  almost  invariably 
associated  with  cerium,  g.  v.  Lanthanite  is  the  carbonate  of 
lanthanum. 

Lead. — Found  chiefly  in  the  sulphide,  galena,  from  which,  by 
alteration,  various  oxides,  the  sulphate,  and  the  carbonate  are  derived. 
Native  lead  is  rare.  A number  of  sulphosalts  are  known,  several 
silicates,  and  also  a phosphate,  an  arsenate,  and  some  vanadates. 
Galena  is  frequently  associated  with  pyrite,  marcasite,  and  sphalerite. 

Lithium. — One  of  the  alkaline  metals.  Traces  of  it  are  found  in 
nearly  all  igneous  rocks,  and  in  the  waters  of  many  mineral  springs. 
The  more  important  lithia  minerals  are  lepidolite,  spodumene,  petal- 
ite,  amblygonite,  triphylite,  and  the  lithia  tourmalines. 

Lutecium. — One  of  the  rare-earth  minerals.  See  “Yttrium  and 
ytterbium.” 

Magnesium. — One  of  the  most  abundant  metals.  In  igneous  rocks 
it  is  represented  by  amphiboles,  pyroxenes,  micas,  and  olivine.  Talc, 
97270°— Bull.  616—16 2 


18 


THE  DATA  OF  GEOCHEMISTRY. 


chlorite,  and  serpentine  are  common  magnesium  silicates,  and 
dolomite,  the  carbonate  of  magnesia  and  lime,  is  also  found  in 
enormous  quantities.  Magnesium  compounds  occur  in  sea  water  and 
in  many  mineral  springs.  The  metal  is  not  found  native. 

Manganese. — Widely  diffused  in  small  quantities.  Found  in  most 
rocks  and  in  some  mineral  waters.  Never  native.  Occurs  commonly 
in  silicates,  oxides,  and  carbonates,  less  frequently  in  sulphides, 
phosphates,  tungstates,  columbates,  etc.  The  dioxide,  pyrolusite, 
and  the  hydroxide,  psilomelane,  are  the  commonest  manganese 
minerals. 

Mercury. — This  metal  is  neither  abundant  nor  widely  diffused. 
Exists  as  native  mercury,  but  is  usually  found,  locally  concentrated, 
in  the  form  of  the  sulphide,  cinnabar.  Chlorides  of  mercury,  the 
oxide,  the  selenide,  and  the  telluride,  are  relatively  rare  minerals. 
Cinnabar  has  been  observed  in  process  of  deposition  by  solfataric 
action  at  Sulphur  Bank,  California;  and  Steamboat  Springs,  Nevada. 

Molybdenum. — One  of  the  rarer  metals.  Most  frequently  found  in 
granite  in  the  form  of  the  sulphide,  molybdenite.  The  molybdates 
of  iron,  calcium,  and  lead  are  also  known  as  mineral  species. 

Neodymium. — One  of  the  rare-earth  metals  associated  with  cerium. 

Neon. — An  inert  gas  of  the  argon  group,  found  in  minute  traces  in 
the  atmosphere. 

Nickel. — Closely  allied  to  cobalt.  Found  native,  alloyed  with 
iron,  in  meteorites  and  in  the  terrestrial  minerals  awaruite  and 
josephinite.  Very  frequently  detected  in  igneous  rocks,  probably 
as  a constituent  of  olivine.  Occurs  primarily  in  silicates,  sulphides, 
arsenides,  antimonides,  and  as  telluride,  and  secondarily  in  several 
other  minerals.  The  presence  of  nickel  is  especially  characteristic 
of  magnesian  igneous  rocks,  and  it  is  generally  associated  in  them 
with  chromium. 

Niton. — The  gaseous  emanation  of  radium.  It  is  the  highest 
member  of  the  argon  group. 

Nitrogen. — The  predominant  element  of  the  atmosphere,  in  which 
it  is  uncombined.  Also  abundant  in  organic  matter,  and  in  such 
derived  substances  as  coal.  Nitrates  are  found  in  the  soil  and  in 
cave  earth;  and  in  some  arid  regions,  as  in  Chile,  they  exist  in 
enormous  quantities.  Some  volcanic  waters  contain  nitrogen  in  the 
form  of  ammonium  compounds. 

Osmium. — A metal  of  the  platinum  group.  See  “Platinum.” 

Oxygen. — The  most  abundant  of  the  elements,  forming  about  one- 
half  of  all  known  terrestrial  matter.  In  the  free  state  it  constitutes 
about  one-fifth  of  the  atmosphere;  and  in  water  it  is  the  chief  ele- 
ment of  the  ocean.  All  important  rocks  contain  oxygen  in  propor- 
tions ranging  from  45  to  53  per  cent. 

Palladium. — A metal  of  the  platinum  group. 


THE  CHEMICAL  ELEMENTS. 


19 


Phosphorus. — Found  in  nearly  all  igneous  rocks,  generally  as  a 
constituent  of  apatite.  With  one  or  two  minor  exceptions,  it  exists 
in  the  mineral  kingdom  only  in  the  form  of  phosphates,  of  which  a 
large  number  are  known.  An  iron  phosphide  occurs  in  meteorites. 
Phosphorus  is  also  an  essential  constituent  of  living  matter,  espe- 
cially of  bones,  and  certain  large  deposits  of  calcium  phosphate  are 
of  organic  origin. 

Platinum. — Platinum,  iridium,  osmium,  ruthenium,  rhodium,  and 
palladium  constitute  a group  of  metals  of  which  the  first  named  is 
the  most  important.  As  a rule  they  are  found  associated  together, 
and  generally  uncombined.  To  the  latter  statement  there  are  two 
known  exceptions — sperrylite  is  platinum  arsenide,  and  laurite  is 
ruthenium  sulphide.  Native  platinum,  platiniridium,  iridosmine, 
and  native  palladium  are  all  reckoned  as  definite  mineral  species.  The 
metals  of  this  group  are  commonly  found  associated  with  magnesian 
rocks,  or  in  gravels  derived  from  them.  Chromite  often  accompanies 
platinum,  and  so  also  do  the  ores  of  nickel.  Sperrylite  is  found  in 
the  nickeliferous  deposits  at  Sudbury,  Canada;  and  has  also  been 
identified  in  the  sulphide  ores  of  the  Rambler  mine  in  Wyoming.  In 
the  latter  ores  palladium  is  present  also,  and  possibly,  like  the 
platinum,  as  arsenide. 

Potassium. — An  abundant  metal  of  the  alkaline  group.  Found  in 
many  rocks,  especially  as  a constituent  of  the  feldspars,  micas,  and 
leucite.  Nearly  all  terrestrial  waters  contain  potassium,  and  the 
saline  beds  near  Stassfurt,  Germany,  are  peculiarly  rich  in  it. 

Praseodymium. — A rare-earth  metal  associated  with  cerium. 

Radium. — A very  rare  metal  of  the  calcium-barium  group.  Ob- 
tained in  minute  quantities  from  uraninite  and  carnotite.  Of  possible 
importance  in  the  study  of  volcanism.  According  to  R.  J.  Strutt,1 
traces  of  radium  can  be  detected  in  all  igneous  rocks. 

Rhodium. — A metal  of  the  platinum  group.  See  “Platinum.” 

Rubidium —An.  alkaline  metal  intermediate  between  potassium 
and  caesium.  Found  in  lepidolite  and  in  some  mineral  springs. 
Rubidium  is  reported  as  present  in  the  waters  of  the  Caspian  Sea. 

Ruthenium. — A metal  of  the  platinum  group.  See  “ Platinum.” 

Samarium.— A rare-earth  metal  obtained  from  samarskite. 

Scandium. — A rare-earth  metal  obtained  from  euxenite,  and  also 
from  wolfram.  According  to  G.  Eberhard  2 it  is  the  most  widely 
diffused  of  all  the  rare-earth  group,  although  it  is  found  only  in  very 
small  quantities. 

Selenium. — A nonmetallic  element  allied  to  sulphur,  with  which  it 
is  commonly  associated.  Found  native,  and  also  in  the  selenides  of 


1 Proc.  Roy.  Soc.,  vol.  77,  ser.  A,  1906,  p.  472. 

2 Sitzungsb.  Berlin  Akad.,  1908,  p.  851.  See  also  a later  paper  in  Chem.  News,  vol.  102, 1910,  p.  211.  On 
scandium  in  American  wolfram,  see  H.  S.  Lukens,  Jour.  Am.  Chem.  Soc.,  vol.  35, 1913,  p.  1470. 


20 


THE  DATA  OF  GEOCHEMISTRY. 


copper,  silver,  mercury,  lead,  bismuth,  and  thallium.  A few  selenites 
exist  as  secondary  minerals. 

Silicon. — Next  to  oxygen,  the  most  abundant  element.  Found  in 
quartz,  tridymite,  opal,  and  all  silicates.  The  characteristic  element 
of  all  important  rocks  except  the  carbonates.  Silica  also  exists  in 
probably  all  river,  well,  and  spring  waters.  From  volcanic  waters  it 
is  deposited  in  the  form  of  sinter. 

Silver. — This  metal  occurs  native,  as  sulphide,  arsenide,  antimonide, 
telluride,  chloride,  bromide,  iodide,  and  in  numerous  sulphosalts. 
Native  gold  generally  contains  some  silver,  and  the  latter  is  also  often 
associated  with  native  copper.  Oxidized  compounds  of  silver  are 
known  only  as  artificial  products.  Small  traces  of  silver  exist  in  sea 
water. 

Sodium. — The  most  abundant  of  the  alkaline  metals.  In  igneous 
rocks  it  is  a constituent  of  the  feldspars,  of  the  nepheline  group  of 
minerals,  and  of  certain  pyroxenes,  such  as  segirite.  Also  abundant 
in  rock  salt,  and  in  nearly  all  natural  waters,  sea  water  especially. 

Strontium. — A metal  intermediate  between  calcium  and  barium, 
but  less  abundant  than  the  latter.  Strontium  in  small  amount  is  a 
common  ingredient  of  igneous  rocks.  The  most  important  strontium 
minerals  are  the  sulphate,  celestite,  and  the  carbonate,  strontianite. 

Sulphur. — Found  native  and  in  many  sulphides  and  sulphates. 
Also  in  igneous  rocks  in  the  sulphatosilicates,  hauynite  and  nosean. 
Native  sulphur  is  abundant  in  volcanic  regions,  and  is  also  formed 
elsewhere  by  the  reduction  of  sulphates.  Pyrite  is  the  commonest 
of  the  sulphides,  gypsum  of  the  sulphates.  Alkaline  sulphates  are 
obtainable  from  many  natural  waters.  Sulphur  also  exists  in  coal 
and  petroleum. 

Tantalum. — A rare  acid-forming  element  akin  to  columbium,  with 
which  it  is  usually  associated. 

Tellurium. — A semimetallic  element,  the  least  abundant  of  the 
sulphur  group.  Found  native,  and  in  the  tellurides  of  gold,  silver, 
lead,  bismuth,  mercury,  nickel,  and  copper.  Its  oxide  and  a few  rare 
tellurates  or  tellurites  are  known  as  alteration  products. 

Terbium. — A rare-earth  metal  of  the  yttrium  group.  See 
“Yttrium.” 

Thallium. — One  of  the  rarer  heavy  metals.  Found  as  an  impurity 
in  pyrite  and  some  other  sulphides.  The  rare  mineral  crookesite  is 
a selenide  of  copper  and  thallium,  and  lorandite  is  sulpharsenide  of 
thallium.  Yrbaite  is  a sulphide  of  arsenic,  antimony,  and  thallium. 

Thorium. — A rare  metal  of  the  titanium-zirconium  group,  the  most 
basic  of  the  series.  Chiefly  obtained  from  monazite  sand.  Also 
known  in  silicates,  such  as  thorite,  in  some  columbo-tantalates,  and 
in  certain  varieties  of  uraninite. 


THE  CHEMICAL  ELEMENTS. 


21 


Thulium. — A rare-earth  metal  of  which  little  is  known. 

Tin. — Very  rare  native.  Most  abundant  as  the  oxide,  cassiterite, 
which  is  found  in  association  with  granitic  rocks.  Traces  of  tin  have 
been  detected  in  feldspar.  Stannite,  or  tin  pyrites,  is  a sulphide  of 
tin,  copper,  and  iron,  and  a few  other  rare  minerals  contain  this  ele- 
ment. 

Titanium. — This  element  is  almost  invariably  present  in  igneous 
rocks  and  in  the  sedimentary  material  derived  from  them.  Out  of 
800  igneous  rocks  analyzed  in  the  laboratory  of  the  United  States 
Geological  Survey,  784  contained  titanium.  Its  commonest  occur- 
rences are  as  titanite,  ilmenite,  rutile,  and  perofskite.  The  element 
is  often  concentrated  in  beds  of  titanic  iron  ore. 

Tungsten—  An  acid-forming  heavy  metal  allied  to  molybdenum. 
Found  as  tungstates  of  iron,  manganese,  calcium,  and  lead  in  the 
minerals  wolfram,  hubnerite,  scheelite,  and  stolzite. 

TJranium. — A heavy  metal  found  chiefly  in  uraninite,  carnotite, 
samarskite,  and  a few  other  rare  minerals.  The  phosphates,  autunite 
and  torbernite,  are  not  uncommon  in  granites,  and  uraninite,  although 
sometimes  obtained  from  metalliferous  veins,  is  more  generally  of 
granitic  association.  Carnotite  occurs  with  sedimentary  sandstones. 

Vanadium. — A rare  element,  both  acid  and  base  forming,  and  allied 
to  phosphorus.  Found  in  vanadates,  such  as  vanadinite,  descloizite, 
and  pucherite,  associated  with  lead,  copper,  zinc,  and  bismuth.  Also 
in  the  silicates  roscoelite  and  ardennite.  Carnotite,  which  was  men- 
tioned in  the  preceding  paragraph,  is  an  impure  vanadate  of  potas- 
sium and  uranium.  Sulvanite  is  a sulphovanadate  of  copper. 
Patronite,  a sulphide  of  vanadium,  forms  a large  deposit  at  one  locality 
in  Peru. 

Xenon. — An  inert  gas,  the  heaviest  member  of  the  argon  group. 
Found  in  minute  traces  in  the  atmosphere. 

Yttrium  and  ytterbium. — Two  rare-earth  metals,  which,  with  lute- 
cium,1 erbium,  and  terbium,  are  best  obtained  from  gadolinite. 
Yttrium  is  also  found  in  the  phosphate,  xenotime,  in  several  silicates, 
and  in  some  of  the  columbo-tantalate  group  of  minerals.  The  min- 
erals of  the  rare  earths  are  generally  found  in  granite  or  pegmatite 
veins. 

Zinc. — Common  and  rather  widely  diffused.  Native  zinc  has  been 
reported,  but  its  existence  is  doubtful.  The  sulphide,  sphalerite,  is 
its  commonest  ore,  but  the  carbonate,  smithsonite,  and  a silicate, 
calamine,  are  also  abundant.  At  Franklin,  New  Jersey,  zinc  is  found 

1 The  old  ytterbium,  the  ytterbium  of  the  first  edition  of  this  work,  has  been  proved  to  he  complex 
by  G.  Urbain  and  Auer  von  Welsbach,  working  independently.  The  two  components  of  the  former  ytter- 
bium are  by  Urbain  named  neoytterbium  and  lutecium.  For  these  Welsbach  proposes  the  names  alde- 
baranium  and  cassiopeium.  The  name  ytterbium  is  here  retained  for  the  main  component  of  the  mixture 
and  lutecium  for  the  other,  as  having  priority  over  its  synonym. 


22 


THE  DATA  OF  GEOCHEMISTRY. 


in  a unique  deposit,  in  which  the  oxide,  zincite;  the  ferrite,  frank- 
linite;  and  the  silicates,  troostite,  and  willemite,  are  the  character- 
istic ores. 

Zirconium. — Allied  to  titanium  and  rather  widely  diffused  in  the 
igneous  rocks.  It  usually  occurs  in  the  silicate,  zircon. 

RELATIVE  ABUNDANCE  OF  THE  ELEMENTS. 

In  any  attempt  to  compute  the  relative  abundance  of  the  chemical 
elements,  we  must  bear  in  mind  the  limitations  of  our  experience. 
Our  knowledge  of  terrestrial  matter  extends  but  a short  distance 
below  the  surface  of  the  earth,  and  beyond  that  we  can  only  indulge 
in  speculation.  The  atmosphere,  the  ocean,  and  a thin  shell  of  solids 
are,  speaking  broadly,  all  that  we  can  examine.  For  the  first  two 
layers  our  information  is  reasonably  good,  and  their  masses  are 
approximately  determined;  but  for  the  last  one  we  must  assume 
some  arbitrary  limit.  The  real  thickness  of  the  lithosphere  need  not 
be  considered;  but  it  seems  probable  that  to  a depth  of  10  miles 
below  sea  level  the  rocky  material  can  not  vary  greatly  from  the 
volcanic  outflows  which  we  recognize  at  the  surface.  This  thickness 
of  10  miles,  then,  represents  known  matter,  and  gives  us  a quantita- 
tive basis  for  study.  A shell  only  6 miles  thick  would  barely  clear 
the  lowest  deeps  of  the  ocean. 

I am  indebted  to  Dr.  R.  S.  Woodward  for  data  relative  to  the 
volume  of  matter  which  is  thus  taken  into  account.  The  volume  of 
the  10-mile  rocky  crust,  including  the  mean  elevation  of  the  con- 
tinents above  the  sea,  is  1,633,000,000  cubic  miles,  and  to  this 
material  we  may  assign  a mean  density  not  lower  than  2.5  nor  much 
higher  than  2.7.  The  volume  of  the  ocean  is  put  at  302,000,000  1 
cubic  miles,  and  I have  given  it  a density  of  1.03,  which  is  a trifle 
too  high.  The  mass  of  the  atmosphere,  so  far  as  it  can  be  deter- 
mined, is  equivalent  to  that  of  1,268,000  cubic  miles  of  water,  the  unit 
of  density.  Combining  these  data,  we  get  the  following  expressions 
for  the  composition  of  the  known  matter  of  our  globe: 


Composition  of  known  matter  of  the  earth. 


Density  of  crust 

2.5 

2.7 

Atmosphere per  cent. . 

Ocean do 

Solid  crust do 

0.  03 
7.  08 
92.  89 

0.  03 
6.58 
93.  39 

100.  00 

100.00 

1 Sir  John  Murray  (Scottish  Geog.  Mag.,  1888,  p.  39)  estimates  the  volume  of  the  ocean  at  323,722,150 

cubic  miles.  K.  Karstens.  more  recently  (Eine  neue  Berechnung  der  mittleren  Tiefen  der  Oceane,  Inaug. 
Diss.,  Kiel,  1894),  put  it  at  1,285,935,211  cubic  kilometers,  or  307,496,000  cubic  miles.  Karstens  gives  a good 
summary  of  previous  estimates,  which  vary  widely.  According  to  O.  Kriimmel,  the  volume  is  319,087,500 
cubic  miles  (Encyc.  Britannica,  11th  ed.,  vol.  19,  p.  974).  To  change  the  figure  given  in  the  text  would 
be  straining  after  unattainable  precision. 


THE  CHEMICAL  ELEMENTS. 


23 


In  short,  we  can  regard  the  surface  layer  of  the  earth,  to  a depth 
of  10  miles,  as  consisting  very  nearly  of  93  per  cent  solid  and  7 per 
cent  liquid  matter,  treating  the  atmosphere  as  a small  correction  to 
be  applied  when  needed.1  The  figure  thus  assigned  to  the  ocean  is 
probably  a little  too  high,  but  its  adoption  makes  an  allowance  for 
the  fresh  waters  of  the  globe,  which  are  too  small  in  amount  to  be 
estimable  directly.  Their  insignificance  may  be  inferred  from  the 
fact  that  a section  of  the  10-mile  crust  having  the  surface  area  of 
the  United  States  represents  only  about  1.5  per  cent  of  the  entire 
mass  of  matter  under  consideration.  A quantity  of  water  equivalent 
to  1 per  cent  of  the  ocean,  or  0.07  per  cent  of  the  matter  now  con- 
sidered, would  cover  all  the  land  areas  of  the  globe  to  a depth  of  290 
feet.  Even  the  mass  of  Lake  Superior  thus  becomes  a negligible 
quantity.  The  significance  of  underground  waters  will  be  discussed 
later. 

The  composition  of  the  ocean  is  easily  determined  from  the  data 
given  by  Dittmar  in  the  report  of  the  Challenger  expedition.2  The 
maximum  salinity  observed  by  him  amounted  to  37.37  grams  of  salts 
in  a kilogram  of  water,  and  by  taking  this  figure  instead  of  a lower 
average  value  we  can  allow  for  saline  masses  inclosed  within  the 
solid  crust  of  the  earth,  which  would  not  otherwise  appear  in  the 
final  estimates.  Combining  this  datum  with  Dittmar’s  figures  for 
the  average  composition  of  the  oceanic  salts,  we  get  the  second  of 
the  subjoined  columns.  Other  elements  contained  in  sea  water,  but 
only  in  minute  traces,  need  not  be  considered  here.  No  one  of  them 
could  reach  0.001  per  cent. 


Composition  of  oceanic  salts. 


NaCl 

77.76 

MgCl2 

10.88 

MgS04 

4. 74 

CaS04 

3. 60 

k2so4 

2. 46 

MgBr2 

22 

CaC03 

34 

100.  00 

Composition  of  ocean. 


0 85.79 

H 10.67 

Cl 2.  07 

Na 1. 14 

Mg 14 

Ca 05 

K 04 

S 09 

Br 008 

C 002 


100.  00 


It  is  worth  while  at  this  point  to  consider  how  large  a mass  of 
matter  these  oceanic  salts  represent.  The  average  salinity  of  the 
ocean  is  not  far  from  3.5  per  cent;  its  mean  density  is  1.027,  and  its 
volume  is  302,000,000  cubic  miles.  The  specific  gravity  of  the  salts, 
as  nearly  as  can  be  computed,  is  2.25.  From  these  data  it  can  be 


1 The  adoption  of  Murray’s  figure  for  the  volume  of  the  ocean  would  make  its  percentage  7.12  to  7.88 
according  to  the  density  (2.5  or  2.7)  assigned  to  the  lithosphere. 

2 In  vol.  1,  Physics  and  chemistry. 


24 


THE  DATA  OF  GEOCHEMISTRY. 


shown  that  the  volume  of  the  saline  matter  in  the  ocean  is  a little 
more  than  4,800,000  cubic  miles,  or  enough  to  cover  the  entire  surface 
of  the  United  States,  excluding  Alaska,  1.6  miles  deep.1  In  the  face 
of  these  figures,  the  beds  of  rock  salt  at  Stassfurt  and  elsewhere, 
which  seem  so  enormous  at  close  range,  become  absolutely  trivial. 
The  allowance  made  for  them  by  using  the  maximum  salinity  of  the 
ocean  instead  of  the  average  is  more  than  sufficient,  for  it  gives  them 
a total  volume  of  325,000  cubic  miles.  That  is,  the  data  used  for  com- 
puting the  average  composition  of  the  ocean  and  its  average  signifi- 
cance as  a part  of  all  terrestrial  matter  are  maxima,  and  therefore 
tend  to  compensate  for  the  omission  of  factors  which  could  not  well 
be  estimated  directly. 

The  average  composition  of  the  lithosphere  is  very  nearly  that  of 
the  igneous  rooks  alone.  The  sedimentary  rocks  represent  altered 
igneous  material,  from  which  salts  have  been  leached  into  the  ocean, 
and  to  which  oxygen,  water,  and  carbon  dioxide  have  been  added 
from  the  atmosphere.  For  these  changes  corrections  can  be  applied, 
and  their  magnitude  and  effect,  as  will  be  shown  later,  is  surprisingly 
small.  The  thin  film  of  organic  matter  upon  the  surface  of  the  earth 
can  be  neglected  altogether.  In  comparison  with  the  10-mile  thick- 
ness of  rock  below  it,  its  quantity  is  too  small  to  be  considered.  Even 
beds  of  coal  are  negligible,  for  their  volume  also  is  relatively  insig- 
nificant. Practically,  we  have  to  consider  at  first  only  10  miles  of 
igneous  rock,  which,  when  large  enough  areas  are  studied,  averages 
much  alike  in  composition  all  over  the  globe.  This  point  was  estab- 
lished in  an  earlier  memoir,  when  groups  of  analyses,  representing 
rocks  from  different  regions,  were  compared.2  The  essential  uni- 
formity of  the  averages  was  unmistakable,  and  it  has  been  still  fur- 
ther emphasized  in  later  computations  by  others  as  well  as  by  myself. 
The  following  averages  are  now  available  for  comparison: 

A.  My  original  average  of  880  analyses,  of  which  207  were  made  in  the  laboratory 
of  the  United  States  Geological  Survey  and  673  were  collected  from  other  sources. 
Many  of  these  analyses  were  incomplete. 

B.  The  average  of  680  analyses  from  the  records  of  the  Survey  laboratories,  plus 
some  hundreds  of  determinations  of  silica,  lime,  and  alkalies.  The  Survey  data  up 
to  January  1,  1897. 

C.  The  average  of  830  analyses  from  the  Survey  records,  plus  some  partial  deter- 
minations. The  Survey  data  up  to  January  1,  1900. 

D.  An  average  of  all  the  analyses,  partial  or  complete,  made  up  to  January  1,  1914, 
in  the  laboratories  of  the  Survey.3 

1 According  to  J.  Joly  (Sci.  Trans.  Roy.  Soc.  Dublin,  2d  ser.,  vol.  7,  1899,  p.  30)  the  sodium  chloride  in 
the  ocean  would  cover  the  entire  globe  112  feet  deep.  If  Krummel’s  figure  for  the  volume  of  the  ocean  is 
taken,  the  volume  of  the  salts  becomes  approximately  5,100,000  cubic  miles. 

2 Bull.  Philos.  Soc.  Washington,  vol.  11, 1889,  p.  131.  Also  in  Bull.  U.  S.  Geol.  Survey  No.  78, 1891,  p.  34. 
A later  and  more  complete  table  is  given  in  Proc.  Am.  Philos.  Soc.,  vol. 51,  p.  214, 1912.  W.  J.  Mead  (Jour. 
Geology,  vol.  22, 1914,  p.  772)  by  a graphic  method  has  obtained  an  average  composition  of  the  igneous 
rocks  very  near  to  mine. 

3 See  Bull.  U.  S.  Geol.  Survey  No.  588,  1915,  p.  20,  for  details. 


THE  CHEMICAL  ELEMENTS. 


25 


E.  An  average,  computed  by  A.  Harker,1  of  536  analyses  of  igneous  rocks  from 
British  localities.  Many  of  these  analyses  were  incomplete,  especially  with  respect 
to  phosphorus  and  titanium. 

F.  An  average  of  1,  811  analyses,  from  Washington’s  tables.2  Calculated  by  H.  S. 
Washington.  The  data  represent  material  from  all  parts  of  the  world. 

Now,  omitting  minor  constituents,  which  rarely  appear  except  in 
the  more  modern  analyses,  these  averages  may  be  tabulated  together, 
although  they  are  not  absolutely  comparable.  The  comparison  as- 
sumes the  following  form: 


Average  composition  of  igneous  rocks. 


Clarke. 

Harker. 

Washing- 

ton. 

A 

B 

c 

D 

E 

F 

Si02 

58.  59 

59.  77 

59.  71 

60.  86 

58.  98 

58.  239 

A1203 

15.  04 

15.  38 

15.  41 

15. 17 

15.  41 

15.  796 

Fe203 

3.  94 

2.  65 

2.  63 

2.  70 

4.  78 

3.  334 

FeO 

3.  48 

3.  44 

3.  52 

3.  52 

2.  70 

3.  874 

MgO 

4.  49 

4.  40 

4.  36 

3.  88 

3.  71 

3. 843 

CaO 

5.  29 

4.  81 

4.  90 

4.  93 

4.  83 

5.  221 

Na20 

3.  20 

3.  61 

3.  55 

3.  44 

3. 18 

3.  912 

KoO 

2.  90 

2.  83 

2.  80 

3.  05 

2.  77 

3. 161 

H20  at  100° 

1 1.96 

. 48 

'I 

.363 

H20  above  100° 

1.  51 

1.  52 

1.  45 

f 2. 17 

1.428 

Ti02 

•.  55 

.53 

.60 

.80 

.52 

1.039 

p2o6 

.22 

.21 

.22 

.29 

.21 

.373 

99.  66 

99. 14 

99.  22 

100.  57 

99.  26 

100.  583 

Although  these  six  columns  are  not  very  divergent,  they  exhibit 
differences  which  may  be  more  apparent  than  real.  Differences  of 
summation  are  due  partly  to  the  omission  of  minor  constituents,  but 
the  largest  variations  are  attributable  to  the  water.  In  two  columns 
hygroscopic  water  is  omitted;  in  two  it  is  not  distinguished  from 
combined  water;  in  two  a discrimination  is  made.  By  rejecting  the 
figures  for  water  and  recalculating  to  100  per  cent  the  averages 
become  more  nearly  alike,  as  follows : 


Average  composition  of  igneous  rocks , reduced  to  uniformity. 


A 

B 

c 

D 

E 

F 

Si02-.: 

59.  97 

61.  22 

61. 12 

61.  69 

60.  76 

58.  96 

ALO, 

15.  39 

15.  75 

15.  77 

15.  38 

15.  87 

15.  99 

Fe203 

4.  03 

2.  71 

2.  69 

2.  74 

4.  92 

3.  37 

FeO 

3.  56 

3.  53 

3.  60 

3.  57 

2.  78 

3.  93 

MgO 

4.  60 

4.  51 

4.  46 

3.  93 

3.82 

3.  89 

CaO 

5.  41 

4.  93 

5.  02 

4.  99 

4..  97 

5.  28 

Na20 

3.  28 

3.  69 

3.  63 

3.  49 

3.  28 

3.  96 

K20 

2.  97 

2.  90 

2.  87 

3. 10 

2.  85 

3.  20 

Ti02 

. 56 

. 54 

. 61 

. 81 

. 53 

1.  05 

PXL 

.23 

.22 

.23 

.30 

.22 

.37 

2 5 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

1 Tertiary  igneous  rocks  of  the  Isle  of  Skye:  Mem.  Geol.  Survey  United  Kingdom,  1904,  p.  416.  An 
earlier  average  appears  in  Geol.  Mag.,  1899,  p.  220. 

2 Prof.  Paper  U.  S.  Geol.  Survey  No.  14,  1903,  p.  106.  In  this  average  and  in  Harker's  there  are  figures 
for  manganese,  which  I leave  temporarily  out  of  account.  On  the  average  composition  of  Minnesota  rocks 
see  F.  F.  Grout,  Science,  vol.  32, 1910,  p.  312. 


26 


THE  DATA  OP  GEOCHEMISTRY. 


Of  the  averages,  only  D and  F need  be  considered  any  further, 
for  they  include  the  largest  masses  of  trustworthy  data.  A was  only 
a preliminary  computation;  B and  C are  included  under  D.  Harker’s 
average  contains  too  many  incomplete  analyses.  D and  F,  however, 
are  not  strictly  equivalent.  Washington’s  average  relates  only  to 
analyses  which  were  nominally  complete  and  made  in  many  labora- 
tories by  very  diverse  methods.  My  average  represents  the  homo- 
geneous work  of  one  laboratory,  and  includes,  moreover,  many  partial 
determinations.  For  the  simpler  salic  rocks  determinations  of  silica, 
lime,  and  alkalies  are  generally  all  that  is  needed  for  petrographic 
purposes.  The  femic  rocks  are  mineralogically  more  complex,  and 
for  them  full  analyses  are  necessary.  The  partial  analyses,  there 
fore,  represent  chiefly  salic  rocks,  and  their  inclusion  in  the  average 
tends  to  raise  the  percentage  of  silica  and  to  lower  the  proportions  of 
other  elements.  The  salic  rocks,  however,  are  more  abundant  than 
those  of  the  other  class,  and  so  the  higher  figure  for  silica  seems  more 
probable.  This  conclusion  is  in  line  with  the  criticisms  of  F.  P. 
Mennell,1  who  thinks  that  the  femic  rocks  received  excessive  weight 
in  my  earlier  averages.  Mennell  has  studied  the  rocks  of  southern 
Africa,  where  granitic  types  are  predominant,  and  believes  that  the 
true  average  should  approximate  the  composition  of  a granite.  His 
criticisms  are  entitled  to  serious  consideration,  but  they  are  not 
absolutely  conclusive.  A study  of  the  composition  of  river  waters 
originating  in  areas  of  crystalline  rocks  reveals  a preponderance  of 
calcium  over  alkalies  which  waters  from  purely  granitic  environment 
could  hardly  possess.  Granitoid  rocks,  such,  for  example,  as  quartz 
monzonite,  are  also  abundant,  and  the  average  composition  is  likely 
to  be  near  that  of  a diorite  or  andesite.2  The  whole  land  surface  of 
the  earth  must  be  taken  into  account  before  the  true  average  can  be 
finally . ascertained . 

So  far,  the  final  average  has  only  been  partly  given;  the  minor  con- 
stituents of  the  rocks  remain  to  be  taken  into  account.  In  the  labor- 
atory of  the  Geological  Survey  the  analyses  of  igneous  rocks  have  been 
unusually  elaborate,  and  many  things  have  been  determined  that  are 
too  often  ignored.  The  complete  average  is  given  in  the  next  table, 
with  the  number  of  determinations  to  which  each  figure  corresponds. 
In  the  elementary  column  hygroscopic  water  does  not  appear,  but 

1 Geol.  Mag.,  1904,  p.  263;  1909,  p.  212.  For  other  discussions  of  the  data  given  in  my  former  papers  see 
L.  De  Launay,  Revue  gen.  sci.,  Apr.  30, 1904;  and  C.  Ochsenius,  Zeitschr.  prakt.  Geologie,  May,  1898.  Com- 
pare also  R.  A.  Daly  (Bull.  U.  S.  Geol.  Survey  No.  209, 1903,  p.  110),  who  argues  that  the  universal  or  funda- 
mental magma  is  approximately  basaltic. 

2 F.  Loewinson-Lessing  (Geol.  Mag.,  1911,  p.  248)  argues  in  favor  of  two  fundamental  magmas,  the  grani- 
toid and  gabbroid.  These  are  thought  to  be  present  in  about  equal  proportions  in  the  lithosphere,  and  then- 
average  composition  is  close  to  that  found  by  Clarke  and  Washington.  On  the  mean  atomic  weight  of  the 
earth’s  crust  see  L.  De  Launay,  Compt.  Rend.,  vol.  150,  1910,  p.  1270.  See  also  A.  E.  Fersmann  (Bull. 
Acad.  St.  Petersburg,  1912,  p.  367)  for  a calculation  of  the  atomic  percentages  of  the  more  important  rock- 
forming elements. 


THE  CHEMICAL  ELEMENTS. 


27 


an  allowance  is  made  for  a small  amount  of  iron  which  was  reported 
in  the  analyses  as  FeS2.  When  a “ trace”  of  anything  is  recorded,  it 
is  arbitrarily  reckoned  as  0.01  per  cent,  and  when  a substance  is 
known  to  be  absent  from  a rock,  by  actual  determination  of  the  fact, 
it  is  assigned  zero  value  in  making  up  the  averages.1 


Average  composition  of  igneous  rocks  in  detail. 


Number  of 
determina- 
tions. 

Average. 

Reduced  to 
100  per 
cent. 

In  elementary  form. 

SiCL  

1,714 

60.  86 

59.  83 

0 

47.  29 

ALfL  

1, 193 

15. 17 

14.  98 

Si 

28.  02 

Fe^Oo  

l'  242 

2.  70 

2.  65 

A1 

7.  96 

FeO  

l'  238 

3.  52 

3.  46 

Fe 

4.  56 

MeO  

1, 328 

3.  88 

3.  81 

Mg 

2.  29 

CaO 

1,  564 

4.  93 

4.  84 

Ca 

3.  47 

Na^O 

1,632 

3.  44 

3.  36 

Na 

2.  50 

K20  

1,  624 

3.  05 

2.  99 

K 

2.  47 

H20- 

912 

.48 

.47 

H 

. 16 

HoO-r 

959 

1.  45 

1. 42 

Ti 

.46 

-i-a-2v''  1 - 

Ti02 

1, 140 

.80 

. 78 

Zr 

.017 

ZrOo 

372 

.023 

.023 

C 

.13 

CO, 

730 

.49 

.48 

P 

. 13 

vv/2  ------------------- 

PXL  

1, 136 

.29 

.29 

S 

. 103 

s!f"  v 

814 

. 104 

.102 

Cl 

.063 

Cl  

265 

.064 

. 063 

F 

. 10 

F 

112 

. 10 

.10 

Ba 

.092 

BaO  

793 

. 104 

. 102 

Sr 

.033 

SrO 

649 

.04 

.04 

Mn 

.078 

MnO 

1, 155 

.10 

. 10 

Ni 

.020 

NiO.  

299 

.026 

.025 

Cr 

.033 

Cro0o . 

293 

.050 

.049 

y 

. 017 

yo0,  

102 

.026 

.025 

Li 

.004 

Li20 

581 

.011 

.011 

101.  708 

100.  000 

100.  000 

In  this  computation  the  figures  for  C,  Zr,  Cl,  F,  Ni,  Cr,  and  V are 
probably  a little  too  high.  They  show,  however,  that  these  elements 
exist  in  igneous  rocks  in  determinable  quantities.  Fluorine,  however, 
exists  in  rocks  chiefly  in  the  mineral  apatite,  and  its  proportion  can 
be  determined  with  much  probability  from  the  percentage  of  phos- 
phorus. Computing  from  that  datum,  the  percentage  of  fluorine 
becomes  only  0.027,  or  little  more  than  one-fourth  of  the  figure  given 
in  the  table.  As  for  carbon,  its  probable  excess  may  be  allowed  to 
stand,  as  a compensation,  in  our  final  reckoning,  for  the  otherwise 
undeterminable  quantities  represented  by  coal  and  petroleum.  The 
elements  not  included  in  the  calculation  represent  minor  corrections, 
to  be  applied  whenever  the  necessity  for  doing  so  may  arise.  For 
estimates  of  their  probable  amounts,  the  papers  by  J.  H.  L.  Vogt 2 


1 In  this  table  all  analyses  of  igneous  rocks  made  in  the  laboratory  of  the  Survey  down  to  Jan.  1,  1914, 
have  been  utilized. 

2 Zeitschr.  prakt.  Geologie,  1898,  pp.  225,  314, 377,  413;  1899,  pp.  10,  274. 


28 


THE  DATA  OF  GEOCHEMISTRY. 


and  J.  F.  Kemp  1 can  be  consulted.  A few  more  definite  estimates  have 
been  made  by  Clarke  and  Steiger  2 from  careful  analyses  of  large  com- 
posite samples  of  rocks  and  clays.-  The  average  percentages  are  as 
follows:  CuO,  0.0130;  ZnO,  0.0049;  PbO,  0.0022;  As205,  0.0005. 
These  figures,  considered  as  orders  of  magnitude,  have  a high  degree 
of  probability.  The  remaining  elements  not  mentioned  here  nor  in 
the  table  can  not  amount  to  more  than  0.5  per  cent  altogether,  and 
even  that  small  figure  is  likely  to  be  an  overestimate. 

Before  we  can  finally  determine  the  composition  of  the  lithosphere, 
the  sedimentary  rocks  are  to  be  taken  into  account ; and  to  do  this  we 
must  ascertain  their  relative  quantity.  First,  however,  we  may  con- 
sider their  composition,  which  has  been  determined  by  means  of  com- 
posite analyses.  That  is,  instead  of  averaging  analyses,  average 
mixtures  of  many  rocks  were  prepared,3  and  these  were  analyzed  once 
for  all.  The  results  appear  in  the  next  table. 


Composite  analyses  of  sedimentary  rocks. 

A.  Composite  analysis  of  78  shales;  or,  more  strictly,  the  average  of  two  smaller  composites,  properly 
weighted. 

B.  Composite  analysis  of  253  sandstones. 

C.  Composite  analysis  of  345  limestones. 


Si02. 

A1203 


FeO.. 

MgO. 

CaO.. 

Na20. 


H20  at  110°.... 
H20  above  110 c 

Ti02 

C02 

p2o5 

S 

so3 

Cl 

BaO 

SrO 

MnO 

Li20 

C,  organic 


A 

B 

C 

58.  38 

78.  66 

5. 19 

15.  47 

4.  78 

.81 

4.  03 

1.  08 

\ .54 

2.  46 

.30 

/ 

2.  45 

1. 17 

7.  90 

3. 12 

5.  52 

42.  61 

1.  31 

.45 

.05 

3.  25 

1.  32 

.33 

1.  34 

.31 

.21 

3.  68 

«1.  33 

a . 56 

.65 

.25 

.06 

2.  64 

5.  04 

41.  58 

.17 

.08 

.04 

.09 

.65 

.07 

.05 

Trace. 

.02 

: 05 

.05 

None. 

None. 

None. 

None. 

Trace. 

Trace. 

.05 

Trace. 

Trace. 

Trace. 

.81 

100.  46 

100.  41 

100.  09 

a Includes  organic  matter. 


1 Science,  Jan.  5,  1906;  Econ.  Geology,  vol.  1,  1905,  p.  207.  See  also  a curious  paper  by  W.  Ackroyd,  in 
Chem.  News,  vol.  86, 1902,  p.  187.  W.  N.  Hartley  and  H.  Ramage  (Jour.  Chem.  Soc.,  vol.  71,  1897,  p.  533) 
have  shown  that  some  of  the  rarest  elements,  such  as  gallium  and  indium,  are  widely  diffused  in  rocks  and 
minerals.  W.  Vernadsky  (Chem.  Zentralbl.,  vol.  2,  1910,  p.  1775)  has  also  found  that  indium,  thallium, 
gallium,  rubidium,  and  caesium  are  widely  distributed  in  spectroscopic  traces.  Vernadsky  (Centralbl. 
Min..  Geol.  u.  Pal.,  1912,  p.  758)  has  also  studied  the  occurrence  of  native  elements  in  the  earth’s  crust. 

2 Jour.  Washington  Acad.  Sci.,  vol.  4,  p.  57, 1914. 

3 These  mixtures  were  prepared  by  G.  W.  Stose,  under  the  direction  of  G.  K.  Gilbert.  The  analyses 
were  made  by  H.  N.  Stokes  in  the  laboratory  of  the  U.  S.  Geological  Survey.  See  Bull.  U.  S.  Geol. 
Survey  No.  228,  1904,  p.  20. 


THE  CHEMICAL  ELEMENTS. 


29 


In  attempting  to  compare  these  analyses  with  the  average  composi- 
tion of  the  igneous  rocks,  we  must  remember  that  they  do  not  repre- 
sent definite  substances,  but  mixtures  shading  into  one  another.  The 
average  limestone  contains  some  clay  and  sand;  the  average  shale 
contains  some  calcium  carbonate.  Furthermore,  they  do  not  cover 
all  the  products  derived  from  the  decomposition  of  the  primitive 
rock,  for  the  great  masses  of  sediments  on  the  bottom  of  the  ocean 
are  left  out  of  account.  There  are  also  metamorphic  rocks  to  be 
considered,  such  as  chloritic  and  talcose  schists,  amphibolites,  and 
serpentines;  although  their  quantities  are  presumably  too  small 
to  seriously  modify  the  final  averages.  They  might,  however,  help 
to  explain  a deficiency  of  magnesium  which  appears  in  the  sedimen- 
tary analyses.  Partly  on  account  of  these  considerations,  and 
partly  because  the  sedimentary  rocks  contain  water  and  carbon  diox- 
ide which  have  been  added  to  the  original  igneous  material,  we  can  not 
recombine  the  composite  analyses  so  as  to  reproduce  exactly  the  com- 
position of  the  primitive  matter.1  To  do  this  is  would  be  necessary 
also  to  allow  for  the  oceanic  salts,  which  represent,  in  part,  at  least, 
losses  from  the  land;  but  that  factor  in  the  problem  is  perhaps  the 
least  embarrassing.  Its  magnitude  is  easily  estimated,  and  it  gives  a 
measure  of  the  extent  to  which  the  igneous  rocks  have  been 
decomposed. 

If  we  assume  that  all  the  sodium  in  the  ocean  was  derived  from 
the  leaching  of  the  primitive  rocks,  and  that  the  average  composition 
of  the  latter  is  correct  as  stated,  it  is  easy  to  show  that  the  marine 
portion  is  very  nearly  one-thirtieth  of  that  contained  in  the  10-mile 
lithosphere.  That  is,  the  complete  decomposition  of  a shell  of  igneous 
rock  one-third  of  a mile  thick  would  yield  all  the  sodium  in  the 
ocean.  Some  sodium,  however,  is  retained  by  the  sediments,  and  the 
analyses  show  that  it  is  about  one-third  of  the  total  amount.  That 
is,  the  oceanic  sodium  represents  two-thirds  of  the  decomposition, 
and  the  estimate  must  therefore  be  increased  one-half.  On  this 
basis,  a rocky  shell  one-half  mile  thick,  completely  enveloping  the 
globe,  would  slightly  exceed  the  amount  needed  to  furnish  the 
sodium  of  the  sea  and  the  sediments. 

In  order  to  make  this  estimate  more  precise,  let  us  consider  the 
detailed  figures.  The  maximum  allowance  for  the  sodium  in  the 
ocean  is  1.14  per  cent.  From  my  average  the  mean  percentage  of 
sodium  in  the  igneous  rocks  is  2.50;  Washington’s  figures  give  2.90. 
Now,  putting  the  ocean  at  7 per  cent  and  the  lithosphere  at  93  per 
cent  of  the  known  matter,  the  following  ratios  between  oceanic 
sodium  and  rock  sodium  are  easily  computed:  Clarke,  1 : 29.8; 
Washington,  1 : 33.9.  Hence,  the  sodium  in  the  ocean  corresponds 


1 For  an  elaborate  attempt  in  this  direction,  see  C.  R.  Van  Hise,  A treatise  on  metamorphism:  Mon. 
U.  S.  Geol.  Survey,  vol.  47,  1904,  pp.  947-1002. 


30 


THE  DATA  OF  GEOCHEMISTRY. 


to  a volume  of  igneous  rocks,  according  to  the  first  ratio,  of  54,800,000 
cubic  miles  or,  for  the  second  estimate,  of  48,200,000  cubic  miles. 

Suppose,  however,  that  the  average  analyses  do  not  represent  the 
true  composition  of  the  primitive  lithosphere.  We  may  then  test 
our  figures  by  another  assumption,  namely,  that  the  real  average 
lies  somewhere  between  two  evident  extremes — the  composition  of 
a rhyolite  and  that  of  a basalt.  In  100  rhyolites,  as  shown  in  Wash- 
ington’s tables,  the  average  percentage  of  sodium  is  2.58,  while  for 
220  basalts  it  is  2.40.  These  figures  give  ratios  of  1 : 30.1  and  1 : 28.4, 
corresponding  to  rock  volumes  of  54,200,000  and  57,500,000  cubic 
miles,  respectively — quantities  of  quite  the  same  order  as  those 
previously  calculated. 

From  the  composite  analyses  of  the  sedimentary  rocks  the  cor- 
rection for  their  retained  sodium  can  be  determined.  This  sodium  is 
chiefly,  but  not  entirely,  in  the  shales,  and  its  amount  is  less  than 
1 per  cent,  with  a probable  value  of  0.90.  This  is  35  per  cent  of  the 
total  sodium  in  the  average  igneous  rock,  and  the  oceanic  sodium 
represents  the  65  per  cent  removed  by  leaching.  Allowing  for  this 
sedimentary  sodium,  the  total  sodium  of  the  ocean  and  of  the  sedi- 
mentary rocks  is  represented  by  the  ratio  of 

65 : 100  = 54,800,000 : 84,300,000, 

the  last  term  giving  the  number  of  cubic  miles  of  igneous  rock  which 
has  undergone  decomposition.  This  quantity  is  that  of  a rock  shell 
completely  enveloping  the  globe  and  0.4215  mile,  or  2,225  feet, 
thick.  If  we  accept  the  highest  ratio  of  all,  that  furnished  by  the 
average  basalt,  the  thickness  may  be  raised  to  2,336  feet,  while 
Washington’s  data  will  give  a much  lower  figure.  A further  allow- 
ance of  10  per  cent,  which  is  excessive,  for  the  increase  in  volume  due 
to  oxidation,  carbonation,  and  absorption  of  water  will  raise  the 
thickness  assignable  to  the  sedimentaries  from  2,225  to  2,447  feet, 
an  amount  still  short  of  the  half-mile  estimate.  No  probable  change 
in  the  composition  of  the  lithosphere  can  modify  this  estimate  very 
considerably;  and  since  the  ocean  may  contain  primitive  sodium,  not 
derived  from  the  rocks,  the  half  mile  must  be  regarded  as  a maximum 
allowance.  If  the  primeval  rocks  were  richer  in  sodium  than  those  of 
the  present  day,  a smaller  mass  of  them  would  suffice ; if  poorer,  more 
would  be  needed  to  account  for  the  salt  in  the  sea.  Of  the  two 
suppositions,  the  former  is  the  more  probable ; but  neither  assumption 
is  necessary.  If,  however,  we  assume  that  our  igneous  rocks  are  not 
altogether  primary  but  that  some  of  them  represent  re-fused  or 
metamorphosed  sedimentaries,  we  must  conclude  that  they  have  been 
partly  leached  and  have  therefore  lost  sodium.  That  is,  the  original 
matter  was  richer  in  sodium,  and  the  half-mile  estimate  is  conse- 
quently much  too  large. 


THE  CHEMICAL  ELEMENTS. 


31 


From  another  point  of  view,  the  thinness  of  the  sediments  can  be 
simply  illustrated.  The  superficial  area  of  the  earth  is  199,712,000 
square  miles,  of  which  55,000,000  are  land.  According  to  Geikie,1  the 
mean  elevation  of  all  the  continents  is  2,411  feet.  Hence,  if  all  the 
land  now  above  sea  level,  25,000,000  cubic  miles,  were  spread  uni- 
formly over  the  globe,  it  would  form  a shell  about  660  feet  thick.  If 
we  assume  this  matter  to  be  all  sedimentary,  which  it  certainly  is  not, 
and  add  to  it  any  probable  allowance  for  the  sediments  at  the  bottom 
of  the  sea  we  shall  still  fall  far  short  of  the  half-mile  shell  which,  on 
chemical  evidence,  is  a maximum.  In  the  following  calculation  this 
maximum  will  be  taken  for  granted. 

The  relative  proportions  of  the  different  sedimentary  rocks  within 
the  half-mile  shell  can  only  be  estimated  approximately.  Such  an 
estimate  is  best  made  by  studying  the  average  igneous  rock  and  deter- 
mining in  what  way  it  can  break  down.  A statistical  examination  of 
about  700  igneous  rocks,  which  have  been  described  petrographic  ally, 
leads  to  the  following  rough  estimate  of  their  mean  mineralogical 


composition : 

Quartz 12.0 

Feldspars 59.  5 

Hornblende  and  pyroxene 16.  8 

Mica.- 3.  8 

Accessory  minerals 7.  9 


100.0 

The  average  limestone  contains  76  per  cent  of  calcium  carbonate, 
and  the  composite  analyses  of  shales  and  sandstones  correspond  to 
the  subjoined  percentages  of  the  component  minerals: 


Average  composition  of  shale  and  sandstone. 


Shale. 

Sandstone. 

Quartz  a 

22.  3 

66.  8 

Feldspar  

30.  0 

11.  5 

Clay  & 

25.  0 

6.  6 

Limonite 

5.  6 

1.  8 

Carbonates 

5.  7 

11. 1 

Other  minerals 

11.4 

2.2 

100.0 

100.0 

a The  total  percentage  of  free  silica. 

b Probably  sericite  in  part.  In  that  case  the  feldspar  figure  becomes  lower. 


If,  now,  we  assume  that  all  of  the  igneous  quartz,  12  per  cent,  has 
become  sandstone,  it  will  yield  18  per  cent  of  that  rock,  which  is 
evidently  a maximum.  Some  quartz  has  remained  in  the  shales. 


1 Textbook  of  geology,  4th  ed.,  vol.  1,  1903,  p.  49. 


32 


THE  DATA  OF  GEOCHEMISTRY. 


One  hundred  parts  of  the  average  igneous  rock  will  form,  on  decom- 
position, less  than  18  parts  of  sandstone. 

The  igneous  rocks  contain  as  shown  in  the  last  analysis  cited,  4.84 
per  cent  of  lime.  This  would  form  8.65  per  cent  of  calcium  carbon- 
ate, or  11.2  per  cent  of  an  average  limestone.  But  at  least  half  of 
the  lime  has  remained  in  the  other  sediments,  so  that  its  true  propor- 
tion can  not  reach  6 per  cent,  or  one-third  the  proportion  of  the 
sandstones.  The  remainder  of  the  igneous  material,  plus  some  water 
and  minus  oceanic  sodium,  has  formed  the  siliceous  residues  which 
are  grouped  under  the  vague  title  of  shale.  Broadly,  then,  we  may 
estimate  that  the  lithosphere,  within  the  limits  assumed  in  this  me- 
moir, contains  95  per  cent  of  igneous  rock  and  5 per  cent  of  sedimen- 
taries.  If  we  assign  4.0  per  cent  to  the  shales,  0.75  per  cent  to  the 
sandstones,  and  0.25  per  cent  to  the  limestones,  we  shall  come  as  near 
the  truth  as  is  possible  with  the  present  data.1  On  this  basis,  the 
average  composition  of  the  lithosphere  may  be  summed  up  as  shown 
in  the  following  table.  The  analyses  of  the  sedimentary  rocks  are 
recalculated  to  100  per  cent. 

Average  composition  of  the  lithosphere. 


Igneous 
(95  per 
cent). 

Shale 
(4  per 
cent). 

Sandstone 
(0.75  per 
cent). 

Limestone 
(0.25  per 
cent). 

Weighted 

average. 

Si02 

59.  83 

58.  10 

78.  33 

5.  19 

59.  77 

ai2o3 

14.  98 

15.40 

4.  77 

.81 

14.  89 

Fe203 

2.  65 

4.  02 

1.  07 

. 54 

2.  69 

FeO 

3.  46 

2.  45 

. 30 

3.  39 

MgO 

3.  81 

2.44 

1. 16 

7.  89 

3.  74 

CaO 

4.  84 

3. 11 

5.  50 

42.  57 

4.  86 

Na20 

3.  36 

1.  30 

.45 

.05 

3.  25 

K20 

2.  99 

3.  24 

1.  31 

.33 

2.  98 

h2o 

' 1.89 

5.  00 

1.  63 

.77 

2.  02 

Ti02 

. 78 

.65 

.25 

.06 

. 77 

Zr02 

.02 

. 02 

co2 

.48 

2.  63 

5.  03 

41.  54 

. 70 

p2o5 

.29 

. 17 

.08 

.04 

.28 

s 

. 11 

.09 

. 10 

so3 

. 64 

. 07 

. 05 

. 03 

Cl 

. 06 

. 02 

.06 

F 

. 10 

. 09 

BaO 

. 10 

. 05 

. 05 

. 09 

SrO 

. 04 

. 04 

MnO 

. 10 

. 05 

.09 

NiO 

. 025 

. 025 

Cr203 

. 05 

. 05 

V90, 

. 025 

. 025 

Li20 

. 01 

.01 

C 

. 80 

.03 

100.  000 

100.  00 

100.  00 

100.  00 

100.  000 

1 C.  R.  Van  Hise  (A  treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  p.  940)  divides 
the  sedimentary  rocks  into  65  per  cent  shales,  including  all  pelites  and  psephites,  30  per  cent  sandstones, 
and  5 per  cent  limestones.  W.  J.  Mead  (Jour.  Geology,  vol.  15,  1907,  p.  238),  by  a graphic  process,  dis- 
tributes the  sedimentaries  into  80  per  cent  shales,  11  per  cent  sandstones,  and  9 per  cent  limestones. 


THE  CHEMICAL  ELEMENTS. 


33 


The  final  average  differs  from  that  of  the  igneous  rocks  alone  only 
within  the  limits  of  uncertainty  due  to  experimental  errors  and  to  the 
assumptions  made  as  to  the  relative  proportions  of  the  sedimentaries. 
The  values  chosen  for  the  sediments  are  approximations  only,  and 
nothing  more  can  be  claimed  for  them.  They  seem  to  be  near 
the  truth — as  near  as  we  can  approach  with  data  which  are  necessarily 
imperfect — and  so  they  may  be  allowed  to  stand  without  further 
emendation. 

In  the  preceding  table  the  hygroscopic  water  of  the  igneous  rocks 
is  taken  into  account,  but  so  far  the  underground  waters  have  been 
neglected.  For  this  omission  the  hygroscopic  water  may  partly 
compensate,  but  the  subject  demands  a little  closer  attention. 
Extravagant  estimates  of  the  quantity  of  underground  water  have 
been  made,  based  upon  the  fact  that  all  rocks  are  more  or  less  porous.1 
Van  Hise,  however,  claims  that  the  pore  spaces  below  a depth  of  6 
miles  are  probably  closed  by  the  pressure  of  the  superincumbent 
strata;  a consideration  which  must  not  be  ignored.  Van  Hise 
estimates  the  volume  of  the  underground  waters  to  a depth  of  10,000 
meters  as  equal  to  that  of  a sheet  covering  the  continental  areas  69 
meters  or  226  feet  deep.  Fuller’s  estimate  is  more  complete,  for  it 
involves  a discussion  of  the  relative  quantities  and  average  porosities 
of  the  sedimentary  and  igneous  rocks,  and  he  concludes  that  the 
volume  of  subterranean  water  is  about  one  one-hundredth  that  of 
the  ocean.  These  conclusions  require  some  modification;  for 
Adams,  by  experiments  upon  the  compression  of  granite,  has  shown 
that  porosity  may  exist  to  a depth  of  at  least  11  miles.  In  any  case 
the  quantity  of  water  is  negligible,  for,  added  to  the  volume  of  the 
hydrosphere  it  would  not  appreciably  affect  the  final  computation. 
The  proportion  of  water  in  known  terrestrial  matter  would  be  in- 
creased by  less  than  0.1  per  cent. 

With  the  data  now  before  us  we  are  in  a position  to  compute  the 
relative  abundance  of  the  chemical  elements  in  all  known  terrestrial 
matter.  For  this  purpose,  the  composition  of  the  lithosphere  is 
restated  in  elementary  form,  with  an  arbitrary  allowance  of  0.5  per 
cent  for  all  the  elements  not  specifically  named.  As  for  the  atmos- 
phere, 0.03  per  cent,  it  is  represented  in  the  final  results  as  if  it  were 
all  nitrogen;  an  exaggeration  which  allows  for  the  traces  of  nitrogen, 

1 See  A.  Delesse,  Bull.  Soc.  g£ol.  France,  vol.  29, 1861,  p.  64;  J.  D.  Dana,  Manual  of  geology,  4th  ed.,  1895, 
p.  209;  W.  B.  Greenlee,  Am.  Geologist,  vol.  18,  1896,  p.  33;  O.  Keller,  Annales  des  mines,  9th  ser.,  vol. 
12,  1897,  p.  32;  C.  S.  Slichter,  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  67,  1902,  p.  14;  T.  C.  Cham- 
berlin and  R.  D.  Salisbury,  Geology,  vol.  1,  1904,  p.  209;  C.  R.  Van  Hise,  A treatise  on  metamorphism: 
Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  p.  129;  M.  L.  Fuller,  Water-Supply  Paper  U.  S.  Geol.  Survey 
No.  160,  1906,  p.  59;  F.  D.  Adams,  Jour.  Geology,  vol.  20, 1912,  p.  97.  See  also  an  address  by  J.  F.  Kemp, 
Trans.  Am.  Inst.  Min.  Eng.,  vol.  14, 1914,  p.  3. 

97270°— Bull.  616—16 3 


34 


THE  DATA  OF  GEOCHEMISTRY. 


rarely  determined,  that  are  present  in  the  rocks.1  The  mean  com- 
position of  the  lithosphere,  the  hydrosphere,  and  the  atmosphere, 
then,  is  as  follows : 

Average  composition  of  known  terrestrial  matter. 


Lithosphere, 
93  per  cent. 

Hydrosphere, 
7 per  cent. 

Average,  in- 
cluding atmos- 
phere. 

Oxygen 

47.33 

85.  79 

50.  02 
25.  80 
7.  30 

Silicon 

27.  74 

Aluminum 

7.  85 

Iron 

4.  50 

4. 18 
3.  22 
2.  08 
2.  36 

Calcium 

3.  47 

. 05 

Magnesium 

2.  24 

. 14 

Sodium 

2.  46 

1. 14 

Potassium 

2.  46 

. 04 

2.  28 
. 95 

Hydrogen 

. 22 

10.  67 

Titanium 

.46 

. 43 

Carbon 

. 19 

.002 

.18 

.20 

Chlorine 

.06 

2.  07 

Bromine 

.008 

Phosphorus 

. 12 

. 11 

Sulphur 

. 12 

.09 

. 11 

Barium 

.08 

.08 

Manganese 

.08 

.08 

Strontium 

.02 

.02 

Nitrogen 

.03 

Fluorine 

. 10 

. 10 

All  other  elements 

.50 

.47 

100.  00 

100.  000 

100.  00 

The  briefest  scrutiny  of  the  foregoing  tables  will  show  that  in 
the  lithosphere  the  lighter  elements  predominate  over  the  heavier. 
All  the  abundant  elements  fall  below  atomic  weight  56,  and  above 
that,  in  the  analyses  given  on  page  27,  only  nickel,  zirconium, 
strontium,  and  barium  appear.  The  heavy  metals,  as  a rule,  occur 
in  apparently  trivial  quantities.  Since,  however,  the  mean  density 
of  the  earth  is  about  double  that  of  the  rocks  at  its  surface,  it  has 
sometimes  been  supposed  that  the  heavier  substances  may  be  con- 
centrated in  its  interior,  a supposition  which  is  possibly  true,  but 
unprovable.  If  the  globe  is  similar  in  constitution  to  a meteorite,  we 
should  expect  iron  and  nickel  to  be  abundant  in  its  mass  as  a whole ; 
but  this,  after  all,  is  nothing  more  than  a suspicion.  One  fact  only 
seems  to  shed  a clear  light  upon  the  problem.  A mixture  of  all  the 
elements,  in  equal  proportions  by  weight  and  in  the  free  state, 
would  have  a density  greater  than  that  of  the  earth.  Combination 


1 See  A.  D.  Hall  and  N.  J.  H.  Miller  (Jour.  Agr.  Sci.,vol.  2,  p.  343), on  nitrogen  in  unweathered  sedi- 
mentary rocks.  From  0.04  to  0.107  per  cent  was  found.  H.  Erdmann  ( Ber.  Deutsch.  chem.  Gesell.,  vol.  29, 
1896,  p.  1710)  found  traces  of  nitrogen  in  several  rare  minerals  from  pegmatite.  In  a later  paper,  in  Arbeiten 
auf  den  Gebieten  der  Gross-Gasindustrie,  No.  1, 1909,  Erdmann  computes  that  each  square  meter  of  land, 
to  a depth  of  15  kilometers,  contains  5 metric  tons  of  nitrogen.  The  total  amount  of  nitrogen  in  the 
rocks  is  much  less  than  that  in  the  atmosphere  alone. 


THE  CHEMICAL  ELEMENTS. 


35 


would  increase  the  density  of  the  mixture,  and  the  effect  of  internal 
pressure  would  make  it  greater  still.  It  is  therefore  plain  that  in 
the  earth  as  a whole,  whatever  may  he  the  composition  or  condition 
of  its  interior,  the  lighter  elements  are  more  abundant  than  the 
denser.  Thus  far  we  can  go,  but  no  farther.  Of  the  actual  propor- 
tions we  know  nothing. 

THE  PERIODIC  CLASSIFICATION. 

Although  the  chemical  elements  are  analytically  distinct,  they  are 
by  no  means  unrelated.  On  the  contrary,  they  fall  into  a number  of 
natural  groups;  and  within  each  one  of  these  the  members  not  only 
form  similar  compounds,  but  also  exhibit,  as  a rule,  a regular  grada- 
tion of  properties.  This  relationship  has  led  to  an  important  gen- 
eralization— the  periodic  law,  or,  more  precisely,  the  periodic  classi- 
fication of  the  elements — and  in  its  light  some  of  their  associations 
become  extremely  suggestive. 

When  the  elements  are  tabulated  in  the  order  of  their  atomic 
weights,  the  periodicity  shown  in  the  following  scheme  at  once  be- 
comes evident : 


Periodic  classification  of  the  elements. a 


36 


THE  DATA  OF  GEOCHEMISTRY. 


05 


iO  od  05 
O vO  lO 


S 3 


2 rC  73 

Ph  Pm 


2 £ § 


C5  ^ 

r*  Q 


PQ 


m 


pq 


CS3 


lO 


<N 

o 

CO 
" <N) 

£ II 

H 


pq 


' c3 

* ° 


o 


2 ^ 
t « 
Q I 

pq 


oq  co 

II  M 

u> 

a ii 

^ C$ 

P3 


Q 


0>  Q 

w £ 


M 


« In  this  table  the  atomic  weights  are  rounded  oil  from  the  more  precise  numbers. 


THE  CHEMICAL  ELEMENTS. 


37 


In  each  vertical  column  the  elements  are  closely  allied,  forming 
the  natural  groups  to  which  reference  has  already  been  made.  The 
alkaline  metals;  the  series  calcium,  strontium,  and  barium;  the  car- 
bon group,  and  the  halogens  are  examples  of  this  regularity.  In 
other  words,  similar  elements  appear  at  regular  intervals  and  occupy 
similar  places.  If  we  follow  any  horizontal  line  of  the  table  from 
left  to  right,  a progressive  change  of  valency  is  shown,  and  in  both 
directions  a systematic  variation  of  properties  is  manifested.  Broadly 
stated,  the  properties  of  the  elements,  chemical  and  physical,  are 
periodic  functions  of  their  atomic  weights,  and  this  is  the  most  gen- 
eral expression  of  the  periodic  law.  At  certain  points  in  the  table 
gaps  are  left,  and  these  are  believed  to  correspond  to  unknown  ele- 
ments. For  three  of  the  spaces  which  were  vacant  when  Mendeleef 
announced  the  law,  he  ventured  to  make  specific  predictions,  and  his 
prophesies  have  been  verified.  The  elements  scandium,  gallium,  and 
germanium  were  described  by  him  in  advance  of  their  actual  dis- 
covery, and  in  every  essential  particular  his  predictions  were  correct. 
Atomic  weights,  densities,  melting  points,  and  the  character  of  the 
compounds  which  the  metals  should  form  were  foretold,  and  in  each 
case  with  a remarkable  approximation  to  accuracy.  This  power  of 
prevision  is  characteristic  of  all  valid  generalizations,  and  its  exhi- 
bition in  the  periodic  system  led  to  the  speedy  adoption  of  the  latter. 
Even  radium  and  its  emanation,  niton,  fall  into  their  proper  places 
in  fine  with  their  near  relatives,  barium  and  argon. 

An  elaborate  discussion  of  the  periodic  law  would  be  out  of  place 
in  a memoir  of  this  kind,  and  its  details  must  be  sought  elsewhere.1 
Only  its  application  to  geochemistry  can  be  considered  now.  In  the 
first  place,  on  looking  at  the  table  vertically  it  is  noticeable  that 
members  of  the  same  elementary  group  are  commonly  associated  in 
nature.  That  is,  similar  elements  have  similar  properties,  form 
similar  compounds,  and  give  similar  reactions,  and  because  of  the 
conditions  last  mentioned  they  are  usually  deposited  together.  Thus 
the  platinum  metals  are  seldom  found  apart  from  one  another;  the 
rare  earths  are  invariably  associated;  chlorine,  bromine,  and  iodine 
occur  under  closely  analogous  circumstances;  selenium  is  obtained 
from  native  sulphur;  cadmium  is  extracted  from  ores  of  zinc,  and 
so  on  through  a long  list  of  regularities.  The  group  relations  govern 
many  of  the  associations  which  we  actually  observe,  although  they 
are  modified  by  the  conditions  which  influence  chemical  union.  Even 
here,  however,  regularities  are  still  apparent.  In  combination  unlike 
elements  seek  one  another,  and  yet  there  appears  to  be  a preference 

1 See  especially  F.  P.  Venable,  Development  of  the  periodic  law,  Easton,  Pennsylvania,  1896.  The  larger 
manuals  of  chemistry  all  discuss  the  law  somewhat  fully.  T.  Carnelley  (Ber.  Deutsch.  chem.  Gesell., 
vol.  17, 1884,  p.  2287)  has  especially  studied  the  bearings  of  the  periodic  law  on  the  occurrence  of  the  elements 
in  nature. 


38 


THE  DATA  OF  GEOCHEMISTRY. 


for  neighbors  rather  than  for  substances  that  are  more  remote.  For 
example,  silicon  follows  aluminum  in  the  order  of  atomic  weights, 
and  silicates  of  aluminum  are  by  far  the  most  abundant  minerals. 
The  next  element  in  order  is  phosphorus,  and  aluminum  phosphates 
are  more  common  and  more  numerous  than  the  precisely  similar  arse- 
nates. On  the  other  hand,  copper,  whose  atomic  weight  is  nearer 
that  of  arsenic,  oftener  forms  arsenates,  although  its  phosphates  are 
also  known.  An  even  more  striking  example  is  furnished  by  the 
compounds  of  the  elementary  series  oxygen,  sulphur,  selenium,  and 
tellurium.  Oxides  >nd  oxidized  salts  of  many  elements  are  found  in 
the  mineral  kingdom,  and  most  commonly  of  metals  having  low 
atomic  weights.  From  manganese  and  iron  upward,  sulphides  are 
abundant ; but  selenium  and  tellurium  are  more  often  united  with 
the  heavier  metals  silver,  mercury,  lead,  or  bismuth,  and  tellurium 
with  gold.  The  elements  of  high  atomic  weight  appear  to  seek  one 
another,  a tendency  which  is  indicated  in  many  directions,  even 
though  it  can  not  be  stated  in  the  form  of  a precise  law.  The  general 
rule  is  evident,  but  its  significance  is  not  so  clear. 

We  have  already  seen  that  the  most  abundant  elements  are  among 
those  of  relatively  low  atomic  weight,  and  this  observation  may  be 
verified  still  further.  In  general,  with  some  exceptions,  the  abun- 
dance of  an  element  within  a group  depends  on  its  atomic  weight, 
but  not  in  a distinctly  regular  manner.  For  instance,  in  the  alkaline 
series,  lithium  is  widely  diffused  in  small  quantities,  sodium  and  potas- 
sium are  very  abundant,  rubidium  is  scarce,  and  caesium  is  the  rarest 
of  all.  The  same  rule  holds  in  the  tetrad  group — carbon,  silicon, 
titanium,  zirconium,  and  thorium;  and  in  the  halogens — fluorine, 
chlorine,  bromine,  and  iodine.  In  each  of  these  series  the  abundance 
increases  from  the  first  to  the  second  member  and  then  diminishes 
to  the  end.  In  the  oxygen  group,  however,  the  first  member  is  much 
the  most  abundant  and  after  that  a steady  decrease  to  tellurium  is 
shown.  An  exception  to  the  rule  is  found  in  the  metals  of  the  alka- 
line earths,  for  strontium  is  less  abundant  than  barium,  at  least  so  far 
as  our  evidence  now  goes.  Other  exceptions  also  seem  to  exist,  but 
they  are  possibly  apparent  and  not  real.  In  the  light  of  better  data 
than  we  now  possess  the  anomalies  may  disappear.  Here  again  we 
are  dealing  with  an  evident  tendency  of  which  the  meaning  is  yet 
to  be  discovered.  That  the  abundance  and  associations  of  the  ele- 
ments are  connected  with  their  position  in  the  periodic  system  seems, 
however,  to  be  clear.  The  coincidences  are  many,  the  exceptions  are 
comparatively  few. 

So  much  for  the  chemical  side  of  the  question.  On  the  geological 
side  other  considerations  must  be  taken  into  account,  and  it  is  easily 
seen  that  the  periodic  law  covers  only  a part  of  the  elementary  asso- 
ciations. Rocks  are  formed  from  magmas  in  which  many  and  com- 


THE  CHEMICAL  ELEMENTS. 


39 


plex  reactions  are  possible  and  the  simpler  rules  governing  single 
minerals  are  no  longer  directly  applicable.  Some  regularities,  how- 
ever, can  be  recognized,  and  certain  elements  are  in  a sense  character- 
istic of  certain  kinds  of  rock.  In  the  summary  already  given  some  of 
these  regularities  are  indicated.  They  have  been  generalized  by 
J.  H.  L.  Vogt1  somewhat  as  follows:  In  the  highly  siliceous  rocks 
we  find  the  largest  proportions  of  the  alkalies,  of  the  rare  earths,  and 
of  the  elements  glucinum,  tungsten,  molybdenum,  uranium,  colum- 
bium,  tantalum,  tin,  zirconium,  thorium,  boron,  and  fluorine.  The 
rocks  low  in  silica  are  richer  in  the  alkaline  earths,  and  in  magne- 
sium, iron,  manganese,  chromium,  nickel,  cobalt,  vanadium,  titanium, 
phosphorus,  sulphur,  chlorine,  and  the  platinum  metals.  To  some 
extent,  of  course,  these  groups  overlap,  for  between  the  two  rock 
classes  no  definite  line  can  be  drawn.  But  the  minerals  of  the  rare 
earths,  with  the  columbo-tantalates,  tinstone,  beryl,  etc.,  seldom  if 
ever  occur  except  in  rocks  which  approach  the  granites  in  general 
composition;  whereas  chromium,  nickel,  and  the  platinum  metals  are 
most  commonly  associated  with  peridotites  or  serpentines.  For  these 
differences  in  distribution  no  complete,  explanation  is  at  hand;  but 
they  are  probably  due  to  differences  of  solubility.  If  we  conceive  of 
a mediosilicic  magma  in  process  of  differentiation  into  a salic  and  a 
femic  portion,  the  minor  constituents  will  evidently  tend  to  con- 
centrate, each  in  the  magmatic  fraction  in  which  it  is  most  soluble. 
Solubilities  of  this  order  are  yet  to  be  experimentally  studied. 

METEORITES. 

The  supposed  analogy  between  the  earth  as  a whole  and  an  enor- 
mous meteorite  has  already  been  mentioned.  A brief  statement  of 
the  chemical  nature  of  meteorites  is  therefore  not  out  of  place  here. 
All  known  meteorites  may  be  divided  into  three  classes — iron  meteor- 
ites, stony  meteorites,  and  carbonaceous  meteorites.  The  last  class, 
so  far  as  direct  observation  goes,  is  very  small,  and  need  not  be  con- 
sidered further.  It  is  possible  that  carbonaceous  meteorites  may  be 
numerous  but  commonly  consumed  before  reaching  the  surface  of  the 
earth,  a supposition,  however,  which  can  only  be  entertained  as  a 
speculation.  The  two  principal  classes  of  meteorites  merge  into  one 
another,  so  that  we  have  irons,  stones,  and  all  sorts  of  intermediate 
mixtures.  The  irons  consist  mainly  of  iron  and  nickel,  with  variable 
and  minor  admixtures  of  graphite,  schreibersite,  troilite,  etc.  The 
terrestrial  nickel-iron  of  Ovifak  in  Greenland  resembles  meteoric  iron 
in  every  essential  particular.  It  is,  therefore,  often  mentioned,  as 
possibly  typical  of  the  material  which  forms  the  centrosphere. 

1 Zeitschr.  prakt.  Geologie,  1898,  p.  324.  H.  S.  Washington  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  39,  1909, 
p.  735)  has  made  a rather  elaborate  study  of  the  distribution  of  the  commoner  elements  with  reference  to 
the  different  magmas. 


40 


THE  DATA  OF  GEOCHEMISTRY. 


The  stony  meteorites  almost,  if  not  quite  invariably,  contain  dis- 
seminated particles  of  nickel-iron,  but  otherwise  are  analogous  to 
rocks  found  on  the  surface  of  the  earth.  They  are,  however,  not  like 
the  predominant  rocks  of  the  lithosphere.  Their  average  composi- 
tion has  been  calculated  by  G.  P.  Merrill 1 from  99  published  analyses 
of  stony  meteorites,  with  the  subjoined  results.  The  first  column  of 
figures  gives  the  actual  average;  the  second  is  recalculated  to  100  per 
cent  after  rejecting  the  admixed  nickel-iron,  sulphides,  and  phosphides. 

Average  composition  of  stony  meteorites. 


Found. 

Recalculated. 

Si02 

38.  98 

45.  46 

A1203 

2.  75 

3.  21 

Fe 

11.  61 

FeO 

16.  54 

19.  29 

CaO 

1.  77 

2.  06 

MgO 

23.  03 

26.  86 

Na20 

. 95 

1. 11 

K20 

. 33 

. 38 

MnO 

. 56 

. 65 

Chromite 

. 84 

.98 

Ni,  Co 

1.  32 

s 

1.  85 

P 

. 11 

100.  64 

100.  00 

From  this  computation  it  appears  that  the  stony  meteorites  have 
essentially  the  composition  of  a peridotite,  and  are  quite  unlike  the 
rocks  which  make  up  the  great  mass  of  the  lithosphere.  If,  therefore, 
the  earth  was  formed  by  an  aggregation  of  meteors,  as  some  writers 
have  supposed,  their  average  character  was  probably  not  that  of 
the  meteorites  known  to-day.  Quartz  and  feldspars  are  the  most 
abundant  minerals  of  the  lithosphere  as  we  know  it,  but  are  almost 
wanting  in  the  meteorites.  A nucleus  of  iron  with  a stony  crust 
could  hardly  be  formed  by  any  clashing  together  of  innumerable 
meteoritic  bodies;  if  the  earth  is  analogous  to  them  it  can  only  be  as  an 
independent,  individual  meteorite  of  quite  dissimilar  composition.2 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  27,  1909,  p.  469.  See  also  W.  A.  Wahl,  Zeitschr.  anorg.  Chemie,  vol.  69, 
1910,  p.  52,  and  O.  C.  Farrington,  Field  Columbian  Museum  Publication  151, 1911. 

2 For  a critical  discussion  of  hypotheses  relative  to  the  nature  and  temperature  of  the  centrosphere  see 
H.  Thiene,  Temperatur  und  Zustand  des  Erdinnern,  Jena,  1907.  Thiene  gives  many  references  to  litera- 
ture. See  also  E . H.  L.  Schwarz,  South  African  Jour.  Sci.,  April,  1910.  Schwarz  advocates  a solid  nucleus 
of  the  earth  and  assigns  to  it  a low  temperature. 


CHAPTER  II. 


THE  ATMOSPHERE. 

COMPOSITION  OF  THE  ATMOSPHERE. 

The  outer  gaseous  envelope  of  our  globe — the  atmosphere — is 
commonly  regarded  as  rather  simple  in  its  constitution,  and  indeed 
so  it  is,  in  comparison  with  the  complexity  of  the  ocean  and  the  solid 
rocks  beneath.  Broadly  considered,  it  consists  of  three  chief  con- 
stituents— namely,  oxygen,  nitrogen,  and  argon — commingled  with 
various  other  substances  in  relatively  small  amounts,  which  may  be 
classed,  with  some  exceptions,  as  impurities.  The  three  essential 
elements  of  air  are  mixed,  but  not  combined;  and  they  vary  but 
little  in  their  proportions.  They  constitute  what  may  be  called 
normal  or  average  air.  I am  indebted  to  Sir  William  Ramsay  for 
the  following  percentage  estimate  of  their  relative  quantities. 


The  principal  constituents  of  the  atmosphere. 


By  weight. 

By  volume. 

Oxygen 

23.  024 

20.  941 

Nitrogen 

75.  539 

78. 122 

Argon 

1.  437 

.937 

100.  000 

100.  000 

With  the  argon  occur  certain  rare  gases  whose  proportions  Ramsay 
estimates  as  follows: 1 


Krypton. 
Xenon... 
Helium . . 
Neon 


Per  cent  by  volume. 

0.028 

005 

0004 

00123 


These  gases,  with  argon,  are  absolutely  inert;  and  as  they  seem  to 
have  little  geological  significance  they  demand  no  further  considera- 
tion here.  Helium,  as  the  end  product  of  radioactive  changes,  will 
demand  some  attention  later. 

In  addition  to  the  elements  enumerated  above,  ordinary  air  con- 
tains, in  varying  quantities,  aqueous  vapor,  hydrogen  dioxide,  ozone, 
carbon  dioxide,  ammonia  and  other  compounds  of  nitrogen,  some- 
times sulphur,  traces  of  hydrogen,  organic  matter,  and  suspended 
solids;  and  among  these  substances  some  of  the  most  active  agents 


1 Proc.  Roy.  Soc.,  vol.  80A,  1908,  p.  599.  See  also  papers  by  G.  Claude,  Compt.  Rend.,  vol.  148,  1909, 
p.  1454,  and  H.  E.  Watson,  Jour.  Chem.  Soc.,  vol.  97, 1910,  p.  810.  A.  Wegener  (Zeitschr.  anorg.  Cbemie, 
vol.  75, 1912,  p . 107)  gives  an  estimate  of  the  composition  of  the  atmosphere,  including  its  minor  constituents. 

41 


42 


THE  DATA  OF  GEOCHEMISTRY. 


in  producing  geological  changes  are  found.  It  will  be  advantageous 
to  consider  them  separately  and  somewhat  in  detail;  and  in  so  doing 
we  shall  see  that  they  all  form  part  of  a great  system  of  circulation 
in  which  the  atmosphere  is  adding  matter  to  the  solid  globe  and 
receiving  matter  from  it  in  return.  Between  these  gains  and  losses 
no  balance  can  be  struck,  and  yet  certain  tendencies  appear  to  be 
distinctly  manifested. 

In  a roughly  approximate  way  it  is  often  said  that  air  consists  of 
four-fifths  nitrogen  and  one-fifth  oxygen,  and  this  is  nearly  true. 
The  proportions  of  the  two  gases  are  almost  constant,  but  not  abso- 
lutely so;  for  the  innumerable  analyses  of  air  reveal  variations  larger 
than  can  be  ascribed  to  experimental  errors.  A few  of  the  better 
determinations  are  given  in  the  subjoined  table,  stated  in  percentages 
by  volume  of  oxygen.  They  refer,  of  course,  to  air  dried  and  freed 
from  all  extraneous  substances. 


Determinations  of  oxygen  in  air,  in  percentage  by  volume. 


Analyst. 

Locality  of  samples. 

Number 

of 

analyses. 

Minimum. 

Maximum. 

Mean. 

V.  Regnault® 

Paris 

100 

20.  913 

20.  999 

20.  960 

R.  W.  Bunsen® 

Heidelberg 

28 

20.  840 

20.  970 

20.  924 

R.  Angus  Smith®. . . 

Manchester 

32 

20.  78 

21.  02 

20.  943 

Do 

Mountains  of  Scot- 
land. 

34 

20.  80 

21. 18 

20.  970 

U.  Kreusler  & . . 

Near  Bonn 

45 

20.  901 

20.  939 

20.  922 

W.  Hempel  c 

Dresden 

46 

20.  877 

20.  971 

20.  930 

Do.® 

Tromsoe 

41 

21.  00 

20.  92 

Do 

Para 

28 

20.  86 

20.  89 

A.  Muntz  and  E. 

Cape  Horn 

20 

20.  72 

20.  97 

20.  864 

Aubin.e 

E.  W.  Morley/ 

F.  G.  Benedict  9 

Cleveland,  Ohio 

Boston 

45 

212 

20.  90 

20.  95 

20.  933 
20.  952 

a See  R.  Angus  Smith’s  excellent  book  Air  and  rain,  London,  1872.  This  work  contains  hundreds  of 
other  analyses. 

b Ber.  Deutsch.  chem.  Gesell.,  vol.  20, 1887,  p.  991. 
c Idem,  vol.  18, 1885,  p.  1800. 
d Idem,  vol.  20, 1887,  p.  1864. 
e Compt.  Rend.,  vol.  102,  1886,  p.  422. 

/ Cited  by  Hempel  in  Ber.  Deutsch.  chem.  Gesell.,  vol.  20, 1887,  p.  1864. 

g Carnegie  Inst.  Washington  Publication  No.  166,  1912.  Benedict  gives  a very  complete  summary  of 
earlier  investigations. 

Some  of  these  variations  are  doubtless  due  to  different  methods 
of  determination,  but  others  can  not  be  so  interpreted.  Hempel, 
comparing  his  analyses  of  air  from  Tromsoe,  Norway,  and  Para, 
Brazil,  infers  that  the  atmosphere  is  slightly  richer  in  oxygen  near 
the  poles  than  at  the  equator,  an  inference  that  would  seem  to  need 
additional  data  before  it  can  be  regarded  as  established.  The  most 
significant  variation  of  all,  however,  has  been  pointed  out  by  E.  W. 
Morley.1  As  oxygen  is  heavier  than  nitrogen,  it  has  been  supposed 

1 Am.  Jour.  Sci.,  3d  sor.,  vol.  18, 1879,  p.  168;  vol.  22, 1881,  p.  417.  For  the  distribution  of  the  different 
gases  in  the  atmosphere  according  to  elevation,  see  W.  J.  Humphreys,  Bull.  Mount  Weather  Observatory, 
vol.  2, 1900,  p.  68. 


THE  ATMOSPHERE. 


43 


that  the  upper  regions  of  the  atmosphere  should  show  a small  defi- 
ciency in  oxygen,  as  compared  with  air  from  lower  levels;  although 
analyses  of  samples  collected  on  mountain  tops  and  from  balloons 
have  not  borne  out  this  suspicion.  It  is  also  supposed  that  severe 
depressions  of  temperature,  the  so-called  “cold  waves,”  are  con- 
nected with  descents  of  air  from  very  great  elevations.  Morley’s 
analyses,  conducted  daily  from  January,  1880,  to  April,  1881,  at 
Hudson,  Ohio,  sustain  this  belief.  Every  cold  wave  was  attended  by 
a deficiency  of  oxygen,  the  determinations,  by  volume,  ranging  from 
20.867  to  21.006  per  cent,  a difference  far  greater  than  could  be 
attributed  to  errors  of  measurement.  Air  taken  at  the  surface  of 
the  earth  seems  to  show  a very  small  concentration  of  the  denser 
gas,  oxygen. 

By  electrical  discharges  in  the  atmosphere  some  oxygen  is  probably 
converted  into  its  allotropic  modification,  ozone,  although  this  point 
has  been  questioned.  Hydrogen  dioxide  is  formed  in  the  same  way, 
and  also  oxides  of  nitrogen,  and  between  these  substances,  in  minute 
traces,  it  is  not  easy  to  discriminate.  They  all  act  upon  the  usual 
reagent,  iodized  starch  paper,  and  therefore  the  identification  of 
ozone  remains  somewhat  uncertain,  at  least  so  far  as  ordinary  chemi- 
cal tests  have  gone.  It  is  known,  however,  that  the  ultra-violet 
rays  in  the  solar  radiations  so  act  upon  cold  dry  oxygen  as  to  convert 
part  of  it  into  ozone.  This  apparently  takes  place  in  the  upper, 
drier,  and  rarefied  strata  of  the  atmosphere,  as  shown  by  absorption 
bands  in  the  solar  spectrum.1  Both  ozone  and  hydrogen  dioxide  are 
powerful  oxidizing  agents,  and  either  or  both  of  them  play  some  part 
in  transforming  organic  matter  suspended  in  the  air  into  carbon 
dioxide,  water,  and  probably  ammonium  nitrate;  but  the  magnitude 
of  the  changes  thus  brought  about  can  not  be  estimated  with  any 
degree  of  definiteness.  Ozone  is  also  a powerful  absorbent  of  solar 
radiations,  and  may  possibly  exert  some  influence  in  modifying 
terrestrial  climates.  Its  generation  by  auroral  discharges  as  well  as 
by  ultra-violet  rays  is  considered  in  this  connection  by  Humphreys. 
According  to  H.  N.  Holmes 2 the  proportion  of  ozone  in  the  atmos- 
phere is  greater  in  winter  than  in  summer. 

Wherever  animals  breathe  or  fire  burns  oxygen  is  being  withdrawn 
from  the  air  and  locked  up  in  compounds.  By  growing  plants  under 
the  influence  of  sunlight,  one  of  these  compounds,  carbon  dioxide,  is 
decomposed  and  oxygen  is  liberated;  but  the  losses  exceed  the  gains. 
So  also,  when  the  weathering  of  a rock  involves  the  change  of  fer- 
rous into  ferric  compounds  oxygen  is  absorbed,  and  only  a portion  of 

1 See  W.  J.  Humphreys,  Astrophys.  Jour.,  vol.  32, 1910,  p.97,  and  authorities  cited  by  him.  Also  Henriet 
and  Bonyssy,  Compt.  Rend.,  vol.  147,  1908,  p.  977.  According  to  W.  Hayhurst  and  J.  N.  Pring  (Jour. 
Chem.  Soc.,  vol.  97, 1910,  p.  868)  the  ozone  in  the  atmosphere  amounts  to  less  than  one  part  in  four  thousand 
millions.  In  another  paper  (Proc.  Roy.  Soc.,  vol.  90A,  p.  204)  Pring  finds  that  air  from  high  altitudes 
contains  more  ozone  than  air  from  low  levels. 

2 Am.  Chem.  Jour.,  vol.  47,  p.  497,  1912. 


44 


THE  DATA  OF  GEOCHEMISTRY. 


it  is  ever  again  released.  The  atmosphere  then  is  slowly  being 
depleted  of  its  oxygen,  but  so  slowly  that  no  chemical  test  is  ever 
likely  to  detect  the  change. 

The  nitrogen  of  the  atmosphere  varies  reciprocally  with  the  oxy- 
gen, the  one  gaining  relatively  as  the  other  loses.  But  here  again 
special  variations  need  to  be  considered.  By  electrical  discharges, 
as  we  have  already  seen,  oxides  of  nitrogen  are  produced,  yielding 
with  the  moisture  of  the  air  nitric  and  nitrous  acids.  Through  the 
agency  of  microbes  certain  plants  withdraw  nitrogen  directly  from 
the  air  and  thus  remove  it  temporarily  from  atmospheric  circulation. 
By  the  decay  or  combustion  of  organic  matter  some  of  this  nitrogen 
is  returned,  partly  in  the  free  state  and  partly  in  gaseous  combina- 
tions. The  significance  of  these  changes  will  be  more  clearly  seen 
when  we  consider  the  subject  of  rain.  It  is  enough  to  note  here  that 
all  the  nitrogen  of  organic  matter  came  originally  from  the  atmos- 
phere, and  that  at  the  same  time  a larger  quantity  of  oxygen  was 
also  removed.  The  relative  proportions  of  the  two  gases  are  evidently 
undergoing  continuous  modification. 

According  to  Armand  Gautier  1 free  hydrogen  is  present  in  the 
atmosphere,  together  with  other  combustible  gases.  Air  collected 
at  the  Roches-Douvres  lighthouse,  off  the  coast  of  Brittany,  yielded 
1.21  milligrams  of  hydrogen  in  100  liters.  Air  from  the  streets  of 
Paris  was  found  to  contain  the  following  substances,  in  cubic  centi- 
meters per  100  liters: 


Free  hydrogen 19.  4 

Methane 12. 1 

Benzene  and  its  homologues 1.7 

Carbonic  oxide,  with  traces  of  olefines  and  acetylenes 2 


In  short,  air,  according  to  Gautier,  contains  by  volume  about  1 part 
in  5,000  of  free  hydrogen,  although  Rayleigh’s  2 experiments  on  the 
same  subject  would  indicate  that  this  estimate  is  at  least  six  times 
too  large.  It  is  known,  however,  that  hydrogen  is  emitted  by  vol- 
canoes in  considerable  quantities,  and  Gautier  has  extracted  the  gas 
from  granite  and  other  rocks.  One  hundred  grams  of  granite  gave 
him  134.61  cubic  centimeters  of  hydrogen  with  other  gases,  and  from 
this  fact  important  inferences  can  be  drawn.  At  the  proper  point, 
farther  on,  this  subject  will  he  discussed  more  fully.  As  for  the 
hydrocarbons,  their  chief  source  is  doubtless  to  be  found  in  the 
decomposition  of  organic  matter,  methane  or  marsh  gas  in  particular 
being  clearly  recognized  among  the  exhalations  from  swamps. 


1 Annales  chim.  phys.,  7th  ser.,  vol.  22, 1901,  p.  5. 

2 Philos. Mag.,  6th  ser.,  vol.  3, 1902,  p.  416.  See  also  a criticism  by  A.  Leduc,  Compt.  Rend.,  vol.  135, 1902, 
p»  860;  and  replies  to  Rayleigh  and  Leduc  by  Gautier,  idem,  vol.  135,  p.  1025;  vol.  136,  p.  21.  Also  a paper 
by  G.  D.  Liveing  and  J.  Dewar,  Proc.  Roy.  Soc.,  vol.  67,  1900,  p.  468.  G.  Claude  (Compt.  Rend.,  vol.  148, 
1909,  p.  1454)  found  less  than  one  part  per  million  of  hydrogen  in  air. 


THE  ATMOSPHERE. 


45 


According  to  H.  Henriet,®  formaldehyde  exists  in  the  atmosphere  in 
quantities  ranging  from  2 to  6 grams  in  100  cubic  meters.  Bodies 
of  this  class  are  impurities  in  the  atmosphere,  and  should  not  be 
reckoned  among  its  normal  constituents. 

Sulphur  compounds,  which  are  also  contaminations  of  the  atmos- 
phere, occur  in  air  in  variable  quantities.  Hydrogen  sulphide  is 
a product  of  putrefaction,  but  it  is  also  given  off  by  volcanoes, 
together  with  sulphur  dioxide.  The  latter  substance  is  also  pro- 
duced by  the  combustion  of  coal,  and  is  therefore  abundant  in  the 
air  of  manufacturing  districts.  At  Lille,  for  example,  A.  Ladureau  6 
found  1.8  cubic  centimeters  of  S02  in  a cubic  meter  of  air.  It  under- 
goes rapid  oxidation  in  presence  of  moisture,  being  converted  into 
sulphuric  acid,  and  that  compound,  either  free  or  represented  by 
ammonium  sulphate,  is  brought  back  to  the  surface  of  the  earth  by 
rain.  In  experiments  running  over  five  years  at  Bothams  ted, 
England,  R.  Warington  c found  that  the  equivalent  of  17.26  pounds 
of  S03  was  annually  poured  upon  each  acre  of  land  at  that  station. 
Quantities  of  this  order  can  not  be  ignored  in  any  study  of  chemical 
erosion. 

One  of  the  most  constant  and  most  important  of  the  accessory 
constituents  of  air  is  carbon  dioxide.  It  is  normally  present  to  the 
extent  of  about  3 volumes  in  10,000,  with  moderate  variations  above 
and  below  that  figure.  In  towns  its  proportion  is  higher;  in  the  open 
country  it  is  slightly  lower;  but  the  agitation  of  winds  and  atmos- 
pheric currents  prevent  its  excessive  accumulation  at  any  point. 
Only  a few  illustrations  of  its  quantity  need  be  given  here/  abnormal 
extremes  being  avoided. 

Determinations  of  carbon  dioxide  in  air. 


Analyst. 

Locality. 

Number  of  de- 
terminations. 

CO 2 (volumes 
per  10,000  of  air). 

J.  Heiset e 

Paris 

3.  027 

Do 

Near  Dieppe 

92 

2.  942 

T.  C.  Van  Niiys  and  B.  F. 

Bloomington,  Ind 

18 

2.816 

Adams./ 

A.  Petermann  and  J.  Graftiau  9. . 

Gembloux,  Belgium 

525 

2.  94 

E.  A.  Letts  and  E.  F.  Blake  h 

Belfast 

46 

2.  91 

a Compt.  Rend.,  vol.  138,  1904,  pp.  203,  1272. 
b Annales  chim.  phys.,  5th  ser.,  vol.  29, 1883,  p.  427. 

c Jour.  Chem.  Soc.,  vol.  51,  1887,  p.  500.  A later  figure  gives  17.41  pounds.  See  N.  H.  J.  Miller,  Jour. 
Agr.  Sci.,  vol.  1, 1905,  p.  292.  Miller  cites  data  from  Catania,  Sicily,  giving  20.89  pounds.  G.  Gray  (Rept. 
Australasian  Assoc.  Adv.  Sci.,  vol.  1, 1888,  p.  138)  found  15.2  pounds  per  acre  per  annum  in  4 \ years’  obser- 
vations at  Lincoln,  New  Zealand. 

d Very  elaborate  data  are  given  in  R.  Angus  Smith’s  Air  and  rain,  to  which  reference  has  already  been 
made.  See  also  the  excellent  paper  by  E.  A.  Letts  and  R.  F.  Blake,  Sci.  Proc.  Roy.  Dublin  Soc.,  vol.  9, 
pt.  2, 1900,  pp.  107-270.  The  latter  memoir  contains  a summary  of  all  the  determinations  previously  made, 
with  a very  thorough  bibliography  of  the  subject. 
e Compt.  Rend.,  vol.  88, 1879,  p.  1007. 

/ Am.  Chem.  Jour.,  vol.  9, 1887,  p.  64. 
g Cited  by  Letts  and  Blake. 

h Sci.  Proc.  Roy.  Dublin  Soc.,  vol.  9,  pt.  2, 1900,  pp.  107-270. 


46 


THE  DATA  OF  GEOCHEMISTRY. 


At  3 parts  in  10,000  the  carbon  dioxide  in  the  atmosphere  amounts 
to  about  2,200,000,000,000  tons,  equivalent  to  600,000,000,000  tons 
of  carbon.1 

Thousands  of  other  determinations  having  meteorological,  sanitary, 
or  agricultural  problems  in  view  are  recorded,  but  their  discussion 
does  not  fall  within  the  scope  of  this  work.2  That  in  general  terms 
the  proportion  of  carbon  dioxide  in  the  atmosphere  is  very  nearly 
uniform  is  the  point  that  concerns  us  now.  How  is  this  apparent 
constancy  maintained  ? 

From  several  sources  carbon  dioxide  is  being  added  to  the  air. 
The  combustion  of  fuels,  the  respiration  of  animals,  and  the  decay  of 
organic  matter  all  generate  this  gas.  From  mineral  springs  and  vol- 
canoes it  is  evolved  in  enormous  quantities.  According  to  J.  B. 
Boussingault,3  Cotopaxi  alone  emits  more  carbon  dioxide  annually 
than  is  generated  by  life  and  combustion  in  a city  like  Paris,  which  in 
1844  threw  into  the  air  daily  almost  3,000,000  cubic  meters  of  the  gas. 
Since  that  time  the  population  of  Paris  has  more  than  doubled,  and 
the  estimate  must  be  correspondingly  increased.  The  annual  con- 
sumption of  coal,  estimated  by  A.  Krogh 4 at  700,000,000  tons  in 
1902,  adds  yearly  to  the  atmosphere  about  one-thousandth  of  its 
present  content  in  carbon  dioxide.  In  a thousand  years,  then,  if  the 
rate  were  constant  and  no  disturbing  factors  interfered,  the  amount 
of  C02  in  the  atmosphere  would  be  doubled.  If  we  take  into  account 
the  combustion  of  fuels  other  than  coal  and  the  large  additions  to  the 
atmosphere  from  the  sources  previously  mentioned,  the  result  becomes 
still  more  startling.  Were  there  no  counterbalancing  of  this  increase 
in  atmospheric  carbon,  animal  life  would  soon  become  impossible 
upon  our  planet.  Figures  like  those  given  above  convey  some  faint 
notion  of  the  magnitude  of  the  chemical  processes  now  under  con- 
sideration. 

On  the  other  side  of  the  account  two  large  factors  are  to  be  con- 
sidered— first,  the  decomposition  of  carbon  dioxide  by  plants,  with 
liberation  of  oxygen ; and,  second,  the  consumption  of  carbon  dioxide 
in  the  weathering  of  rocks.  To  neither  of  these  factors  can  any 
precise  valuation  be  given,  although  various  writers  have  attempted 
to  estimate  their  magnitude.  E.  H.  Cook,5 * * * * *  for  instance,  from  very 
uncertain  data,  computes  that  leaf  action  alone  more  than  compen- 

1 A.  Krogh  (Meddelelser  om  Groenland,  vol.  26, 1904,  p.  419)  estimates  the  total  C02in  the  atmosphere 
at  2.4X1012  tons.  Van  Hise  (Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  p.  964)  and  Dittmar  (Challenger 
Report,  vol.  1,  pt.  2,  p.  954)  gives  figures  of  the  same  order.  Chamberlin  (Jour.  Geology,  vol.  7, 1899,  p.  682) 
makes  a somewhat  higher  estimate. 

2 For  example,  E.  L.  Moss  (Proc.  Roy.  Dublin  Soc.,  2d  ser.,  vol.  2,  1878, p.  34)  found  that  Arctic  air  is 

richer  in  carbon  dioxide  than  the  air  of  England.  In  air  from  Greenland  A.  Krogh  (Meddelelser  om  Groen- 

land, vol.  26, 1904,  p.  409)  found  the  proportion  of  carbon  dioxide  to  vary  from  2.5  up  to  7 parts  in  10,000. 

The  proportion  determined  by  R.  Legendre  (Compt.  Rend.,  vol.  143,  1906,  p.  526)  in  ocean  air  was  3.35 

in  10,000. 

a Annales  chim.  phys.,  3d  ser.,  vol.  10, 1844,  p.  456. 

* Loc.  cit.  The  present  consumption  of  coal  exceeds  1,000,000,000  tons.  Krogh ’s  figures  should  be  corre- 

spondingly modified. 

e Philos.  Mag.,  5th  ser.,  vol.  14, 1882,  p.  387. 


THE  ATMOSPHERE. 


47 


sates  for  the  production  of  carbon  dioxide,  and  that  without  such 
compensation  the  quantity  present  in  the  air  would  double  in  about 
100  years.  Some  of  the  carbon  dioxide  thus  absorbed  is  annually 
returned  to  the  atmosphere  by  the  autumnal  decay  of  leaves,  but 
part  of  it  is  permanently  withdrawn. 

T.  Sterry  Hunt 1 illustrates  the  effect  of  weathering  by  the  state- 
ment that  the  production  from  orthoclase  of  a layer  of  kaolin,  500 
meters  thick  and  completely  enveloping  the  globe,  would  consume 
21  times  the  amount  of  carbon  dioxide  now  present  in  the  atmos- 
phere. He  also  computes  that  a similar  shell  of  pure  carbon,  of 
density  1.25  and  0.7  meter  in  thickness,  would  require  for  its  com- 
bustion all  the  oxygen  of  the  air.  Such  estimates  may  have  slight 
numerical  value,  but  they  serve  to  show  how  vast  and  how  im- 
portant the  processes  under  consideration  really  are.  The  carbon 
of  the  coal  measures  and  of  the  sedimentary  rocks  has  all  been 
drawn,  directly  or  indirectly,  from  the  atmosphere.  Soluble  carbon- 
ates, produced  by  weathering,  are  washed  into  the  ocean,  and  are 
there  transformed  into  sediments,  into  shells,  or  into  coral  reefs; 
but  the  atmosphere  was  the  source  from  which  all,  or  nearly  all,  of 
the  carbon  thus  stored  away  was  taken.  The  carbon  of  the  sedi- 
mentary rocks,  as  computed  with  the  aid  of  data  given  in  the  pre- 
ceding chapter,  is  about  30,000  times  as  much  as  is  now  contained 
in  the  atmosphere.  T.  C.  Chamberlin  2 estimates  that  the  amount 
of  carbon  dioxide  annually  withdrawn  from  the  atmosphere  is 
1,620,000,000  tons,  but  the  method  by  which  this  figure  was  obtained 
is  not  clearly  stated.  In  calculations  of  this  sort  there  is  a certain 
fascination,  hut  their  chief  merit  seems  to  lie  in  their  suggestiveness. 

THE  RELATIONS  OF  CARBON  DIOXIDE  TO  CLIMATE. 

From  a geological  standpoint  the  carbon  dioxide  of  the  air  has  a 
twofold  significance — first,  as  a weathering  agent,  and  second,  as  a 
regulator  of  climate.  The  subject  of  weathering  will  receive  due 
consideration  later;  but  the  climatic  value  of  atmospheric  carbon 
may  properly  be  mentioned  now.  Both  carbon  dioxide  and  aqueous 
vapor  serve  as  selective  absorbents  for  the  solar  rays,  and,  by  blanket- 
ing the  earth,  they  help  to  avert  excessive  changes  of  temperature. 
On  the  physical  side,  and  as  regards  carbon  dioxide,  this  question 
has  been  discussed  by  S.  Arrhenius,3  who  argues  that  if  the  quantity 
of  the  gas  in  the  atmosphere  were  increased  about  threefold,  the 
mean  temperature  of  the  Arctic  regions  would  rise  8°  or  9°.  A 
corresponding  loss  of  carbon  dioxide  would  lead  to  a lowering  of 
temperature;  and  in  variations  of  this  kind  we  may  find  an  explana- 
tion of  the  alterations  of  climate  which  have  undoubtedly  occurred. 
The  glacial  period,  for  example,  may  have  been  due  to  a loss  of  carbon 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  19,  1880,  p.  349. 

2 Jour.  Geology,  vol.  7, 1899,  p.  G82. 

3 Philos.  Mag.,  5th  ser.,  vol.  41, 189G,  p.  237.  Annalen  d.  Physik,  4th  ser.,  vol.  4, 1901,  p.  G90. 


48 


THE  DATA  OF  GEOCHEMISTRY. 


dioxide  from  the  atmosphere.  To  account  for  such  gains  and  losses, 
Arrhenius  cites  with  great  fullness  the  work  of  A.  G.  Hogbom, 
who  regards  volcanoes  as  the  chief  source  of  supply.  Just  as  indi- 
vidual volcanoes  vary  in  activity  from  quietude  to  violence,  so 
the  volcanic  activity  of  the  globe  has  varied  from  time  to  time. 
During  periods  of  great  energy  the  carbon  dioxide  of  the  air  would 
be  abundant;  at  other  times  its  quantity  would  be  smaller.  Hogbom 
estimates  that  the  total  carbon  of  the  atmosphere  would  form  a 
layer  1 millimeter  thick,  enveloping  the  entire  globe.  The  quantity 
of  carbon  in  living  matter  he  regards  as  being  of  the  same  order, 
neither  many  fold  greater  nor  many  fold  less.  The  combustion  of 
coal  he  reckons  as  about  balancing  the  losses  of  the  atmosphere 
by  weathering;  and  in  this  way  he  reaches  his  conclusion  that  vol- 
canic action  is  the  important  factor  of  the  problem. 

This  theory  of  Arrhenius  has  been,  however,  a subject  of  much 
controversy.  It  was  strongly  endorsed  by  F.  Freeh,1  who  has 
attempted  by  means  of  it  to  account  for  glacial  periods.  E.  Kayser,2 
on  the  other  hand,  has  attempted  to  prove  that  the  views  of  Arrhenius 
are  untenable,  on  the  ground  of  K.  J.  Angstrom’s  3 physical  researches. 
Angstrom  has  shown  that  carbon  dioxide  in  the  atmosphere  can 
not  possibly  absorb  more  than  16  per  cent  of  the  terrestrial  radiations, 
and  that  variations  in  its  amount  are  of  very  small  effect.  Further- 
more, C.  G.  Abbot  and  F.  E.  Fowle 4 have  shown  that  aqueous 
vapor  is  present  in  the  atmosphere  in  quantities  so  large  as  to  make 
the  climatic  significance  of  carbon  dioxide  negligible.  The  principal 
absorbent  of  terrestrial  radiations  is  the  vapor  of  water.  Whether 
the  theory  of  Arrhenius  is  in  harmony  with  the  facts  of  historical 
geology — that  is,  whether  periods  of  volcanic  activity  have  coincided 
with  warmer  climates,  and  a slackening  of  activity  with  lowering  of 
temperature — is  also  in  dispute.  The  controversy  is  not  yet  ended.5 

One  other  suggested  regulative  agency  remains  to  be  mentioned. 
The  ocean  is  a vast  reservoir  of  carbon  dioxide,  which  is  partly  in 
solution  and  partly  combined.  Between  the  surface  of  the  sea  and 
the  atmosphere  there  is  a continual  interchange,  each  one  sometimes 
losing  and  sometimes  gaining  gas.  Upon  this  fact  a theory  of 
climatic  variations  has  been  founded,  and  in  another  chapter,  upon 
the  ocean,  it  will  be  stated  and  discussed. 

1 Zeitschr.  Gesell.  Erdkunde,  Berlin,  vol.  37,  1902,  pp.  611,  671;  idem,  1906,  p.  533.  Neues  Jahrb.,  1908, 
pt.  2,  p.  74. 

2 Centralbl.  Min.,  Geol.  u.  Pal.,  1908,  p.  553;  1909,  p.  660.  Rejoinder  by  Arrhenius,  idem,  1909,  p.  481. 
Later  papers  by  Arrhenius  and  Kayser  are  in  the  same  journal  for  1913,  pp.  582,  764. 

3 Annalen  d.  Physik,  4th  ser.,  vol.  3,  1900,  p.  720;  vol.  6,  1901,  p.  163.  Angstrom  himself  criticizes  Arr- 
henius. 

4 Annals  Astrophys.  Observ.,  vol.  2,  1908,  pp.  172,  175. 

5 On  the  geologic  side  of  the  question  see  Kayser,  loc.  cit.,  and  Lehrbuch  der  allgemeinen  Geologie,  3d 
ed.,  1909,  pp.  81-83.  Also  E.  Koken,  Neues  Jahrb.,  Fest  Band,  1907,  p.  530,  and  E.  Philippi , Centralbl. 
Min.,  Geol.  u.  Pal.,  1908,  p.  360.  The  papers  referred  to  contain  many  other  references  to  literature.  On 
the  influence  of  volcanic  dust  on  climate,  see  W.  J.  Humphreys,  Jour.  Washington  Acad.  Sci.,  vol.  3,  p. 
365,  1913. 


THE  ATMOSPHERE. 


49 


RAINFALL. 

Among  all  the  constituents  of  the  atmosphere  aqueous  vapor  is  the 
most  variable  in  amount  and  the  most  important  geologically.  It  is 
not  merely  a solvent  and  disintegrator  of  rocks,  but  it  is  also  a carrier, 
distributing  other  substances  and  making  them  more  active.  To  the 
circulation  of  atmospheric  moisture  we  owe  our  rivers,  and  through 
them  erosion  is  effected.  The  process  of  erosion  is  partly  chemical 
and  partly  mechanical,  and  the  two  modes  of  action  reinforce  each 
other.  By  flowing  streams  the  rocks  are  ground  to  sand,  and  so  new 
surfaces  are  exposed  to  chemical  attack.  On  the  other  hand,  chemical 
solution  weakens  the  rocks  and  renders  them  easier  to  remove  mechan- 
ically. As  water  evaporates  from  the  surface  of  the  sea,  it  lifts,  by 
inclusion  in  vapory  vesicles,  great  quantities  of  saline  matter,  which 
are  afterward  deposited  by  rainfall  upon  the  land.  It  is  through 
the  agency  of  rain  or  snow  that  the  atmosphere  produces  its  greatest 
geological  effects;  but  the  chemical  side  of  its  activity  is  all  that  con- 
cerns us  now.  Aqueous  vapor  dissolves  and  concentrates  the  other 
ingredients  of  air  and  brings  them  to  the  ground  in  rain. 

In  one  sense  oxygen  is  the  most  active  of  the  atmospheric  gases,  but 
without  the  aid  of  moisture  its  effectiveness  is  small.  Perfectly  dry 
oxygen  is  comparatively  inert;  for  example,  phosphorus  burns  in  it 
slowly  and  without  flame,  but  the  merest  trace  of  water  gives  the  gas 
its  usual  activity.1  More  than  this  trace  is  always  present  in  the  air, 
and  when  it  condenses  to  rain  it  dissolves  oxygen,  nitrogen,  carbon 
dioxide,  and  other  gases.  These  substances  differ  in  solubility,  and 
therefore  dissolved  air  contains  them  in  abnormal  proportions.  In 
air  extracted  from  rain  water,  Humboldt  and  Gay-Lussac  found  31 
per  cent  of  oxygen.  R.  W.  Bunsen,2  who  examined  air  from  rain 
water  at  different  temperatures,  gives  the  following  table  to  illustrate 
its  composition  by  volume: 


Composition  of  dissolved  air  at  different  temperatures. 


0° 

5° 

10° 

15° 

20° 

n2 

63.  20 

63.  35 

63.  49 

63.  62 

63.  69 

02 

33.  88 

33.  97 

34.  05 

34. 12 

34. 17 

co2 

2.  92 

2.  68 

2.  46 

2.26 

2. 14 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

In  air  from  sea  water  O.  Pettersson  and  K.  Sonden3  found  nearly 
34  per  cent  of  oxygen.  In  dissolved  air,  then,  and  especially  in  rain, 
oxygen  is  concentrated,  and  in  that  way  its  effectiveness  is  increased. 


1 See  H.  Brereton  Baker,  Proc.  Roy.  Soe.,  vol.  45, 1888,  p.  1. 

s Liebig’s  Annalen,  vol.  93,  1855,  p.  48.  See  also  M.  Baumert,  idem,  vol.  88, 1853,  p.  17,  for  evidence  of 
the  same  order. 

* Ber.  Deutsch.  chem.  Gesell.,  vol.  22, 1889,  p.  1439. 

97270°— Bull.  GIG— 10 4 


50 


THE  DATA  OF  GEOCHEMISTRY, 


The  same  is  true  of  carbon  dioxide.  Rain  brings  it  to  the  surface  of 
the  earth,  where  its  eroding  power  comes  into  play. 

As  a carrier  of  ammonia,  nitric  acid,  sulphuric  acid,  and  chlorine, 
rain  water  performs  a function  of  the  highest  significance  to  agricul- 
ture, but  whose  geological  importance  has  not  been  generally  recog- 
nized. Rain  and  snow  collect  these  impurities  from  the  atmosphere, 
in  quantities  which  vary  with  local  conditions,  and  redistribute  them 
upon  the  soil.  Many  analyses  of  rain  water  have  therefore  been 
made,  not  only  at  agricultural  experiment  stations,  but  also  for  sani- 
tary purposes,  and  a few  of  the  results  obtained  are  given  below.® 
Figures  for  sulphuric  acid  have  already  been  cited.  The  values 
given  are  stated  in  pounds  per  acre  per  annum  brought  to  the  surface 
of  the  earth  at  the  several  stations  named.  For  nitrogen  compounds 
the  data  are  as  follows: 

Nitrogen  brought  to  the  surface  of  the  earth  by  rain. 


[Pounds  per  acre  per  annum.] 


Locality. 

Nitrogen. 

Remarks. 

Ammoniacal. 

Nitric. 

Total. 

Rothamsted,  England  & 

2.  406 

5 years’  average. 
1888-1901. 

Rothamsted,  England  c 

2.  71 

1. 13 

3.  84 

N ear  Paris  ^ 

8.  93 

11  years’  average. 

Caracas,  Venezuela  e 

.516 

Gembloux,  Belgium  / 

9.  20 

2\  years’  average. 
5 years’  average. 
20  years’  average. 
3 years’  average. 

3 years’  average. 

3 years’  average. 

4 J years’  average. 
11  months’  aver- 

Barbados 9 

1.  009 

2.  443 

3.  452 

British  Guiana  A 

1.  006 

1.  886 

3.  541 

Kansas  * 

2.  63 

1.  06 

3.  69 

Utah  j 

5.  06 

.356 

5.  42 

Mississippi  & 

3.  636 

New  Zealand  J 

2.  08 

Iceland  * 

. 802 

. 263 

1.  065 

Hebrideo  m 

.311 

.289 

. 600 

age. 

11  month’s  aver- 

age. 

a For  the  older  data  see  R.  Angus  Smith,  Air  and  rain,  London,  1872.  For  nitrogen  and  chlorides  in  rain 
and  snow  at  Mount  Vernon,  Iowa,  see  G.  II.  Wiesner.  Chem.  News,  vol.  103, 1914,  p.  85.  See  also  W.  J. 
Knox,  for  data  from  the  same  locality,  Chem.  News,  vcl.  Ill,  1915,  p.  61.  F.  T.  Shutt  (Trans.  Roy. 
Soc.  Canada,  3d  ser.,  vol.  8,  1914,  p.  83)  gives  data  for  nitrogen  in  rain  and  snow  during  seven  years’ 
observations  at  Ottawa.  The  observations  cover  14  weeks  only.  The  annual  report  of  the  Rothamsted 
Station,  England,  for  1913.  contains  additional  data  on  nitrogen. 

b R.  Warington,  Jour.  Chem.  Soc.,  vol.  51, 1S87,  p.  500. 

c N.  II.  J.  Miller,  Jour.  Agr.  Sci.,  vol.  1,  1905,  p.  2S3.  See  also  R.  Warington,  Jour.  Chem.  Soc.,  vol.  35, 
1889,  p.  537,  for  earlier  figures.  Miller  gives  a table  for  35  localities,  and  also  an  excellent  bibliography  of 
the  entire  subject  of  nitrogen,  sulphuric  acid,  and  chlorine  in  rain. 

d Albert  Levy,  Jour.  Chem.  Soc.,  vol.  56,  1889,  p.  299.  (Abstract.)  10.01  kilos  per  hectare. 

e A.  Muntz  and  V.  Marcano,  Compt.  Rend.,  vol.  108, 1889,  p.  10C2. 

/ A.  Petermann  and  J.  Graftiau,  Jour.  Chem.  Soc.,  vol.  04, 1893,  abst.  ii,  p.  548.  10.31  kilos  per  hectare. 

g J.  B.  Harrison  and  J.  Williams,  Jour.  Am.  Chem.  Soc.,  vol.  19, 1897,  p.  1. 

A J.  B.  Harrison,  Rept.  Dept.  Sci.  and  Agr.,  British  Guiana,  1909-10.  For  earlier  figures  see  preceding 
reference. 

i G.  H.  Failyer  and  C.  M.  Breese,  Second  Ann.  Rept.  Exper.  Sta.,  Kansas  Agr.  Coll.,  1889. 

j R.  W.  Erwin,  Fourth  Ann.  Rept.  Utah  Agr.  Coll.  Exper.  Sta.,  1893. 

k Hutchinson,  Tenth  Ann.  Rept.  Mississippi  Agr.  and  Mech.  Coll.  Exper.  Sta.,  1897.  See  also  Eighth 
Ann.  Rept. 

i G.  Gray,  Rept.  Australasian  Assoc.  Adv.  Sci.,  vol.  1, 1888,  p.  138.  The  figures  include  some  albumi- 
noid nitrogen. 

m N.  H.  J.  Miller,  Jour.  Chem.  Soc.,  vol.  106,  i,  1914,  p.  128,  Abstract. 


THE  ATMOSPHERE. 


51 


In  most  cases  ammonia  is  in  excess  over  nitric  acid;  but  in  the 
Tropics  the  reverse  seems  to  be  true.  The  substance  actually  brought 
to  earth,  then,  is  in  great  part  ammonium  nitrate,  but  the  conditions 
are  modified  when  hydrochloric  or  sulphuric  acid  happens  to  be 
present  in  the  air.  A large  part  of  the  combined  nitrogen  has  of 
course  been  added  to  the  atmosphere  by  organic  decomposition  at  the 
surface  of  the  earth;  but  some  of  it  is  due,  as  we  have  already  seen, 
to  electrical  discharges  during  thunderstorms.  The  geological  sig- 
nificance of  free  acids  in  rain  is  obvious,  for  it  means  an  increase  in 
the  eroding  power  of  water. 

Furthermore,  in  this  circulation  of  nitrogen  between  the  ground 
and  the  air,  the  ground  gains  more  than  it  loses.  All  of  the  nitrogen 
thus  fixed  in  combination  is  not  released  again  to  the  atmosphere; 
only  a part  so  returns.1 

The  figures  for  atmospheric  chlorine  are  even  more  surprising; 
but  they  represent  in  general  salt  raised  by  vapor  from  the  ocean. 
Where  chemical  industries  are  carried  on,  free  hydrochloric  acid  may 
enter  the  air,  and  some  hydrochloric  acid  is  also  evolved  from  volca- 
noes; but  these  are  minor  factors  of  little  more  than  local  signifi- 
cance. Chlorine  is  abundant  in  the  air  only  near  the  sea,  and  its 
proportion  rapidly  diminishes  as  we  recede  from  the  coast.  This  is 
clearly  shown  by  the  “ chlorine  map”  of  Massachusetts,2  and  by 
several  later  documents  of  the  same  kind,  in  which  the  “ normal 
chlorine”  of  the  potable  waters  is  indicated  by  isochlors  that  follow 
the  contour  of  the  shore.  Near  the  ocean  the  waters  are  rich  in 
chlorides,  which  diminish  rapidly  as  we  follow  the  streams  inland. 

The  amount  of  salt  precipitated  by  rain  upon  the  land  is  by  no 
means  inconsiderable.  For  quantitative  data  a few  examples  must 
suffice,  stated  in  the  same  way  as  for  nitrogen. 


1 T.  Schloesing  (Contributions  a 1’ etude  de  la  chimie  agricole,  1888,  p.  55)  estimates  the  average  ammonia 
in  the  atmosphere  at  0.02  milligram  per  cubic  meter.  This  amounts  to  1,600  grams  over  every  hectare  of 
the  earth’s  surface. 

On  nitrates  in  the  atmosphere  see  A.  Muntz  and  E.  Laine,  Compt.  Rend.,  vol.  152,  1911,  p.  167.  J. 
Hirschwald  (Die  Priifung  der  natiirlichen  Bausteine,  Berlin,  1908,  p.  5)  gives  many  data  for  ammonia 
and  nitrates  in  the  air. 

2 See  T.  M.  Drown,  in  Rept.  Massachusetts  State  Board  of  Health,  etc.,  vol.  1,  December,  1889.  Mrs. 
Ellen  S.  Richards,  who  was  associated  with  Drown  in  this  investigation,  has  since  published,  jointly  with 
A.  T.  Hopkins,  a similar  map  of  Jamaica  (Tech.  Quart.,  vol.  11, 1898,  p.  227).  For  a chlorine  map  of  Long 
Island,  see  G.  C.  Whipple  and  D.  D.  Jackson,  Tech.  Quart.,  vol.  13,  1900,  p.  145.  One  of  Connecticut 
appears  in  the  report  of  the  State  board  of  health  for  1895.  For  a general  chlorine  map  of  New  York  and 
New  England,  see  Jackson,  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  144,  1905. 


52 


THE  DATA  OF  GEOCHEMISTRY. 


Chlorides  brought  to  the  surface  of  the  earth  by  rain. 

[Pounds  per  acre  per  annum.] 


Locality. 

Chlorine. 

Sodium 

chloride. 

Remarks. 

Cirencester,  England® 

36. 10 

26  years’  average. 

Rothamsted,  England  b 

Rothamsted,  England  c 

14.  40 
14.  87 

24.  00 

Perugia,  Italy  d 

37.  95 

In  1887. 

Ceylon6 

180.  63 

Calcutta6 

32.  87 

Madras  6 

36.  27 

Odessa,  Russia/ 

17.  00 

Barbados  9 

116.  98 

5 years’  average. 
20  years’  average. 
4|  years’  average. 

British  Guiana  b 

129.  24 

195.  00 

New  Zealand* 

61.  20 

a E.  Kinch,  Jour.  Chem.  Soc.,  vol.  77,  1900,  p.  1271. 
b R.  Warington,  idem,  vol.  51,  1887,  p.  500. 

cN.  H.  J.  Miller,  Jour.  Agr.  Sci.,  vol.  1,  1905.  p.  292.  Miller  gives  figures  for  several  other  localities. 
d G.  Bellucci,  Jour.  Chem.  Soc.,  abstract,  vol.  56,  1899,  p.  299.  42.531  kilos  per  hectare. 

« Cited  by  Miller,  loc.  cit. 

/ J.  Pirovaroff,  Ann.  geol.  min.  Russie,  vol.  9,  1908,  p.  274.  19  kilos  per  hectare. 
g J.  B.  Harrison  and  J.  Williams,  Jour.  Am.  t hem.  Soc.,  vol.  19,  1897,  p.  1. 

h J.  B.  Harrison,  Rept.  Dept.  Sci.  and  Agr.,  British  Guiana,  1909-10.  For  earlier  figures  see  preceding 
reference. 

i  G.  Gray,  Rept.  Australian  Assoc.  Adv.  Sci.,  vol.  1,  1888,  p.  138. 


Furthermore,  we  have  the  older  researches  of  Pierre,1  whose  anal- 
yses were  made  in  1851  at  Caen,  in  Normandy,  where  each  hectare  of 
soil  was  found  to  receive  annually,  in  rain,  the  following  impurities: 


Kilograms. 

NaCl 37.5 

KC1 8. 2 

MgCl2 2.  5 

CaCl2 1.  8 


Kilograms. 

Na2S04 8.4 

K2S04 .....  8. 0 

CaS04 6. 2 

MgS04 5.9 


These  citations  are  enough  to  show  the  great  geological  impor- 
tance of  rainfall,  over  and  above  its  ordinary  mechanical  effects, 
and  its  value  as  a solvent  after  it  enters  the  groimd. 

The  atmospheric  circulation  of  salt  has  received  much  attention, 
and  F.  Posepny,2  as  long  ago  as  1877,  attempted  to  show  that  the 
sodium  chloride  of  inland  waters  was  derived  largely  from  this 
source.  Of  late  years  the  same  idea  has  been  strongly  urged  by 
W.  Ackroyd,3  who  has  gone  so  far  as  to  attribute  the  salinity  of  the 
Dead  Sea  to  chlorides  brought  by  winds  from  the  Mediterranean. 
Furthermore,  A.  Muntz  4 has  pointed  out  that  without  this  circu- 


1 See  R.  Angus  Smith,  Air  and  rain,  1872,  pp.  223-232.  Pierre  also  cites  valuable  data  obtained  by  Barral, 
Bineau,  Liebig,  Boussingault,  and  others.  See  also  A.  Bobierre,  Compt.  Rend.,  vol.  58,  1864,  p.  755,  for 
the  composition  of  rain  water  collected  at  Nantes  in  1863.  The  average  sodium  chloride  amounted  to  14.09 
grams  per  cubic  meter. 

2 Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  76,  Abth.  1, 1877,  p.  179.  See  also  a discussion  of  this  memoir  by 
E.  Tietze,  Jahrb.  K.*k.  geol.  Reichsanstalt,  vol.  27,  1877,  p.  341.  In  a recent  discussion  of  this  subject 
E.  Dubois  (Arch.  Mus6e  Teyler,  2d  ser.,  vol.  10,  1907,  p.  441)  has  estimated  the  amount  of  atmospheric 
salt  annually  precipitated  in  rainfall  on  two  provinces  of  Holland  as  about  6,000,000  kilograms. 

3 Geol.  Mag.,  4th  ser.,  vol.  8,  1900,  p.  445.  Proc.  Yorkshire  Geol.  and  Polytech.  Soc.,  vol.  14,  p.  408. 
Chem.  News,  January  8, 1904. 

* Compt.  Rend.,  vol.  112, 1891,  p.  449. 


THE  ATMOSPHERE. 


53 


lation  of  salt,  and  its  replenishment  of  the  land,  the  latter  would  soon 
be  drained  of  its  chlorides,  and  living  beings  would  suffer  from  the 
loss.  These  writers  probably  overemphasize  the  importance  of 
“cyclic  salts,”  as  they  have  been  called,  but  their  arguments  are 
enough  to  show  that  the  phenomena  under  consideration  are  by  no 
means  insignificant.  Wind-borne  salt  plays  a distinct  part  in  the 
economy  of  nature;  but  its  influence  is  yet  to  be  studied  in  definite, 
quantitative  terms.  An  exception  to  this  statement  is  furnished  by 
the  Sambhar  Salt  Lake  in  India,  which  will  be  considered  in  detail 
in  another  chapter. 

Apart  from  its  function  in  carrying  soluble  salts,  the  atmosphere 
performs  a great  work  in  mechanically  transporting  other  solids.  Its 
effectiveness  as  a carrier  of  dust  is  well  understood;  dust  from  the 
explosion  of  Krakatoa  was  borne  twice  around  the  globe,  but  such 
processes  bear  indirectly  upon  chemistry.  In  desert  regions  the  sand- 
storms help  to  disintegrate  the  rocks,  and  so  to  render  them  more 
susceptible  to  chemical  change.  Dust,  also,  whether  cosmic  or  ter- 
restrial, furnishes  the  nuclei  around  which  drops  of  rain  are  formed, 
and  so  reinforces  the  activity  of  atmospheric  moisture.1 

THE  PRIMITIVE  ATMOSPHERE. 

Although  the  main  purpose  of  this  treatise  is  to  assemble  and 
classify  data,  rather  than  to  discuss  speculations,  a few  words  as  to 
the  origin  of  our  atmosphere  may  not  be  out  of  place.  Upon  this 
subject  much  has  been  written,  especially  in  recent  years;  but  none 
of  the  widely  variant  theories  so  far  advanced  can  be  regarded  as 
conclusive.  The  problem,  indeed,  is  one  of  cosmology,  and  chemical 
data  supply  only  a single  line  of  attack.  Physical,  astronomical, 
mathematical,  and  geological  evidence  must  be  brought  to  bear  upon 
the  question  before  anything  like  an  intelligent  conclusion  can  be 
reached.  Even  then,  with  every  precaution  taken,  we  can  hardly  be 
sure  that  our  fundamental  premises  are  sound. 

One  phase  of  the  discussion,  to  which  I have  already  referred, 
relates  to  the  constancy  or  variability  of  the  atmosphere.  The  accu- 
mulations of  carbon  in  the  lithosphere,  such  as  the  coal  measures, 
the  limestones,  and  the  like,  have  led  some  geologists  to  assume  that 
the  atmosphere  at  some  former  time  was  vastly  richer  in  carbonic 
acid  than  it  is  now;  but  the  fossil  records  of  life  suggest  that  the 
differences  could  not  have  been  extreme.  With  a large  excess  of  car- 
bon dioxide  the  existence  of  air-breathing  animals  would  be  impos- 
sible. Only  anaerobic  organisms  could  live.  It  is  clear  that  the 
stored  carbon  of  the  sedimentary  rocks  was  once  largely  in  the  atmos- 
phere, but  was  it  ever  all  present  there  at  any  one  time  ? 


1 See  J.  Aitken,  Proc.  Roy.  Soc.  Edinburgh,  vol.  17,  1890,  p.  193.  An  interesting  lecture  by  A.  Ditte 
(Revue  scient.,  5th  ser.,  vol.  2,  1904,  p.  709),  on  metals  in  the  atmosphere,  is  well  worthy  of  notice.  It 
deals  with  dust,  meteoric  matter,  cyclic  salts,  ammonium  compounds,  etc. 


54 


THE  DATA  OF  GEOCHEMISTRY. 


Such  a supposition  is  improbable.  The  known  carbon  of  the 
lithosphere,  if  converted  into  carbon  dioxide,  would  yield  nearly  25 
times  the  present  mass  of  the  entire  atmosphere,  and  the  atmospheric 
pressure  at  the  surface  of  the  earth  would  be  enormously  increased.1 
It  is  more  likely  that  carbon  dioxide  has  been  added  to  the  atmosphere 
by  volcanic  agency,  in  some  such  manner  as  this:  Primitive  carbon, 
like  the  graphite  found  in  meteorites,  at  temperatures  no  greater 
than  that  of  molten  lava,  reduced  the  magnetite  of  igneous  rocks  to 
metallic  iron,  such  as  is  found  in  many  basalts,  and  was  itself  thereby 
oxidized.  Then,  discharged  into  the  atmosphere  as  dioxide,  it  became 
subject  to  the  familiar  reactions  which  restored  it  to  the  lithosphere 
as  coal  or  limestone. 

In  order  to  account  for  the  observed  phenomena,  several  essentially 
distinct  hypotheses  have  been  proposed.  T.  Sterry  Hunt,2  for 
example,  argued  in  favor  of  a cosmical  atmosphere,  pervading  all 
space,  from  which  a steady  supply  of  carbon  dioxide  has  been  drawn. 
This  theory,  which  was  also  favored  by  Alexander  Winchell,3  postu- 
lates a universal,  exhaustless  reservoir  of  carbon,  which  should  be 
able  to  satisfy  all  demands.  But  what  evidence  have  we  that  such 
an  atmosphere  exists  ? 

S.  Meunier,4  criticizing  Hunt,  points  out  that  some  planets  have 
excessive  and  others  deficient  atmospheres,  and  that  a cosmic  uni- 
formity is  therefore  improbable.  Meunier  prefers  the  volcanic  theory, 
for  which  we  have  at  least  some  basis  of  fact.  We  know  that  gases 
are  emitted  from  volcanoes,  even  though  there  is  no  certain  measure 
of  their  quantity,  and  the  question  to  he  determined  relates  to  the 
adequacy  and  the  source  of  the  supply.  That  question  I shall  not 
now  attempt  to  answer;  but,  obviously,  if  the  volcanic  hypothesis 
be  true,  the  cessation  of  volcanism  would  signify  the  end  of  life  on 
the  globe.  It  would  be  followed  by  the  consumption  of  all  available 
carbon  dioxide,  so  that  plant  life,  and  consequently  animal  life, 
could  no  longer  be  supported.  A cosmical  atmosphere  has  no 
assignable  limit ; an  atmosphere  of  volcanic  origin  must  sooner  or  later 
be  exhausted.  May  not  the  moon  be  an  example  of  such  an  atmos- 
pheric death?5 

Another  theory  relative  to  the  atmosphere  is  based  upon  the  belief 
that  the  unoxidized,  but  oxidizable,  substances  in  the  primitive  rocks 
are  sufficient  in  quantity  to  absorb  all  the  oxygen  of  the  air.  If  our 
globe  solidified  from  a molten  condition,  and  if,  as  commonly  sup- 

1 For  a curious  speculation  on  the  mass  of  the  atmosphere,  see  R.  H.  McKee,  Science,  vol.  23, 1906,  p.  271. 
He  argues  that  the  present  atmosphere  is  as  great  as  the  earth  is  capable  of  retaining. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  19, 1880,  p.  349. 

2 Science,  vol.  2, 1883,  p.  820. 

4 Compt.  Rend.,  vol.  87,  1878,  p.  541. 

6 It  is  probable  that  the  combustion  of  carbonaceous  meteorites  in  the  atmosphere  may  add  carbon 
dioxide  to  it,  but  the  quantity  so  supplied  can  hardly  be  estimated.  It  is  possibly  large. 


THE  ATMOSPHERE. 


55 


posed,  oxidized  compounds  were  the  first  to  form,  the  observed  con- 
ditions are  not  easy  to  explain.  C.  J.  Koene,  indeed,  assumed  that 
the  primitive  atmosphere  contained  no  free  oxygen,  and  he  has  been 
followed  of  late  years  by  T.  L.  Phipson,1  J.  Lemberg,2  John  Steven- 
son,3 and  Lord  Kelvin.4  Lemberg  and  Kelvin,  however,  do  not  go 
to  extremes,  but  admit  that  possibly  some  free  oxygen  was  present 
even  in  the  earliest  times.  Lemberg  argued  that  the  primeval  atmos- 
phere contained  chiefly  hydrogen,  nitrogen,  volatile  chlorides,  and 
carbon  compounds,  the  oxygen  which  is  now  free  being  then  united 
with  carbon  and  iron.  The  liberation  of  oxygen  began  with  the 
appearance  of  low  forms  of  plant  life,  possibly  reached  a maximum 
in  Carboniferous  time,  and  has  since  diminished.  Stevenson’s  argu- 
ment is  much  more  elaborate,  and  starts  with  an  estimate  of  the 
uncombined  carbon  now  existent  in  the  sedimentary  formations. 
In  the  deposition  of  that  carbon,  oxygen  was  liberated,  and  from  data 
of  this  kind  it  is  argued  that  the  atmospheric  supply  of  oxygen  is 
steadily  increasing,  while  that  of  carbon  dioxide  diminishes.  The 
statement  that  no  oxygen  has  been  found  in  the  gases  extracted  from 
rocks  is  also  adduced  in  favor  of  the  theory.  First,  an  oxidized  crust 
and  no  free  oxygen  in  the  air;  then  processes  of  reduction  coming  into 
play;  and  at  last  the  appearance  of  lower  forms  of  plants,  which  pre- 
pared the  atmosphere  to  sustain  animal  life.  The  arguments  are  inge- 
nious, but  to  my  mind  they  exemplify  the  result  of  attaching  excessive 
importance  to  one  set  of  phenomena  alone.  It  is  not  clear  that  due 
account  has  been  taken  of  the  checks  and  balances  which  are  actually 
observed.  At  present  the  known  losses  of  oxygen  seem  to  exceed  the 
gains.  For  example,  C.  H.  Smyth5 6  has  estimated  that  the  oxygen 
withdrawn  from  the  air  by  the  change  of  ferrous  to  ferric  compounds, 
and  so  locked  up  in  the  sedimentary  rocks,  is  equal  to  68.8  per  cent 
of  the  quantity  now  present  in  the  atmosphere. 

But  were  oxidized  compounds  the  first  compounds  to  form?  If 
they  were,  then  the  arguments  just  cited  are  valid,  but  the  premises 
are  doubtful.  If  the  molten  globe  was  as  hot  as  has  been  supposed, 
it  is  likely  that  carbides,  silicides,  nitrides,  etc.,  would  be  generated 
first,  and  in  that  case  all  the  oxygen  of  the  lithosphere  would  be 
atmospheric.  This  supposition  is  based  upon  the  results  obtained 
with  the  aid  of  the  electric  furnace  at  temperatures  which  decompose 
oxygen  compounds  in  the  presence  of  carbon,  silicon,  or  nitrogen, 
substances  of  the  class  just  named  being  then  produced.  Considera- 

1 Chem.  News,  vol.  67, 1893,  p.  135.  Also  several  notes  in  vols.  68, 69,  and  70.  For  Koene’s  work  see  Phip- 
son’s  papers,  1893-94. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  40,  1888,-  pp.  630-634. 

3 Philos.  Mag.,  5th  ser.,  vol.  50,  1900,  pp.  312, 399;  6th  ser.,  vol.  4,  1902,  p.  435;  vol.  9,  1905,  p.  88;  vol.  11, 

1906,  p.226. 

* Idem,  5th  ser.,  vol.  47,  1899,  pp.  85-89. 

6 Jour.  Geology,  vol.  13,  1905,  p.  319. 


56 


THE  DATA  OF  GEOCHEMISTRY. 

tions  of  this  kind  have  been  elaborately  developed  by  H.  Lenicque,1 
who,  however,  pushes  them  to  extremes.  He  even  goes  so  far  as  to 
ascribe  great  masses  of  limestone  to  the  atmospheric  oxidation  of 
primitive  carbides.  It  will  be  observed  at  once  that  theories  of  this 
order  are  directly  related  to  the  hypotheses  which  postulate  an  inor- 
ganic origin  for  petroleum — a subject  which  will  be  more  fully  dis- 
cussed in  the  proper  chapter.  For  the  present  it  is  enough  to  see 
that  cogent  arguments  may  lead  us  to  either  of  two  opposite  beliefs — 
that  the  primitive  atmosphere  was  rich  in  oxygen,  or  that  it  was 
oxygen  free. 

The  balance  or  lack  of  balance  between  carbon  and  oxygen  is,  after 
all,  only  one  factor  in  the  problem.  The  origin  of  the  atmosphere 
as  a whole  is  a much  larger  question,  and  our  answers  to  it  must 
depend  upon  our  views  as  to  the  genesis  of  the  solar  system.  If  we 
accept  the  nebular  hypothesis,  we  are  likely  to  conclude  that  the 
atmosphere  is  merely  a residuum  of  uncombined  gases  which  were 
left  behind  when  the  globe  assumed  its  solid  form.  That  seems  to  be 
the  prevalent  opinion,  although  it  must  be  modified  by  the  observed 
facts  of  volcanism.  The  outer  envelope  of  the  earth  receives  rein- 
forcements from  within,  whose  sources  will  be  considered  at  length 
in  another  chapter. 

Quite  a different  theory  of  the  earth’s  origin  has  lately  been  de- 
veloped by  T.  C.  Chamberlin,2  who  imagines  a planet  built  up  by 
slow  aggregations  of  small,  solid  bodies.  Each  of  these  particles, 
or  meteorites,  carried  with  it  entangled  or  occluded  atmospheric  mate- 
rial. In  time  the  accumulation  of  originally  cold  matter  developed 
pressure  enough  to  raise  the  central  portions  of  the  mass  to  a high 
temperature,  and  gases  were  then  expelled.  Thus  the  atmosphere 
was  generated  from  within  the  globe  instead  of  remaining  as  a 
residuum  around  it.  We  know  that  meteorites  contain  occluded 
gases,  and  that  gases  are  also  extractable  from  igneous  rocks,  and 
these  facts  lend  to  the  hypothesis  a certain  plausibility.  The  gases 
thus  obtainable  from  the  lithosphere  are  equivalent  to  many  potential 
atmospheres,  although,  as  we  have  already  seen,  oxygen  is  not  among 
them.  On  Chamberlin’s  hypothesis  the  atmosphere  has  grown  from 
small  beginnings;  the  nebular  conception  assumes  that  it  was  largest 
at  first.  E.  H.  L.  Schwarz,3  who  accepts  Chamberlin’s  views,  con- 
cludes that  the  primitive  atmosphere  is  actually  represented  to-day 
by  the  gases  extractable  from  meteorites.  Hydrogen,  nitrogen,  me- 
thane, and  both  oxides  of  carbon  are  the  gases  in  question,  but  there 
is  no  free  oxygen. 

1 M4m.  Soc.  ingen.  civils  France,  October,  1903,  p.  346. 

* Join.  Geology,  vol.  5, 1897,  p.  653;  vol.  6, 1898,  pp.  459, 609;  vol.  7, 1899,  pp.  545, 667, 751.  See  also  H.  L. 
Faircbild,  Am.  Geologist,  vol.  33,  1904,  p.  94. 

3 Causal  geology,  London,  1910,  p.  93. 


THE  ATMOSPHERE. 


57 


One  curious  speculation,  which  may  be  connected  with  the  theory 
just  described,  relates  to  the  nature  of  the  earth’s  interior.  From 
the  known  fact  that  the  temperature  rises  as  we  descend  into  the 
crust  of  the  earth,  calculations  have  been  made  to  show  that  the  tem- 
perature of  the  centrosphere  must  be  enormously  high.  In  fact, 
if  the  rate  of  increase  is  constant,  the  temperature  must  reach  a 
degree  far  above  the  critical  point  of  any  known  element.  Matter 
in  the  interior  of  the  earth,  then,  should  be  gaseous  or  quasi-gaseous. 
This  suggestion  was  first  offered  by  Herbert  Spencer,1  later  by  A. 
Ritter,2  and  has  been  more  recently  developed  by  S.  Arrhenius.3  It 
has,  however,  only  speculative  value,  for  it  rests  upon  assumptions 
which  can  not  be  tested  experimentally,  and  which  may  never  be 
verified.  A discussion  of  the  subject  falls  without  the  scope  of  this 
memoir,  and  only  these  brief  references  to  it  are  admissible  here.4 


1 See  his  essays  on  the  nebular  hypothesis  (1858)  and  the  constitution  of  the  sun  (1865).  Cited  from  New 
York  edition  of  1892. 

2 Wied.  Annalen,  vol.  5, 1878,  p.  405. 

3 Geol.  Foren.  Forhandl.,  vol.  22, 1900,  p.  395. 

* For  a historical  summary  relative  to  the  supposed  gaseous  interior  of  the  earth  see  S.  Gunther,  Jahresb. 
Geog.  Gesell.  Miinchen,  1890-91,  Heft  14,  p.  1.  See  also  the  monograph  by  H.  Thiene,  Temperatur  und 
Zustand  des  Erdinnern,  Jena,  1907. 


CHAPTER  III. 

LAKES  AND  RIVERS.1 

ORIGIN. 

When  rain  falls  upon  the  surface  of  the  earth,  bringing  with  it  the 
impurities  noted  in  the  preceding  chapter,  part  of  it  sinks  deeply 
underground  to  reappear  in  springs.  Another  part  runs  off  directly 
into  streams,  a part  is  retained  as  the  ground  water  of  soils  and  the 
hydration  water  of  clays,  and  a portion  returns  by  evaporation  to  the 
atmosphere.  According  to  an  estimate  by  Sir  John  Murray,2  the  total 
annual  rainfall  upon  all  the  land  of  the  globe  amounts  to  29,347.4 
cubic  miles,  and  of  this  quantity  6,524  cubic  miles  drain  off  through 
rivers  to  the  sea.  A cubic  mile  of  river  water  weighs  4,205,650,000 
tons,  approximately,  and  carries  in  solution,  on  the  average,  about 
420,000  tons  of  foreign  matter.  In  all,  about  2,735,000,000  tons  of 
solid  substances  are  thus  carried  annually  to  the  ocean.3  Suspended 
sediments,  the  mechanical  load  of  streams,  are  not  included  in  this 
estimate;  only  the  dissolved  matter  is  considered,  and  that  repre- 
sents the  chemical  work  which  the  percolating  waters  have  done. 

Although  the  minerals  which  form  the  rocky  crust  of  the  earth  are 
relatively  insoluble,  they  are  not  absolutely  so.  The  feldspars  are 
especially  susceptible  to  change  through  aqueous  agencies,  yielding 
up  their  lime  or  alkalies  to  percolating  water  and  forming  a residue 
of  clay.  Rain  water,  as  we  have  already  seen,  contains  carbonic  acid 
in  solution,  and  that  impurity  increases  its  solvent  power,  particularly 
with  regard  to  limestones.  The  moment  that  water  leaves  the 
atmosphere  and  enters  the  porous  earth  its  chemical  and  solvent 
activities  begin,  and  continue,  probably  without  interruption,  until 
it  reaches  the  sea.  The  character  and  extent  of  the  work  thus  done 
varies  with  local  conditions,  such  as  temperature,  the  nature  of  the 
minerals  encountered,  and  so  on;  but  it  is  never  zero.  Sometimes 
larger  and  sometimes  smaller,  it  varies  from  time  to  time  and  place 
to  place.  The  entire  process  of  weathering  will  be  considered  more 
fully  later;  we  have  now  to  study  the  nature  of  the  dissolved  matter 
alone,  or,  in  other  words,  the  composition  of  rivers  and  lakes.  The 


1 Excluding  those  belonging  to  closed  basins. 

2 Scottish  Geog.  Mag.,  vol.  3,  p.  65, 1887. 

3 Estimates  by  F.  W.  Clarke  (A  preliminary  study  of  chemical  denudation:  Smithsonian  Misc.  Coll., 
vol.  56,  No.  5, 1910).  Murray’s  figures  are  762,587  tons  per  cubic  mile,  and  nearly  5,000,000,000  tons  in  the 
total  run-oS.  His  analytical  data  were  too  few  and  too  limited  in  range  for  a close  computation. 


LAKES  AND  RIVERS. 


59 


data  are  abundant,  but  unfortunately  complicated  by  a lack  of  uni- 
formity in  the  methods  of  statement,  which  latter  are  often  unsatis- 
factory and  even  misleading.  The  analysis  of  a water  can  be  reported 
in  several  different  ways,  as  in  grains  per  gallon  or  parts  per  million; 
in  oxides,  in  supposititious  salts,  or  in  radicles;  so  that  two  analyses 
of  the  same  material  may  seem  to  be  totally  dissimilar,  although  in 
reality  they  agree.  Before  we  can  compare  analyses  one  with 
another  we  must  reduce  them  to  a common  standard,  for  then  only 
do  their  true  differences  appear.  The  task  of  reduction  may  be 
tedious,  but  it  is  profitable  in  the  end. 

STATEMENT  OF  ANALYSES. 

In  the  usual  statement  of  water  analyses  an  essentially  vicious 
mode  of  procedure  has  become  so  firmly  established  that  it  is  difficult 
to  set  aside.  For  example,  a water  is  found  to  contain  sodium, 
potassium,  calcium,  magnesium,  chlorine,  and  the  radicles  of  sul- 
phuric and  carbonic  acids;  or,  in  ordinary  parlance,  three  acids  and 
four  bases.  If  these  are  combined  into  salts  at  least  12  such 
compounds  must  be  assumed,  and  there  is  no  definite  law  by  which 
their  relative  proportions  can  be  calculated.  A combination,  how- 
ever, is  commonly  taken  for  granted,  and  each  chemist  allots  the 
several  acids  to  the  several  bases  according  to  his  individual  judg- 
ment. The  12  possible  salts  rarely  appear  in  the  final  statement; 
all  the  chlorine  may  be  assigned  to  the  sodium  and  all  the  sulphuric 
acid  to  the  lime,  and  the  result  is  a meaningless  chaos  of  assumptions 
and  uncertainties.  We  can  not  be  sure  that  the  chosen  combinations 
are  correct,  and  we  know  that  in  most  analyses  they  are  too  few. 

But  are  the  radicles  combined  ? This  is  a point  at  issue.  Although 
no  complete  theory,  covering  all  the  phonemena  of  solution,  has  yet 
been  developed,  it  is  the  prevalent  opinion,  at  least  among  physical 
chemists,  that  in  dilute  solutions  the  salts  are  dissociated  into  their 
ions,  and  that  with  the  latter  only  can  we  legitimately  deal. 
Whether  this  theory  of  dissociation  shall  ultimately  stand  or  fall  is 
a question  which  need  not  concern  us  now;  we  can  use  it  without 
danger  of  error  as  a basis  for  the  statement  of  analyses,  putting  our 
results  in  terms  of  ions  which  may  or  may  not  be  actually  combined.1 
Upon  this  foundation  all  water  analyses  can  be  rationally  compared, 
with  no  unjustifiable  assumptions  and  with  all  the  real  data  reduced 
to  the  simplest  uniform  terms.  We  do  not,  however,  get  rid  of  all 
difficulties,  and  some  of  these  must  be  met  by  pure  conventions.  For 
example,  Is  silica  present  in  colloidal  form,  or  as  the  silicic  ion  Si03  ? 

1 The  ionic  form  of  statement  has  been  used  in  the  Survey  laboratory  since  1883.  In  Europe  it  has  had 
strong  advocacy  from  Prof.  C.  von  Than,  Min.  pet.  Mitt.,  vol.  11, 1890,  p.  487.  It  is  now  rapidly  supplant- 
ing the  older  system.  For  an  excellent  discussion  of  the  statement  of  water  analyses,  see  It.  B.  Dole,  Jour. 
Ind.  Eng.  Chem.,  vol.  6, 1914,  p.  770. 


60 


THE  DATA  OF  GEOCHEMISTRY. 


Are  ferric  oxide  and  alumina  present  as  such,  or  in  the  ions  of  their 
salts  ? The  iron  may  represent  ferrous  carbonate,  the  alumina  may 
be  equivalent  to  alum;  but  as  a rule  the  quantities  found  are  so 
trivial  that  the  true  conditions  can  not  be  determined  from  the 
ratios  between  acidic  and  basic  radicles.  The  unavoidable  errors  of 
analysis  are  commonly  too  large  to  permit  a final  settlement  of  these 
questions;  and  only  in  exceptional  cases  can  definite  conclusions  be 
drawn. 

For  convenience,  then,  we  may  regard  these  substances  as  col- 
loidal oxides  and  tabulate  them  in  that  form.1  The  procedure 
may  not  be  rigorously  exact,  but  the  error  in  it  is  usual  Ly  very 
small.  If  we  consider  an  analysis  as  representing  the  composition 
of  the  anhydrous  inorganic  matter  which  is  left  when  a water  has 
been  evaporated  to  dryness,  the  difficulty  as  regards  iron  disappears, 
for  ferrous  carbonate  is  then  decomposed  and  ferric  oxide  remains. 
A similar  difficulty  in  respect  to  the  presence  of  bicarbonates  also 
vanishes  at  the  same  time,  for  the  bicarbonates  of  calcium  and  mag- 
nesium can  only  exist  in  solution  and  not  in  the  anhydrous  residues. 
If  in  a given  water  notable  quantities  of  lime,  magnesia,  and  car- 
bonic acid  are  found,  bicarbonic  ions  must  be  present,  for  without 
them  the  bases  could  not  continue  dissolved;  but  after  evapora- 
tion only  the  normal  salts  remain.  Sodium  and  potassium  bicar- 
bonates are  not  so  readily  broken  down;  but  even  with  them  it  is 
better  to  compare  the  monocarbonates,  so  as  to  secure  a uniformity 
of  statement.  In  fact,  some  analysts  report  only  normal  salts,  and 
others  bicarbonates;  so  that  for  the  comparison  of  different  analyses 
we  are  compelled  to  adopt  an  adjustment  such  as  that  which  is  here 
proposed.  In  other  words,  we  eliminate  the  variable  factors  and 
study  the  constants  alone. 

One  other  large  variable  remains  to  be  considered — the  variation 
due  to  dilution.  A given  solution  may  be  very  dilute  at  one  time  and 
much  more  concentrated  at  another,  and  yet  the  mineral  content  of 
the  water  is  possibly  the  same  in  both  cases.  For  example,  average 
ocean  water  contains  3.5  per  cent  of  saline  matter,  while  that  of  the 
Black  Sea  carries  little  more  than  half  as  much;  and  yet  the  salts 
which  the  two  waters  yield  upon  evaporation  are  nearly,  if  not  quite, 
identical.  In  some  cases,  as  we  shall  presently  see,  it  is  desirable  to 
compare  waters  directly;  but  in  most  instances  it  is  also  convenient 
to  study  the  composition  of  the  solid  residues  in  percentage  terms. 
In  that  way  essential  similarities  are  brought  to  light  and  the  data 
become  intelligible. 

Before  proceeding  farther,  it  may  be  well  to  consider  a single 
water  analysis,  in  order  to  illustrate  the  various  methods  of  state- 

1 This  rule  applies  to  such  waters  only  as  are  considered  in  this  chapter.  To  many  volcanic  waters, 
geyser  waters,  mine  waters,  etc.,  it  does  not  apply.  Their  discussion  is  left  to  later  chapters. 


LAKES  AND  RIVERS. 


61 


ment.  For  this  purpose  I will  take  W.  P.  Headden’s  analysis  of 
water  from  Platte  River  near  Greeley,  Colo.,1  which  he  himself 
states  in  several  forms.  In  the  first  column  of  the  subjoined  table 
the  results  are  given  in  oxides,  etc.,  as  in  a mineral  analysis,  and  in 
grains  to  the  imperial  gallon.  In  the  second  column  they  are  stated 
in  terms  of  salts,  and  I have  here  recalculated  Headden’s  figures  into 
parts  per  million  of  the  water  taken.  Finally,  in  a third  column  I 
give,  as  proposed  in  the  foregoing  pages,  the  composition  of  the 
residue  in  radicles  or  ions  and  in  percentages  of  total  anhydrous 
inorganic  solids. 

Analysis  of  water  stated  in  different  forms. 


Si02 

Grains 

per 

imperial 

gallon. 

. . . . 0.  891 

CaS04 

Parts  per 
million. 

457.  7 

Si02 

Per 

cent. 

. . . . 1.  26 

so3 

....  32.601 

MgS04 

236.  0 

S04 

....  55.28 

co2 

. . . . 4.  554 

k2so4 

9.4 

co3 

. . . . 8.  78 

Cl 

. . . . 2.  681 

Na2S04 

62.5 

Cl 

. . . . 3.  79 

Na20 

....  11.463 

NaCl 

63.2 

Na 

....  12.02 

K20 

355 

Na2C03 

156.  9 

K 

41 

CaO 

....  13.117 

Na-jSiOg 

21.9 

Ca 

....  13.24 

MgO 

. . . . 5. 530 

(FeAl)203 

2.7 

Mg 

. . . . 4.  69 

(FeAl)203 

189 

Mn203 

2.7 

f2o3 

53 

Mn203 

189 

Ignition 

34.2 

100.  00 

Ignition 

. . . . 2.  397 

Excess  S102 

1.3 

“Ignition”  o 

mitte d . 

Less  0=C1 

73.  967 
604 

73.  363 

1, 048.  5 

Salinity,  1,014 
million. 

parts  per 

So  far  as  appearance  goes,  these  statements  might  represent  three 
different  waters;  and  yet  the  analytical  data  are  the  same.  A change 
in  the  last  column  of  Si02  into  the  radicle  SiOs  would  affect  the  other 
figures  but  slightly.  The  compactness  and  simplicity  of  the  ionic 
form  of  statement  are  evident  at  a glance.  Under  it,  as  “salinity,” 
I have  given  the  concentration  of  the  water  in  terms  of  parts  per 
million.  One  million  parts  of  this  water  contain  in  solution  1,014 
parts  of  anhydrous,  inorganic,  solid  matter. 

THE  INTERPRETATION  OF  ANALYSES. 

In  the  interpretation  of  any  water  analysis  the  first  question  to  ask 
is  as  to  its  accuracy.  Every  analysis  is  subject  to  errors,  great  or 
small,  and  in  each  individual  instance  it  is  important  to  decide 
whether  its  error  is  serious  or  negligible.  When  an  analysis  is 
stated  in  terms  of  salts,  the  errors  are  obscured,  as  in  the  smoothing 
of  a curve,  and  an  accurate  estimate  of  its  value  is  not  possible.  In 


1 Bull.  Colorado  Agr.  Exper.  Sta.  No.  82, 1903,  p.  56. 


62 


THE  DATA  OF  GEOCHEMISTRY. 


such  a case  the  reputation  of  the  analyst  is  the  safest  criterion  upon 
which  to  base  a judgment. 

When,  however,  an  analysis  is  stated  in  terms  of  the  radicles 
actually  determined,  a decision  as  to  its  value  is  much  simpler. 
The  negative  or  acid  radicles  and  the  positive  or  basic  radicles  must 
be  chemically  equivalent,  at  least  within  the  limits  of  permissible 
experimental  errors.  To  this  rule,  which  applies  to  nearly  all  waters, 
there  are  some  apparent  but  not  real  exceptions.  If  the  basic 
radicles  are  much  in  excess  of  the  acid,  it  is  possible  that  a part  of  the 
alkaline  ions  may  be  balanced  or  held  in  equilibrium  by  silica;  that 
is,  the  usually  colloidal  silica  may  represent  an  alkaline  silicate; 
which,  however,  is  hydrolyzed  in  solution.  Some  geyser  waters  of 
the  Yellowstone  National  Park  have  this  peculiarity.  On  the  other 
hand,  certain  volcanic  waters  are  strongly  acid;  and  then  it  is  nec- 
essary to  assume  the  presence  of  hydrogen  ions  in  order  to  completely 
balance  the  negative  radicles.  Another  source  of  acidity  is  found 
in  some  mineral  springs,  in  which  the  iron  and  aluminum  are  pre- 
sumably in  equilibrium  as  sulphates.  The  iron  and  aluminum 
must  then  be  counted,  not  as  colloids,  but  as  among  the  basic  radi- 
cles. Examples  of  these  exceptional  waters  are  cited  in  chapter  6 
of  this  treatise,  and  demand  no  further  attention  here. 

The  calculations  implied  in  the  preceding  paragraph  are  very 
simple,  and  may  be  based  either  upon  the  analysis  as  stated  in  parts 
per  million  or  upon  its  percentages.  The  quantity  found  for  each 
radicle  is  divided  by  its  chemical  equivalent,  and  the  quotients  for 
each  group,  acid  or  basic,  are  separately  added  together.  The  two 
sums  should  then  be  equal,  or  so  nearly  equal  that  the  difference  can 
be  ascribed  to  the  small,  inevitable  errors  of  analysis.  For  the 
univalent  radicles  Na,  K,  Cl,  N03,  and  HC03  the  chemical  equiva- 
lent and  the  atomic  weight  are  the  same;  for  the  bivalent  radicles 
Ca,  Mg,  S04,  and  C03  the  atomic  weights  should  be  halved.  This 
is  the  usual  procedure.  H.  Stabler,1  however,  has  proposed  a modi- 
fication of  the  method,  in  which  the  quantities  determined  are 
multiplied  by  the  reciprocals  of  the  equivalents,  which  he  calls  the 
“ reaction  coefficients”  of  the  radicles.  The  products  so  obtained, 
the  “ reacting  values”  of  the  radicles,  are  identical  with  the  quotients 
of  the  ordinary  process  and  must  balance  in  the  same  way.  A table 
of  Stabler’s  coefficients  may  save  some  labor  when  large  numbers  of 
analyses  are  to  be  discussed,  but  the  economy  is  probably  small. 

The  interpretation  of  a water  analysis,  then,  is  founded  upon  a 
study  of  equilibria.  Even  the  hypothetical  combination  of  the 
radicles  is  a crude  attempt  at  such  a study — an  attempt,  however, 
which,  as  we  have  already  seen,  is  based  ordinarily  upon  un verifiable 
assumptions.  I speak  now,  of  course,  of  such  waters  as  commonly 
occur  in  nature.  A solution  of  a single  salt,  or  one  in  which,  as  in 


1 Water-Supply  Paper  U.  S.  Geol.  Survey  No.  274,  1911,  pp.  165-181. 


LAKES  AND  EIVEES. 


63 


certain  brines,  one  salt  overwhelmingly  predominates,  is  obviously 
easy  to  deal  with.  A more  refined  attack  upon  the  problem  of  inter- 
pretation has  been  made  by  Chase  Palmer,1  who  has  examined  in 
detail  the  relations  between  the  equivalent  ratios  or  reacting  values 
described  above,  and  so  correlated  the  analyses  with  the  properties 
of  the  waters  analyzed.  His  procedure,  briefly,  is  as  follows:  Two 
fundamental  properties  are  recognized — namely,  alkalinity  and 
salinity,  which  are  subdivided  into  groups.  Salinity  is  measured  by 
the  sum  of  the  strong-acid  radicles,  S04,  Cl,  and  N03,  which  balance 
an  equivalent  number  of  basic  radicles.  If  the  basic  radicles  are 
partly  or  wholly  alkaline,  that  is,  Na  or  K,  their  proportion  of  the 
salinity  is  said  to  be  'primary . The  remaining  salinity,  due  to  the 
radicles  Ca,  Mg,  and  Fe"  is  called  secondary.  If,  however,  the  acid 
radicles  are  in  excess  of  the  basic,  tertiary  salinity  or  acidity  appears, 
and  hydrogen  ions  must  be  taken  into  account.  When  the  alkaline 
radicles  exceed  those  of  the  strong  acids,  their  excess  is  the  measure 
of  primary  alkalinity,  which  represents  hydrolyzed  carbonates  or 
bicarbonates.  The  weak-acid  radicles  C03  and  HC03,  which  balance 
any  excess  of  the  alkaline  earths  over  the  stronger  acids,  produce 
secondary  alkalinity. 

Upon  these  properties  Palmer  has  developed  a classification  of 
natural  waters,  which  correlates  them  with  their  geologic  origin. 
Waters  issuing  from  areas  of  crystalline,  feldspathic  rocks,  are  char- 
acterized by  high  primary  alkalinity,  low  concentration,  and  a 
notable  proportion  of  silica.  Waters  from  sedimentary  regions, 
especially  where  limestone  is  abundant,  show  secondary  alkalinity. 
Ocean  water  and  other  similar  brines  are  almost  entirely  saline,  and 
alkalinity  is  nearly  or  even  wholly  wanting  in  them.  Palmer  gives 
numerous,  carefully  worked  out,  illustrations  of  the  applicability  of 
his  method  of  discussion  to  geochemical  problems,  but  the  details 
can  not  well  be  presented  here. 

SPRINGS. 

When  water  first  emerges  from  the  earth  as  a spring  its  mineral 
composition  is  dependent  upon  local  conditions.  Some  spring  waters 
are  exceedingly  dilute;  others  are  heavily  charged  with  saline  impuri- 
ties. To  the  subject  of  “ mineral”  springs,  a separate  chapter 
will  be  given,  and  only  a few  analyses  of  spring  water,  all  taken 
from  the  records  of  the  United  States  Geological  Survey,  need  be 
given  here.  They  represent  the  beginnings  of  streams,  and  are  there- 
fore significant  in  this  connection.  All  these  analyses  are  reduced 
to  a uniform  standard,  in  accordance  with  the  rules  laid  down  in  the 
preceding  pages.2 

1 The  geochemical  interpretation  of  water  analyses:  Bull.  U.  S.  Geol.  Survey  No.  479, 1911. 

2 innumerable  analyses  of  wells,  springs,  and  underground  waters  generally  are  to  he  found  scattered 
through  the  literature.  See  for  example,  S.  W.  McCallie,  Bull.  Geol.  Survey  Georgia  No.  15,  1908,  and 
E.  Bartow,  Bull.  Univ.  Illinois,  vol.  6,  No.  3, 1908. 


64 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  spring  water. 

A.  Sprirg  near  Magnet  Cove,  Arkansas.  Analysis  by  H.  N.  Stokes. 

B.  Spring  1 mile  west  of  Santa  Fe,  New  Mexico.  Analysis  by  F.  W.  Clarke. 

C.  Spring  near  Mountain  City,  Tennessee.  Analysis  by  T.  M.  Cbatard. 

D.  Caledonia  Spring,  Caledonia,  New  York.  Analysis  by  H.  N.  Stokes. 

E.  Spring  3 miles  west  of  Lowesville,  North  Carolina.  Analysis  by  F.  W.  Clarke. 

F.  Spring  near  Mount  Mica,  Paris,  Maine.  Analysis  by  F.  W.  Clarke. 


A 

B 

c 

D 

E 

F 

co3 

53.  59 

47. 14 

27.  29 

11.  73 

12. 15 

6.  22 

so4 

3.  40 

6.  67 

16.  37 

31.  62 

51.  86 

60.  97 

Cl 

1.  35 

4. 18 

1.  50 

22.  28 

. 45 

Trace. 

Ca 

30.  95 

22.  67 

14.  39 

19.  49 

23.  58 

22. 37 

Mg 

3.  45 

6.17 

2.  23 

3.  25 

1.47 

2.  62 

Na 

1.  08 

| 5.32 

5.  72 

10.  62 

4. 16 

4.  32 

K 

. 63 

3.  97 

.34 

.34 

.21 

Si02 

5.  55 

7.  85 

27. 17 

.67 

5.  99 

2. 80 

A1203 

Trace. 

Fe203 

1.  36 

.49 

Salinity,  parts  per  million | 

100.  00 
224 

100.  00 
280 

100.  00 
80 

100. 00 
925 

100.  00 
642 

100.  00 
606 

Some  of  these  waters  yield  carbonates  on  evaporation,  one  yields 
mainly  sulphates,  and  between  the  two  extremes  the  carbonic  and 
sulphuric  radicles  vary  almost  reciprocally.  One  water  is  character- 
ized by  its  high  proportion  of  chlorine  and  another  by  its  large  per- 
centage of  silica;  but  in  all  of  them  calcium  is  the  dominant  metal.  In 
salinity  they  differ  somewhat  widely,  but  the  most  concentrated 
example  contains  only  925  parts  per  million,  or  52  grains  to  the 
United  States  gallon,  of  foreign  solids.  It  will  be  seen  as  we  go 
farther  that  carbonate  waters  are  the  most  common,  for  the  reason 
that  rain  water  brings  carbonic  acid  from  the  air,  and  that  substance 
is  most  active  as  a solvent  of  mineral  matter. 

CHANGES  OF  COMPOSITION. 

As  spring  water  flows  from  its  source  it  rapidly  changes  in  char- 
acter. It  receives  other  water  in  the  form  of  rain  or  of  ground  water 
flowing  from  the  soil,  and  it  blends  with  other  rivulets  to  produce 
larger  streams.  Under  certain  conditions  a part  of  its  dissolved  load 
may  be  precipitated,  and  the  composition  of  a river  as  it  approaches 
the  sea  represents  the  aggregate  effect  of  all  these  agencies.  A river 
is  the  average  of  all  its  tributaries,  plus  rain  and  ground  water,  and 
many  rivers  show  also  the  effects  of  contamination  from  towns  and 
factories.  Small  streams  are  the  most  affected  by  local  conditions, 
and  show  the  greatest  differences  in  composition;  large  rivers,  as  a 
rule,  resemble  one  another  more  nearly. 

How  rapidly  and  how  profoundly  the  composition  of  a river  may 
be  modified  are  well  illustrated  in  Headden’s  bulletin,  which  I have 


LAKES  AND  RIVERS. 


65 


already  cited.1  Cache  la  Poudre  River  in  Colorado  flows  first  through 
a rocky  canyon,  over  bowlders  of  schist  and  granite,  and  thence 
emerges  upon  the  Plains.  Its  waters  are  then  diverted  into  ditches 
and  reservoirs  for  purposes  of  irrigation,  and  finally  reach  the  Platte 
near  Greeley.  In  performing  the  work  of  irrigation  they  acquire  a 
new  load  of  solid  matter,  and  the  progressive  changes  in  their  com- 
position are  clearly  shown  by  Headden’s  analyses.  Some  of  the  latter 
I will  cite,  first,  as  Headden  gives  them  in  grains  to  the  imperial  gallon, 
and  then  in  a second  table  reduced  to  ions  and  percentages. 

Analysis  E is  the  one  cited  on  page  59  to  show  different  forms  of 
statement.  In  all  cases  I omit  Headden’s  figures  for  “ignition,”  and 
deal  with  the  anhydrous  residues  alone. 

Analyses  of  water  from  Colorado  rivers. 

A.  Cache  la  Poudre  River  above  the  north  fork. 

B.  Cache  la  Poudre  River  water  from  faucet  in  laboratory  at  Fort  Collins. 

C.  Cache  la  Poudre  River  2 miles  above  Greeley. 

D.  Cache  la  Poudre  River  3 miles  below  Greeley. 

E.  Platte  River  below  mouth  of  the  Cache  la  Poudre. 

Grains  per  imperial  gallon. 


A 

B 

c 

D 

E 

co2 

0.  6029 

2.  3731 

5.  920 

5.  087 

4.  554 

so3 

. 1916 

1.  8699 

54.  970 

30. 374 

32.  601 

Cl 

. 1037 

. 1055 

2.  770 

2. 145 

2.  681 

CaO 

.5238 

3.  0364 

18.  938 

14.  087 

13. 117 

SrO 

Trace. 

. 0223 

MgO 

. 1257 

. 8857 

12. 190 

5.  592 

5.  539 

Na20 

. 3750 

. 6631 

14.  590 

9. 117 

11.  463 

K20 

.0855 

. 1921 

. 451 

. 372 

. 355 

Si02 

. 6053 

. 6245 

1.035 

. 951 

. 891 

(Al,Fe)20, 

.0113 

.0171 

. 079 

. 039 

. 189 

MrioOo 

.0018 

.0112 

Trace. 

.078 

.189 

Less  0=C1 

2.  6296 
.0234 

9. 8009 
.0238 

110. 943 
.624 

67.  842 
.483 

71.  570 
.604 

2.  6062 

9.  7771 

110.  319 

67.  359 

70.  966 

Reduced  analyses,  in  percentages. 


co3 

31.  91 

33.  68 

7.  34 

10.  34 

8.  78 

so4 

9.  07 

23.  36 

59.  99 

54.  33 

55.  28 

Cl 

4.  03 

1. 10 

2.  52 

3. 19 

3.  79 

Ca 

14.  53 

22.  58 

12.  31 

15.  00 

13.  24 

Sr 

. 19 

Mg 

2.  93 

5.  53 

6.  65 

5.  00 

4.  69 

Na 

10.  80 

5. 12 

9.  84 

10.  09 

12.  02 

K 

2.  72 

1.  66 

.34 

.46 

.41 

Si02 

23.  50 

6.  49 

.94 

1.  42 

1.  26 



.51 

.29 

.07 

.17 

.53 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million 

37 

137 

1,  571 

958 

1,011 

i Bull.  Colorado  Agr.  Exper.  Sta.  No.  82, 1903. 
97270°— Bull.  610—16 5 


66 


THE  DATA  OF  GEOCHEMISTRY. 


We  have  here,  first,  a very  pure  mountain  water,  relatively  high 
in  carbonates  and  rich  in  silica.  At  the  end  of  the  series  we  have 
waters  in  which  sulphates  predominate  and  the  proportion  of  silica 
is  very  low.  The  change  is  extremely  great  in  all  respects,  and  is 
partly  due  to  the  use  of  the  water  for  irrigating  an  originally  arid  soil 
containing  much  soluble  matter.  Probably  when  the  soil  shall  have 
been  thoroughly  leached  by  long  periods  of  cultivation  the  changes 
in  the  water  will  be  less  exaggerated.  A similar  alteration  is  also 
shown  in  Headden’s  analyses  of  water  from  Arkansas  River,  first  at 
Canon  City,  where  it  emerges  from  the  mountains,  and  second  at 
Rockyford,  nearly  100  miles  below.1  The  analyses  are  as  follows, 
reduced  to  the  common  standard  adopted  in  this  memoir.  Headden 
regards  the  silica  as  present  partly  in  the  form  of  alkaline  silicates,  a 
supposition  which  is  probably  correct.  F or  present  purposes,  however, 
the  difference  between  Si02  and  the  Si03  radicle  may  be  neglected. 


Analyses  of  water  from  Arkansas  River  at  two  points  in  Colorado. 


Canon  City. 

Rockyford. 

co3 

37.  55 

2.  65 

so4 

14.  62 

60.  69 

Cl 

3.  77 

4.89 
12.  78 

Ca 

20.  24 

Mg 

5. 13 

3.  76 

Na 

9.  57 

14.  50 

K 

. 60 

.28 

sio2 : 

8. 19 

.45 

Ro(X  . 

.33 

Salinity,  parts  per  million 

100.  00 
148 

100.  00 
2, 134 

Changes  of  a different  order  are  shown  by  the  waters  of  the  River 
Chelif,  in  Algeria,  according  to  the  investigation  by  L.  Ville.2  This 
stream  flows  through  an  arid  region,  in  which  incrustations  or  efflores- 
censes  of  salt  and  gypsum  abound.  Lower  in  its  course  it  receives 
affluents  much  poorer  in  mineral  matter,  and  its  character,  at  least  as 
regards  salinity,  is  modified.  Ville’s  analyses  reduced  to  a modern 
standard  are  as  follows: 

1 Bull.  Colorado  Agr.  Exper.  Sta.  No.  82,  1903.  Headden  also  gives  analyses  of  water  from  St.  Vrain, 
Big  Thompson,  Boulder,  and  Clear  creeks,  and  from  many  reservoirs,  irrigating  ditches,  and  wells.  See 
also  Am.  Jour.  Sci.,  4th  ser.,  vol.  16, 1903,  p.  169. 

2 Bull.  Soc.  g6ol.  France,  2d  ser.,  vol.  14, 1857,  p.  352.  A later  analysis  by  Balland  is  given  in  Jour.  Chem. 
Soc.,  vol.  36,  1879,  p.  699,  abstract.  Still  another,  by  F.  de  Marigny,  is  cited  by  Roth.  In  Annales  des 
mines,  5th  ser.,  vol.  11, 1857,  p.  667,  Marigny  gives  analyses  of  two  other  Algerian  rivers. 


LAKES  AND  RIVERS. 


67 


Analyses  of  water  from  River  Chelif,  Algeria. 

A.  Sample  taken  at  Ksar-Boghari  during  extreme  low  water. 

B.  Sample  taken  at  the  same  point  a few  days  later,  after  a rise. 

C.  Sample  from  Orleansville,  much  farther  downstream. 


A 

B 

C 

co3 

0.  93 

1. 11 

9.  31 

so4 

40.  36 

25.  87 

29.  64 

Cl 

26.  40 

39.  28 

26.  54 

Ca 

7.  46 

6.  63 

11.  85 

Ms.  

4. 12 

4.  42 

4. 11 

Na 

20.  64 

22.  61 

17.  03 

Si02 

.06 

. 04 

. 34 

FeXL  . 

.03 

.04 

1. 18 

Salinity,  parts  per  million 

100.  00 
6,670 

100.  00 
5,  342 

100.  00 
1, 182 

The  effect  of  dilution  by  affluents  is  shown  by  analysis  C;  but  the 
interesting  feature  of  the  series  is  the  difference  between  high  and 
low  water  at  Ksar-Boghari.  Ville  attributes  this  difference  to  the 
fact  that  salt  is  much  more  soluble  than  gypsum  and  that  therefore 
during  a flood  it  is  dissolved  out  more  freely  and  more  rapidly  from 
the  soil.  At  low  water  sulphates  are  in  excess  of  chlorides ; at  high 
water  the  reverse  is  true. 

The  examples  thus  far  cited  serve  to  show  the  danger  of  attempting 
to  draw  general  conclusions  from  a single  analysis  of  a water,  espe- 
cially when  the  latter  is  collected  at  only  one  point.  If  we  wish  to 
determine  the  total  load  carried  by  a river  to  the  ocean,  the  samples 
should  be  taken  as  near  as  possible  to  its  mouth,  but  far  enough  up- 
stream to  avoid  tidal  contamination;  and  the  analyses  should  be 
numerous  enough  to  give  a fair  average  result.  Without  such  pre- 
cautions no  valid  conclusions  can  be  reached.  The  data  must  be 
adequate  to  the  purpose  in  view — a condition  which  is  not  always 
fulfilled. 


68 


THE  DATA  OF  GEOCHEMISTRY. 


ANALYSES  OF  RIVER  WATERS. 

Many  analyses  of  river  and  lake  water  are  to  be  found  scattered 
through  chemical  and  geological  literature.  Only  a part  of  the 
material  can  be  considered  here,  and  preference  will  be  given  but  not 
exclusively,  to  analyses  not  cited  in  the  classical  works  of  J.  Roth  and 
G.  Bischof.  Many  of  the  analyses  were  made  in  the  laboratories  of 
the  United  States  Geological  Survey  and  especially  in  those  of  the 
water-resources  branch.  The  work  of  that  branch,  in  this  particular 
direction,  is  mainly  but  not  exclusively  represented  by  six  publi- 
cations,1 in  which  a large  number  of  American  rivers  have  been 
studied  with  remarkable  exhaustiveness.  For  each  river  or  lake 
many  analyses  were  made,  in  such  a manner  as  to  give  its  average 
composition  for  an  entire  year.  As  a rule,  samples  of  water  were 
taken  daily,  and  combined  into  composite  samples  of  seven  to  ten 
which  were  analyzed.  The  analyses,  however,  some  thouands  in 
number,  are  not  absolutely  complete.  Alumina,  for  example,  was 
not  determined,  and  the  alkalies,  as  a rule,  were  weighed  together 
and  calculated  as  all  sodium.  Later  work,  by  Chase  Palmer,  cor- 
rected the  latter  omission,  and  I have  been  able  to  recalculate  the 
published  analyses  with  the  introduction  of  Palmer’s  figures2  for 
Na  and  K.  All  the  analyses  cited  in  the  following  pages  have  been 
reduced  to  the  uniform  standard  which  was  outlined  in  the  preceding 
pages;  but  the  original  figures  can  usually  be  found  through  the 
references  to  the  literature.  In  addition  to  the  substances  enumerated 
in  the  analyses,  waters  contain  many  other  constituents  in  minute, 
almost  undeterminable  traces.  One  of  those,  fluorine,  has  recently 
been  determined  in  several  river  waters  by  A.  Gautier  and  P.  Claus- 
mann.3  The  quantities  found  ranged  from  0.02  to  0.6  milligram 
per  liter,  being  highest  in  waters  emerging  from  primitive  rocks. 

1 Water-Supply  Papers  No.  236,  by  R.  B.  Dole,  1909;  No.  237,  by  Walton  Van  Winkle  and  F.  M.  Eaton, 
1910;  No.  239,  by  W.  D.  Collins,  1910;  No.  273,  by  H.  N.  Parker  and  E.  H.  S.  Bailey,  1911;  and  Nos.  339 
and  363,  by  W.  Van  Winkle,  1914.  Water-Supply  Paper  No.  274,  by  Herman  Stabler,  also  contains 
many  analyses  of  river  waters. 

2 Supplied  by  Palmer.  For  details  see  Bull.  U.  S.  Geol.  Survey  No.  479,  1911. 

a Compt.  Rend.,  vol.  158, 1914,  p.  1389. 


LAKES  AND  RIVERS. 


69 


THE  ST.  LAWRENCE  BASIN. 

For  geological  purposes  a regional  classification  of  the  data  would 
seem  to  be  the  most  practicable,  for  the  members  of  a river  system 
belong  naturally  together.  Taking  North  American  rivers  first  in 
order,  let  us  begin  with  the  St.  Lawrence  and  its  tributaries.  The 
selected  analyses  are  as  follows: 

Analyses  of  water  from  the  Great  Lakes  and  the  St.  Lawrence. 

A.  Lake  Superior  at  Sault  Ste.  Marie.  Mean  of  11  analyses  of  samples  taken  monthly  between  Sep- 
tember 22,  1906,  and  August  22,  1907.  Other  analyses  of  Lake  Superior  water  have  been  made  by  W.  A. 
Noyes,  Eleventh  Ann.  Rept.  Minnesota  Geol.  Survey,  1882,  p.  174;  by  W.  F.  Jackman,  cited  by  A.  C. 
Lane  in  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  31, 1899,  p.  27;  and  by  G.  L.  Heath,  Rept.  State  Board 
Geol.  Survey  Michigan,  1903,  p.  119. 

B.  Lake  Michigan  at  St.  Ignace.  Mean  of  11  samples  taken  between  September  20,  1906,  and  August 
20,  1907.  Analyses  of  Lake  Michigan  water  at  Milwaukee  and  of  Milwaukee  River,  by  G.  Bode,  are  pub- 
lished in  Geology  of  Wisconsin,  vol.  1,  1883,  p.  308.  Another  analysis  of  the  lake  water,  by  J.  H.  Long, 
is  given  in  Report  on  the  boiler  waters  of  the  Chicago,  Burlington  & Quincy  Railroad,  published  by  that 
company  in  1888. 

C.  Lake  Huron  at  Port  Huron.  Mean  of  9 samples  taken  between  September  21,  1906,  and  June  21,1907. 

D.  Lake  Erie  at  Buffalo.  Mean  of  11  samples  taken  between  September  19, 1906,  and  August  28,1907. 

E.  The  St.  Lawrence  at  Ogdensburg.  Mean  of  11  samples  taken  between  September  18,  1906,  and 
August  19,  1907. 

Analyses  A to  E by  R.  B.  Dole  and  M.  G.  Roberts.  See  Water-Supply  Paper  U.  S.  Geol.  Survey  No. 
236. 

F.  The  St.  Lawrence  at  Pointe  des  Cascades,  near  Vaudreuil,  above  Montreal.  Analysis  by  T.  Sterry 
Hunt,  Philos.  Mag.,  4th  ser.,  vol.  13,  1857,  p.  239. 

G.  The  St.  Lawrence  opposite  Montreal.  Analysis  by  Norman  Tate,  cited  by  T.  Mellard  Reade,  in 
Evolution  of  earth  structure,  1903. 


A 

B 

c 

D 

E 

F 

G 

co3 

47.42 

49.  45 

47.  26 

44.  70 

45.  70 

41.  66 

44.  43 

so4 

3.  62 

6. 15 

5.  77 

9.  83 

9. 15 

5. 19 

11. 17 

Cl 

1.  89 

2.  31 

2.  42 

6.  58 

5.  87 

1.  51 

2.  41 

NO, 

. 86 

. 26 

. 38 

.23 

. 23 

Ca 

22.  42 

22.  21 

22.  33 

23.  45 

23.  66 

20.  08 

20.  67 

Mg 

5.  35 

7.  01 

6.  52 

5.  75 

5.49 

4.  52 

6.  44 

Na 

\ 5.52 

\ 4.02 

\ 4.10 

\ 4.92 

\ 4.81 

3.  20 

4.  87 

K 

/ 

/ 

/ 

/ 

/ 

. 72 

Si02 

12.  76 

8.  54 

11. 16 

4.  46 

5.  03 

23. 12 

10.  01 

Fe90o 

. 16 

.05 

.06 

.08 

.06 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  mil- 

lion  

0.  60 

118 

108 

133 

134 

160 

148 

70 


THE  DATA  OF  GEOCHEMISTRY. 


The  following  analyses  represent  tributaries  to  the  St.  Lawrence: 1 

Analyses  of  water  from  tributaries  to  the  St.  Lawrence. 

H.  Pigeon  River,  Minnesota.  Analysis  by  W.  A.  Noyes,  Eleventh  Ann.  Rept.  Minnesota  Geol.  Survey, 
1882,  p.  174. 

I.  Grand  River  at  Grand  Rapids,  Michigan.  Mean  of  34  composites  of  samples  taken  between  October 
1,  1906,  and  October  5,  1907.  Analyses  by  R.  B.  Dole,  M.  G.  Roberts,  C.  Palmer,  and  W.  D.  Collins. 

J.  Kalamazoo  River  near  Kalamazoo,  Michigan.  Mean  of  35  composites,  September  19, 1906,  to  Sep- 
tember 21,  1907.  Same  analysts  as  under  I. 

K.  Maumee  River  at  Toledo,  Ohio.  Mean  of  36  composites  taken  between  September  9,  1906,  and 
October  7, 1907.  Dole,  Roberts,  and  Palmer,  analysts. 

L.  Genesee  River  at  Rochester,  New  York.  Analysis  by  C.  F.  Chandler,  cited  by  I.  C.  Russell  in  Mon. 
U.  S.  Geol.  Survey,  vol.  11,  1885,  opp.  p.  176. 

M.  Oswegatchie  River  at  Ogdensburg,  New  York.  Mean  of  35  composites,  September  9, 1906,  to  Sep- 
tember 9,  1907.  Same  analysts  as  under  I. 

N.  Ottawa  River  at  Ottawa,  Canada.  High  water,  July,  1907.  Analysis  by  F.  T.  Shutt  and  A.  G. 
Spencer,  Trans.  Roy.  Soc.  Canada,  3d  ser.,  vol.  2,  1908,  p.  175.  Another  incomplete  analysis  is  also  given. 

O.  Lake  Champlain.  Average  of  five  analyses  of  samples  taken  in  the  broad  lake,  by  M.  O.  Leighton, 
Water-Supply  Paper  U.  S.  Geol.  Survey  No.  121,  1905.  This  paper  contains  analyses  of  water  from  the 
upper  end  of  the  lake,  of  Bouquet  River,  and  of  Ticonderoga  Creek. 

Analyses  I,  J,  K,  and  M,  from  Water-Supply  Paper  236,  contain  corrections  for  the  alkalies  as  furnished 
by  Palmer.  An  earlier  analysis  of  water  from  the  Maumee,  by  Chandler,  and  one  of  the  Ottawa,  by  T.  S. 
Hunt,  are  given  in  the  first  edition  of  this  book  (Bulletin  330). 


H 

I 

J 

K 

L 

M 

N 

0 

co3 

42.  00 

44.  37 

47.  32 

29.  63 

37.  94 

39. 10 

35.  44 

45.  81 

so4 

4.  69 

12.88 

9.  54 

16.  25 

25.  29 

12.24 

8.  57 

11.03 

Cl 

6.  09 

3.  00 

1.41 

13.  55 

1.  41 

.59 

1.42 

1.  78 

NO, 

. 89 

. 79 

1.  52 

. 59 

Ca 

18.  08 

21.  85 

22.  82 

19.  29 

24.  48 

19.  40 

16.  58 

21. 19 

Mg 

5.  74 

7.  42 

7.47 

5.  44 

5.  29 

5.  23 

4.  74 

4.21 

Na 

5. 13 

3.  20 

2.  87 

6.  79 

2.  59 

6.  57 

4.  51 

\ 8.80 

K 

2.  55 

.89 

.70 

1.  62 

1.35 

1.  80 

1.  59 

/ 

Si02 

14. 15 

5.  46 

7.  05 

5.  78 

.82 

14.  03 

20.  03 

5.  58 

Fe203 

AloO, 

1.  57 

.04 

.03 

. 13 

1 .83 

J 

.45 

W.  12 

J 

1 1.60 

J o* 

1 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

Salinity,  parts  per 

million 

51 

258 

242 

298 

170 

77 

45 

67 

a Includes  small  amounts  of  P04  and  Mn304. 


Between  these  waters  there  are  distinct  resemblances,  in  that  car- 
bonates are  the  predominating  salts  and  calcium  is  the  chief  metal. 
Ottawa  River  is  characterized  by  high  silica ; but  the  Genesee  and  the 
Maumee,  which  flow  through  areas  of  sedimentary  rocks,  contain  a 
larger  proportion  of  sulphates.  The  increase  in  salinity  or  concen- 
tration in  passing  from  Pigeon  River,  at  the  head  of  Lake  Superior, 
to  the  St.  Lawrence  at  Montreal  is  also  noteworthy.  The  two  Mont- 
real analyses,  F and  G,  are,  however,  far  from  concordant  and  can 
not  be  given  much  weight. 


1 Other  tributaries  that  have  been  analyzed  are  as  follows:  Goose  Lake,  Michigan  (Geol.  Survey  Michigan, 
vol.  8,  pt.  3,  1903,  p.  235);  Torch  Lake,  Portage  Lake,  Pine  River,  Thunder  River  (Rept.  State  Board 
Geol.  Survey  Michigan,  1903);  Traverse  Bay,  Detroit,  Shiawassee,  Grand,  Cass,  Chippewa,  Tittabawassee, 
and  Boardman  rivers,  Manistee  and  Muskegon  lakes,  cited  by  A.  C.  Lane  in  Water-Supply  Paper  U.  S. 
Geol.  Survey  No.  31,  1903. 


LAKES  AND  RIVERS. 


71 


According  to  estimates  made  by  engineers  of  the  United  States 
Army,  the  flow  of  the  St.  Lawrence  past  Ogdensburg  is  248,518  cubic 
feet  per  second.  This,  with  a salinity  of  134  parts  per  million,  cor- 
responds to  a transport  of  dissolved  matter  of  29,722,000  metric  tons 
annually.  The  area  drained,  exclusive  of  water  surface,  is  286,900 
square  miles,  and  from  each  square  mile  103.6  tons  are  removed  in 
solution  each  year. 

THE  ATLANTIC  SLOPE. 

For  the  rivers  and  lakes  of  the  Atlantic  slope  south  of  the  St.  Law- 
rence the  data  are  now  fairly  abundant.  The  subjoined  analyses  are 
the  most  useful.  In  all  of  them  bicarbonates  are  reduced  to  normal 
form,  and  organic  matter  is  omitted  from  the  calculation. 

Analyses  of  waters  of  Atlantic  slope — I. 

A.  Moosehead  Lake,  Maine. 

B.  Rangeley  Lake,  Maine. 

C.  Androscoggin  River  at  Brunswick,  Maine,  above  the  falls.  Average  of  38  analyses  of  weekly  samples 
taken  between  April  25,  1905,  and  January  16,  1906.  Analyses  A,  B,  and  C made  by  F.  C.  Robinson,  for 
the  water-resources  branch  of  the  United  States  Geological  Survey.  C as  recalculated  by  Dole  in  Water- 
Supply  Paper  236.  The  undetermined  C03  is  computed  to  satisfy  bases. 

D.  Merrimac  River  above  Concord,  New  Hampshire.  Analysis  by  H.  E.  Barnard  for  the  water-resources 
branch  of  the  Geological  Survey. 

E.  Hudson  River  at  Hudson,  New  York.  Mean  analysis  of  36  weekly  composites  taken  between  Sep- 
tember 16,  1906,  and  September  22,  1907.  Analyses  by  R.  B.  Dole,  M.  G.  Roberts,  C.  Palmer,  and  W.  D. 
Collins,  Water-Supply  Paper  236,  1909.  Analyses  by  C.  F.  Chandler  of  water  from  the  Hudson  and  its 
tributaries,  the  Mohawk  and  the  Croton,  are  cited  in  the  first  edition  of  this  book  (Bulletin  330). 

F.  Raritan  River  at  Bound  Brook,  New  Jersey.  Mean  of  35  composite  samples  taken  between  Sep- 
tember 10,  1906,  and  September  12, 1907.  Same  analysts  and  reference  as  under  E.  Analyses  of  several 
New  Jersey  streams  are  given  by  A.  H.  Chester  in  the  report  on  water  supply,  New  Jersey  Geol.  Survey, 
1894.  An  analysis  of  water  from  Passaic  River,  by  E.  N.  Horsford,  is  published  in  Geology  of  New  Jersey, 
1868,  p.  703;  and  another  by  H.  Wurtz  in  Am.  Chemist,  vol.  4, 1873,  pp.  99,  133. 

G.  Delaware  River  at  Lambertville,  New  Jersey.  Mean  of  34  composite  samples,  September  8,  1906, 
to  September  12, 1907.  Same  analysts  and  reference  as  under  E.  A similar  average  analysis  of  the  Lehigh 
is  also  given  by  Dole.  For  an  earlier,  single  analysis  of  Delaware  water  see  H.  Wurtz,  Am.  Jour.  Sci., 
2d  ser.,  vol.  22,  1856,  p.  125.  Analyses  of  water  from  the  Schuylkill  are  given  by  C.  M.  Cresson  in  a report 
entitled  “Results  of  examinations  of  water  from  the  River  Schuylkill,”  Philadelphia,  1875. 

H.  Susquehanna  River,  at  Danville,  Pennsylvania.  Mean  of  36  composite  samples,  September  10, 1906, 
to  September  17, 1907.  Same  analysts  and  reference  as  under  E.  Similar  annual  averages  for  the  river  at 
West  Pittston  and  W illiamsport  are  also  given  by  Dole.  The  Susquehanna  shows  the  effects  of  contamina- 
tion by  coal-mine  drainage. 

In  analyses  E,  F,  G,  and  H the  alkalies  are  given  as  corrected  by  Palmer. 


A 

B 

C 

D 

E 

F 

G 

H 

C03 

26.  83 

26.  53 

20.  29 

28. 15 

35.45 

29.  48 

32.  95 

23.54 

so4 

14.  46 

13.  08 

24.  85 

12.  78 

15.  84 

14.  08 

17.49 

27.  53 

Cl 

no3 

13.  83 

12.  72 

4.76 

8.  78 

3.  96 
.79 

5.  52 
2.  23 

4.  23 
1.  60 

7. 19 
3.  02 

Ca 

14.94 

14.  78 

15.  33 

17. 14 

20.  79 

14.  08 

17.49 

18.  64 

Mg 

1.  80 

1.  69 

2.  27 

4. 18 

3.  76 

4.  58 

4.  81 

4.  08 

Na 

12.  79 

11.  63 

5. 17 

16. 16 

6.  53 

9.  27 

6.  70 

6.  84 

K 

4.  29 

4.  42 

2.  07 

Trace. 

1.  78 

1.  76 

1.46 

1.  33 

Si02 

A1203 

9.  68 
| 1.38 

13.  33 
| 1.82 

18.  63 

18. 14 
1.  34 

10.  90 

18.  77 

13. 12 

7.  72 

Fe203 

| 6.  63 

3.  33 

.20 

.23 

.15 

.11 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

14.5 

16.5 

48.3 

170 

108 

85 

70 

112 

72 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  A and  B are  remarkable  because  of  their  relatively  high 
content  in  alkaline  chlorides.  These  waters,  however,  are  very  dilute, 
and  the  absolute  quantity  of  chlorides  in  them  is  probably  no  more 
than  they  would  receive  from  rainfall.  The  Androscoggin  rises 
in  the  Rangeley  Lakes,  but  the  composition  of  its  water  is  pro- 
foundly modified  by  drainage  from  factories  and  pulp  mills.  Its  head- 
waters, flowing  from  a region  of  crystalline  rocks,  mainly  granitic, 
are  remarkably  pure. 

Analysis  of  waters  of  Atlantic  slope — II. 

I.  Potomac  River  at  Cumberland,  Maryland.  Mean  composition  of  36  composite  samples  taken  between 
September  11, 1906,  and  September  14,  1907.  Analyses  by  Dole,  Roberts,  Palmer,  and  Collins. 

J.  Shenandoah  River  at  Millville,  West  Virginia.  Composite  of  36  samples,  September  12,  1906,  to 
September  9, 1907.  Same  analysts  as  under  I. 

K.  Potomac  River  above  Great  Falls,  Maryland.  Average  of  twelve  samples  taken  at  intervals  of  one 
month  between  April,  1904,  and  April,  1905.  Analyses  by  Raymond  Outwater,  Water-Supply  Paper 
U.  S.  Geol.  Survey  No.  192,  1907,  pp.  296-297.  This  report  contains  thirty-four  other  analyses  of  water 
from  the  upper  Potomac  and  its  important  tributaries. 

L.  James  River  at  Richmond,  Virginia.  Composite  of  36  samples,  September  10,  1906,  to  September 
9, 1907.  Same  analysts  as  under  I.  A thesis  by  A.  F.  White,  Washington  and  Lee  University,  1906,  con- 
tains partial  analyses  of  tributaries  of  the  James  near  Lexington,  Virginia.  See  also  an  analysis  of  James 
River  water  by  W.  H.  Taylor,  Rept.  to  Richmond  Board  of  Health,  1877,  cited  in  the  first  edition  of 
this  book  (Bulletin  330). 

M.  Dan  River  at  South  Boston,  Virginia.  Composite  of  21  samples,  September  3,  1906,  to  May  2,  1907. 
Dole,  Roberts,  and  Palmer,  analysts. 

N.  Roanoke  River  at  Randolph,  Virginia.  Composite  of  20  samples,  September  7, 1906,  to  May  12, 1907. 
Same  analysts  as  under  M. 

O.  Neuse  River  at  Raleigh,  North  Carolina.  Composite  of  36  samples,  October  1,  1906,  to  October  19, 
1907.  Same  analysts  as  under  I. 

All  the  analyses  in  this  table  except  K are  recalculated  from  Water-Supply  Paper  236,  with  the  alkali 
determinations  as  corrected  by  Palmer.  Each  composite  sample  represents  ten  daily  collections. 


I 

J 

K 

L 

M 

N 

O 

co3 

13.  69 

47.  22 

44.  37 

36.  02 

25.  43 

34.  99 

24.  93 

so4 

44.  85 

4.  43 

7.  68 

8.  67 

5.  34 

5.  90 

4.  90 

Cl 

4.  95 

2. 14 

4.44 

2.  81 

5.  03 

2.  95 

6.  34 

NO, 

. 70 

1.  86 

. 37 

1.  73 

. 67 

.43 

Ca 

18.  56 

22.  85 

27.  40 

17. 10 

8.  79 

12.  74 

8.  50 

Mg 

3.  56 

5.  86 

4.  08 

3.  66 

2.  35 

4.  69 

2.  59 

Na 

6. 11 

3.  86 

2.  83 

7.  20 

9. 10 

6.  70 

10.  09 

K 

1.  08 

1.  00 

.55 

1.  34 

2.  04 

1.47 

1.  87 

Si02 

A1?03 

6.  35 

10.  71 

4.  56 

21.98 

37.  68 

28. 15 

37.  47 

Fe203 

.15 

.07 

| 4. 09 

.85 

2.  51 

1.  74 

2.  88 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

130 

140 

115 

89 

71 

79 

73 

The  first  three  analyses  in  the  foregoing  table  are  peculiarly  sug- 
gestive. The  Potomac  at  Cumberland  shows  the  effect  of  drainage 
from  coal  mines.  The  Shenandoah  adds  to  the  Potomac  a large 
volume  of  water  which  is  little  contaminated  and  which  represents 
to  a considerable  extent  the  influence  of  a limestone  country.  At 
Great  Falls  the  Potomac,  modified  by  its  numerous  affluents, 


LAKES  AND  RIVERS, 


73 


approaches  the  normal  or  average  type  of  river  waters.  According 
to  estimates  made  by  Outwater  the  Potomac  annually  carries  past 
Point  of  Pocks  771,000,000  kilograms  of  dissolved  matter  and 
212,000,000  kilograms  of  solids  in  suspension,  or  sediments.  The 
sum  of  the  two  quantities  is  983,000  metric  tons,  or  a little  over  102 
metric  tons  per  square  mile  of  the  territory  drained.  The  dissolved 
matter  corresponds  to  80  tons  per  square  mile. 

Analysis  of  waters  of  Atlantic  slope — III. 

P.  Cape  Fear  River  at  Wilmington,  North  Carolina.  Mean  analysis  of  30  composite  samples  taken 
between  October  2,  1906,  and  October  9,  1907.  Dole,  Roberts,  Palmer,  and  Collins,  analysts.  Water 
probably  modified  by  tidal  contamination.  * 

Q.  Peedee  River  near  Peedee,  North  Carolina.  Mean  of  24  composites,  October  26, 1906,  to  October  19, 
1907.  Dole,  Palmer,  Collins,  and  J.  R.  Evans,  analysts. 

R.  Saluda  River  near  Columbia,  South  Carolina.  Mean  of  16  composites,  October  27,  1906,  to  May  3, 
1907.  Evans,  analyst. 

S.  Wateree  River  near  Camden,  South  Carolina.  Mean  of  34  composites,  October  21,  1906,  to  October 
25,  1907.  Dole,  Evans,  Palmer,  and  Collins,  analysts. 

T.  Savannah  River  near  Augusta,  Georgia.  Mean  of  34  composites,  October  25,  1906,  to  October  22,  1907. 
Same  analysts  as  under  Q. 

U.  Ocmulgee  River  near  Macon,  Georgia.  Mean  of  33  composites,  October  19,  1906,  to  October  21,  1907. 
Same  analysts  as  under  Q. 

V.  Oconee  River  near  Dublin,  Georgia.  Mean  of  32  composites,  October  18,  1906,  to  October  17,  1907. 
Same  analysts  as  under  Q.  Analysis  P to  V are  from  W ater-Supply  Paper  236.  Potassium  determinations 
supplied  by  Palmer. 

W.  Lake  Okechobee,  Florida.  Analysis  by  W.  T.  Read,  cited  by  R.  B.  Dole  in  Carnegie  Inst.  Wash- 
ington Pub.  No.  182,  1914,  p.  76.  Bicarbonates  reduced  to  normal  carbonates,  organic  matter  omitted. 


P 

Q 

R 

s 

T 

u 

V 

w 

co3 

26.  57 

23.  33 

26.  01 

25. 15 

22.  49 

21.  06 

26.  00 

35.  96 

so4 

6.  91 

5.  95 

8.  01 

6.33 

9. 12 

7.  48 

8.  86 

4.  69 

Cl 

12.  52 

4.  60 

5.  61 

4.  22 

3.19 

4.  28 

4.  86 

18.  00 

no3 

.43 

.89 

.69 

.60 

.91 

1.  07 

1.  43 

.06 

Ca 

10.  80 

10.  25 

13.  46 

9.  49 

8.  67 

9.  62 

12. 14 

19.  93 

Mg 

3.  24 

1.  93 

2.  08 

2.  71 

1.22 

1.  83 

2.  29 

4.  50 

Na... 

14.  04 

10.  99 

1 9.62 

10.  84 

14.  42 

10.  23 

10. 14 

10.  28 

K 

1.  95 

2.  82 

/ 

2.  41 

4. 12 

2.  90 

2.  85 

1.  28 

Si02 

21.  38 

38.  65 

33.  65 

37.  65 

34.  95 

39.  70 

30.  00 

5.  27 

Fe2C3 

2. 16 

.59 

.87 

.60 

.91 

1.  83 

1.  43 

.03 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

57 

69 

62 

73 

60 

69 

68 

155.6 

74 


THE  DATA  OF  GEOCHEMISTRY- 


The  water  of  Lake  Okechobee  is  remarkably  high  in  sodium  and 
chlorine.  Is  this  due  to  cyclic  salt  brought  down  in  rain  ? 

Analyses  of  eastern  tributaries  to  the  Gulf  of  Mexico. 

A.  Flint  River  near  Albany,  Georgia.  Mean  analysis  of  20  composite  samples  taken  between  October 
23,  1906,  and  May  12,  1907.  J.  R.  Evans,  analyst. 

B . Chattahoochee  River  at  W est  Point,  Georgia.  Mean  of  34  composites,  October  26, 1906,  to  October  18, 
1907.  Dole,  Evans,  Palmer,  and  Collins,  analysts. 

C.  Oostanaula  River  near  Rome,  Georgia.  Mean  of  31  composites,  October  21,  1906,  to  October  28, 1907. 
Same  analysts  as  under  B. 

D.  Cahaba  River  near  Birmingham,  Alabama.  Mean  of  30  composites,  November  1, 1906,  to  November 
1,  1907.  Same  analysts  as  under  B.  For  a single  analysis  of  water  from  the  Cahaba  see  R.  S.  Hodges, 
Geol.  Survey  Alabama,  U nderground  water  resources,  1907.  This  report  contains  many  analyses  of  springs 
and  wells. 

E.  Alabama’River  at  Selma,  Alabama.  Mean  of  33  composites,  November  5, 1906,  to  October  17,  1907. 
Evans,  Dole,  Palmer,  Collins,  and  W.  Van  Winkle,  analysts. 

F.  Tombigbee  River  near  Epes,  Alabama.  Mean  of  33  composites,  October  24, 1906,  to  October  24, 1907. 
Same  analysts  as  under  B. 

G.  Pearl  River,  near  Jackson,  Mississippi.  Mean  of  32  composites,  October  16, 1906,  to  October  19, 1907. 
Same  analysts  as  under  B. 

All  the  analyses  in  this  table  are  recalculated  from  Water-Supply  Taper  236  and  include  later  alkali 
determinations  by  Palmer. 


A 

B 

C 

D 

E 

F 

G 

co3 

22.  73 

21/32 

32.  06 

32.  53 

27.  86 

33.  34 

25.  29 

so4 

8.  95 

8.  49 

5.  04 

11. 18 

10.  63 

6.  37 

10.  31 

Cl 

4. 17 

3.  96 

2.  21 

2.  79 

2.  72 

3.  03 

5.  48 

no3 

.90 

1.  32 

.50 

.76 

.83 

.61 

1. 12 

Ca 

13. 12 

9.  06 

14.  74 

16.  52 

15.  35 

18. 18 

11.  43 

Mg 

2.  09 

1.  51 

3. 19 

3. 17 

3. 42 

1.  82 

1.  77 

Na 

\ 10.44 

12.  08 

9.  60 

8.  78 

11.  33 

8. 18 

11.  59 

K 

/ 

3.  40 

1.  96 

3. 18 

2.12 

2.  32 

3.  22 

Si02 

35.  77 

37.  73 

29.  48 

20.  33 

24.  79 

25.  25 

28.  99 

Fe203 

1.  83 

1. 13 

1.  22 

.76 

.95 

.90 

.80 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

67 

52 

82 

76 

82 

94 

59 

A glance  at  the  foregoing  table  and  the  two  immediately  preceding 
it  reveals  a remarkable  similarity  between  the  waters  of  the  southern 
rivers  from  the  James  to  the  Pearl  inclusive.  All  are  low  in  salinity 
and  relatively  high  in  silica  and  the  alkalies.  In  several  of  the 
analyses  the  alkaline  radicles  are  in  excess  of  calcium.  River  waters, 
in  short,  seem  to  exhibit  distinct  regional  peculiarities,  which,  in 
most  cases,  if  not  in  all,  are  due  to  the  geology  of  the  region  traversed. 
These  waters,  with  one  or  two  exceptions,  flow  from  areas  of  crystal- 
line schists,  and  owe  little  to  sedimentary  environments. 


LAKES  AND  RIVERS. 


75 


THE  MISSISSIPPI  BASIN. 

For  the  great  river  system  of  the  Mississippi  the  chemical  data  are 
abundant,  but  of  very  unequal  value.  The  river  itself  has  been 
studied  from  near  its  source  to  near  its  mouth,  and  the  waters  of 
many  tributaries  have  also  been  analyzed.  Taking  the  Mississippi 
itself  first,  the  useful  data  are  as  follows,  arranged  in  order  going 
southward : 

Analyses  of  water  from  Mississippi  River. a 

A.  Mississippi  River  at  Brainerd,  Minnesota.  Analysis  by  C.  F.  Sidener,  Thirteenth  Ann.  Rept.  Geol. 
Nat.  Hist.  Survey  Minnesota,  1884,  p.  102. 

B.  Mississippi  River  at  Minneapolis,  Minnesota.  Average  of  35  analyses,  by  W.  M.  Barr,  H.  S.  Spauld- 
ing, and  W.  Van  Winkle,  of  samples  each  formed  by  ten  daily  collections  between  September  10, 1906,  and 
September  11,  1907. 

C.  Mississippi  River  near  Moline,  Illinois.  Mean  of  18  composite  samples  taken  between  February  1, 
and  July  31, 1906.  W.  D.  Collins,  analyst. 

D.  Mississippi  River  near  Quincy,  Illinois.  Mean  of  36  composite  samples  taken  between  August  1, 
1906,  and  July  31,  1907.  W.  D.  Collins,  analyst. 

E.  Mississippi  River  near  Chester,  Illinois.  Mean  of  31  composite  samples  taken  between  August  1, 

1906,  and  July  31,  1907.  W.  D.  Collins,  analyst. 

F.  Mississippi  River  at  Memphis,  Tennessee.  Mean  of  35  composite  samples  taken  between  January  10, 

1907,  and  January  1,  1908.  Analyses  by  J.  R.  Evans,  W.  Van  Winkle,  R.  B.  Dole,  Chase  Palmer,  and 
W.  D.  Collins.  Later  alkali  determinations  by  Palmer. 

G.  Mississippi  River  above  Carrolton,  Louisiana.  Analysis  by  C.  H.  Stone,  Science,  vol.  22,  1905, 
p.  472.  Sample  taken  6 feet  below  surface.  Recalculated  from  bicarbonates. 

H.  Mississippi  River  at  New  Orleans.  Mean  of  52  composite  samples  taken  daily  between  April  29, 
1905,  and  April  28, 1906.  J.  S.  Porter,  analyst. 

The  analyses,  except  A and  G,  are  recalculated  from  the  figures  given  by  Collins  in  Water-Supply  Paper 
239  and  Dole  in  Water-Supply  Paper  236. 


A 

B 

C 

D 

E 

F 

G 

H 

CO, 

51.  65 

48.  03 

42.  27 

43. 15 

33.  23 

30.  23 

30.  27 

34.  98 

so4 

1.  05 

9.  35 

13.  58 

12.  55 

21.  74 

20.  50 

19.  69 

15.  37 

Cl 

.48 

.83 

2.  09 

2.  21 

3.  79 

4. 10 

11.  05 

6.  21 

NO, 

.73 

1. 01 

1. 10 

1.  05 

.81 

1.  60 

P04 

. 27 

Ca 

22.  94 

20.  77 

18.  68 

18.  06 

17.  08 

17. 16 

20.  25 

20.  50 

Mr 

4.  09 

7.  27 

7.  35 

8.  03 

6.  22 

5.  72 

4.  66 

5.  38 

Na 

5. 14 

| 5. 19 

| 5.65 

| 5.52 

| 8.15 

8.  09 

6.  86 

| 8.33 

K 

1.  75 

1.  52 

1.  57 

SiOo 

9.  40 

7.78 

J 9.09 

J 9.03 

J 8.54 

11.44 

5.  07 

7.  05 

AloOo 

2.  01 

.12 

.45 

Fe203 

1.  49 

.05 

.28 

.35 

.20 

.43 

.08 

.13 

M113O4 

.11 

Salinity,  parts  per 
million 

100.  00 
195 

100.  00 
200 

100.  00 
179 

100.  00 
203 

100.  00 
269 

100.  00 
202 

100.  00 
146 

100.  00 
166 

a For  two  analyses  of  Mississippi  water,  taken  above  and  below  Minneapolis,  see  J.  A.  Dodge,  Tenth 
Ann.  Rept.  Geol.  Nat.  Hist.  Survey  Minnesota,  1882,  p.  207.  These  analyses  are  given  in  the  first  edition 
of  this  book.  Bailey  Willis  (Jour.  Geology,  vol.  1, 1893,  p.  509)  cites  some  imperfect  analyses  of  the  Missis- 
sippi and  Missouri  near  St.  Louis.  Iowa  Geol.  Survey,  vol.  6,  1896,  p.  365,  contains  other  analyses  of 
Mississippi  water, and  also  of  Missouri,  Cedar,  Des  Moines,  Coon,  Boyer,  Wapsipiniccn,  Skunk,  Chariton, 
Grand,  Nodaway , and  West  Nishnabotna  rivers.  These  too  are  incomplete.  The  early  analyses  of  Missis- 
sippi water  by  Avequin  and  by  Jones  are  of  no  value  for  present  purposes.  Partial  analyses,  containing 
some  useful  data,  are  given  in  Report  of  the  sewage  and  water  board,  New  Orleans,  1903.  These  relate  to 
the  lower  Mississippi  near  New  Orleans. 


This  table  tells  a definite  story.  The  upper  Mississippi  is  low  in 
sulphates  and  chlorides,  which  tend  to  accumulate  in  the  lower 


76 


THE  DATA  OF  GEOCHEMISTRY. 


stream.  The  chlorides  come  in  part  from  human  contamination,  a 
subject  to  be  considered  later;  but  more  largely,  together  with  sul- 
phates, from  western  tributaries,  notably  from  the  Missouri.  At 
New  Orleans,  also,  there  is  probably  some  “cyclic  sodium”  brought 
in  rainfall  from  the  Gulf  of  Mexico.  On  the  whole,  carbonates  pre- 
dominate in  the  Mississippi  water,  with  all  else  subordinate. 

The  next  table  gives  analyses  of  waters  tributary  to  the  upper 
Mississippi  within  the  States  of  Minnesota  and  Wisconsin.1 

Analyses  of  waters  tributary  to  upper  Mississippi  River. 

A.  Lake  Minnetonka.  Analysis  by  W.  A.  Noyes,  Geology  of  Minnesota,  vol.  2,  1888,  p.  311. 

B.  Mille  Lacs  Lake.  Analysis  by  J.  A.  Dodge,  Geology  of  Minnesota,  vol.  4,  1899,  p.  38. 

C.  Bigstone  Lake.  Analysis  by  C.  F.  Sidener,  Thirteenth  Ann.  Rept.  Geol.  Nat.  Hist.  Survey  Minne- 
sota, 1884,  p.  98.  Empties  into  Minnesota  River. 

D.  Heron  Lake.  Analysis  by  Noyes,  Eleventh  Ann.  Rept.  Geol.  Nat.  Hist.  Survey  Minnesota,  1882, 
p.  173.  Empties  into  Des  Moines  River. 

E.  Rock  River  at  Luveme,  Minnesota.  A tributary  of  Sioux  River.  Analysis  by  Noyes,  Geology  of 
Minnesota,  vol.  1,  1884,  p.  550. 

F.  Minnesota  River  at  Shakopee,  Minnesota.  Mean  analysis  of  30  composite  samples  taken  between 
September  24,  1906,  and  October  1,  1907.  W.  M.  Barr,  H.  S.  Spaulding,  W.  Van  Winkle,  R.  B.  Dole, 
C.  Palmer,  and  W.  D.  Collins,  analysts.  Alkali  determinations  as  corrected  by  Palmer. 

G.  Chippewa  River  near  Eau  Claire,  Wisconsin.  Mean  of  35  composites,  September  14,  1906,  to  Sep- 
tember 12,  1907.  Barr,  Spaulding,  and  Van  Winkle,  analysts. 

H.  Wisconsin  River  near  Portage,  Wisconsin.  Mean  of  24  composites,  September  11,  1906,  to  May  17, 
1907.  Same  analysts  as  under  G. 

Analyses  F,  G,  H are  recalculated  from  the  figures  given  by  Dole  in  Water-Supply  Paper  236. 


A 

B 

c 

D 

E 

F 

G 

H 

COb 

58.81 

59.03 

20. 13 

42.65 

47.94 

31.59 

30. 49 

31.43 

S04 

.88 

34.  36 

18.62 

8.64 

31.  26 

18.09 

18.74 

Cl 

.72 

.59 

1.65 

1.14 

.44 

1.  02 

1.42 

2.31 

no3 

1.39 

.43 

. 78 

.99 

Ca 

25.52 

15.  25 

8.00 

20.  71 

20.  51 

17.81 

16.80 

15.44 

Mg 

7.23 

10.  71 

8.61 

8.00 

7.43 

7.61 

6.07 

7.50 

Na 

1.03 

6.68 

6.69 

2.94 

3.31 

4. 12 

jlO.  46 

| 8.93 

K 

2.32 

2.24 

1.01 

1.32 

.51 

1. 15 

Si02 

4.37 

2.  97 

19.26 

2.61 
} .62 

7.65 

4.  99 

15.  50 

j 14.33 

Fe203 

1.65 

.29 

3.21 

.02 

.39 

.33 

A1203 

.36 

) 

Salinity,  parts  per 
•million 

100. 00 
110 

100.  00 
144 

100.  00 
554 

100. 00 
272 

100. 00 
275 

100. 00 
480 

100. 00 
90 

100. 00 
98 

i For  analyses  of  several  other  Minnesota  waters,  see  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  193, 
1907,  p.  133. 


LAKES  AND  RIVERS. 


77 


The  following  table  gives  analyses  of  waters  tributary  to  the  Mis- 
sissippi in  Illinois  and  Iowa: 

Analyses  of  tributaries  in  Illinois  and  Iowa. 

A.  Rock  River  near  Sterling,  Illinois.  Mean  analysis  of  36  composite  samples  taken  between  August  1, 

1906,  and  July  31,  1907.  W.  D.  Collins,  analyst.  Collins  also  gives  a similar  annual  average  for  the  river 
at  Rockford. 

B.  Illinois  River  near  Kampsville,  Illinois.  Mean  of  36  composites,  August  1,  1906,  to  July  31,  1907. 
Collins,  analyst.  He  aIso~gives  similar  analyses  for  the  river  near  Lasalle  and  Peoria. 

C.  Kaskaskia  River  at  Carlyle,  Illinois.  Mean  of  34  composites,  August  1,  1906,  to  July  31, 1907.  Collins, 
analyst.  A similar  average  is  given  for  the  river  near  Shelbyville. 

D.  Cedar  River  near  Cedar  Rapids,  Iowa.  Mean  of  37  composites,  September  6,  1906,  to  September  17, 

1907.  W.  M.  Barr,  H.  S.  Spaulding,  and  W.  Van  Winkle,  analysts. 

E.  Iowa  River  at  Iowa  City,  Iowa.  Mean  of  36  composites,  September  6,  1906,  to  September  16,  1907. 
Same  analysts  as  under  D. 

F.  Des  Moines  River  at  Keosauqua,  Iowa.  Mean  of  36  composites,  September  10,  1906,  to  September  9, 
1907.  Same  analysts  as  under  D. 

Analyses  A,  B,  and  C are  recalculated  from  the  figures  given  by  Collins  in  Water-Supply  Paper  239;  the 
others  are  from  Dole,  Water-Supply  Paper  236. 

Collins  also  gives  annual  averages  for  the  composition  of  the  waters  of  Kankakee,  Pox,  Vermilion, 
Sangamon,  Muddy,  Embarrass,  Little  Wabash,  and  Cache  rivers.  In  all,  19  rivers  were  studied,  including 
the  Mississippi. 


A 

B 

c 

D 

E 

F 

COs 

48.  56 

38.42 

42. 13 

44.80 

42.17 

34.96 
23.  37 
1.58 
1.09 
19.09 
6.91 
| 5.59 

S04 

9.34 

16.30 

13.  64 

i3.  08 

14.  70 

Cl 

2.06 

5.82 

2.  77 

1.48 

1.  47 

no3 

1.42 

1.67 

1.92 

1.35 

1. 15 

Ca 

18.  30 

18.24 

18.86 

20.  91 

20.00 

Mg 

10.09 

7.  76 

8.02 

6.97 

6.  94 

Na 

| 4.48 

| 6.98 

| 5.62 

| 5.23 

| 5.67 

K 

Si02 

5.60 

4.  65 

6.84 

6. 10 

7.  76 
.14 

7.24 

.17 

F62O3 

.15 

.16 

.20 

.08 

Salinity,  parts  per  million 

100. 00 
267 

100. 00 
267 

100.  00 
248 

100. 00 
228 

100. 00 
247 

100.00 

312 

78 


THE  DATA  OF  GEOCHEMISTRY, 


In  the  following  table  I give  analyses  of  waters  which  reach  the 
Mississippi  from  the  eastward  by  way  of  the  Ohio.1  For  the  Ohio 
itself  I have  found  no  satisfactory  data. 

Analyses  of  waters  tributary  to  Ohio  River. 

A.  Allegheny  River  at  Kittanning,  Pennsylvania.  Mean  analysis  of  36  composite  samples  taken  between 
September  13, 1906,  and  September  10,  1907.  R.  B.  Dole,  M.  G.  Roberts,  and  C.  Palmer,  analysts. 

B.  Monongahela  River  at  Elizabeth,  Pennsylvania.  Mean  of  37  composites,  August  25, 1906,  to  Septem- 
ber 2,  1907.  Same  analysts  as  under  A.  Dole  also  gives  an  annual  average  for  the  composition  of  Y oughio- 
gheny  water. 

C.  Muskingum  River  at  Zanesville,  Ohio.  Mean  of  27  composites,  September  3,  1906,  to  September  13, 
1907.  Same  analysts  as  under  A. 

D.  Miami  River  at  Dayton,  Ohio.  Mean  of  34  composites,  September  16,  1906,  to  September  17,  1907. 
Dole,  Roberts,  Palmer,  and  Collins,  analysts. 

E.  East  Fork  of  White  River  near  Azalia,  Indiana.  Mean  of  37  composites,  September  12,  1906,  to 
October  3,  1907.  Barr,  Spaulding,  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts. 

F.  West  Fork  of  White  River  near  Indianapolis,  Indiana.  Mean  of  35  composites,  September  8,  1906, 
to  September  12,  1907.  Barr,  Spaulding,  and  Van  Winkle,  analysts. 

G.  Wabash  River  at  Vincennes,  Indiana.  Mean  of  31  composites,  September  9,  1906,  to  September  16, 
1907.  Same  analysts  as  under  F. 

H.  Kentucky  River  at  Frankfort,  Kentucky.  Mean  of  36  composites,  August  28,  1906,  to  September  4, 

1907.  Same  analysts  as  under  D . 

I.  Cumberland  River  at  Kuttawa,  Kentucky.  Mean  of  34  composites,  January  11, 1907,  to  January  11, 

1908.  Evans,  Dole,  Palmer,  and  Collins,  analysts.  Another  average  is  given  for  the  water  near  Nashville, 
Tennessee. 

J.  Tennessee  River  near  Gilbertsville,  Kentucky.  Mean  of  33  composites,  October  24,  1906  to  October 
24,  1908.  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts.  Another  average  is  given  for  the  water  at 
Knoxville,  Tennessee. 

All  the  analyses  in  this  series  are  recalculated  from  the  figures  given  by  Dole  in  Water-Supply  Paper 
236,  as  corrected  by  the  later  alkali  determinations  of  Palmer. 


A 

B 

C 

D 

E 

co3 

21.51 

11.  47 

24.  71 

43.  64 

47.  85 

so4 

19.  55 

42.  52 

18.  36 

13.  88 

10.  58 

Cl 

16. 10 

4. 12 

17.  07 

1.  42 

1. 10 

no3 

.82 

2.32 

.69 

2.  98 

1.  97 

Ca 

16. 10 

15.  47 

18.  36 

20.  46 

21.  51 

Mg 

3.46 

2.  84 

4. 06 

8.  33 

8. 11 

Na 

11.  04 

8. 12 

9.  39 

2.  49 

2.  75 

K 

2.  09 

1.42 

1.  28 

.83 

. 77 

Si02 

9.  09 

10.  82 

5.  98 

5.  89 

5.  29 

Fe203 

.24 

.90 

.10 

.08 

.07 

Salinity,  parts  per  million 

100.  00 
87 

100.  00 
81 

100.  00 
244 

100.  00 
289 

100.  00 
279 

F 

G 

H 

I 

J 

co3 

31.  76 

34.  09 

38.  51 

40.57 

34.  57 

so4 

12.  88 

16.  57 

8.  32 

7.  85 

10.  74 

Cl 

17.  32 

10.  84 

2.  01 

2.  43 

2.  93 

no3 

1.  36 

1.  93 

2.  51 

1.  46 

1. 17 

Ca 

16.  44 

18.  37 

21.  06 

22.  67 

18.  56 

Mg 

6.  44 

6.  63 

3.  71 

3. 48 

4.  00 

Na 

| 10.  66 

| 7.56 

5.  82 

4.  29 

5.  08 

K 

1.41 

2.  34 

2.  83 

Si02 

3. 10 

3.  92 

16.  05 

14.  59 

19.54 

Fe203 

.04 

.09 

.60 

.32 

.58 

Salinity,  parts  per  million 

100.  00 
450 

100.  00 
336 

100.  00 
104 

100.  00 
124 

100.00 

101 

1 An  analysis  of  Monongahela  water  by  C.  D.  Howard  and  one  of  water  from  the  Cumberland  by  N.  T. 
Lupton  are  given  in  the  first  edition  of  this  book  (Bulletin  330). 


LAKES  AND  RIVERS. 


79 


For  the  largest  tributary  of  the  Mississippi — the  Missouri — several 
analyses  are  available.  They  are  given  in  the  following  table,  together 
with  analyses  of  its  affluents.1 

Analyses  of  water  from  Missouri  River  and  tributaries. 

A.  Missouri  River  near  Florence,  Nebraska.  Mean  analysis  of  36  composite  samples  taken  between 
October  1, 1906,  and  October  14,  1907.  Barr,  Spaulding,  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts. 

B.  Missouri  River  near  Kansas  City,  Missouri.  Mean  of  38  composites,  October  4,  1906,  to  October  21, 
1907.  Same  analysts  as  under  A. 

C.  Missouri  River  near  Ruegg,  Missouri.  Mean  of  36  composites,  September  24,  1906,  to  October  6,  1907. 
Same  analysts  as  under  A. 

D.  North  Platte  River  at  North  Platte,  Nebraska.  Mean  of  29  composites,  September  10,  1906,  to  June 
30, 1907.  Barr,  Spaulding,  and  Van  Winkle,  analysts. 

E.  Platte  River  at  Fremont,  Nebraska.  Mean  of  33  composites,  October  10,  1906,  to  November  2, 1907. 
Barr,  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts.  Another  series  of  analyses  of  the  water  at 
Columbus  is  also  given.  An  analysis  of  the  Platte  at  Greeley,  Colorado,  is  given  on  p.  61,  ante,  together 
with  some  of  its  tributary,  Cache  la  Poudre  River. 

F.  Laramie  River  20  miles  above  Laramie,  Wyoming.  Average  of  three  analyses  by  E.  E.  Slosson, 
Bull.  Wyoming  Exper.  Sta.  No.  24,  1895. 

G.  Laramie  River  50  miles  below  Laramie.  Analysis  by  E.  E.  Slosson,  loc.  cit.  Slosson  also  gives 
analyses  of  Popo  Agie  and  Little  Goose  creeks.  Another  analysis  of  the  Laramie  is  printed  in  Fifth  Rept. 
Bur.  Soils,  U.  S.  Dept.  Agr.,  1903. 

H.  Yellowstone  Lake.  Analysis  by  J.  E.  Whitfield,  Bull.  U.  S.  Geol.  Survey  No.  47, 1888.  This  bulletin 
also  gives  analyses  of  Firehole  and  Gardiner  rivers. 

Analyses  A to  E are  recalculated  from  Dole’s  Water-Supply  Paper  236,  with  potassium  determinations 
communicated  by  Palmer. 


A 

B 

c 

D 

E 

F 

G 

H 

co3 

22. 42 

24.  23 

25.  63 

24. 13 

29.  43 

27.  35 

19.  59 

20.  93 

so4 

37.69 

32.  74 

30.  44 

32.  77 

22. 18 

11. 16 

37.  48 

7. 12 

Cl 

NO, 

1.  99 
.40 

3. 15 
.54 

3.  52 
.85 

3. 15 
.53 

2. 18 
.33 

3. 11 

6.  32 

7.  96 

Ca 

14.  58 

15.  04 

15.  22 

15.  05 

15.  80 

13.  75 

15.  07 

7.  29 

Mg 

4.  48 

4.  37 

4.  68 

4.  37 

3.  67 

2.  45 

5. 10 

.25 

Na 

9.  64 

9.  22 

9.  07 

110.  68 

8.  06 

7.  34 

8.  82 

13.  22 

K 

nh4 

1.  70 

1.  50 

1.  90 

/ 

2. 42 

.85 

1.  96 

3.  99 
. 34 

Si02 

A1203 

6.  95 

8.  97 

8. 49 

8.  98 

15.  80 

31.  73 

4.  54 

35.  51 
3.  39 

Fe,0, 

.15 

.24 

.20 

.34 

.13 

1 2.26 

} 1. 12 

J 

) 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

454 

426 

346 

426 

302 

212 

429 

118 

In  all  but  three  of  these  waters  sulphates  predominate  over  car- 
bonates, and  calcium  is  less  conspicuous  than  in  the  analyses  preceding 
this  group.  The  high  silica  of  the  Yellowstone  Lake  and  the  upper 
Laramie  is  also  noticeable. 


1 Two  analyses  of  water  from  the  Missouri,  not  used  here,  are  given  in  the  first  edition  of  this  book. 
Another  analysis  by  F.  W.  Traphagen  is  cited  in  E.  W.  Hilgard’s  Soils,  p.  23,  but  the  point  of  collection 
is  not  named. 


80 


THE  DATA  OF  GEOCHEMISTRY. 


For  one  other  tributary  of  the  Missouri  a particularly  interesting 
group  of  analyses  is  at  hand.  Kansas  or  Kaw  River,  with  its  chief 
affluents,  has  been  studied  by  E.  H.  S.  Bailey  and  his  assistants,1 
whose  data,  reduced  as  usual,  are  given  in  the  next  table.  The  locali- 
ties mentioned  are  all  in  the  State  of  Kansas,  and  the  arrangement  of 
the  streams  is  from  the  west,  eastward. 

Analyses  of  water  from  Kansas  River  and  its  tributaries. 

A.  Smoky  Hill  River  at  Lindsborg.  Mean  of  28  analyses  of  composite  samples  of  water  taken  between 
November  27,  1906,  and  November  29,  1907.  F.  W.  Bushong  and  A.  J.  Weith,  analysts. 

B.  Saline  River  at  Sylvan  Grove.  Mean  of  34  composite  samples  taken  between  November  27,  1906, 
and  November  29,  1907.  Analyses  by  Bushong. 

C.  Solomon  River  at  Beloit.  Mean  of  32  composite  samples  taken  between  December  1,  1906,  and  De- 
cember 5,  1907.  Bushong  and  Weith,  analysts. 

D.  Republican  River  at  Junction.  Mean  of  25  composite  samples  taken  between  November  26,  1906, 
and  September  10.  1907.  Bushong  and  Weith,  analysts. 

E.  Big  Blue  River  at  Manhattan.  Mean  of  34  composite  samples  taken  between  December  19, 1906,  and 
December  20, 1907.  Bushong  and  Weith,  analysts. 

F.  Delaware  River  at  Perry  and  Valley  Falls.  Mean  of  27  composite  samples  taken  between  January 
4 and  November  29, 1907.  Bushong  and  Weith,  analysts. 

G.  Kansas  River  at  Holliday.  Mean  of  72  composite  samples  taken  between  December  29,  1906,  and 
December  31,  1908.  Two  years’  average.  Analyses  by  F.  W.  Bushong,  A.  J.  Weith,  and  W.  L.  Sippy. 
Analyses  of  several  other  tributaries  of  the  Kansas  are  also  given  in  the  paper. 


A 

B 

C 

D 

E 

F 

G 

co3 

14.  40 

6.  02 

26. 17 

34.  36 

35.  53 

39.  47 

31.  78 

so4 

26.  87 

18.  26 

19.  50 

12.  56 

12.  32 

12. 17 

15. 14 

Cl 

21.  61 

38.  57 

12.  09 

7.11 

5.  89 

3.  85 

10. 18 

no3 

.21 

.03 

.54 

. 71 

.64 

1.  07 

.57 

Ca 

12.  93 

5.  03 

16.  61 

16.  35 

18.  74 

20.  78 

18. 12 

Mg : 

2.  41 

1.  98 

2.  89 

3.  32 

3.  92 

4.  75 

3.  98 

Na,  K 

18.  26 

28.  97 

15.  52 

13.  50 

12.  32 

9.  79 

12.  66 

Si02 

3. 18 

1.  07 

6.  32 

11.  38 

9.  52 

6.  82 

7. 19 

Fe203 

.13 

.07 

.36 

.71 

1. 12 

1.  30 

.38 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million. . . 

882 

2,  624 

554 

422 

357 

337 

403 

The  two  westernmost  of  these  streams  flow  from  a relatively  arid 
region  and  are  characterized  by  high  salinity.  They  are  peculiarly 
poor  in  carbonates  but  rich  in  sodium  and  chlorine,  conditions  which 
may  be  correlated  with  the  great  abundance  of  salt  in  Kansas.  In 
the  Solomon  River  carbonates  begin  to  predominate;  and  in  the 
easternmost  rivers  of  the  group  there  is  a close  approximation  in 
chemical  character  to  some  streams  of  the  Atlantic  slope.  Kansas 
River  itself  represents  a blending  of  all  the  waters  which  flow  into  it.2 

1 U.  S.  Geol.  Survey  Water-Supply  Paper  No.  273,  1911.  Some  earlier  analyses  by  Bailey  and  Franklin 
are  cited  in  the  previous  editions  of  this  work. 

2 Partial  analyses  of  about  50  streams  in  Oklahoma  may  be  found  in  Water-Supply  Paper  U.  S.  Geol. 
Survey  No.  148,  1905.  A paper  by  J.  H.  Norton  on  the  drainage  of  Richland  Creek,  Arkansas,  appeared 
in  Jour.  Am.  Chem.  Soc.,  vol.  30,  1908,  p.  1186.  An  analysis  of  water  from  the  Wakarusa  River  is  cited  in 
the  second  edition  of  this  work. 


LAKES  AND  RIVERS. 


81 


Two  analyses  of  water  from  Arkansas  River  have  already  been 
cited,  and  need  not  be  repeated  here.  Other  analyses  of  this  river 
and  its  tributaries,  together  with  Osage  and  Red  rivers  will  end 
this  summary  of  the  Mississippi  Basin.1 

Analyses  of  water  from  the  Arkansas  and  other  rivers. 

A.  Osage  River,  at  Boicourt,  Kansas.  Mean  of  33  analyses  of  composite  samples  of  water  taken  between 
November  29, 1906,  and  November  30,  1907.  F.  W.  Bushong  and  A.  J.  Weith,  analysts.  This  stream  is  a 
tributary  of  the  Missouri. 

B.  Arkansas  River  at  Deerfield,  Kansas.  Mean  of  26  composite  samples  taken  between  December  11, 
1906,  and  December  2, 1907.  Bushong  and  Weith,  analysts. 

C.  Arkansas  River  near  Great  Bend,  Kansas.  Mean  of  33  composite  samples  taken  between  November 
26,  1906,  and  December  7,  1907.  Bushong  and  Weith,  analysts. 

D.  Arkansas  River  at  Arkansas  City,  Kansas.  Mean  of  27  composite  samples  taken  between  December 
7,  1906,  and  December  10,  1907.  Bushong  and  Weith,  analysts. 

E.  Arkansas  River  at  Little  Rock,  Arkansas.  Mean  of  22  composite  samples  taken  between  November 
1,  1906,  and  October  24,  1907.  Barr,  Spaulding,  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts.  Recal- 
culated from  Water-Supply  Paper  No.  236. 

F.  Cimarron  River  at  Englewood,  Kansas.  Mean  of  30  composite  samples  taken  between  November 
30,  1906,  and  November  30,  1907.  Bushong  and  Weith,  analysts.  A tributary  of  the  Arkansas. 

G.  Neosho  River  at  Emporia,  Kansas.  Mean  of  35  composite  samples  taken  between  December  5, 1906, 
and  December  5,  1907.  Bushong  and  Weith,  analysts.  A tributary  of  the  Arkansas.  An  earlier,  single 
analysis  of  Neosho  water  by  C.  F.  Gustavsen  appears  in  Kansas  Univ.  Sci.  Bull.,  vol.  2,  p.  243,  1903. 

H.  Red  River  near  Shreveport,  Louisiana.  Mean  of  34  composite  samples  taken  between  March  19, 
1906,  and  March  19,  1908.  Dole,  Palmer,  Collins,  and  Evans,  analysts.  Recalculated  from  Water-Supply 
Paper  236,  with  later  alkali  determinations  by  Palmer.  All  these  analyses  except  E and  H are  taken  from 
Water-Supply  Paper  No.  273.  In  this  paper  there  are  also  analyses  of  the  Marmaton,  Walnut,  Medicine 
Lodge,  Chikaskia,  Verdigris,  Fall,  Cottonwood,  and  Spring  rivers,  with  some  minor  streams,  all  in  Kansas. 


A 

B 

C 

D 

E 

F 

G 

H 

co3 

37.  26 

7.  55 

9.  95 

12.  33 

11.  89 

11.42 

39.02 

13.  01 

so4 

12.  31 

54.  70 

47. 19 

19. 18 

15. 19 

11.  87 

10.  61 

25.  65 

Cl 

3. 41 

4.  77 

8.  72 

29.  03 

33. 17 

37.  65 

2.  25 

22. 16 

no3 

1.  20 

.21 

.17 

.18 

.33 

.13 

1.  09 

.07 

Ca 

22.  90 

12.  31 

13. 13 

9.44 

8.  99 

6.  93 

20.  60 

13.  56 

Mg 

4. 10 

4. 11 

3.  52 

2.  39 

2. 13 

2.  57 

4.  05 

3. 12 

Na 

K 

| 9.56 

jl4.  24 

|14. 71 

|24. 15 

123. 53 

|26.  91 

| 7.80 

15.  74 
.91 

Si02 

J 8.20 

j 1.92 

J 2.46 

J 3.08 

* 4.57 

J 2.87 

13.  77 

5.  49 

Fe203 

1.  06 

.19 

.15 

.22 

.20 

.15 

.81 

.29 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

293 

1,  510 

1, 136 

1,  006 

630 

1,  323 

320 

561 

i Two  analyses  by  R.  N.  Brackett  of  water  from  the  Arkansas  are  given  in  Ann.  Rept.  Arkansas  Geol. 
Survey,  1891,  vol.  2,  pp.  159,  160. 


97270°— Bull.  616—16 6 


82 


THE  DATA  OF  GEOCHEMISTRY. 


SOUTHWESTERN  RIVERS. 

A few  of  the  rivers  of  the  southwestern  United  States  have  been 
studied  with  much  care.  The  following  analyses  represent  this 
group.1 

Analyses  of  water  from  southwestern  rivers. 

A.  Brazos  River  at  Waco,  Texas.  Mean  analysis  of  30  composite  samples  taken  between  December 
14,  1906,  and  November  19,  1907.  Barr,  Spaulding,  Van  Winkle,  Dole,  Palmer,  and  Collins,  analysts. 
Recalculated  from  Water-Supply  Paper  236,  with  later  alkali  determinations  by  Palmer. 

B.  Colorado  River  of  Texas,  at  Austin.  Mean  of  36  composites,  August  1, 1905,  to  July  27, 1906.  W.  H. 
Heileman,  analyst,  Water-Supply  Paper  236. 

C.  Rio  Grande  at  Laredo,  Texas.  Mean  of  37  composites,  August  1, 1905,  to  August  2, 1906.  Heileman, 
analyst,  loc.  cit. 

D.  Rio  Grande  at  Mesilla,  New  Mexico.  Average  composition  for  an  entire  year,  June,  1893,  to  June, 
1894.  Analyses  by  Arthur  Goss,  Bull.  New  Mexico  Agr.  Exper.  Sta.  No.  34,  1900.  This  bulletin  also 
contains  analyses  of  water  from  Animas  River,  Santa  Fe  River,  and  Rio  Bonito. 

E.  Pecos  River,  New  Mexico.  Average  of  six  samples  analyzed  by  Goss,  loc.  cit. 

F.  Colorado  River  at  Yuma,  Arizona.  Average  of  seven  composite  samples,  covering  collections  made 
between  January  10,  1900,  and  January  24,  1901.  Analyzed  by  R.  H.  Forbes  and  W.  W.  Skinner,  Bull. 
Univ.  Arizona  Agr.  Exper.  Sta.  No.  44,  1902.  The  average  composition  of  the  water  during  a year. 

G.  Gila  River  at  head  of  Florence  canal,  below  The  Buttes,  Arizona.  Average  of  four  analyses  by 
Forbes  and  Skinner  representing  twenty-one  weekly  composites.  Samples  taken  between  November 
28, 1899,  and  November  5, 1900. 

H.  Salt  River  at  Mesa,  Arizona.  Average  of  six  analyses  covering  forty  weekly  composites  of  water 
taken  between  August  1,  1899,  and  August  4,  1900.  Analyses  by  Forbes  and  Skinner,  loc.  cit.  Salt  River 
and  the  Gila  are  tributaries  of  the  Colorado.  Forbes  and  Skinner  report  their  silica  as  the  silicate  radicle 
SiC>3.  This  is  reduced  to  SiC>2  in  the  table. 


A 

B 

C 

D 

E 

F 

G 

H 

co3 

7.  09 

28.  60 

11.  55 

17.  28 

1.54 

13.  02 

12. 10 

9.  61 

so4 

25.  49 

12. 48 

30. 10 

31.  33 

43.  73 

28.  61 

16.  07 

8.  29 

Cl 

30.  87 

17.  52 

21.  65 

13.  55 

22.  56 

19.  92 

29.  78 

41. 56 

no3 

.20 

Ca 

11.  06 

15.  45 

13.  73 

14.  78 

13.  43 

10.  35 

8.  03 

7. 15 

Mg 

1.  74 

5. 14 

3.  03 

2.  05 

3.  62 

3. 14 

2.  52 

2.  69 

Na 

20.  83 

13.  07 

14.  78 

14.  43 

14.  02 

19.  75 

24.  53 

26.  38 

K 

.67 

1.  50 

.85 

1.  95 

.77 

2. 17 

2.  31 

1.  38 

Si02 

2.01 

5.  32 

3.  83 

l 

1 

3. 04 

4.  66 

2.  94 

A1203 

1 

1 4.  63 

l .33 

Fe90q 

.04 

> . 92 

f .48 

J 

x 2,  o 

J 

J 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

1, 136 

321 

791 

399 

2,  384 

702 

1,  023 

1,  234 

These  waters  are  characterized,  as  is  evident  on  inspection  of  the 
table,  by  high  salinity,  the  predominance  of  alkaline  sulphates  and 
chlorides,  and  a deficiency  of  carbonates  and  of  lime.  From  figures 
given  by  Forbes  I have  computed  that  the  Colorado  carries  to  the 
Gulf  of  California  annually,  in  solution,  13,416,400  metric  tons  of 
salts,  or  about  59.6  metric  tons  from  each  square  mile  of  its  basin. 


i An  analysis  of  Rio  Grande  water  by  O.  Loew  is  given  in  Rept.  U.  S.  Geog.  Surveys  W.  100th  Mer., 
vol.  3,  1875,  p.  576.  In  the  annual  report  of  the  same  Survey  for  1876  Loew  gives  an  analysis  of  water  from 
Virgin  River,  a tributary  of  the  Colorado.  For  two  analyses  of  the  Pecos  see  B.  S.  Tilson,  Bull.  Geol. 
Survey  Texas  No.  2, 1910.  Analyses  of  Rio  Grande  water  by  Fraps  and  Tilson  are  cited  in  Circular  103, 
Office  Exper.  Sta.,  U.  S.  Dept.  Agr.,  1911. 


LAKES  AND  RIVERS. 


83 


RIVERS  OF  CALIFORNIA. 

For  the  river  waters  of  California  the  data  are  now  very  abundant, 
but  only  a small  part  of  them  can  be  utilized  here.  A number  of 
individual  analyses  are  to  be  found  in  the  former  editions  of  this 
book;1  the  following  table  is  recalculated  from  the  figures  reported 
by  W.  Van  Winkle  and  F.  M.  Eaton  in  Water-Supply  Paper  237, 
1910.  In  that  paper  the  average  composition  of  a river  water  is 
ascertained  by  many  analyses  of  composite  samples,  representing 
daily  collections,  as  was  done  in  the  investigations  under  Dole  and 
Collins  which  have  already  been  freely  cited.  The  composition  of 
each  water  is  thus  determined  for  a sufficiently  long  time  to  give  the 
figures  real  significance  in  geochemical  research.  Van  Winkle  and 
Eaton,  by  this  general  method,  studied  37  rivers  of  California. 

Analyses  of  water  from  rivers  of  California. 

A.  Russian  River  near  Ukiah.  Mean  analysis  of  37  composite  samples  taken  between  December  31, 

1907,  and  December  31,  1908. 

B.  Sacramento  River  above  Sacramento.  Mean  of  two  series  of  analyses  covering  the  years  1906  and 

1908.  Potassium  was  separately  determined  during  the  first  half  of  1906,  and  the  same  is  true  of  total 
Fe203+Al203.  In  recalculating,  these  determinations  are  assumed  to  be  fair  averages.  Van  Winkle  and 
Eaton  also  give  annual  averages  for  Feather,  Yuba,  and  American  rivers  and  Cache  Creek,  all  tributaries 
of  the  Sacramento. 

C.  San  Joaquin  River  at  Lathrop.  Mean  of  two  series,  1906  and  1908,  recalculated  as  in  the  case  of  the 
Sacramento.  Similar  averages  for  one  year  or  less  are  given  for  the  tributary  rivers  Mokelumne,  Stanislaus, 
Tuolumne,  Merced,  and  Kern. 

D . Salinas  River  at  Paso  Robles.  Mean  of  30  composites  taken  in  1908.  From  about  July  18  to  October 
1 the  river  bed  was  dry.  Data  are  given  for  several  tributaries  of  the  Salinas. 

E.  Santa  Maria  River  25  miles  above  Santa  Maria.  Mean  of  36  composites  covering  the  year  1906.  K 
and  total  R2O3  were  only  determined  during  the  first  half  year. 

F.  Santa  Ynez  River  at  Santa  Barbara.  Mean  of  33  composites  covering  the  year  1906.  K and  R2O3 
determined  during  the  first  half  year  only. 

G.  San  Gabriel  River  near  Rivera.  Mean  of  37  composites  covering  the  year  1908.  Another  average 
is  given  for  the  river  at  Azusa. 

H.  Santa  Ana  River  above  Mentone.  Mean  of  two  series,  1906  and  1908.  K and  R2O3  determined 
during  the  first  half  of  1906.  Another  annual  average  is  given  for  the  river  near  Corona. 


A 

B 

c 

D 

E 

F 

G 

H 

co3 

39. 07 

30. 14 

18. 43 

30.  66 

5.  82 

19.  33 

40.  54 

35.  78 

so4 

10.  81 

12.  21 

17. 41 

21.  35 

58.  35 

42.  58 

12.  62 

11.  34 

Cl 

4.  70 

5.  79 

20.  62 

8.  59 

4.  89 

3.  71 

3.  22 

3.  70 

N03. 

. 77 

.48 

.54 

. 16 

. 73 

. 50 

Ca 

14.  61 

11.  45 

10.13 

13.  21 

14.  07 

14.  98 

21.  04 

17]  02 

Mg 

7.  62 

5.  59 

4.  82 

6. 17 

6. 19 

6.  68 

4.  59 

4.  00 

Na 

\10. 17 

9.  78 

15.  81 

112.  99 

8.  94 

8. 10 

\ 8.41 

10.  67 

K 

/ 

1.  68 

1.  08 

/ 

. 37 

. 51 

/ 

1.  33 

Si02 

' 12.  07 

19. 12 

9.  38 

6.  82 

1. 12 

3.  56 

8.  79 

13*.  68 

ALO3 

3.  35 

1.  56 

.24 

.53 

1.  86 

Fe203 

.18 

.41 

.22 

.05 

.01 

.02 

.06 

.12 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

145 

118.5 

183 

448 

2,  412 

714 

246 

152 

1 Clear  Lake,  analysis  by  T.  Price,  cited  in  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  45,  1901.  Feather 
River,  by  E.  W.  Hilgard,  Rept.  Agr.  Exper.  Sta.,  Univ.  California,  1898-1901.  San  Lorenzo  River,  by 
A.  Seidell,  Field  Operations  Bur.  Soils,  U.  S.  Dept.  Agr.,  1901.  Santa  Clara  River,  by  B.  E.  Brown,  same 
reference  as  the  preceding.  Santa  Ynez  River  and  three  of  its  tributaries,  by  J.  A.  Dodge,  Water-Supply 
Paper  U.  S.  Geol.  Survey  No.  116, 1904.  Other  analyses,  by  H.  G.  Kelsey,  appear  in  University  of  Cali- 
fornia, Rept.  Coll.  Agric.,  1882. 


84 


THE  DATA  OF  GEOCHEMISTRY, 


THE  COLUMBIA  RIVER  BASIN. 

The  waters  of  Oregon  and  Washington  have  been  studied  with 
much  thoroughness  by  W.  Van  Winkle  1 and  a selection  from  among 
his  abundant  data  is  given  in  the  following  tables.  The  Columbia 
and  its  tributaries  come  first. 

Analyses  of  water  from  Columbia  and  Snake  rivers. 

A.  Columbia  River  at  Northport,  Washington.  Mean  of  37  analyses  of  composite  samples  of  water 
taken  between  February  1, 1910,  and  January  31, 1911. 

B.  Columbia  River  at  Pasco,  Washington.  Mean  of  37  composite  samples  taken  between  February  1, 
1910,  and  January  31, 1911. 

C.  Columbia  River  at  Cascade  Locks.  Mean  of  30  composite  samples  taken  between  March  13  and 
December  31, 1910,  and  37  composite  samples  taken  between  August  11, 1911,  and  August  14, 1912.  Nearly 
two  years’  average. 

D.  Snake  River  near  Weiser,  Idaho.  Mean  of  37  composite  samples  taken  between  August  11,  1911, 
and  August  14, 1912. 

E.  Snake  River  at  Burbank,  Washington.  Mean  of  33  composite  samples  taken  between  March  13, 
1910,  and  January  31, 1911. 


A 

B 

c 

D 

E 

co3 

42.  38 

42.  81 

36. 15 

31.  02 

31.  95 

so4 

14.  12 

13.  08 

13.  52 

16.  45 

16.  37 

Cl 

. 71 

. 84 

2.  82 

7.  99 

6.  31 

no3 

. 27 

. 16 

. 49 

. 28 

. 41 

Ca 

21. 19 

21.  40 

17.  87 

15.  51 

14.  81 

Mg 

5.  53 

5.  35 

4.  38 

4.  52 

4.  37 

Na 

| 5.53 

| 7.14 

8. 12 

10.  34 

| 10.91 

K 

1.  95 

1.  64 

Si02 

R203 

‘ 10.24 
.03 

9. 16 
.06 

14.  62 
.08 

12.  22 
.03 

14.  81 
.06 

Salinity,  parts  per  million. . . .• 

100.  00 

85 

100.  00 

84 

100.  00 
92.  4 

100.  00 
213 

100.  00 
128 

i Water-Supply  Papers  U.  S.  Geol.  Survey  Nos.  339,  363,  1914. 


LAKES  AND  RIVERS, 


85 


Analyses  of  water  from  tributaries  to  the  Columbia. 

F.  Spokane  River  at  Spokane,  Washington.  Mean  of  35  composite  samples  taken  between  February  1, 
1910,  and  January  31, 1911. 

G.  Yakima  River  at  Prosser,  Washington.  Mean  of  37  composite  samples  taken  between  February  1, 

1910,  and  January  31, 1911. 

H.  Owyhee  River  near  Owyhee,  Oregon.  Mean  of  37  composite  samples  taken  between  August  11, 

1911,  and  August  14, 1912. 

I.  Grand  Ronde  River  at  Elgin,  Oregon.  Mean  of  37  composite  samples  taken  between  August  11, 
1911,  and  August  14, 1912. 

J.  Umatilla  River  near  Umatilla,  Oregon.  Mean  of  36  composite  samples  taken  between  August  11, 
1911,  and  August  14,  1912.  Analyses  are  given  by  Van  Winkle  for  samples  collected  at  two  other  points 
also. 

K.  John  Day  River  at  McDonald,  Oregon.  Mean  of  37  composite  samples  taken  between  August  11, 
1911,  and  August  14, 1912.  Analyses  are  given  for  the  water  at  Dayville  also. 

L.  Deschutes  River  at  Moody,  Oregon.  Mean  of  34  composite  samples  taken  between  August  21, 1911, 
and  July  25, 1912.  Analyses  are  given  for  the  water  at  Bend  also. 

M.  Willamette  River  at  Salem,  Oregon.  Mean  of  37  composite  samples  taken  between  August  11, 1911, 
and  August  14, 1912. 

Van  Winkle  gives  analyses,  most  of  them  annual  averages,  for  13  other  rivers  of  the  Columbia  Basin. 


F 

G 

H 

I 

J 

K 

L 

M 

co3 

35.  94 

32.  30 

31.  24 

30.03 

31.  49 

39.  79 

31.  81 

28.  32 

so4 

14.  43 

17.  39 

15.  85 

6. 12 

12.  71 

8.  51 

5.  68 

8.  19 

Cl 

. 94 

4.  30 

5.  89 

1.  85 

5.18 

1.  92 

2.  38 

4.  21 

N03 

. 36 

. 28 

. 29 

. 86 

.62 

. 78 

.75 

. 79 

Ca 

17. 19 

13.  25 

11.  78 

11.  55 

12.  71 

14. 18 

9.  66 

11.  73 

Mg 

5.  62 

5.  05 

2.  90 

3.  23 

3.  65 

5.  39 

3.  06 

3.  09 

Na 

| 8.  28 

jll.  59 

15.  85 

9.  00 

12. 15 

9.  22 

12.  50 

8.  41 

K 

2.  08 

2.  31 

2.  65 

1.  70 

2.  28 

1.  77 

Si02 

17. 19 

15.  73 

14.  04 

34.  64 

18.  78 

18.  44 

31.  81 

33.  18 

Fe90q 

.05 

.11 

.08 

.41 

.06 

.07 

.07 

.31 

Salinity,  parts  per 
million 

100.  00 
64 

100.  00 
121 

100.  00 
221 

100.  00 
87 

100.  00 
181 

100.  00 
141 

100.  00 
88 

100.  00 
45 

According  to  Van  Winkle  the  Columbia  carried  in  solution  past 
Cascade  Locks,  in  1910,  21,638,000  short  tons  of  dissolved  matter, 
and  in  1911-12,  17,000,000  tons.  This,  for  a drainage  area  of  239,600 
square  miles,  is  equivalent  to  90.3  and  71  tons  per  square  mile;  an 
average  of  80.6,  or  73  metric  tons.1  Similar  estimates  are  given  for 
each  of  the  tributaries. 


1 For  earlier  single  analyses  of  the  Columbia,  Snake,  Willamette,  and  Powder  rivers,  see  the  second 
edition  of  this  work,  p.  78.  Powder  River  is  a tributary  of  the  Snake. 


86 


THE  DATA  OF  GEOCHEMISTRY. 


OTHER  NORTHWESTERN  RIVERS. 

In  the  next  table  analyses  are  given  of  waters  from  Oregon  and 
Washington,  with  one  from  Alaska.  Except  when  otherwise  stated, 
the  analyses  are  by  W.  Van  Winkle,1  and  represent  annual  averages. 

Analyses  of  northwestern  waters. 

A.  Yukon  River  at  Eagle,  Alaska.  Single  analysis  by  G.  Steiger.  Reported  by  F.  W.  Clarke,  Jour. 
Am.  Chem.  Soc.,  vol.  27,  1905,  p.  111. 

B.  Skagit  River  at  Sedro  Woolley,  Washington.  Mean  of  37  analyses  of  composite  samples  of  water 
taken  between  February  1, 1910,  and  January  31, 1911. 

C.  Chehalis  River  at  Centralia,  Washington.  Mean  of  35  composite  samples  taken  between  February 
1, 1910,  and  January  31, 1911. 

D.  Rogue  River  near  Tolo,  Oregon.  Mean  of  34  composite  samples  taken  between  September  10, 1911, 
and  August  14, 1912. 

E.  Umpqua  River  near  Elkton,  Oregon.  Mean  of  22  composite  samples  taken  between  August  1, 1911, 
and  August  15, 1912. 

F.  Goose  Lake,  Oregon.  Single  analysis  by  Van  Winkle. 

G.  Lost  River,  Klamath  County,  Oregon.  Single  analysis  by  A.  L.  Knisely.  Ann.  Rept.  Irr.  and 
Drainage  Investigation,  U.  S.  Dept.  Agr.,  1904,  p.  264. 

H.  Crater  Lake,  Oregon.  Single  analysis  by  N.  M.  Finkbiner.  Cited  by  Van  Winkle  in  W.  S.  Paper 
363,  p.  43.  Included  here  on  account  of  its  analogy  to  the  river  waters  of  Oregon,  although  it  properly 
belongs  in  the  chapter  on  closed  basins.2 


A 

B 

c 

D 

E 

F 

G 

H 

co3 

46. 16 

30.  78 

26.  06 

28.  83 

28.  66 

34.  30 

52.  64 

20.  62 

so4 

10.  75 

17.  71 

10.  93 

6.  32 

8.  43 

4.  92 

3.  37 

13.  75 

Cl 

.41 

1.  95 

8.  88 

2. 16 

4.  85 

10.92 

1.  46 

13.  75 

no3 

. 52 

. 18 

.40 

. 49 

. 16 

.47 

PCX, 

. 12 

.01 

Ca 

22.  21 

17.  06 

12. 12 

11. 11 

12.  80 

1.  96 

14. 12 

8.  88 

Mg 

4.  71 

3.  67 

3.  24 

2.  62 

3.  58 

.22 

12.  06 

3.50 

Na 

6. 14 

1 7.78 

111.  10 

9.  41 

9.  24 

38.  23 

2.  78 

13.  75 

K 

Trace. 

/ 

/ 

2.  00 

2.  59 

3.  71 

10.  78 

2.  75 

Si02 

7.  78 

20.  30 

27.  31 

37.  00 

29. 14 

5.  46 

10.  42 

22.50 

Fe203 

A1203 

1.  84 

.23 

.18 

.15 

.22 

Trace. 

} 2.  37 

.02 

) 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

98 

46 

59 

65 

62 

916 

220 

80 

1 See  Water-Supply  Papers  U.  S.  Geol.  Survey  Nos.  339  and  363,  1914. 

2 Van  Winkle  also  gives  analyses  of  waters  from  Wood  Creek,  Cedar,  and  Green  rivers  in  Washington, 
and  of  Link,  Wood,  and  Siletz  rivers  in  Oregon.  For  an  earlier  analysis  of  water  from  Cedar  River,  see 
H.  G.  Knight,  Washington  Geol.  Survey,  vol.  1,  p.  285, 1901.  Analyses  of  water  from  Lower  Klamath  Lake 
are  given  in  U.  S.  Dept.  Agr.  Field  Oper.  Bur.  Soils,  1908,  p.  1412. 


LAKES  AND  RIVERS. 


87 


THE  SASKATCHEWAN  SYSTEM. 

This  complex  river  system  comprises  a number  of  important 
branches,  which  finally  unite  in  the  Nelson  River  and  empty  into 
Hudson  Bay.  The  following  analyses  represent  waters  from  this 
great  drainage  basin: 

Analyses  of  waters  from  Saskatchewan  system. 

A.  Red  River  of  the  North  at  Fergus  Falls,  Minnesota.  Analysis  by  W.  A.  Noyes,  Eleventh  Ann. 
Rept.  Minnesota  Geol.  Nat.  Hist.  Survey,  1884,  p.  173. 

B . Red  River  of  the  North  at  St.  Vincent,  Minnesota,  near  the  Canadian  boundary.  Analysis  by  W.  A. 
Noyes,  op.  cit.,  p.  172. 

C.  Red  River  of  the  North  below  the  Assiniboine. 

D.  Assiniboine  River  above  its  junction  with  the  Red.  Analyses  D and  E by  F.  D.  Adams,  Rept. 
Progress  Geol.  Survey  Canada,  1878-79,  p.  10  H. 

E.  Nelson  River  near  its  mouth. 

F.  Hayes  River  opposite  York  Factory.  This  stream  enters  Hudson  Bay  near  the  Nelson.  Analyses 
F and  G by  W.  Dittmar,  Rept.  Progress  Geol.  Survey  Canada,  1879-80,  p.  77  C. 


A 

B 

c 

D 

E 

F 

co3 

32.  52 

41.  20 

31.  47 

39.  70 

16.  78 

50.  36 

so4 

25.  56 

15.  71 

22.  06 

16.  52 

41.  85 

Cl 

.69 

4.  89 

8.  78 

5.  58 

4.  68 

3.  08 

PCL 

. 19 

no3 

. 28 

Ca 

30.  39 

17.  55 

12.  89 

13.  59 

15.  91 

21.  88 

Ms 

8.  23 

7.  99 

7.  72 

5.  65 

5.  24 

Na 

1.  97 

5.  64 

9.  67 

11.  08 

6.  22 

4.  22 

K 

1. 19 

1.  37 

1. 18 

1. 16 

.97 

1.  37 

Li 

. 02 

Si02 

. 60 

4.  57 

5.  72 

4.  41 

7.  30 

11.  48 

(ALFebO, 

7.  08 

.35 

.24 

.24 

.64 

2.  37 

Salinity,  parts  per  million 

100.  00 
202 

100.  00 
284 

100.  00 

551 

100.  00 
509 

100.  00 
180 

100.  00 
115 

88 


THE  DATA  OF  GEOCHEMISTRY. 


The  following  table  gives  analyses  of  the  Bow  River  and  its  tribu- 
taries, the  Bow  being  the  main  western  branch  of  the  Saskatchewan. 
All  these  streams  are  in  the  Alberta  district,  Northwest  Territory, 
Canada.  The  analyses  were  made  by  F.  G.  Wait.1  The  samples 
were  collected  at  low  water. 

Analyses  of  water  from  Bow  River  and  tributaries. 

H.  Bow  River  at  Calgary. 

I.  Elbow  River  at  Calgary. 

J.  Highwood  River  at  High  River. 

K.  Fish  Creek  at  McLeod  Trail. 

L.  Sheep  River  near  Dowdney. 


H 

I 

J 

K 

L 

CO, 

48.  21 

44.  66 

47.  78 

53.  57 

45.  55 

so4 

14.  69 

18.  80 

13.  22 

5.  59 

17. 13 

Cl 

. 94 

. 56 

. 65 

. 51 

. 57 

Ca 

25.  23 

24.  39 

24.  48 

18.  82 

23.  69 

Mg 

6.  95 

6.  55 

6.  23 

7.  57 

6.  32 

Na 

2.  42 

2.  77 

3.  28 

7. 14 

3.  92 

K 

Trace. 

. 42 

Trace. 

1.  34 

. 43 

Si02 

1.  56 

1.  85 

4.  36 

5.  46 

2.  39 

Fe203 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Salinity,  parts  per  million 

100.  00 
128 

100.  00 
217 

100.  00 
183 

100.  00 
238 

100.  00 
209 

SUMMARY  FOR  NORTH  AMERICA. 

If  now  we  look  back  over  the  analyses  of  North  American  rivers, 
we  shall  see  that,  in  spite  of  all  differences,  certain  general  tendencies 
are  manifest.  In  the  first  place,  practically  all  the  waters  from 
east  of  the  Missouri  River,  with  one  or  two  minor  exceptions,  are 
waters  in  which  carbonates  are  largely  in  excess  of  sulphates  and 
chlorides,  and  calcium  is  the  dominating  metal.  The  same  rule 
holds  for  the  extreme  northern  and  northwestern  rivers;  but  the 
western  tributaries  of  the  Missouri,  in  general,  tell  a different  story. 
So  also  do  the  waters  of  New  Mexico  and  Arizona.  Here  sulphates 
are  in  excess  of  carbonates,  and  calcium,  although  sometimes  domi- 
nant, is  not  always  so.  In  short,  where  the  rainfall  is  abundant  and  the 
soil  is  naturally  fertile,  carbonate  waters  are  the  rule;  in  arid  regions 
sulphates  and  chlorides  prevail.  This  statement  applies  to  the 
evidence  now  in  hand,  and  must  not  be  construed  too  sweepingly. 
We  are  dealing  not  with  invariable  laws,  but  with  tendencies. 

The  condition  thus  indicated  is  probably  the  outcome  of  various 
causes,  but  one  of  the  latter  is  easily  found.  In  a fertile  region 
organic  matter  is  abundant  and  great  quantities  of  carbonic  acid  are 


1 Rept.  Geol.  Survey  Canada,  new  ser.,  vol.  9,  1878,  pp.  39-45  R. 


LAKES  AND  RIVERS. 


89 


generated  by  its  decay.  This  carbonic  acid,  absorbed  by  the  ground 
water  of  the  soil,  acts  as  a solvent  of  mineral  matter,  and  carbonates 
are  carried  into  the  streams  more  abundantly  than  other  salts.  In 
arid  regions  there  is  less  organic  decomposition,  less  carbonic  acid, 
and  a smaller  proportion  of  carbonates  is  found.  Water  from  a 
swamp  or  forest  is  very  different  from  water  which  has  leached  a 
desert  soil.  In  the  Kansas  River  and  its  tributaries  the  passage  from 
one  set  of  conditions  to  the  other  is  clearly  apparent.  Western  Kan- 
sas is  relatively  arid,  and  the  western  branches  of  the  river  are  poor 
in  carbonates.  Eastern  Kansas  is  fertile,  and  the  eastern  affluents 
reflect  its  character.  It  must  be  borne  in  mind,  however,  that  we  are 
now  considering  relative  proportions  of  substances  and  not  absolute 
amounts.  The  lower  course  of  a stream  is  a blend  of  many  waters; 
and  the  change  from  one  type  to  another  does  not  necessarily  imply 
that  anything  has  been  lost.  Precipitation  may  have  taken  place, 
but  in  many  cases  the  transformation  from  sulphate  to  carbonate  is 
probably  due  to  an  overwhelming  influx  of  the  latter.  The  Missis- 
sippi itself,  in  its  course  southward,  must  receive  carbonates  more 
freely  than  sulphates;  and  its  final  character  as  it  enters  the  Gulf  of 
Mexico  should  be  that  of  a carbonate  water.  So  much  at  least  can 
be  safely  inferred  from  the  data  already  in  hand.  To  small  streams, 
it  must  be  remembered,  these  considerations  do  not  always  apply. 
Local  conditions  are  operative  in  such  cases,  and  a river  issuing  from 
a region  rich  in  gypsum,  or  fed  by  brooks  affected  by  beds  of  pyrite, 
may  have  a sulphate  character  quite  independent  of  the  climatic 
influences  which  otherwise  seem  to  rule. 

The  local  peculiarities  of  river  water  have  been  the  subject  of  a 
considerable  number  of  geochemical  and  hydrochemical  investiga- 
tions, some  of  which  will  be  noticed  later.  In  general  it  may  be  said 
that  a water  at  or  near  its  source  reflects  in  some  measure  the  com- 
position of  the  rocks  from  which  it  rises.  We  have  already  seen 
the  remarkable  uniformity  of  character  displayed  by  the  rivers  of  the 
South  Atlantic  and  eastern  Gulf  States.  The  waters  of  Illinois  and 
Iowa,  flowing  through  a rich  agricultural  area,  underlain  by  sedi- 
mentary rocks  exclusively,  show  a similar  uniformity  of  composi- 
tion. Water  from  limestone  is  rich  in  lime,  that  from  dolomite  con- 
tains more  magnesia,  that  from  granite  is  characterized  by  rela- 
tively higher  silica  and  alkalies.  In  small  streams  these  resemblances 
appear  quite  clearly;  in  large  rivers  the  commingling  of  the  tribu- 
taries tends  to  produce  an  average  composition  which  may  be  called 
that  of  a normal  water.  The  great  continental  rivers  resemble  one 
another  much  more  nearly  than  do  their  component  branches. 


90 


THE  DATA  OF  GEOCHEMISTRY. 


RIVERS  OF  SOUTH  AMERICA. 

The  river  waters  of  South  America,  except  in  British  Guiana,  the 
Argentine  Republic,  and,  Brazil,  seem  to  have  received  very  little 
attention  from  chemists.  A.  Muntz  and  V.  Marcano1  have  described 
certain  waters,  from  unnamed  tributaries  of  the  Orinoco  and  Amazon, 
which  are  colored  nearly  black  by  organic  acids  but  contain  not  over 
16  parts  per  million  of  mineral  matter,  and  from  which  lime  is  prac- 
tically absent.  These  peculiarities  are  shared  to  some  extent, 
although  not  so  strikingly,  by  certain  river  waters  of  British  Guiana, 
which  are  brown  in  color,  low  in  salinity,  and  rich  in  organic  matter. 
Fourteen  of  these  waters  have  been  analyzed  by  J.  B.  Harrison  and 
K.  D.  Reid,2  from  whose  table  the  following  selection  has  been  made. 
Their  data  are  reduced  here  to  the  usual  standard  form,  with  normal 
carbonates  and  with  organic  matter  omitted.  The  color  is  supposed 
to  be  due  to  organic  compounds  of  iron,  and  the  proportion  of  iron 
found,  here  reported  as  Fe203,  is  unusually  large.  As  stated  here 
the  analyses  represent  the  anhydrous  inorganic  matter  which  the 
waters  could  ultimately  deposit. 


Analyses  of  waters  from  British  Guiana. 

A.  Barima  River  above  Eclipse  Falls. 

B.  Waini  River  above  First  Falls. 

C.  Essequibo  River  above  Wataputa  Falls. 

D.  Demerara  River  above  Malalli  Falls.  Another  analysis  of  water  taken  in  time  of  drought  is  also 
given. 

E.  Courantyne  River: 

F.  Potaro  River,  above  Tumatumari  Falls.  Analyses  are  also  given  of  the  Barama,  Cuyuni,  Puruni, 
Mazaruni,  Rupununi,  Mahaica,  and  Berbice  rivers,  and  of  Abary  Creek. 


A 

B 

C 

D 

E 

F 

co3 

22. 12 

28.  40 

15.  74 

12.  84 

22. 14 

25.  89 

so4 

1.  39 

.92 

5.  65 

1. 15 

1.  22 

1.  89 

Cl 

6.  45 

6.  50 

3.  36 

10.  32 

6.  86 

2.  88 

no3 

.51 

.13 

1. 11 

.97 

.30 

2.00 

10.  21 

5.  45 

3.  84 

.38 

5. 16 

2.  25 

Mg 

4.  01 

3.  02 

2.  96 

2.  65 

2.  39 

.97 

Na 

2.  67 

12.  88 

6.  97 

10.  93 

8.  75 

18. 14 

K 

.08 

1.  88 

.54 

1.  69 

2.  65 

1.  26 

Si02 

43.  43 

25.  04 

52.  80 

55.  92 

41.  90 

38.  54 

Fe203 

9. 13 

15.  78 

7.  03 

3. 15 

8.  63 

6. 18 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

Salinity,  parts  per  million 

78 

45 

30 

73 

40 

44 

The  very  high  silica  and  generally  high  sodium  in  these  waters 
suggest  that  they  emerge  from  areas  of  crystalline  rocks.  The  high 
proportion  of  chlorine,  however,  with  some  of  the  sodium,  may  be 
due  to  cyclic  salt,  the  saline  content  of  rainfall. 


1 Compt.  Rend.,  vol.  107, 1888,  p.  908.  See  also  J.  Reindl,  Natur.  Wochenschr.,  vol.  20,  1905,  p.  353. 

2 Official  Gazette,  Georgetown,  Demerara,  July  26, 1913. 


LAKES  AND  RIVERS. 


91 


In  the  next  table  I give  the  available  data  for  the  Amazon  and 
some  of  its  tributaries. 

Analyses  of  water  from  Amazon  River  and  tributaries. 

A.  The  Amazon  between  the  Narrows  and  Santarem.  Analysis  by  P.  F.  Frankland,  cited  by  T.  Mel- 
lard  Reade  in  Evolution  of  earth  structure. 

B.  The  Amazon  at  Obidos.  Mean  of  two  analyses  by  F.  Katzer.  See  Grundziige  der  Geologie  des 
unteren  Amazonasgebietes,  Leipzig,  1903.  Katzer  estimates  that  the  Amazon  carries  annually  past  Obidos 
618,515,000  metric  tons  of  dissolved  and  suspended  matter. 

C.  The  Xingu.  Analysis  by  Katzer,  loc.  cit. 

D.  The  Tapajos.  Analysis  by  Katzer,  loc.  cit.  Katzer  also  gives  analyses  of  water  from  Parana-mirim, 
the  Maecuru,  the  Itapacurd-mirim,  and  several  fresh-water  lakes  or  lagoons. 


A 

B 

c 

D 

CO, 

34.  75 

24. 15 

26.  78 

29.  60 

so4 

7.  37 

2.  26 

10.  57 

7.  39 

Cl  

3.  85 

6.  94 

6.  96 

5.  77 

Ca 

21. 12 

14.  69 

15.  77 

16.  84 

Mg 

2.  57 

1.  40 

3.  92 

3.  60 

Na 

1.  94 

4.  24 

2.  08 

1.  80 

K 

2.  31 

4.  76 

4. 18' 

3.  67 

Si02 

18.  80 

28.  59 

21. 15 

24.  02 

(Al,~Fe),0, 

7.  29 

12.  97 

8.  59 

7.  31 

Salinity  parts  per  million 

100.  00 
59 

100.  00 
37 

100.  00 
45 

100.  00 
38 

From  the  southern  parts  of  South  America  the  following  waters 
have  been  analyzed: 

Analyses  of  water  from  rivers  in  southern  part  of  South  America. 

A.  River  Plata  5 miles  above  Buenos  Aires.  Analysis  by  J.  J.  Kyle,  Chem.  News,  vol.  38, 1878,  p.  28. 

B.  River  Plata  near  Buenos  Aires.  Analysis  by  R.  Schoeller,  Ber.  Deutsch.  chem.  Gesell.,  vol.  20, 
1887,  p.  1784.  Water  possibly  affected  by  tidal  contamination.  For  other  data  relative  to  the  Plata  and 
the  Mercedes,  see  M.  Puiggari,  An.  Soc.  cient.  Argentina,  vol.  13,  p.  49, 1882. 

C.  The  Parana  5 miles  above  its  entry  into  the  Plata.  Analysis  by  Kyle,  loc.  cit. 

D.  The  Uruguay  midstream  opposite  Salto.  Analysis  by  Kyle,  loc.  cit. 

E.  The  Uruguay  above  Fray  Bentos.  Analysis  by  Schoeller,  loc.  cit. 

F.  Rio  Negro  above  Mercedes.  Analysis  by  Schoeller,  loc.  cit.  An  analysis  of  Rio  Negro  by  Will  is 
cited  by  S.  Rivas,  An.  Soc.  cient.  Argentina,  vol.  1,  1877,  p.  326. 

G.  Colorado  River,  Argentina.  Analysis  by  Kyle,  An.  Soc.  cient.  Argentina,  vol.  43,  1897,  p.  19.  In 
this  memoir  Kyle  gives  analyses  of  numerous  Argentine  rivers . The  nomenclature , however , is  confusing, 
for  descriptive  names,  such  as  Negro,  Colorado,. Salado,  Saladillo,  etc.,  are  applied  to  more  than  one  stream 
in  Argentina,  and  it  is  not  always  easy  to  identify  the  river  to  which  a given  analysis  applies. 


A 

B 

C 

D 

E 

F 

G 

co3 

17.  45 

11.  59 

17.  73 

24.  23 

21.  59 

39. 10 

8. 19 

so4 

7.  69 

17.  97 

10. 13 

3.  90 

6. 15 

1.  23 

30.  58 

Cl 

12.  59 

18. 11 

15.  92 

.61 

5. 12 

4.  43 

24.  51 

NO, 

6.  68 

5.  50 

1.  95 

Ca 

6. 18 

3.  71 

7.37 

9.  82 

10.  01 

17.  82 

16.  24 

Mg 

3.  31 

1.  42 

2.  78 

2.  85 

2.  97 

1.  96 

1.  46 

Na 

17.  34 

24.89 

14.  96 

3.  75 

5.  92 

10.  24 

15.  78 

K 

3.  09 

4.  06 

3. 12 

Si02 

21.  32 

10.  82 

20.  73 

46.  22 

44.  32 

21.  75 

3.  24 

ALO, 

6.  62 

3.  21 

'l 

Fe203 

4.41 

S 4.  81 

3.  21 

} 3.  92 

1.  52 

) 

J 

J 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million.. . 

91 

206 

98 

40 

66 

132 

651 

92 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  water  from  rivers  in  southern  part  of  South  America — Continued. 

H.  Rio  Primero,  Argentina. 

I.  Rio  de  los  Papagayos,  Argentina.  Analyses  H and  I by  M.  Siewert,  in  R.  Napp's  The  Argentine 
Republic,  1876,  pp.  242,  244. 

J.  Rio  Saladillo,  Argentina.  Analysis  by  A.  Doering. 

K.  Rio  de  Arias,  Salto,  Argentina.  Analysis  by  M.  Siewert. 

L.  Rio  de  los  Reyes,  Jujuy,  Argentina.  Analysis  by  M.  Siewert.  For  analyses  J,  K,  and  L,  see  Bol. 
Acad.  nac.  cien.  Cordoba,  vol.  5,  1883,  p.  440. 

M.  Rio  Frio,  district  of  Taltal,  Chile.  Analysis  by  A.  Dietze,  cited  by  L.  Darapsky  in  Das  Departement 
Taltal,  Berlin,  1900,  p.  93. 

N.  Rio  Copiapo,  Chile.  Analysis  by  P.  Lem6tayer,  cited  by  F.  J.  San  Rom&n  in  Desierto  i Cordilleras 
de  Atacama,  vol.  3,  Santiago,  1902,  p.  191. 


H 

I 

J 

K 

L 

M 

N 

co3 

39.  47 

0.  06 

9.  94 

39. 13 

28.  27 

18.  06 

6.  46 

so4 

5.  76 

31.  81 

27.  75 

13.  24 

18. 17 

24.  45 

36.  50 

Cl 

6.  41 

32.  63 

21.  51 

2.  77 

5.  53 

8.  04 

no3 

Trace. 

Ca 

16.  53 

8.  01 

11.  29 

19.  63 

13.  20 

14.  93 

6.  61 

Mg 

3.  27 

. 36 

2.  87 

5.  20 

2.  53 

2.  63 

3.  52 

Na 

9.  09 

26.  48 

16. 12 

1.  82 

7. 19 

15.  37 

8.  96 

K 

4.  67 

.49 

4.  41 

5.  75 

10.  20 

. 36 

Si02 

8.  58 

6. 11 

11.  57 

12.  33 

13.  22 

35.  39 

A1203 

1. 10 

.49 

Fe203 

5. 12 

.89 

2.  09 

3.  30 

j 2.20 

J 

S 

.16 

Salinity,  parts  per  million. . . 

100.  00 
160 

100.  00 
9, 185 

100.  00 
1, 213 

100.  00 
127 

100.  00 
104 

100.  00 
186 

100.  00 
731 

These  waters  show  the  same  order  of  variation  as  those  of  North 
America.  The  water  of  the  Amazon,  flowing  through  forests  and 
in  a humid  climate,  is  characterized  by  dominant  carbonates  and  low 
salinity.  In  Argentina  many  of  the  streams  flow  through  semiarid 
plains.  In  their  waters  sulphates  and  chlorides  predominate  and  the 
alkalies  are  commonly  in  excess  of  lime.  The  Uruguay  and  some 
rivers  of  British  Guiana  are  peculiar  because  of  their  high  propor- 
tion of  silica — a condition  which  will  be  discussed  later  in  the  chapter. 


LAKES  AND  RIVERS. 


93 


LAKES  AND  RIVERS  OF  EUROPE. 

Both  Bischof  and  Both  cite  numerous  early  and  often  incomplete 
analyses  of  European  river  waters,  but  it  is  not  necessary  to  reproduce 
them  all  here.  They  tell  the  same  story  as  that  told  by  the  eastern 
rivers  of  the  United  States.  The  predominance  of  calcium  and  the 
carbonic  radicle  is  clearly  shown  in  most  cases.  For  present  pur- 
poses it  is  well  to  begin  with  British  waters,  and  then  to  pass  on 
eastward. 

Analyses  of  British  waters. 

A.  Loch  Baile  a Ghobhainn,  Lismore  Island,  Scotland.  Analysis  by  W.  E.  Tetlow,  Proc.  Roy.  Soc. 
Edinburgh,  vol.  25,  1905,  p.  970.  Organic  matter  not  included  in  this  recalculation.  A typical  calcium 
carbonate  water  springing  from  limestone. 

B.  River  Dee  near  Aberdeen,  Scotland. 

C.  River  Don  near  Aberdeen. 

Analyses  B and  C by  J.  Smith,  Jour.  Chem.  Soc.,  vol.  4, 1850,  p.  123.  Organic  matter  rejected. 

D.  The  Thames  at  Thames  Ditton. 

E.  The  Thames  at  Kew. 

F.  The  Thames  at  Barnes. 

Analyses  D,  E,  F,  by  T.  Graham,  W.  A.  Miller,  and  A.  W.  Hofmann,  Jour.  Chem.  Soc.,  vol.  4, 1850,  p. 
376.  Analyses  are  also  given  of  the  Thames  at  Battersea  and  Lambeth,  of  the  New  River,  and  several 
springs.  For  other  analyses  of  the  Thames  see  J.  M.  Ashleyj  Jour.  Chem.  Soc.,  vol.  2,  1848,  p.  74,  and 

G.  F.  Clark,  idem,  vol.  1, 1848, p.  155.  Also  R.  D.  Thomson,  idem,  vol.  8,  1856,  p.  97,  and  H.  M.  Witt, 
Philos.  Mag.,  4th  ser.,  vol.  12, 1856,  p.  114. 

G.  Lough  Neagh,  Ireland.  Analysis  by  J.  F.  Hodges,  Chem.  News,  vol.  30, 1870,  p.  103.  An  analysis  of 
the  river  Bann  is  also  given. 

See  also  C.  M.  Tidy,  Jour.  Chem.  Soc.,  vol.  37, 1880,  p.  268,  for  partial  analyses  of  the  Thames,  Lea,  Severn, 
and  Shannon.  E.  Hull,  Geol.  Mag.,  1893,  p.  171,  cites  analyses  of  Thirlmere,  Bala  Lake,  and  the  Severn, 
which  I am  unable  to  trace  to  the  original  publications.  In  T.  E . Thorpe’s  Manual  of  inorganic  chemistry  ,- 
vol.  1,  p.  207,  analyses  of  the  Clyde  and  Loch  Katrine  are  given.  For  analyses  of  the  River  Trent,  see  Jour. 
Soc.  Chem.  Ind.,  vol.  30, 1911,  p.  70. 


A 

B 

c 

D 

E 

F 

G 

co3 

57.  49 

23.  35 

23. 15 

41.  86 

39.  53 

33.  90 

35.  23 

so4 

Trace. 

15.  70 

16.  29 

11.  82 

14.  72 

18. 10 

10.  68 

Cl 

1.  41 

17.  08 

14.19 

5.  20 

4.57 

5.  70 

9.  62 

NO, 

Trace. 

. 84 

Trace. 

Trace. 

. 02 

Ca 

37.  77 

17.  22 

16.  32 

30. 10 

28.  57 

27.  00 

i7.  71 

Mg 

.25 

2.  98 

3.  54 

1.  95 

1.  82 

1.  70 

1.  31 

Na 

\ .94 

113.  60 

1 9. 17 

2.  26 

3.  28 

3.  70 

15.41 

K 

/ 

/ 

/ 

2.  25 

1.  55 

1. 10 

SiO, 

A1203 

1.  62 

6.  41 

10.62 

3.  26 

1 

2.  36 

5.  00 

3.32 

Fe203 

.50 

| 3.  66 

| 6.  72 

> . 46 

| 3.  60 

| 3.  80 

6.  72 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million. . . 

160 

31 

81 

272 

266 

286 

155 

The  high  chlorine  and  sodium  in  some  of  these  analyses  is  probably 
due  in  part  to  the  proximity  of  the  ocean.  In  the  Thames  the  regular 
increase  in  these  radicles  as  we  follow  the  stream  downward  is  quite 
evident.  The  Thames,  however,  rises  in  the  midland  counties  of 
England,  where  the  waters  issuing  from  the  oolite  are  relatively  rich 
in  chlorides.1 


See  W.  W.  Fisher,  The  Analyst,  vol.  29,  1904,  p.  29. 


94 


THE  DATA  OF  GEOCHEMISTRY, 


The  next  group  of  analyses  1 relates  to  the  waters  of  western  Europe, 
namely  of  Belgium,  France,  and  Spain.  Some  Swiss  waters  are 
included,  as  tributary  to  the  Rhone. 

Analyses  of  waters  in  western  Europe. 

A.  The  Meuse  at  Liege,  Belgium.  Computed  from  data  given  by  W.  Spring  and  E.  Prost,  Ann.  Soc. 
g6ol.  Belgique,  vol.  11, 1884,  p.  123.  The  Meuse  carries  past  Liege,  in  solution,  nearly  1,082,000  metric 
tons  of  solids  annually,  or  139  tons  from  each  square  mile  of  territory  drained.  Earlier  analyses  of  the 
Meuse  by  J.  T.  P.  Chandelon  and  J.  W.  Gunning  are  cited  by  Bischof. 

B.  The  Seine  at  Bercy.  Analysis  by  H.  Sainte-Claire  Deville,  Annales  chim.  phys.,  3d  ser.,  vol.  23, 
1848,  p.  42. 

C.  The  Loire  near  Orleans.  Analysis  by  Deville,  loc.  cit. 

D.  The  Garonne  at  Toulouse.  Analysis  by  Deville,  loc.  cit. 

E.  The  Doubs  at  Rivotte.  Analysis  by  Deville,  loc.  cit. 

F.  The  Isere.  Analysis  by  J.  Grange,  Annales  chim.  phys.,  3d  ser.,  vol.  24,  1848,  p.  496.  Grange  also 
gives  analyses  of  several  small  tributaries  and  correlates  them  with  their  geological  surroundings. 

G.  The  Rhone  at  Geneva.  Analysis  by  Deville,  loc.  cit. 

H.  The  Rhone.  Average  of  five  analyses  by  L.  Lossier,  Arch.  sci.  phys.  nat.,  2d  ser.,  vol.  62, 1878,  p.  220. 
Organic  matter  rejected. 

I.  The  Arve.  Average  of  six  analyses  by  Lossier,  loc.  cit. 

J.  Lac  Leman.  Analysis  by  R.  Brandenbourg,  cited  by  F.  A.  Forel  in  Mem.  Soc.  Helv6t.,  vol.  29, 1884. 
Forel  cites  several  other  analyses  of  Lac  Leman.  See  also  Risler  and  Walter,  Bull.  Soc.  vaud.,  vol.  12, 1878, 
p.  175. 

K.  Lac  d’Annecy.  Analysis  by  L.  Duparc,  Compt.  Rend.,  vol.  114, 1872,  p.  248. 

L.  The  Douro.  Analysis  cited  in  Mem.  Com.  mapa  geol.  Espana,  Prov.  Salamanca.  Analyst  not  named. 


A 

B 

c 

D 

E 

F 

co3 

36.  48 

39.  78 

30.  92 

33.  07 

50.41 

34.  14 

S04 

13. 13 

8.  57 

1.  72 

5.  59 

1.  53 

24.11 

Cl 

3.  83 

2.  95 

2. 16 

1.  40 

. 74 

4.53 

no3 

2.  86 

4.  44 

2.  35 

Ca 

28.  90 

29. 13 

14.  31 

18.  99 

33.  20 

25.40 

Mg 

2.  68 

.63 

1.  34 

. 67 

.40 

3.  67 

Na : 

2.  24 

2.  87 

6.  93 

4.42 

1.  53 

1 4.32 

K 

.87 

.86 

1.  64 

2.  50 

.70 

/ 

Li  . .. 

. 05 

Si02 

6.  02 

9.  59 

31.  59 

29.  53 

6.  91 

1.  97 

A1203  

> 

. 19 

5.  29 

. 92 

1.  86 

Fe203 

^ 2.  94 

.99 

4. 10 

2.  28 

1.  31 

Trace. 

Mn203 

1.  55 

100.  00 

100.  00 

100.00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million.  . . . 

254 

134 

137 

230 

188 

G 

H 

I 

J 

K 

L 

C03 

27.92 

36.  69 

42.  37 

33.  87 

59. 14 

33.  73 

so4 

23. 18 

26.  68 

18.  81 

26.  66 

Trace. 

23.  37 

Cl 

.55 

. 71 

1.  46 

.52 

.69 

7.  74 

no3  

3. 13 

. 31 

. 32 

PCL 

.41 

Ca 

24.  89 

26.  42 

29.64 

27.  81 

34.  40 

23.93 

Mg 

1.  48 

3.  66 

3. 17 

2.  23 

3.  06 

6.  05 

Na 

2.  75 

\ 3.98 

\ 2.53 

2.  53 

Trace. 

2.00 

K 

. 88 

/ 

/ 

.25 

Trace. 

1.  64 

Si02 

13.  08 

1.  55 

1.  70 

5.63 

2.  71 

1.  03 

ALOo 

2. 14 

I *50 

iTraces. 

. 10 

ilA2v3  ----- 

Fe203 



F 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

100.  00 

Salinity,  parts  per  million.  . . . 

182 

170 

192 

152 

144 

195 

» J.  Thoulet  (Bull.  Soc.  gdog.,  7th  ser.,  vol.  15, 1894,  p.  557)  gives  partial  analyses  of  lakes  in  the  Vosges. 
For  French  lakes  in  general,  see  A.  Delebecque,  Les  lacs  frangais,  Paris,  1898.  See  also  A.  Delebecque  and 
L.  Duparc,  Compt.  Rend.,  vol.  114,  1892,  p.  984;  and  Arch.  sci.  phys.  nat.,  3d  ser.,  vol.  27,  1892,  p.  569; 
VOl.  28,  1892,  p.  502. 


LAKES  AND  RIVERS. 


95 


In  the  mountain  complex  of  the  Alps,  including  the  Bavarian  and 
Austrian  highlands,  several  great  rivers  of  western  and  central  Europe 
take  their  rise.  At  their  headwaters  are  many  small  lakes,  and  these 
have  been  exhaustively  studied.  In  an  elaborate  thesis  by  F.  E. 
Bourcart,1  analyses  are  given  of  33  Alpine  lakes,  and  each  one  is  dis- 
cussed in  the  light  of  its  geologic  relations.  The  following  table  gives 
a selection  from  this  mass  of  material. 

Analyses  of  water  from  Alpine  lakes. 

A.  Lac  Taney,  Canton  Valais.  In  the  Cretaceous.  A typical  calcareous  water.  Drains  into  the  Rhone. 

B.  Lac  de  Champex,  Canton  Valais.  In  microgranulite  and  protogine.  A type  of  the  water  derived 
from  igneous  rocks.  Drains  into  the  Rhone. 

C.  Lac  Noir,  Canton  Fribourg.  In  the  Flysch,  but  also  fed  by  waters  from  the  Trias.  Drains  through 
the  Aar  into  the  Rhine. 

D.  Lac  d’Amsoldingen,  Canton  Berne.  In  the  Flysch  and  Molasse.  Drains  into  the  Aar. 

E.  Lac  Ritom,  above  Airolo,  Canton  Ticino.  Surface  water. 

F.  Lac  Ritom,  lower  layer  of  water,  below  13  meters  depth.  This  lake  drains  southward  into  Italy. 


A 

B 

c 

D 

E 

F 

co3 

53.  21 

29.  96 

26.  94 

53.  84 

20.  00 

2.  29 

so4 

5.  29 

11.93 

38.  35 

3.  32 

47.  27 

69.  89 

Cl  

.87 

9.  96 

.57 

1.  77 

Ca 

33.  74 

19. 15 

29.  65 

33.  30 

22. 12 

22. 15 

Mg 

1.  99 

1.  32 

2.  27 

1.  76 

5.  47 

4.  96 

Na 

.75 

8. 32 

.64 

1.  80 

1.  22 

.09 

K 

.74 

4.  00 

.38 

.93 

1.  64 

.15 

Si02 

2.  37 

13.  93 

.71 

3.  03 

2.  28 

.42 

Al203-f-Fe203a 

v 1.04 

1.43 

.49 

.25 

Trace. 

.05 

100.  00 

100.  00 

100.  00 

100.  00 

100. 00 

100.  00 

Salinity,  parts  per  million 

122 

27 

| 

270.5 

201.7 

122.5 

2,  373 

o Including  traces  of  manganese. 


Analyses  A to  D well  illustrate  the  differences  in  origin  of  the 
waters.  E and  F represent  a lake  of  extraordinary  character.  It 
contains  two  distinct  layers  of  water  of  quite  dissimilar  nature.  The 
upper  layer  is  merely  the  water  of  its  affluents,  which  flows  over  the 
denser  water  below.  The  latter  is  essentially  a strong  solution  of 
calcium  sulphate,  derived  from  neighboring  beds  of  gypsum.  The 
two  layers  do  not  commingle,  and  the  lower  one  has  a distinctly 
higher  temperature  than  the  upper,  except  at  the  surface.  At  11 
meters  depth  the  temperature  is  5.1°;  at  the  bottom  it  is  6.6°.  A 
similar  phenomenon,  but  even  more  strongly  marked,  is  shown  by 
the  Illyes  Lake  in  Hungary,  which  will  be  described  later. 

The  following  table  contains  recalculated  analyses  of  water  from 
several  lakes  in  the  Bavarian  and  Austrian  highlands.2  They  belong 
to  the  basin  of  the  Danube,  into  which  they  drain  through  the  valleys 

1 Thesis,  Univ.  Geneva,  1906.  Les  lacs  alpines  suisses,  4°,  130  pp.  A few  selected  analyses  appear  in 
Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  15, 1903,  p.  467. 

2 See  also  incomplete  analyses  of  the  Stamberger,  Kochel,  and  Walchen  lakes  by  J.  Gebbing,  Jahresb. 
Geol.  Gesell.  Miinchen,  1901-2,  p.  55.  Also  W.  Ule’s  monograph  on  the  Wiirmsee,  published  by  the  Verein 
fur  Erdkunde,  Leipzig,  in  1901. 


96 


THE  DATA  OF  GEOCHEMISTRY. 


of  the  Isar,  Inn,  and  Traun.  One  Italian  lake  is  included  in  this 
table  on  account  of  its  Alpine  relationship. 

Analyses  of  water  from  Bavarian  and  AiLStrian  lakes. 

A.  Walchensee. 

B.  Kochelsee. 

C.  Stamberger-  or  Wiirmsee. 

D.  Tegemsee.  Mean  of  two  analyses. 

E.  Schliersee.  Mean  of  two  analyses. 

F.  Chiemsee.  Mean  of  five  analyses. 

G.  Konigsee.  Mean  of  two  analyses. 

Analyses  A to  G by  A.  Schwager,  Geognost.  Jahresbefte,  1894,  p.  91;  1897,  p.  65.  All  these  lakes  are  in 
the  Bavarian  highlands. 

H.  Hallstattersee,  Upper  Austria.  Mean  of  two  analyses,  summer  and  winter  samples,  by  N.  von 
Lorenz,  Mitt.  Geog.  Ges.  Wien,  vol.  41, 1898,  p.  1. 

I.  Traun-  or  Gmundenersee,  Upper  Austria.  Analysis  by  R.  Godeflroy,  Jahresb.  Chemie,  1882,  p. 
1623.  Organic  matter  rejected. 

J.  Lago  di  Garda,  northern  Italy.  Analysis  by  Schwager,  Geognost.  Jahreshefte,  1894,  p.  91.  Analyses 
of  Italian  waters  seem  to  be  rare.  For  partial  analyses  of  three  small  streams  near  Oderzo,  in  northwest- 
ern Italy,  see  M.  Spica  and  G.  Halagian,  Gazz.  chim.  itaL,  voL  17,  1887,  p.  317. 


A 

B 

c 

D 

E 

co3 

50.83 

48.  46 

54.  69 

48.  25 

50.  74 

so4 

11.  62 

14.  78 

4.  73 

15.  24 

11. 15 

Cl 

.58 

.48 

1.  57 

.58 

. 55 

NO, 

.07 

Ca 

26.49 

24.  66 

24.  09 

26. 17 

26.  94 

Mg 

7.00 

6. 17 

7.  98 

6.  56 

5.  78 

Na 

.99 

1.  52 

.96 

1. 10 

1.  05 

K 

. 58 

1.  52 

2. 14 

.88 

1.  07 

Si02 

1.00 

1.  60 

1. 26 

.44 

1.  62 

AI2O3 

} .91 

.73 

2.44 

.73 

1.  05 

Fe203 

.04 

.07 

. 05 

. 05 

Ti02 

.04 

100.  00 

100.00 

100.00 

100.00 

100.00 

Salinity,  parts  per  million * 

121 

227 

139 

207 

190 

F 

G 

H 

I 

J 

49.  58 

50.  59 

38.  43 

51.68 

53.  29 

soj 

12.  09 

6.54 

9.43 

8.  99 

4.17 

Cl.. 

1.  92 

.65 

10.  94 

2.44 

3. 13 

PCL 

. 05 

Ca 

23.  22 

32.  65 

26.  37 

27.54 

24  56 

Mg 

8. 17 

3.  41 

3.  88 

5.  21 

6.  66 

Na 

2. 18 

.70 

6.50 

2.  82 

2.  49 

K 

.97 

1.  24 

2.  77 

2. 01 

Si02 

.92 

1.  73 

1. 31 

.31 

2.  33 

A1203 

.89 

2. 33 

1 .37 

\ 1.01 

1.  21 

Fe203 

.06 

.11 

/ 

/ 

. 15 

100.00 

100.00 

100.00 

100.00 

100.00 

Salinity,  parts  per  million 

191 

98 

137.5 

99 

178 

These  lakes  are  surrounded  by  sedimentary  rocks,  and  all  except 
that  of  Hallstatt  are  much  alike  chemically.  Magnesium,  with  two 
exceptions,  is  decidedly  above  its  average  amount  in  lake  and  river 
waters,  a fact  which  is  due  to  the  presence  of  much  dolomite  in  the 
lake  region.  The  high  chlorine  and  sodium  of  the  Hallstatt  lake  are 
derived  from  neighboring  salt  beds. 


LAKES  AND  RIVERS. 


97 


For  the  Rhine  and  its  tributaries  a good  number  of  analyses  are 
available.®  The  table  following  contains  a part  of  them,  recalculated 
to  modern  standards,  with  organic  matter  rejected. 

Analyses  of  water  from  the  Rhine  and  its  tributaries. 

A.  Lake  of  Zurich.  Analyses  by  Moldenhauer,  1857,  cited  by  Roth,  Allgemeine  und  chemische  Geologie, 
vol.  1,  p.  456. 

B.  The  Aar  at  Bern.  Analysis  by  J.  S.  F.  Pagenstecher,  1837,  cited  by  Roth. 

C.  The  Rhine  at  Basel.  Analysis  by  Pagenstecher,  loc.  cit. 

D.  The  Rhine  at  Strasburg.  Analysis  by  H.  Sainte-Claire  Deville,  Annales  chim.  phys.,  3d  ser.,  vol.  23, 
1848,  p.  42. 

E.  The  Rhine  near  Mainz.  Analysis  by  E.  Egger,  Notizbl.  Ver.  Erdkunde,  Darmstadt,  1887,  p.  9.  An 
earlier  analysis  is  in  the  volume  for  1886,  p.  21. 

F.  The  Rhine  at  Cologne.  Mean  of  seven  analyses  by  H.  Vohl,  Jahresb.  Chemie,  1871,  p.  1§23. 

G.  The  Rhine  at  Arnheim.  Analysis  by  J.  W.  Gunning,  Jahresb.  Chemie,  1854,  p.  767. 

H.  The  White  Main. 

I.  The  Red  Main. 

J.  The  united  Main.  Analyses  H,  I,  and  J by  E.  Spaeth,  Inaug.  Diss.  Erlangen,  1889.  Spaeth  also 
gives  analyses  of  water  from  the  Rodach,  Haslach,  and  Kronach,  tributaries  of  the  Main. 

K.  The  Main  above  Offenbach.  Analysis  by  C.  Merz,  Jahresb.  Chemie,  1866,  p.  9S7. 

L.  The  Main  at  Frankfort.  Analysis  by  G.  Kerner.  Cited  by  F.  C.  Noll,  Inaug.  Diss.  Tubingen,  1866, 
from  a report  published  at  Frankfort  in  1861. 

M.  The  Main  near  its  mouth.  Analysis  by  E.  Egger,  Notizbl.  Ver.  Erdkunde,  Darmstadt,  1886,  p.  17. 

N.  The  Nahe  at  Bingen.  Analysis  by  Egger,  idem,  1887,  p.  5. 


A 

B 

c 

D 

E 

F 

G 

co3 

51.  64 

48.  60 

53.  05 

36.  69 

41. 12 

46.  96 

35.  79 

S64 

7.  90 

14.  63 

7.  96 

8.  38 

11. 13 

12.  95 

12.  23 

Cl 

.59 

.08 

.57 

.52 

3.  65 

4.  22 

7. 10 

NO,  

1.  00 

1.  63 

po,  

(6) 

31.  81 

.24 

Ca 

29. 10 

30.  54 

33.  53 

25.  30 

26.  48 

26. 18 

Mg 

5. 11 

4.  71 

2.  87 

.61 

3.  95 

6. 15 

3.  84 

Na -- 

1.  60 

} -18 

| .73 

2. 17 

2.  08 

2.  73 

6.  34 

K 

2.  00 

.66 

1.  05 

.02 

4.  04 

Si02 

2.  06 

1.26 

1.  29 

21.  07 

2.  69 
} .89 

. 15 

3.  59 
| .89 

A1203 

1.  09 

.04 



2.  51 

.06 

— ~ a - - 

* 

Salinity, 

million . 

parts 

per 

100.  00 
141 

100.  00 
213 

100.  00 
166 

100.  00 
232 

100.  00 
178 

100.  00 
190 

100.  00 
159 

H 

I 

J 

K 

L 

M 

N 

C03 

36. 15 

41.  83 

39.  69 

34.  39 

35.  85 

29.  43 

35.  43 

S04 

16.  33 

14.  89 

15.  46 

26.  41 

24.  69 

22.  43 

7.  91 

Cl 

5.  60 

5.  00 

4.  76 

4.  69 

1.  91 

8.  39 

15.  37 

NO,  

1.  66 

.71 

1.  43 

1. 12 

2.  61 

(a) 

19.  57 

. 41 

Ca 

22.  58 

23.  91 

23.07 

23.  56 

21.  81 

18.  64 

Mg 

4.  26 

5.  85 

5.  52 

6.  90 

7.  30 

5.  77 

5.  54 

Na 

4. 10 

2.  64 

2.  86 

1.  73 

1.  25 

6.  64 

4.  28 

K 

1.  66 

1.  75 

2.  04 

Trace. 

1.  44 

5.  40 

Si02 

6.  47 
} 1.19 

J 

3. 10 

} .32 

J 

4.  69 
} .48 

1.  90 
} .42 

6.  67 

i ro 

4. 12 

4.  05 

A1203 

. 99 

FO..O 

?•  . 52 

.10 

\ . 36 

0 

J 

J 

) 

Salinity, 

million  _ 

parts 

per 

100.  00 
126 

100.  00 
194 

100.  00 
147 

100.  00 
240 

100.  00 
221 

100.  00 
299 

100.  00 
182 

a For  an  imperfect  analysis  of  the  Bodensee  (Lake  of  Constance)  see  II.  Bauer  and  H.  Vogel,  Jahres- 
hefte  Ver.  vaterl.  Naturk.  Wurttemberg,  vol.  48,  1892,  p.  13.  Many  partial  analyses  of  waters  from 
Rhine  tributaries  are  given  by  E.  Egger,  Notizbl.  Ver.  Erdkunde,  Darmstadt,  1908,  p.  105;  1909,  p.  87. 
These  two  papers  are  on  the  hydrochemistry  of  the  Rhine. 
b Included  with  AI2O3,  etc. 


97270°— Bull.  616—16 7 


98 


THE  DATA  OF  GEOCHEMISTRY, 


These  analyses  are  evidently  of  very  unequal  value.  The  high 
silica  found  in  the  Khine  by  Deville  is  suspicious,  and  yet  Deville  was 
an  accurate  manipulator. 

One  of  the  most  thorough  hydro  chemical  studies  ever  made  of  any 
European  river  system  is  that  of  the  Elbe  and  its  Bohemian  tribu- 
taries by  J.  Hanamann.1  In  two  memoirs  upon  the  waters  of  Bo- 
hemia he  gives  over  one  hundred  and  twenty  analyses,  tracing  nearly 
all  of  the  important  streams  in  the  upper  Elbe  basin  to  their  sources, 
correlating  each  one  with  the  geological  formations  in  which  it  rises, 
and  showing  the  effect  produced  by  their  union.  Of  the  Elbe  itself 
thirteen  analyses  are  given;  of  the  Eger,  eight;  of  the  Iser,  six, 
and  so  on.  From  this  wealth  of  material  only  a small  part  can  be 
reproduced  here,  recalculated  as  usual  to  our  uniform  standard  and 
beginning  with  the  tributaries.  A few  analyses  are  also  given  from 
a rich  mass  of  data  derived  from  other  authorities.2 


Analyses  of  the  Elbe  and  its  tributaries. 

A.  The  Moldau  above  Prague.  Mean  of  three  analyses  by  A.  BSlohoubek,  Sitzungsb.  K.  bohm.  Gesell. 
Wiss.,  1876,  p.  27. 

B.  The  Moldau  below  Kralup. 

C.  The  Adler  near  its  mouth. 

D.  The  Iser  at  its  source. 

E.  The  Iser  near  its  mouth. 

F.  The  Eger  at  its  source.  Analysis  by  E.  Spaeth,  Inaug.  Diss.,  Erlangen,  1889. 

G.  The  Eger  above  Konigsberg. 

H.  The  Eger  near  its  mouth,  at  Bauschowitz. 


A 

B 

c 

D 

E 

F 

G 

H 

co3 

32.  86 

34.  52 

46.  23 

21.  29 

47.74 

11.  68 

26.  64 

26.84 

so4 

11.  95 

10.  20 

7.44 

6.  94 

6.  55 

7.  06 

19.  22 

27.  45 

Cl 

10.  69 

10. 17 

3.20 

11.  08 

3.  00 

23.  85 

8. 16 

6.  55 

NO, 

1.  76 

1.  43 

1.  24 

. 78 

. 50 

.46 

. 47 

.36 

Ca 

13.  52 

16.  71 

26.  73 

8. 14 

28. 15 

6.  79 

12.  86 

15.  42 

Mg 

4.  88 

4.  64 

2.  45 

2. 19 

2.  47 

2.  24 

3.  51 

4.  05 

Na 

10.  22 

8.  40 

4.  29 

13.  86 

3.  71 

11.  93 

11.  66 

10.  46 

K 

5. 19 

4.  05 

2.  38 

5.  54 

2.  01 

6.  71 

2.  98 

3.  50 

Si02 

8.  96 

4.  99 

5.  53 

28.  39 

4.  96 

26.  07 

12. 19 

4. 17 

(Al,Fe)A 

1.  26 

4.  20 

.32 

1.  33 

.63 

3.  67 

2.  28 

1. 10 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

74 

104 

195 

16 

183 

17 

80 

176 

1 Archiv  Natur.  Landesdurchforschung  Bohmen,  vol.  9,  No.  4,  1894;  vol.  10,  No.  5,  1898. 

2 Other  data  relative  to  the  Elbe  and  its  tributaries  are  given  by  J.  J.  Breitenlohner  (Verhandl.  K.-k. 
geol.  Reichsanstalt,  1876,  p.  172)  and  F.  Ullik  (Abhandl.  K.  bohm.  Gesell.  Wiss.,  6th  ser.,  vol.  10,  1880). 
For  analyses  of  the  Elbe  at  Lauenburg,  Hamburg,  and  Neufeldt,  see  H.  Siissenguth,  cited  by  F.  Schucht, 
Jahrb.  K.  preuss.  geol.  Landesanstalt,  vol.  25, 1897,  p.  442.  An  analysis  of  the  Moldau  at  Prague  by  F.  Stolba 
is  given  in  Jour.  Chem.  Soc.,  vol.  27,  1874,  p.  971.  For  an  analysis  of  River  Radbuza  above  Pilsen,  see  the 
same  author,  Jahresb.  Chemie,  1880,  p.  1521.  According  to  A.  Schwager  (Geognost.  Jahreshefte,  1891,  p. 
35),  the  Saale  carries  out  of  Bavaria,  annually,  17,380,000  kilograms  of  dissolved  matter,  and  the  Eger  carries 
14,000,000  kilograms.  For  additional  data  on  the  waters  of  the  Elbe  and  the  Saale,  see  R.  Kolkwitz  and 
F.  Ehrlich,  Mitt.  K.  Priifungsanstalt  fur  Wasserversorgung,  Heft  9,  Berlin,  1907,  p.  1. 


LAKES  AND  RIVERS. 


99 


Analyses  of  the  Elbe  and  its  tributaries — Continued. 

I.  The  Saale  near  its  source.  Analysis  hy  Spaeth,  loc.  cit. 

J.  The  Saale  at  Blankenstein.  Analysis  by  A.  Schwager,  Geognost.  Jahreshefte,  1891,  p.  91.  Sch wager 
also  gives  analyses  of  the  Saale  at  three  other  points,  of  its  tributaries  the  Pulsnitz,  Schwesnitz,  Regnitz, 
and  Selbitz,  of  the  Eger,  and  of  the  upper  Main. 

K.  The  Weisswasser,  one  of  the  two  chief  sources  of  the  Elbe. 

L.  The  Elbe  at  Celakowitz,  above  the  mouth  of  the  Iser. 

M.  The  Elbe  at  Melnik,  above  the  mouth  of  the  Moldau. 

N.  The  Elbe  at  Leitmeritz,  above  the  Eger. 

O.  The  Elbe  at  Lobositz,  below  the  Eger.  ’ 

P.  The  Elbe  at  Tetschen,  near  the  Bohemian  frontier. 

The  analyses  are  by  Hanamann,  except  where  otherwise  stated. 


I 

J 

K 

L 

M 

N 

0 

P 

co3 

14.  71 

27.  01 

16.  84 

45.  87 

45.04 

40.  27 

38.  41 

35.  88 

S04 

5.  84 

20.  94 

12.  86 

8.  95 

8.  88 

10.  86 

12.  45 

14.  88 

Cl 

no2 

19.  40 

10.  34 
.43 

7.  61 

3.  27 

3.  56 

5.  00 

5.  96 

5.  87 

N03 

1.  62 

4.  28 

. 90 

.94 

1.  22 

1.  28 

1.  40 

Ca 

4.  02 

14.- 19 

8.  76 

26.  41 

26.  37 

22.  87 

22. 19 

20.  92 

Mg 

6.  37 

5.  98 

2. 19 

3.  21 

2.  77 

3.  24 

3.  23 

3.  63 

Na 

9.  90 

8.  98 

11.  06 

3.  93 

4.  02 

5.  62 

6.  35 

6.  09 

K 

4.  66 

2.  99 

2.  01 

2.  46 

3.  06 

2.  79 

2.  87 

3. 16 

Si02 

35. 10 

4.  79 

31.  21 

4.  09 

4.  66 

7.  27 

6.  42 

7. 13 

A1203 

F6203 

j>Traces 

1.  88 
.85 

} 3. 18 

} .91 

| .70 

CO 

00 

} .84 

} 1.04 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

17 

117 

13 

221 

205 

157 

153 

148 

At  their  sources  these  streams  are  characterized  by  very  low 
salinity  and  a high  proportion  of  silica  and  alkalies.  They  grad- 
ually increase  in  salinity,  and  by  blending  one  with  another  approach 
more  and  more  nearly  the  normal  type  of  river  waters.  The  Eger 
is  unusually  rich  in  alkalies  and  chlorine.  The  minor  tributaries  of 
the  Elbe  vary  widely  in  composition,  but  in  general  calcium  and  car- 
bonates are  the  chief  constituents.  In  the  Schladabach,  however, 
a small  affluent  of  the  Eger,  sodium  and  the  sulphuric  radicle  pre- 
dominate, and  in  the  Chodaubach,  another  tributary  of  the  same 
river,  there  is  a solution  of  gypsum  with  no  carbonates.  When  the 
Schladabach  enters  the  Franzensbad  moor  it  carries  94  parts  per 
million  of  fixed  mineral  matter;  it  leaves  the  moor  with  a load  of 
1,542  parts.  This  change  serves  to  show  the  importance  of  ground 
water  in  modifying  the  chemical  character  of  a stream — a point 
already  noticed  in  studying  the  rivers  of  Colorado.  For  details  con- 
cerning these  and  many  other  small  tributaries  of  the  Elbe  basin, 
Hanamann’s  original  memoirs  should  be  consulted.  They  will  well 
repay  careful  study. 


100 


THE  DATA  OF  GEOCHEMISTRY. 


One  table  of  analyses  given  by  Hanamann  is  peculiarly  instructive. 
It  consists  of  averages,  showing  the  composition  of  Bohemian  waters 
as  related  to  the  rocks  from  which  they  flow.  These  averages, 
reduced  to  the  standard  herein  adopted,  are  as  follows: 

Average  composition  of  Bohemian  waters,  classified  according  to  source. 

A.  From  phyllite,  five  analyses. 

B.  From  granite,  six  analyses. 

C.  From  mica  schist,  six  analyses. 

D.  From  basalt,  four  analyses.  * 

E.  From  the  Cretaceous,  four  analyses. 


A 

B 

c 

D 

E 

co3 

35.  94 

30.  49 

32.14 

46.  85 

33.  01 

so4 

6.  45 

14. 12 

12.  86 

7.  94 

27.  69 

Cl 

10. 15 

6.  39 

7.  24 

1.  66 

2.  87 

Ca 

11.  91 

11.  89 

12.  61 

20.  07 

22. 12 

Mg 

5.  02 

3.  58 

5.  08 

5.  76 

5.  29 

Na 

11.  20 

10.  57 

10.  85 

6.  22 

3.  43 

K 

4.  39 

5.  63 

4.  22 

3.  20 

2.  72 

Si02 

14.  94 

17.  33 

15.  00 

7.  67 

2.  87 

Fe203 

.63 

Salinity,  parts  per  million 

100.  00 
48 

100.  00 
65 

100.  00 
74 

100.00 

343 

100.00 

603 

The  high  figures  for  silica  and  sodium  in  the  first  three  of  these 
analyses  reflects  the  origin  of  the  waters  in  areas  of  crystalline  rocks. 

The  water  of  the  Danube  and  its  tributaries  above' Vienna  has  been 
the  subject  of  many  investigations.  The  following  table  contains  a 
selection  from  among  them.  Except  when  otherwise  stated  the 
analyses  are  by  A.  Schwager.1 


1 Geognost.  Jahreshefte,  1893,  p.  84.  In  Schwager’s  analyses  the  iron  is  given  as  FeO.  It  is  here  recal- 
culated into  Fe203.  Traces  of  Mn,  Ti02,  and  P205  are  ignored. 


LAKES  AND  RIVERS. 


101 


Analyses  of  water  from  the  Danube  and  its  tributaries. 

A.  The  Woemitz  above  Wassertriidingen,  Bavaria. 

B.  The  Altmuhl  above  Herrieden,  Bavaria. 

Analyses  A,  B,  by  E.  Muller,  Inaug.  Diss.,  Erlangen,  1893.  Other  dissertations  upon  Bavarian  waters 
are  by  E.  Kohn,  1889;  M.  Lechler,  1892;  J.  Mayrhofer,  1885;  all  from  Erlangen.  Spaeth’s  dissertation  has 
already  been  cited.  There  is  also  one  from  W iirzburg,  by  F.  Pecher,  1887.  In  each  dissertation  the  waters 
are  studied  geologically. 

C.  TheNaab. 

D.  The  Regen.  For  older  but  incomplete  analyses  of  the  Regen,  Ilz,  and  Rachelsee,  see  H.  S.  Johnson, 
Liebig’s  Annalen,  vol.  95,  1855,  p.  230.  An  analysis  of  Danube  water  taken  at  Vienna  was  made  by  G. 
Bischof  in  1852.  An  analysis  of  the  Naab  at  its  source  is  given  by  Spaeth,  loc.  cit. 

E.  The  Isar.  For  an  analysis  of  the  Isar  at  Munich,  see  G.  Wittstein,  Jahresb.  Chemie,  1861,  p.  1097. 

F.  The  Vils  at  Vilshofen.  Analysis  by  C.  Metzger,  Inaug.  Diss.,  Erlangen,  1892.  Metzger  also  gives 
analyses  of  the  Regen,  Naab,  Ilz,  and  Inn,  of  the  two  Arber  Lakes  and  Black  Lake  at  the  headwaters  of 
the  Regen,  of  the  Luhe,  Pfreimt,  and  lesser  Vils,  tributaries  of  the  Naab,  and  of  the  Danube  at  five  differ- 
ent points.  His  work  curiously  overlaps  or  coincides  with  that  published  by  Schwager.  It  includes 
geologic  correlations. 

G.  The  Ilz. 

H.  The  Inn. 

I.  The  Erlau. 

J.  The  Danube  above  the  Naab. 

K.  The  Danube  above  Regensburg. 

L.  The  Danube  above  the  Ilz  and  Inn. 

M.  The  Danube  12  kilometers  below  Passau. 

N.  The  Danube  at  Greifenstein,  20  kilometers  above  Vienna.  Mean  of  23  analyses  by  J.  F.  Wolfbauer, 
of  samples  taken  at  intervals  of  16  days  throughout  the  year  1878.  Monatsh.  Chemie,  vol.  4,  1883,  p.  417. 

O.  The  Danube  at  Budapest.  Analysis  by  M.  Ballo,  Ber.  Deutsch.  chem.  Gesell.,  vol.  11,  1878,  p.  441. 
Bicarbonates  are  here  reduced  to  normal  salts. 


A 

B 

C 

D 

E 

F 

G 

H 

CO,  

41. 14 

12.  64 

47.  23 

27.  55 

49.  53 

52. 43 

15.  87 

44.  85 

so4 

19.  36 

50.31 

9.54 

11. 14 

12.07 

3.  29 

18.  26 

14.  40 

Cl 

3.  66 

1.  93 

4. 42 

5.  88 

.46 

2. 01 

2.  78 

2.  20 

NO,  

.11 

.37 

.59 

.09 

NO,  

.23 

. 71 

.59 

. 28 

Ca 

21.  81 

23.  63 

20.  70 

12.  07 

25.  65 

21.  81 

4.  37 

25. 10 

Us 

7.  54 

1. 15 

8. 14 

4.  02 

6.04 

7.  85 

2. 18 

6.  23 

Na 

2.  37 

1.  26 

3. 11 

6.  50 

2. 14 

3.  67 

9.  92 

2.  20 

K 

2.  29 

7.  40 

1.  81 

4.  37 

1.41 

4.  79 

4.  37 

1. 13 

Si02 

1.  28 
} .55 

.98 

3.  51 

19.  50 

1.  45 

3.  72 

1 

32.  54 

2.  89 

ALO, 

. 90 

6.  50 

1.  04 

7.  94 

.44 

Fe,0,  

^ . 70 

.30 

1.  39 

.21 

} *43 

.59 

.19 

J 

J 

Salinity,  parts  per 
million 

100.  00 
325 

100.  00 
461.5 

100.  00 
110 

100.  00 
38.3 

100.  00 
203.5 

100.  00 
217 

100.  00 
30 

100.  00 
166 

I 

J 

K 

L 

M 

N 

O 

co3 

16.  77 

53.  51 

51.  70 

50. 16 

48.  29 

50. 10 

49.03 

S04 

14.  78 

7. 11 

8.  54 

8.  85 

10.  52 

8.  81 

13.  69 

Cl 

N02 

5.  75 
.41 

1.  20 

1.  31 
.06 

1.  20 
.06 

2.  25 
.06 

1.  44 

1.40 

NO, 

.41 

.23 

.25 

2. 14 

1. 19 

1.  24 

Ca 

8.  62 

26.  88 

27.  40 

26.  59 

25.  46 

26.  28 

26.  78 

Mg 

1.  50 

6.  21 

6.  00 

6.  01 

6.  31 

5.  95 

6.  97 

Na 

8.  95 

1.47 

1. 12 

1.  34 

1.  84 

1.  69 

.93 

K 

4.  37 

.96 

. 72 

1. 12 

1.  36 

.94 

Si02 

28.  73 
9.  30 

1.59 

.78 

2.  42 
.42 

2.  01 
.46 

2.  20 
.46 

3.  35 

1.  20 

Fe203 

.41 

.06 

.06 

.06 

.06 

.20 

Trace. 

Salinity,  parts  per 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

million 

47 

217 

204 

201 

184 

167 

151 

102 


THE  DATA  OF  GEOCHEMISTRY. 


Although  the  tributary  waters  (which  should  include  the  waters  of 
the  Bavarian  lakes  as  given  in  a previous  table)  show  great  differ- 
ences in  character,  the  regularity  exhibited  by  the  Danube  itself  is 
very  striking.  The  water  of  the  Danube  is  essentially  a calcium 
carbonate  water,  but  the  sulphates  in  it  tend  to  increase  in  going 
downstream.  According  to  Wolfbauer,  the  river  carries  past  Vienna 
a daily  charge  of  25,000  metric  tons  of  matter  in  solution.  This  is 
equivalent  to  an  annual  load  of  9,125,000  metric  tons.  The  mechani- 
cal sediment  transported  at  the  same  time  is  only  three-fifths  as 
much. 

Analyses  of  a few  more  waters  of  central  Europe  are  given  in  tne 
next  table.1 

Analyses  of  water  from  central  Europe. 

A.  The  Weser  at  Return,  41  kilometers  above  its  mouth.  Mean  of  two  analyses  by  F.  Seyfert,  Inaug. 
Diss.,  Rostock,  1893.  Contamination,  tidal  or  other,  is  evident. 

B.  The  Oder  near  Breslau.  Sample  taken  at  high  water.  Analysis  by  O.  Luedecke,  Das  Wasser  des 
Oderthales,  etc.,  Leipzig,  1907.  Another  sample  at  low  water  showed  contamination.  Other  analyses  of 
ground  and  well  waters  are  given. 

C.  The  Vistula  at  Culm.  Analysis  by  G.  Bischof,  Lehrbuch  der  chemischen  und  physikalischen  Geo- 
logie,  2d  ed.,  vol.  1,  1863,  p.  275. 

D . Balaton-  oi  Plattensee,  Hungary . Analysis  by  L.  von  Ilosvay , in  Resultate  der  wissensch.  Erforsch. 
Balatonsees,  vol.  1,  1898,  p.  6.  Reduced  from  bicarbonate  form. 


A 

B 

C 

D 

CO, 

22. 13 

17.  92 

47.  78 

38.  80 

so4 

22.  77 

23.  60 

9.  49 

21. 47 

ci : 

17.  54 

5. 46 

2.  70 

2.  98 

Ca 

18.  50 

28.  09 

28.  52 

8.  87 

Mg 

3. 11 

3.  28 

4.  44 

12.  81 

Na 

10.  25 

6.  45 

1.  57 

6. 14 

K 

1.  95 

5.  35 

.39 

3.  27 

Si02 

3.  75 

6.  57 

4.  49 

4.  48 

ALO, 

.82 

Fe203 

| 3.28 

} . 62 
) 

.36 

Salinity,  parts  per  million 

100.  00 

281 

100.  00 
91.5 

100.  00 
178 

100.  00 
512 

The  Balaton  Lake  has  an  exceptional  composition.  The  other 
analyses  in  the  table  are  of  minor  importance.  The  rivers  repre- 
sented by  them  need  more  study. 

1 For  three  small  lakes  near  Halle  and  Eisleben  see  W.  Ule,  Die  Mansfelder  Seen,  Inaug.  Diss.,  Halle, 
1888.  A memoir  by  J.  Wolff  (Chemische  Analyse  der  wichtigsten  Fliisse  und  Seen  Mecklenburgs,  Wies- 
baden, 1872)  contains  analyses  of  several  small  rivers  and  lakes.  See  also  A.  Jentzsch  ( Abhandl.  K.  preuss. 
geol.  Landesanstalt,  new  ser.,  Heft  51,  p.  98, 1912)  for  other  analyses  of  North  German  lakes. 


LAKES  AND  RIVERS. 


103 


For  Sweden  a single  table  of  analyses  must  suffice,  reduced  from 
the  data  given  by  O.  Hofman-Bang.1  The  month  in  which  the 
water  was  taken  is  given  for  each  analysis. 


Analyses  of  Swedish  waters. 


A.  The  Byske-elf,  July. 

B.  The  Klarelf,  April. 

C.  The  Klarelf,  October. 

D.  The  Ljusnan,  June. 


E.  The  Indalself,  June. 

F.  The  Fyris,  April. 

G.  The  Fyris,  October. 


A 

B 

c 

D 

E 

F 

G 

co3 

50.  60 

39.  44 

38.  68 

43. 11 

43.  93 

29. 14 

14.  30 

so4 

4.  01 

5.  85 

7.  63 

4.  57 

7.  24 

24.  58 

39.  08 

Cl 

4.  75 

5. 10 

2.  24 

4.  53 

3.  81 

3.15 

3.  27 

NO, 

.46 

Trace. 

Trace. 

.13 

P04 

Trace. 

Ca 

11.57 

14.  95 

11.  67 

17.  34 

18.  04 

27. 49 

27.  99 

Mg 

.64 

.51 

.51 

.24 

.38 

1.  69 

2.11 

Na 

9.  90 

I 18.  77 

8.  42 

9.  05 

11.  33 

2.  92 

3.  33 

K 

9.  00 

/ 

3.  78 

5.  87 

4.  89 

2.  36 

1.  73 

Si02 

7.  57 

13.  09 

19. 17 

13.  70 

5.  78 

6.  00 

6. 19 

(Al,Fe)203 

1.  96 

2.  29 

7.  44 

1.  59 

4.  60 

2.  67 

1.  87 

100. 00 

100. 00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

19.  25 

27.6 

25.5 

24.8 

33.7 

170.3 

178.1 

The  remarkably  low  magnesia  and  high  proportion  of  alkalies  are 
distinctive  peculiarities  of  these  waters.  The  variability  of  the 
Fyris  affords  another  good  example  of  the  fact  that  little  significance 
can  be  attached  to  a single  analysis  of  a river  water. 


i Bull.  Geol.  Inst.  Upsala,  vol.  6, 1905,  p.  101.  In  addition  to  his  own  work  the  author  cites  other  analyses 
of  Swedish  river  and  spring  waters.  Solvent  denudation  in  Norrland  he  estimates  at  9 metric  tons  per 
square  kilometer,  or  23.3  tons  per  square  mile. 


104 


THE  DATA  OF  GEOCHEMISTRY. 


Of  Russian  fresh  waters  only  a few  analyses-  are  available,  as 
follows : 


Analyses  of  Russian  waters. 


A.  The  Angemsee.  Mean  of  two  analyses. 

B.  The  Babitsee. 

Analyses  A and  B by  F.  Ludwig,  Die  Kiistenseen  des  Rigaer  Meerbusens,  published  by  the  Naturforscher- 
Verein  at  Riga,  1908.  This  memoir  contains  analyses  of  27  small  lakes  near  Riga  and  close  to  the  Gulf  of 
Riga.  Most  of  them  are  of  calcium  carbonate  waters,  but  in  a few  the  sulphate  is  predominant. 

Analyses  C to  G are  all  by  C.  Schmidt  of  Dorpat. 

C.  Lake  Onega.  Mel.  chim.  phys.  Acad.  St.  Petersburg,  vol.  11,  1882,  p.  637. 

D.  Lake  Peipus.  Bull.  Acad.  St.  Petersburg,  vol.  24,  1878,  p.  423.  Schmidt  has  also  analyzed  water 
from  the  smallrivers  Embach  and  Velikaya,  tributary  to  Lake  Peipus.  See  Mel.  chim.  phys.,  vol.  8, 1873. 
p.  494. 

E.  The  Dwina  at  Archangel.  Analysis  cited  by  J.  Roth,  Allgemeine  chemische  Geologie,  vol.  1,  p.  457. 

F.  River  Om  above  Omsk.  Mem.  Acad.  St.  Petersburg,  vol.  20,  No.  4,  1873. 

G.  Lake  Baikal,  Siberia.  Same  reference  as  analysis  B. 

H.  The  Dniester  near  Odessa.  Analysis  by  J.  G.  N.  Dragendorff,  Jahresb.  Chemie,  1863,  p.  885. 

Partial  analyses  of  five  Finnish  river  and  lake  waters  are  given  by  O.  Aschan,  Jour,  prakt.  Chemie,  2dser., 

vol.  77, 1908,  p.  172.  For  an  analysis  of  the  small  Lake  Ingol,  Government  of  Yeneseisk,  Siberia,  see  S.  S. 
Zaleski,  Chem.  Zeitung,  vol.  16,  1892,  p.  594. 


A 

B 

c 

D 

E 

F 

G 

H 

co3 

51.  80 

40. 14 

25.  76 

59.  57 

26.  38 

43.  73 

49.  85 

32. 51 

so4 

7.  51 

23. 45 

5.  36 

.62 

18.  95 

2. 15 

6.  93 

23.  62 

Cl 

2.  99 

1.  09 

13.  97 

3.  69 

17.  71 

12.  81 

2.44 

8.  93 

NO, 

4. 11 

.45 

.21 

P04 

.47 

. 14 

.29 

.72 

Ca 

23.  57 

27. 10 

8.99 

25.  54 

12.  38 

11.  24 

23.  42 

25.  25 

Mg 

7.  89 

5.  49 

6.86 

4. 15 

7.58 

9.  68 

3.  57 

5.33 

Na 

2. 18 

.88 

13.  34 

2.  75 

8.  98 

9.64 

5.  85 

.61 

K 

1.00 

.33 

9.52 

2.  07 

5.55 

2.  82 

3.44 

3.  75 

Rb 

. 11 

Trace. 

NH4.  . 

.56 

. 10 

.08 

■ * * 

Si02 

1.  61 

.84 

10.  52 

. 78 

1.  74 

6. 51 

2.03 

AloO, 

. 57 

. 55 

•*j-a2v^3  

Fe,0, 

.88 

. 13 

.43 

.14 

.44 

1.42 

1. 46 

100.  00 

100.  00 

100.  00 

100.00 

100.  00 

100.  00 

100.00 

100.00 

Salinity,  parts  per 

million 

131 

238 

49.4 

106 

187 

447 

69 

197 

LAKES  AND  RIVERS. 


105 


RIVERS  OF  INDIA  AND  JAVA. 

Analyses  of  Asiatic  fresh  waters,  apart  from  the  two  Siberian 
examples  cited  in  the  preceding  table,  seem  to  be  very  rare.  A few 
only  are  available  for  citation. 

Analyses  of  waters  from  India  and  Java. 

A.  The  Mahanuddy  near  Cuttack,  India.  Analysis  by  E.  Nicholson,  Jour.  Chem.  Soc.,  vol.  26,  1873, 
p.  229.  Fe  recalculated  into  Fe203.  Part  of  the  silica  is  probably  combined  as  a silicate,  being  needed  to 
saturate  the  bases. 

B.  The  Serajoe  at  Djenggawoer,  Java.  Analysis  by  E.  C.  J.  Mohr,  Mededeelingen  Dep.  Landbouw, 
No.  5,  Batavia,  1908,  p.  81.  Another  analysis  is  given  of  the  river  at  another  point. 

C.  The  Merawoe.  Analysis  by  Mohr. 

D.  The  Pekatjangan.  Analysis  by  Mohr. 

The  last  two  rivers  are  tributaries  of  the  Serajoe.  Mohr  did  not  determine  carbonic  acid.  It  is  here 
calculated,  in  all  three  analyses,  to  satisfy  bases.  The  salinity  here  therefore  differs  from  that  given  by 
Mohr. 


A 

B 

c 

D 

co3 

27.  06 

26.  01 

29.  38 

30.  84 

so4 

1.  08 

14.  78 

16.  84 

18.  26 

Cl 

2.04 

5.  74 

5.  61 

3.04 

NO, 

7.44 

P04 

.72 

1.  64 

1.  31 

1.  21 

Ca 

15.  78 

11.  75 

14.  69 

16.  64 

Mg 

4.  62 

3.  45 

3.  37 

2.  43 

Na 

5.  92 

9. 12 

4.  95 

6.  59 

K 

1.  64 

3.  37 

3.  83 

3.  34 

Si02 

33.  45 

23.  81 

19.  65 

1 c>i-r 

17.  25 
} .40 

A1203 

Fe90o 

.25 

} .33 

S .37 

J 

J 

J 

Salinity,  parts  per  million 

100.  00 
86 

100.  00 
122 

100.  00 
107 

100.  00 
99 

The  Mahanuddy  rises  in  a region  of  igneous  and  crystalline  rocks 
and  its  silica  is  therefore  relatively  high.  The  same  appears  to  be 
true  of  the  Javanese  rivers. 


106 


THE  DATA  OF  GEOCHEMISTRY. 


THE  NILE.1 

The  water  of  the  Nile  2 has  been  repeatedly  analyzed,  with  varying 
results.  The  best  data  are  as  follows: 

Analyses  of  water  from  the  Nile. 

A.  The  Victoria  Nyanza.  Analysis  by  O.  Chadwick  and  B.  Blount,  Minutes  of  Proc.  Inst.  Civil  Eng., 
vol.  56,  p.  39, 1904. 

B.  The  White  Nile  near  Khartoum.  Average  of  three  analyses. 

C.  The  Blue  Nile.  Average  of  three  analyses.  Analyses  B and  C by  W.  Beam,  Second  Kept.  Well- 
come Research  Lab.,  Khartoum,  1906. 

D.  Average  of  12  analyses  of  monthly  samples,  taken  from  the  lower  Nile  between  June  8,  1874,  and 
May  13,  1875.  Analyses  by  H.  Letheby,  cited  by  S.  Baker  in  Proc.  Inst.  Civil  Eng.,  vol.  60,  1880,  p.  376. 
The  total  solids  contained  10.36  per  cent  of  organic  matter. 

E.  The  Nile,  about  two  hours’  journey  below  Cairo.  Analysis  by  O.  Popp,  Liebig’s  Annalen,  vol.  155, 
1870,  p.  344.  The  total  solids  contained  12.02  per  cent  of  organic  matter. 


A 

B 

c 

D 

E 

CO, 

42. 10 

42.  97 

41.  74 

36.  50 

36.  02 

so4 

1.  92 

. 25 

5.  62 

17.  44 

3.  93 

Cl 

9.  28 

4.  58 

2. 19 

4.  47 

2.  83 

NO, 

.25 

. 11 

Trace. 

P04 

Trace. 

. 59 

Ca 

6.  96 

9.  78 

18.  38 

20. 10 

13.  31 

Mg 

5.  08 

3.  00 

4.  66 

4.  01 

7.  39 

Na 

25. 13 

17.  66 

5.  43 

3.  04 

13. 14 

K 

6.  79 

1.  32 

7.  97 

3.  26 

Si02 

7.  61 

14.  72 

20.  55 

16.  88 

Fe203 

1.  92 

} 6. 47 

2.  65 

J 

Salinity,  parts  per  million 

100.  00 
135 

100.  00 
174 

100.  00 
130 

100.  00 
168 

100.  00 
119 

In  Letheby’s  analyses  the  excess  of  potassium  over  sodium  is  very 
peculiar,  and  highly  improbable.  Numerous  partial  analyses  of 
Nile  water  cited  by  Lucas  discredit  the  determinations,  and  also 
show  that  the  composition  of  the  water  is  very  variable.  In  the 
White  Nile  the  proportion  of  sulphates  is  insignificant.  Beam 
accounts  for  the  latter  fact  by  supposing  the  sulphates  to  be  reduced 
to  carbonates  by  the  organic  matter  of  the  “sudd.”  South  of  the 
“sudd”  the  White  Nile  contains  appreciable  sulphates;  after  leaving 
the  “sudd”  it  is  nearly  free  from  them. 


1 An  important  memoir  by  A.  Lucas  (The  chemistry  of  the  River  Nile:  Survey  Dept.  Paper  No.  12, 
Ministry  of  Finance,  Egypt,  1908)  contains  much  chemical  matter  in  addition  to  the  analyses  cited  here. 
A Chelu  (Le  Nil,  le  Soudan,  l’Egypte,  Paris,  1891)  gives  some  very  questionable  analyses  of  the  Blue  Nile, 
the  White  N ile,  and  the  N ile  near  Cairo.  According  to  Ch41u  the  river  carries  past  Cairo  annually  51,428,500 
metric  tons  of  suspended  solids  and  20,772,400  metric  tons  in  solution.  On  nitrates  in  the  Nile  see  A.  Muntz, 
Compt.  Rend.,  vol.  107,  1888,  p.  231. 

2 Analyses  of  the  other  great  African  rivers  seem  to  be  lacking.  For  the  ChGif  and  references  to  some 
smaller  Algerian  streams  see  p.  67  of  this  bulletin. 


LAKES  AND  RIVERS. 


107 


ORGANIC  MATTER  IN  WATERS. 


Up  to  this  point  we  have  considered  only  the  fixed  inorganic 
matter  found  in  natural  waters;  but  other  impurities  which  have 
geological  significance  are  also  present.  All  such  waters  contain 
dissolved  gases,  especially  oxygen,  nitrogen,  and  carbon  dioxide,  and 
sometimes  hydrogen  sulphide.  The  rain  brings  also  nitric  acid  and 
ammonia  to  the  soil,  and  so  into  the  ground  water;  and  organic 
substances  are  invariably  found  in  it  in  greater  or  smaller  quantities. 
These  gases  and  compounds  interact  in  a great  variety  of  ways,  and 
directly  or  indirectly  play  an  important  part  in  the  decomposition 
of  rocks.  We  have  already  noted  the  importance  of  carbonic  acid 
as  a weathering  agent,  we  have  seen  in  a previous  chapter  how  dis- 
solved air  represents  a concentration  of  oxygen,  but  so  far  the 
organic  matter  of  water  has  been  tacitly  ignored.  Its  quantity,  in 
percentages  of  total  solids,  can  be  computed  in  some  cases  from 
published  analyses.  A few  of  the  available  figures  are  as  follows: 


Percentage  of  organic  matter  in  the  dissolved  solids  of  river  waters . 


Danube 

James 

Maumee 

Nile 

Hudson. . . . 

Rhine 

Cumberland 
Thames. . . . 
Genesee 


3.  25 
4. 14 

4.  55 

10.  36 

11.  42 

11.  93 

12.  08 
12. 10 
12.  80 


Amazon 

Mohawk 

Delaware 

Lough  Neagh 

Xingu 

Tapajos 

Plata 

Negro 

Uruguay 


15.  03 
15.34 

16.  00 
16.  40 
20.  63 
24. 16 
49.  59 
53.  89 
59.  90 


The  range  of  figures  is  rather  wide,  but  the  highest  values  represent 
tropical  streams.  That  is,  leaving  artificial  pollution  out  of  account, 
waters  flowing  through  tropical  swamps  carry  the  largest  proportion 
of  organic  matter.  Lough  Neagh,  in  Ireland,  doubtless  shows  the 
effects  of  bog  water. 

The  organic  matter  is  derived  from  the  decay  of  vegetable  sub- 
stances, and  by  further  oxidation  may  be  converted  into  carbonic 
acid  and  water.  Its  chemical  constitution  is  not  completely  known, 
but  it  consists  in  part  at  least  of  a vague  group  of  colloidal  sub- 
stances, whose  precise  nature  is  yet  to  be  made  out.  They  appear  to 
possess  feebly  acidic  properties,  and  have  therefore  received  specific 
names,  humic,  crenic,  apocrenic,  and  ulmic  acids,  which  terms,  how- 
ever, if  not  actually  obsolete,  are  at  least  obsolescent.  The  salts  of 
these  11 acids”  are  partly  soluble  and  partly  insoluble,  and  the  acids 
themselves  are  commonly  reputed  to  be  powerful  agents  in  the 


108 


THE  DATA  OF  GEOCHEMISTRY. 


solution  of  rocks.1  The  humus  acids  are  said  to  decompose  silicates,2 
but  the  evidence  is  contradictory  or  at  best  inadequate.  The  state- 
ment, long  current  in  chemical  and  geological  literature,  that  the 
acids  absorb  nitrogen  from  rain  water  and  the  air,  and  silica  from  the 
soil,  forming  a series  of  silico-azohumic  acids,  rests  upon  the  unsup- 
ported assertions  of  P.  Thenard,3  who  gives  no  adequate  experimental 
data  to  sustain  his  views,  which  need  not  be  considered  further. 
The  observed  facts  are  capable  of  much  simpler  interpretation. 

A comparison  of  the  preceding  table  with  the  analyses  of  river 
waters  generally,  will  show  that  waters  relatively  high  in  organic 
matter  are  likely  to  be  high  in  silica  also.  From  this  it  has  been 
inferred  that  the  organic  matter  holds  the  silica  in  solution,  although 
the  connection  between  the  two  is  not  invariable.  The  rivers  of 
British  Guiana  and  the  Uruguay  are  so  far  the  extreme  examples  of 
this  supposed  relation,  and  the  other  tropical  streams  lend  support  to 
the  view.  The  humus  acids,  however,  are  almost  insoluble  in  water 
alone,  but  readily  soluble  in  alkaline  solutions.  It  appears  possible, 
therefore,  that  the  alleged  relation  between  humus  and  silica  is  purely 
coincidental  and  that  the  alkalies  in  the  first  instance  are  the  really 
effective  solvents.  There  is  no  proof  that  humus  acids  can  dissolve 
silica  when  alkalies  are  absent.  As  colloids  they  are  more  likely  to 
precipitate  silica  than  to  bring  it  into  solution.  On  oxidation,  how- 
ever, they  yield  carbonic  acid,  and  that  in  aqueous  solution  is  an 
active  disintegrator  of  rocks. 

In  fact,  the  amount  of  silica  in  a water  is  quite  independent  of 
organic  matter.  Many  small  streams,  near  their  sources,  especially 
if  they  rise  from  crystalline  rocks,  carry  a large  relative  proportion 
of  silica,  although  its  absolute  amount  may  be  trivial.  This  pecu- 
liarity is  shown  in  many  of  the  analyses  cited  in  the  preceding  pages, 
and  is  so  marked  that  a water  low  in  salinity  but  relatively  high  in 
silica  and  alkalies  may  almost  certainly  be  attributed  to  igneous 
rather  than  to  sedimentary  surroundings.  This  silica  is  directly 
derived  from  the  rocks  at  the  time  of  their  decomposition  by  car- 
bonated waters,  and  forms  a large  part  of  the  material  which  is  at 
first  taken  into  solution.  The  seepage  or  ground  water  which  after- 
ward enters  the  streams  is  much  poorer  in  silica,  and  so  the  propor- 
tion of  the  latter  tends  to  diminish  as  a river  flows  toward  the  sea. 


1 See  A.  A.  Julien,  Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  28, 1879,  p.  311.  On  the  organic  matter  of  waters 
in  Finland,  see  O.  Asclian,  Zeitschr.  prakt.  Geologie,  vol.  15,  1907,  p.  56.  On  the  chemical  nature  of  the 
organic  matter  in  soils,  see  O.  Schreiner  and  E.  C.  Shorey,  Bull.  Bur.  Soils  No.  74,  U.  S.  Dept.  Agr.  See 
also  S.  Od6n,  Ark.  Kem.  Min.  Geol.,  vol.  4,  No.  26, 1912,  and  S.  L.  Jodidi,  Join.  Franklin  Inst.,  vol.  176, 
p.  565, 1913. 

2 A.  Rodzyanko,  Jour.  Chem.  Soc.,  vol.  62,  pt.  2, 1892,  p.  1373.  Abstract  from  Jour.  Russ.  Chem.  Soc., 
vol.  22,  p.  208. 

2 Compt.  Rend.,  vol.  70, 1870,  p.  1412. 


LAKES  AND  RIVERS. 


109 


CONTAMINATION  BY  HUMAN  AGENCIES. 


In  any  complete  discussion  of  river  waters  account  must  be  taken 
of  contamination  by  human  agencies.  Towns  and  factories  drain 
into  the  streams,  and  the  extent  of  the  pollution  is,  for  our  immedi- 
ate purposes,  best  measured  by  the  proportion  of  chlorine.  A good 
example  is  furnished  by  the  Chicago  drainage  canal,  which  empties 
into  the  Desplaines  River  and  thence  passes  through  the  Illinois 
River  into  the  Mississippi.  For  the  waters  thus  affected  there  are 
abundant  data,  and  the  sanitary  analyses  by  the  late  A.  W.  Palmer 
are  especially  valuable.1  His  annual  averages  for  1900,  represent- 
ing Illinois  River,  are  stated  below;  the  percentages  have  been  calcu- 
lated by  me.  The  localities  are  arranged  in  order  downstream. 


Chlorine  in  Illinois  and  Mississippi  rivers. 


Total 

dissolved 

solids. 

Chlorine. 

Illinois  River — 

At  Morris 

Parts  'per 
million. 

235.3 

Parts  per 
million. 

23.1 

Per  cent. 

9. 82 

At  Ottawa 

269.4 

21.4 

7.  94 

At  Lasalle  

245.4 

18.7 

7.  62 

At  Averyville 

245.2 

17.5 

7.14 

At  Havana  

236.3 

14.8 

6.  27 

At  Kampsville  

234.3 

14.0 

5.  98 

At  Grafton 

232.6 

13.1 

5.  63 

Mississippi  River  at  Grafton 

150.1 

3.1 

2.06 

The  decrease  in  the  proportion  of  chlorine  as  we  follow  the  Illinois 
downstream  is  most  striking;  but  even  more  surprising  are  the  data 
concerning  the  Mississippi  a little  farther  south,  at  Alton.  Here 
samples  were  taken  100  feet  from  the  Illinois  shore,  one-fourth  the 
distance  across,  in  midstream,  three-fourths  over,  and  100  feet  from 
the  Missouri  shore.  The  figures  represent  averages  covering  periods 
of  from  nine  months  to  nearly  the  entire  year  1900. 


Chlorine  in  Mississippi  River  at  Alton,  III. 


Total 

dissolved 

solids. 

Chlorine. 

100  feet  from  Illinois  shore 

Parts  per 
million. 
194. 1 

Parts  per 
million. 
7.  7 

Per  cent. 

3.  97 
3.  87 
2.  74 

One-fourth  distance  across 

182.8 

7. 1 

Midstream 

160.  6 

4.4 

Three-fourths  distance  across 

155.0 

4. 1 

2.  65 

100  feet  from  Missouri  shore 

154.2 

3.5 

2.  27 

i Chemical  survey  of  the  waters  of  Illinois,  1897-1902,  Univ.  Illinois,  1903. 


110 


THE  DATA  OF  GEOCHEMISTRY. 


The  influence  of  the  Illinois  River  on  the  eastern  side  of  the  Missis- 
sippi is  perfectly  evident.  The  chief  cause  of  the  diminution  of 
chlorine  in  the  Illinois  is,  of  course,  the  dilution  of  the  water  by  other 
less  contaminated  sources  of  supply.  In  the  Kankakee  at  Wilming- 
ton the  proportion  of  chlorine  during  the  same  period  was  only  1.21 
per  cent,  and  in  the  Fox  River  it  was  1.98  per  cent,  calculated  from 
the  total  matter  in  solution.  The  Kankakee  and  Fox  rivers  represent 
an  approximation  to  the  normal  chlorine  of  the  region;  the  Illinois, 
into  which  they  flow,  shows  the  exaggeration  produced  by  artificial 
means.  Near  the  ocean  the  normal  chlorine  in  fresh  waters  is  much 
higher  and  the  effects  of  pollution  are  less  conspicuous  than  in  inland 
streams.1 

GAINS  AND  LOSSES  IN  WATERS. 

In  fresh-water  lakes  and  rivers  the  salinity  is  naturally  low — that 
is,  their  waters  are  very  dilute  solutions,  which  do  not  approach  the 
point  of  saturation  for  even  the  less  soluble  of  their  constituents. 
The  relatively  insoluble  carbonates  of  calcium  and  magnesium  are 
held  in  solution  by  the  excess  of  carbonic  acid  which  is  always 
present,  and  are  therefore  to  be  regarded,  while  dissolved,  as  bicar- 
bonates. Without  this  solvent  much  of  the  load  would  be  deposited, 
as  indeed  it  is  by  the  evaporation  of  percolating  waters  in  limestone 
caves,  when  stalactites  and  stalagmites  are  formed.  In  a flowing 
river,  which  continually  receives  carbon  dioxide  from  the  air  and 
from  decaying  vegetation,  such  depositions  are  not  likely  to  occur, 
at  least  not  to  any  notable  extent;  but  when  pools  are  left  from  an 
overflow,  incrustations  of  solid  matter  may  soon  form.  The  sedi- 
ments found  in  streams  are  mostly  claylike  in  character,  and  rarely 
contain  any  conspicuous  proportion  of  carbonates  or  sulphates.  Liv- 
ing organisms,  especially  corals,  mollusks,  and  some  aquatic  plants, 
withdraw  calcium  carbonate  from  solution;  but  how  great  their 
influence  may  be,  relatively  to  an  entire  flow,  we  have  no  means  of 
estimating.  Many  agencies  thus  combine  to  modify  the  composition 
of  a water,  but  the  relative  magnitude  of  the  several  factors  can 
hardly  be  determined.  The  waters  gain  and  lose  solid  matter,  but 
on  the  whole,  as  we  follow  a stream  downward  in  its  course,  the 
gains  exceed  the  losses.  When  we  exclude  the  elements  of  dilution 
by  tributaries  and  the  variations  in  concentration  between  high  and 
low  stages  of  water  we  find  that  salinity  generally  increases  until  a 
river  reaches  the  sea. 

Speaking  broadly,  lake  and  river  waters  may  be  divided  into  two 
great  classes — namely,  sulphate  and  carbonate  waters,  according  as 

1 A good  summary  of  the  relations  between  normal  and  polluted  waters  in  the  eastern  and  middle  States 
is  given  by  M.  O.  Leighton  in  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  79, 1903.  The  subject  of  normal 
chlorine  is  considered  and  the  classical  “chlorine  map”  of  Massachusetts  is  reproduced. 

See  also  Sixth  Rept.  Rivers  Pollution  Commission,  1868,  on  the  domestic  water  supply  of  Great  Britain. 
This  report  contains  abundant  data  on  chlorine  in  waters. 


LAKES  AND  RIVERS. 


Ill 


carbonic  or  sulphuric  ions  predominate.  The  classification  can  be 
still  further  subdivided  with  reference  to  the  abundance  of  chlorides 
or  of  silica,  and  again  with  regard  to  bases;  but  the  two  main  divi- 
sions still  hold.  Most  river  waters  are  either  carbonate  or  sulphate 
in  type,  and  we  have  already  seen  how  climatic  considerations  deter- 
mine, in  part  at  least,  the  chemical  character  of  a stream.  The  car- 
bonates are  derived  from  the  carbonic  acid  of  rain  or  from  that 
produced  by  organic  matter,  which  may  act  either  upon  crystalline 
rocks  directly  or  by  solution  of  limestones.  The  sulphates  originate 
in  the  oxidation  of  pyrite  or  by  the  solution  of  gypsum,  and  the 
two  classes  of  waters  are  almost  invariably  commingled.  Carbonate 
waters  are  by  far  the  most  common,  as  the  cited  analyses  show,  and 
the  reasons  for  this  fact  have  already  been  made  clear.  We  have 
also  seen  how  a river  can  change  its  type  in  flowing  from  one  point 
to  another,  and  we  have  noted  the  probability  that  this  transforma- 
tion is  commonly  due  to  the  blending  of  streams,  or  even  to  the 
accession  of  ground  waters.  One  other  point  in  this  connection  re- 
mains to  be  noted — namely,  the  possible  influence  of  micro-organisms. 
It  is  more  than  probable  that  these  minute  creatures,  acting  in  pres- 
ence of  other  organic  matter,  may  reduce  sulphates,  with  elimination 
of  hydrogen  sulphide  and  the  formation  of  carbonates  in  their  stead. 
That  reactions  of  this  kind  occur  in  saline  and  brackish  waters  seems 
to  be  well  established.1  A suggestive  instance  came  within  the  expe- 
rience of  the  United  States  Geological  Survey.  A quantity  of  water 
rich  in  sulphates,  from  one  of  the  alkaline  lakes  of  California,  was 
sent  to  the  laboratory  in  a wooden  barrel.  When  received,  the 
water  had  become  fetid  with  hydrogen  sulphide  and  discolored  by 
extract  from  the  wood — so  much  so  as  to  be  unfit  for  analysis. 
How  far  such  changes  may  occur  in  nature,  especially  in  swamp 
waters,  remains  to  be  determined.  At  all  events,  the  possibility  of 
similar  transformations  can  not  be  ignored.  That  bacteria  are 
active  agents  in  precipitating  calcium  carbonate  is  well  known;  but 
that  subject  will  be  considered  more  fully  in  another  chapter. 

CHEMICAL  DENUDATION. 

Now,  to  sum  up:  A river  is  formed  by  the  union  of  waters  from 
many  sources,  and  each  one  owes  its  peculiarities  to  the  conditions 
existing  at  its  starting  point.  Carbonic  acid,  either  of  atmospheric 
or  of  organic  origin,  is  the  most  abundant  and  generally  the  most 
potent  of  the  agents  that  dissolve  mineral  matter  from  the  rocks. 
Hence  carbonate  waters  are  the  commonest,  and,  as  streams  blend 
to  form  the  great  continental  rivers,  the  carbonate  type  tends  to 
become  more  and  more  pronounced.  In  the  temperate  zone,  at 


1 See  N.  Zelinsky,  Jour.  Chem.  Soc.,  vol.  66,  pt.  2,  1894,  abstract,  p.  200;  also  M.  W.  Beyerinck,  idem, 
vol.  80,  pt.  2,  abstract,  p.  119;  and  R.  H.  Saltet  and  C.  S.  Stockvis,  idem,  vol.  80,  pt.  2, 1901,  p.  265. 


112 


THE  DATA  OF  GEOCHEMISTRY. 


least,  the  larger  streams  resemble  one  another  chemically,  and  seem 
on  the  average  to  do  pretty  much  the  same  chemical  work  in  pretty 
much  the  same  way.  The  composition  of  their  waters  gives  a meas- 
ure of  the  effects  which  they  have  produced;  and  if  the  data  were 
adequate  the  study  of  chemical  denudation  would  be  both  profitable 
and  easy.  But  the  data  are  not  adequate,  except  for  certain  areas, 
and  therefore  any  estimate  which  may  be  reached  as  to  the  quantity 
of  solid  matter  annually  carried  in  solution  by  rivers  to  the  sea 
must  be  subject  to  future  revision.  It  is  clear  that  an  analysis  of 
river  water,  taken  at  a single  point  and  at  one  stage  of  concentra- 
tion, tells  us  little  or  nothing  of  what  the  stream  as  a whole  may  do. 
Annual  averages  of  water  taken  near  the  mouths  of  rivers  are  needed 
before  the  problems  of  chemical  denudation  can  be  even  approxi- 
mately solved. 

For  example,  Sir  John  Murray 1 has  computed,  by  averaging  the 
analyses  of  19  rivers,  not  only  the  total  amount  of  saline  matter 
carried  annually  to  the  ocean,  but  also  its  composition.  But  his 
estimate,  published  in  1887,  was  based  almost  necessarily  upon  Euro- 
pean data  and  to  a large  extent  upon  inconclusive  analyses.  Evi- 
dence as  to  the  chemical  character  of  the  greater  American,  African, 
and  Asiatic  streams  was  then  practically  unobtainable,  and  therefore 
the  computation  was  only  a rough  indication  of  what  the  truth  may 
be.  Data  from  all  the  greater  river  basins  of  the  world  are  required 
before  we  can  determine  the  full  significance  of  chemical  denudation. 

The  problem,  however,  is  not  entirely  hopeless.  It  can  be  attacked 
locally,  with  reference  to  specific  areas,  and  a fairly  probable  approxi- 
mation to  the  truth  can  be  made  from  the  evidence  which  now  exists. 
T.  Mellard  Reade,2  for  instance,  in  a well-known  investigation,  has 
calculated  the  amount  of  solid  matter  annually  dissolved  by  water 
from  the  rocks  of  England  and  Wales.  Putting  the  average  salinity 
of  the  waters  at  12.23  parts  in  100,000,  he  estimates  that  the  total 
annual  run-off  from  the  area  in  question  carries  in  solution  8,370,630 
tons  of  dissolved  mineral  matter,  or  143.5  tons  from  each  square  mile 
of  surface.  At  this  rate,  by  the  solvent  action  of  water  alone,  the 
level  of  England  and  Wales  would  be  lowered  1 foot  in  12,978  years. 
Reade  also,  from  such  data  as  he  could  obtain,  for  the  most  part  single 
analyses,  made  similar  but  rough  estimates  for  several  European 
river  basins,  which,  in  British  tons  per  square  mile,  may  be  tabulated 
as  follows : 


Rhone 232 

Thames 149 

Garonne 142 


Seine 97 

Rhine 92.  3 

Danube 72.  7 


1 Scottish  Geog.  Mag.,  vol.  3,  1887,  p.  65. 

2 Proc.  Liverpool  Geol.  Soc.,  vol.  3, 1876-77,  p.  211.  Reprinted  under  the  title  “Chemical  denudation  in 
relation  to  geological  time.” 


LAKES  AND  RIVERS. 


113 


The  average  for  the  entire  land  surface  of  the  globe  he  put  at  100 
tons  per  square  mile,  a figure  that  was  not  much  better  than  a guess.1 

From  investigations  made  in  the  water-resources  branch  of  the 
United  States  Geological  Survey,  lower  figures  are  obtained.  By 
combining  the  results  of  careful  river  gaging  with  the  data  for  salinity 
as  determined  in  the  laboratory,  R.  B.  Dole  and  H.  Stabler  2 have 
deduced  a table,  of  which  the  following  is  an  abridgment.  The 
Great  Basin  and  the  Red  River  of  the  North  are  here  left  out  of 
account. 

Chemical  denudation  in  the  United  States. 


Drainage  area. 

Area  drained 
(square  miles). 

Dissolved  solids 
(tons  per  square 
mile). 

North  Atlantic 

159,  400 
123,  900 
142, 100 
315,  700 
1,  265,  000 
175,  000 
230,  000 
72, 700 

130 

South  Atlantic 

94 

Eastern  Gulf  of  Mexico 

117 

Western  Gulf  of  Mexico 

36 

Mississippi  River 

108 

Laurentian  Basin  (United  States  area) 

116 

Colorado  River  of  Arizona 

51 

South  Pacific 

177 

North  Pacific 

270,  000 

100 

Total 

2,  753,  800 

a 98 

a Short  tons  of  2,000  pounds.  The  metric  ton  equals  2,205  pounds. 


For  the  entire  United  States,  3,088,500  square  miles,  regarding 
the  denudation  of  the  Great  Basin  as  zero — that  is,  as  not  con- 
tributory to  the  ocean— the  average  denudation  is  estimated  by  Dole 
and  Stabler  as  87  short  tons,  or  78.9  metric  tons  per  square  mile,  a 
figure  which  is  not  likely  to  be  much  changed  by  future  investigations. 
It  refers,  however,  only  to  inorganic  matter.  If  organic  impurities 
are  included  it  should  be  increased  by  perhaps  10  per  cent;  that  is, 
to  86.8  metric  tons  per  square  mile.  The  variation  in  the  denudation 
factors  assigned  to  the  several  areas  is  quite  important.  The  Colo- 
rado drains  an  arid  region,  and  much  of  the  area  ascribed  to  the 
river  adds  little  or  nothing  to  it.  The  humid  basin  of  the  St.  Law- 
rence, on  the  other  hand,  is  a liberal  contributor  of  saline  substances. 
The  Mississippi,  with  humid  regions  to  the  east  and  semiarid  plains 
to  the  west,  shows  an  intermediate  figure  for  the  chemical  erosion. 

1 For  other  estimates  of  the  amount  of  material  carried  by  various  rivers,  see  A.  Geikie,  Text-book  of 
geology,  4th  ed.,  vol.  1,  1903,  p.  489.  The  Thames,  for  example,  carries  in  solution  past  Kingston  548,230 
tons  of  fixed  inorganic  matter  in  a year.  See  also  the  thesis  of  A.  F.  White  on  the  waters  of  Rockbridge 
County,  Virginia  (Washington  and  Lee  Univ.,  1906).  This  thesis  deals  with  North  River,  a tributary  of 
the  James. 

2 Water-Supply  Paper  U.  S.  Geol.  Survey  No.  234,  1909,  p.  78.  The  figures  are  given  in  much  greater 
detail  than  is  practicable  here.  Some  of  the  areas,  etc.,  differ  slightly  from  those  cited  in  previous  pages 
of  this  book ; but  the  differences  are  trivial  and  do  not  appreciably  affect  the  final  result.  The  recent  (1914) 
data  relative  to  the  Columbia  River,  etc.,  are  not  included  in  this  estimate. 

97270°— Bull.  616—16 8 


114 


THE  DATA  OF  GEOCHEMISTRY. 


For  the  rest  of  North  America  only  a rough  estimate  is  possible. 
The  analyses  of  Canadian  rivers  given  in  previous  pages  indicate  an 
average  composition  and  salinity  much  like  that  of  the  St.  Lawrence. 
For  Mexican  and  Central  American  rivers  no  data  are  at  hand,  but 
it  is  probable  that  for  northern  Mexico,  at  least,  they  would  resemble 
those  of  Texas,  New  Mexico,  and  Arizona.  That  is,  the  waters  north 
of  the  United  States  and  south  of  it  vary  from  the  mean  found  for 
the  United  States  in  opposite  directions,  and  so  tend  to  balance 
each  other.  In  short,  the  average  for  the  United  States  probably 
represents  fairly  wrell  the  average  for  the  entire  continent.  If  we 
assume  that  six  millions  of  square  miles  in  North  America  lose  79 
metric  tons  in  solution  per  square  mile  per  annum,  and  that  the 
composition  of  the  saline  matter  so  transported  is  that  found  for 
the  United  States  alone,  we  shall  be  fairly  near  the  truth.  ^ 

Evidence  for  South  America  is  very  scanty.  On  the  basis  of 
Frankland’s  analysis,  Reade  1 estimates  the  denudation  factor  of 
the  Amazon  at  50  tons  per  square  mile.  Using  the  same  analysis, 
and  Murray’s  estimate  of  the  total  run-off,  I find  that  53  tons  is 
rather  more  probable.  Similar  estimates  for  the  Uruguay  and  the 
Negro  give  a factor  of  50  tons.  About  four  millions  of  square  miles 
in  South  America  may  be  assigned  the  latter  figure,  with  a reasonable 
degree  of  probability.  The  Amazon  dominates  the  entire  combina- 
tion, and  its  low  salinity  is  due  to  the  fact  that  it  drains  a vast  tropical 
forest,  which  is  thoroughly  leached.  Through  much  of  its  course  it 
has  scanty  access  to  fresh  rocks  and  therefore  finds  but  little  material 
to  dissolve.  Large  areas  in  South  America;  like  western  Peru  and 
central  Argentina,  contribute  nothing  to  the  ocean  and  count  for  zero 
in  measuring  chemical  denudation.2 

Some  figures  relative  to  European  waters  have  already  been  given. 
According  to  Geikie  the  Thames  carries  in  solution  past  Kingston 
548,230  British,  or  556,930  metric  tons  of  inorganic  matter  annually. 
The  drainage  area  is  6,100  square  miles,  hence  a denudation  factor 
of  91.3  metric  tons  per  square  mile.  For  the  Meuse  above  Liege 
the  figures  published  by  Spring  and  Prost  give  a factor  of  139  tons. 
In  Sweden  the  chemical  denudation  is  much  smaller,  but  seems  to 
have  been  estimated  for  only  a very  limited  area.  Reade’s  estimate 
for  all  Europe  is  100  tons  per  square  mile,  and  that  seems  to  be 
fairly  probable.  For  Europe,  then,  I shall  assume  that  3,000,000 
square  miles  suffer  solvent  denudation  at  the  rate  of  100  tons  per 
mile,  a figure  wdiich  is  not  far  from  that  assigned  to  the  Laurentian 
Basin.  Europe  is  generally  well  watered,  and  its  waters  have  all  the 


1 Evolution  of  earth  structures,  London,  1903,  pp.  255-282. 

2 The  rivers  of  British  Guiana  are  not  included  in  this  discussion,  which  was  completed  before  their 
analyses  were  made. 


LAKES  AND  RIVERS. 


115 


characteristics  of  those  from  the  humid  areas  of  the  United  States. 
In  the  latter  the  denudation  factor  is  lowered  by  the  arid  regions  of 
the  Southwest. 

The  African  material  is  very  imperfect.  According  to  Chelu,1  the 
Nile  carries  20,772,400  metric  tons  in  solution  annually.  This,  for 
an  ostensible  drainage  basin  of  1,293,050  square  miles,  gives  a denu- 
dation factor  of  only  16  tons.  Much  of  northern  Africa  resembles 
the  Valley  of  the  Nile  so  far  as  denudation  is  concerned.  We  may 
safely  assume  that  1,500,000  square  miles  are  represented  by  the 
Nile,  and  also  that  6,500,000  are  equivalent  in  character  to  South 
America  with  its  tropical  streams.  The  desert  regions,  like  the 
Sahara,  of  course,  are  negligible. 

The  data  relative  to  Asiatic  waters  are  even  more  defective.  The 
water  of  Lake  Baikal  resembles  that  of  the  St.  Lawrence,  while  the 
Mahanuddy  has  the  peculiarities  of  tropical  rivers.  With  these 
feeble  clues  I can  only  make  a very  rough  estimate  for  Asia,  as 
follows:  Assume  3,000,000  square  miles  to  average  like  Europe, 
3,000,000  like  the  United  States,  and  1,000,000  like  South  America. 
Large  areas  in  Asia  are  obviously  left  out  of  consideration — the 
Caspian  depression,  the  central  deserts,  and  the  Arabian  peninsula. 
The  streams  reaching  the  sea  from  Arabia  are  too  small  to  carry 
any  weight  in  the  general  discussion. 

To  sum  up,  the  crude  figures  for  chemical  denudation  are  as 
follows : 

North  America 6,000,000  square  miles  at  79  tons 474,000,000  tons 

South  America 4,000,000  square  miles  at  50  tons 200,000,000  tons 

Europe 3,000,000  square  miles  at  100  tons 300,000,000  tons 

Asia 7,000,000  square  miles  at  84  tons 588,000,000  tons 

Africa 8,000,000  square  miles  at  44  tons 352,000,000  tons 

28,000,000  square  miles  at  68.  4 tons..  1,914,000,000  tons 

The  incompleteness  of  the  foregoing  figures  is  due  to  the  fact  that 
large  areas  of  land  either  do  not  drain  into  the  ocean,  or  add  little  or 
nothing  to  it.  The  total  land  area  to  be  considered — that  is,  the 
area  which  contributes  to  the  salinity  of  the  ocean — is,  according  to 
Murray,  39,697,400  square  miles,  or,  in  round  numbers,  40,000,000. 
Assuming  that  the  figures  so  far  given  represent  a fair  average,  the 
amount  of  saline  matter  carried  into  the  ocean  by  the  river  drainage 
of  the  world  is  2,735,000,000  metric  tons  annually,  an  estimate  only 
a little  more  than  half  that  given  by  Murray.2  The  rivers  studied  by 
Murray  must  have  been  for  the  most  part,  if  not  exclusively,  in  the 
Temperate  Zone,  where  alternations  of  freezing  and  thawing  tend  to 

Le  Nil,  le  Soudan,  l’Egypte,  Paris,  1891. 

2 For  more  details  with  reference  to  these  computations,  see  F.  W.  Clarke  A preliminary  study  of  chem- 
ical denudation:  Smithsonian  Misc.  Coll.,  vol.  56,  No.  5, 1910. 


116 


THE  DATA  OF  GEOCHEMISTRY, 


break  up  the  rocks  and  so  to  render  them  more  easily  decomposed 
by  percolating  waters.  With  even  moderate  humidity  the  activity 
of  the  waters  is  great,  and  large  amounts  of  material  are  transported 
by  them.  On  the  other  hand,  Arctic  rivers  flow  to  a noteworthy 
extent  over  tundra,  which  is  frozen  during  the  greater  part  of  the 
year.  They  therefore  have  comparatively  small  influence  in  rock 
solution,  and  much  of  their  flow  must  be  mere  surface  run-off.  The 
low  salinity  of  tropical  streams  has  already  been  noted.  The  total 
amount  of  chemical  denudation  depends  upon  the  balancing  of  these 
varying  tendencies. 

With  the  aid  of  the  foregoing  estimates,  and  of  the  analyses  cited 
in  this  chapter,  a probable  average  can  be  computed  for  the  compo- 
sition of  the  fresh  waters  of  the  globe.  Such  an  average  is  shown  in 
the  next  table. 

Average  composition  of  river  and  lake  waters. 

A.  Waters  of  North  America.  Average  computed  from  the  data  given  by  Dole  in  Water-Supply  Paper 
236,  and  by  Dole  and  Stabler  in  Water-Supply  Paper  234.  Each  analysis  is  weighted  proportionately  to 
the  total  amount  of  material  annually  carried  by  the  river.  The  alkalies  are  given  with  Palmer’s  determina- 
tions of  potassium. 

B.  Waters  of  South  America.  Average  made  up  from  the  cited  analyses,  weighted  as  follows:  Amazon, 
12;  Uruguay,  1;  Negro,  1;  all  smaller  streams,  2.  The  Rio  de  la  Plata  is  left  out  of  account,  for  the  analyses 
are  not  conclusive. 

C.  Waters  of  Europe.  Average  of  300  analyses  of  river  and  lake  waters,  first  by  groups,  and  then  weight- 
ing each  group  proportionately  to  its  drainage  area. 

D.  Waters  of  Asia.  Made  up  of  the  averages  A,  B,  C,  weighted  3 : 3 : 1 as  explained  in  a previous  para- 
graph. 

E . W aters  of  Africa.  Made  up  of  the  average  for  the  N ile  and  that  for  South  America  as  already  described. 

F.  General  average,  in  which  each  of  the  foregoing  averages  is  weighted  proportionally  to  the  number  of 
tons  given  in  the  preceding  table. 

G.  Sir  John  Murray’s  average  composition  of  river  water  (Scottish  Geog.  Mag.,  vol.  3,  1887,  p.  65), 
reduced  to  the  uniform  standard  adopted  in  this  book.  Organic  matter  as  given  by  Murray  is  10.37  per 
cent  of  the  total  solids. 


, 

A 

B 

C 

D 

E 

F 

G 

CO, 

33.  40 

32.  48 

39.  98 

36.  61 

32.  75 

35. 15 

41.  33 

so4 

15.  31 

8.  04 

11.  97 

13.  03 

8.  67 

12. 14 

8.  22 

Cl 

7.  44 

5.  75 

3.44 

5.  30 

5.  66 

5.  68 

1.  85 

no3 

1. 15 

. 62 

. 90 

. 98 

. 58 

. 90 

2.  82 

Ca 

19.  36 

18.  92 

23. 19 

21.  23 

19.  00 

20.  39 

20.  46 

Mg 

4.  87 

2.  59 

2.  35 

3.  42 

2.  68 

3.  41 

4.  65 

Na 

7.  46 

5.  03 

4.  32 

5.  98 

4.  90 

5.  79 

3.  47 

K 

1.  77 

1.  95 

2.  75 

1.  98 

2.  35 

2. 12 

1.  33 

(Fe,Al)oO, 

. 64 

5.  74 

2.  40 

1.  96 

5.  52 

2.  75 

4.  76 

Si02 

8.  60 

18.  88 

8.  70 

9.  51 

17.  89 

11.67 

10.  75 

Minor  constituents 

.36 

Weight 

100.  00 
10 

100.  00 
4 

100.  00 
6 

100.  00 
11 

100.  00 
7 

100.  00 

100.00 

The  general  mean  F,  regardless  of  corrections  to  be  considered  later, 
is  curiously  near  the  average  figures  for  three  great  rivers,  the  Missis- 
sippi, the  Amazon,  and  the  Nile.  It  may  be  too  high  in  silica,  but 
on  the  whole  it  is  as  near  the  truth  as  can  be  determined  with  existing 


LAKES  AND  RIVERS. 


117 


data.  Analyses  of  the  greater  rivers  of  Asia  and  Africa  may  modify 
it  slightly,  but  the  order  of  magnitudes  shown  by  the  several  radicles 
is  not  likely  to  be  changed. 

Recurring  now  to  Reade's  estimate  of  chemical  denudation  in  Eng- 
land and  Wales,  a rate  of  one  foot  in  12,978  years,  the  new  data  may 
be  applied  to  a similar  discussion  for  the  entire  land  surface  of  the 
globe.  For  the  United  States,  excluding  the  Great  Basin,  the  denu- 
dation factor  of  79  tons  per  square  mile  per  annum  gives  for  a lower- 
ing of  one  foot  23,984  years.  For  South  America  the  figures  are  50 
tons  and  37,896  years;  for  Europe,  100  tons  and  18,948  years,  and  for 
the  Nile  Valley,  16  tons  and  118,424  years.  For  the  entire, 40, 000, 000 
square  miles  of  land  the  average  values  are  68.4  tons  and  27,700  years; 
estimates  that  are  subject  to  corrections  of  a kind  which  Reade  did  not 
take  into  consideration. 

On  critical  examination  of  the  data  it  is  clear  that  the  total  appar- 
ent amount  of  solvent  denudation  is  not  a true  measure  of  rock 
decomposition.  In  the  general  mean  of  all  the  river  analyses  now 
under  discussion,  0.90  per  cent  of  N03  and  35.15  per  cent  of  C03 
appear.  The  N03  came  entirely  or  practically  so  from  atmospheric 
sources;  the  C03  was  derived  partly  from  the  atmosphere  and  partly 
from  the  solution  of  limestones.  Dealing  now  only  with  the  existing 
discharge  of  rivers,  we  must  subtract  these  atmospheric  additions 
from  the  total  annual  load  of  dissolved  inorganic  matter  before  we 
can  compute  the  real  amount  of  rock  denudation. 

The  land  surface  of  the  earth  is  covered,  nearly  enough  for  present 
purposes,  by  75  per  cent  of  sedimentary  and  25  per  cent  of  igneous 
and  crystalline  rocks;  1 and  it  is  on  or  near  this  surface  that  the  flow- 
ing waters  act.  The  limestones,  as  shown  in  Chapter  I,  constitute 
only  one- twentieth  of  the  sediments,  or  3.75  per  cent  of  the  entire 
area,  but  the  proportion  of  carbonates  derived  from  them  must  be 
very  much  larger.  The  composite  and  average  analyses  of  rocks 
give,  for  lime,  4.81  per  cent  in  the  igneous,  and  5.42  in  all  the  sedi- 
mentaries,  equivalent  to  3.78  and  4.26  per  cent  of  C02  respectively. 
Assuming  that  all  the  surface  rocks  yield  lime  at  an  equal  rate,  which 
is  obviously  not  quite  true,  and  multiplying  these  figures  by  the  areas 
represented  as  1 to  3,  the  relative  proportions  of  the  C03  radicle 
become  3.78:12.78,  or  1:3.4  nearly.  The  last  figure  should  be  higher, 
because  of  the  more  rapid  solution  of  the  limestone,  but  if  we  accept 
the  ratio  as  it  stands  we  may  use  it  to  determine  the  approximate 
proportions  of  the  C03  radicle  derived  from  limestones  and  from  the 
atmosphere  acting  upon  crystalline  rocks.  On  this  basis,  8 per  cent 
of  C03  should  be  deducted  from  the  percentage  in  the  river  waters, 
together  with  the  0.9  per  cent  of  N03.  Making  the  subtraction  from 


1 Estimate  by  A.  von  Tillo,  actually  75.7  and  24.3. 


118 


THE  DATA  OP  GEOCHEMISTRY. 


the  total  river  load  of  dissolved  matter,  2,735,000,000  tons,  there 
remains  2,491,585,000  tons,  or  about  62.3  tons  per  square  mile  on  the 
average,  for  the  40,000,000  of  square  miles  of  land  which  are  assumed 
to  drain  into  the  ocean.  This  implies  a lowering  of  the  land  by  solvent 
denudation  at  the  rate  of  one  foot  in  30,414  years,  or  30,000  in  round 
numbers.  The  last  estimate  may  be  subject  to  large  future  cor- 
rections, but  probably  it  is  correct  within  10  per  cent.  There  are, 
for  example,  corrections  for  the  amount  of  chlorine  and  its  equivalent 
sodium  brought  in  rainfall  from  the  atmosphere,  or  by  sewage  from 
towns.1  These  will  be  considered  in  the  next  chapter  in  relation  to 
the  use  of  the  data  in  measuring  geologic  time. 

1 Spring  and  Prost,  in  their  work  on  the  Meuse,  and  Ullik,  in  his  study  of  the  Elbe,  have  attempted  to 
measure  the  amount  of  human  contamination.  This,  obviously,  must  be  very  variable.  In  rivers  like 
the  Yukon  or  the  Colorado  it  is  negligible;  in  the  Mississippi  or  the  Hudson  it  is  doubtless  large.  In  small 
streams  in  thickly  settled  manufacturing  districts  the  amount  of  pollution  is  often  enormous. 


CHAPTER  IV. 

THE  OCEAN. 

ELEMENTS  IN  THE  OCEAN. 

For  obvious  reasons,  some  of  them  purely  scientific  and  some 
utilitarian,  the  water  of  the  ocean  has  been  the  subject  of  long  and 
elaborate  scientific  investigations.  Considered  broadly,  its  composi- 
tion is  relatively  simple  and  remarkably  uniform;  studied  minutely, 
It  is  found  to  contain  many  substances.1 

In  his  great  memoir  on  the  chemical  composition  of  sea  water,  G. 
Forchhammer 2 gave  a list  of  the  various  elements  which,  up  to  his 
time,  had  been  detected  in  it.  The  elements  which  are  sufficiently 
abundant  to  be  determined  in  ordinary  analyses  will  be  considered 
later;  the  substances  that  are  less  frequently  estimated  may  be 
briefly  considered  now. 

Iodine. — Chiefly  found  in  the  ashes  of  seaweeds.  According  to  E. 
Sonstadt,3  it  is  present  in  sea  water  in  the  form  of  calcium  iodate. 
The  quantity  estimated  was  one  part  of  this  salt  in  250,000  of  water, 
equivalent  to  about  two  parts  per  million  of  iodine.  A.  Gautier,4 
examining  surface  water  from  the  Mediterranean,  found  iodine  only 
in  the  organic  matter  which  he  separated  by  filtration,  but  at  depths 
beyond  800  meters  its  compounds  were  detected  in  the  water  itself. 
Living  organisms  withdraw  iodine  from  solution.  The  largest 
amount  of  iodine,  organic  and  inorganic,  reported  by  Gautier,  is 
2.38  milligrams  to  the  liter.  J.  Koettstorfer,5  in  an  earlier  investi- 
gation, found  much  smaller  quantities. 

Fluorine. — Found  directly  and  also  in  the  boiler  scale  of  oceanic 
steamers.  A.  Carnot's  determinations  6 show  that  the  water  of  the 
Atlantic  contains  0.822  gram  of  fluorine  to  the  cubic  meter.7  Recent 

1 For  the  volume  of  the  ocean  and  of  its  contained  salts  see  pp.  23,  24. 

2 Philos.  Trans.,  vol.  155, 1865,  pp.  203-262.  See  also  J.  Roth,  Allgemeine  und  chemische  Geologie,  vol.  1, 
1879,  p.  400;  and  W.  Dittmar,  Kept.  Challenger  Exped.,  Physics  and  chemistry,  vol.  1,  1884,  pp.  1-251. 
A volume  by  Ren£  Quinton  (L’eau  de  mer,  Paris,  1904)  contains  (pp.  221-235)  a good  summary  of  earlier 
work  on  the  less  important  elements  in  sea  water.  The  book  is  essentially  biochemical  in  character  and 
deals  mainly  with  the  relations  of  sea  water  to  life. 

3 Chem.  News,  vol.  25, 1872;  pp.  196,  231,  241;  vol.  74, 1896,  p.  316. 

< Compt.  Rend.,  vol.  128, 1899,  p.  1069;  vol.  129, 1899,  p.  9. 

s Zeitschr.  anal.  Chemie,  vol.  17, 1878,  p.  305. 

e Annales  des  mines,  9th  ser.,  vol.  10, 1896,  p.  175. 

7 See  also  earlier  determinations  by  G.  Forchhammer  and  G.  Wilson,  Edinburgh  New  Philos.  Jour.,  vol. 
48,  1850,  p.  345. 


119 


120 


THE  DATA  OF  GEOCHEMISTRY. 


determinations  by  A.  Gautier  and  P.  Clausmann 1 gave  only  0.3  milli- 
gram per  liter.  P.  Carles2  has  reported  fluorine  in  the  shells  of 
mollusks. 

Nitrogen. — Present  as  ammonia,  in  organic  matter,  and  in  dissolved 
air.  The  ammonia  of  sea  water  has  been  repeatedly  investigated. 
A.  Audoynaud,3  in  water  from  the  coast  of  France,  found  0.16  to  1.22 
milligrams  of  NH3  per  liter.  L.  Dieulafait,4  in  waters  from  the  Red 
Sea  and  the  coast  of  Asia,  reports  quantities  from  0.136  to  0.340 
milligram.  T.  Schloesing  5 found  a still  larger  amount,  namely,  0.4 
milligram.  According  to  J.  Murray  and  R.  Irvine,6  ammonia  is 
mom  abundant  around  coral  reefs  than  in  the  North  Atlantic  or 
German  Ocean.  It  occurs  principally  as  ammonium  carbonate, 
formed  by  the  decomposition  of  organic  matter.  Elaborate  determi- 
nations of  ammonia  in  the  Mediterranean  are  given  by  K.  Natterer.7 

Phosphorus. — Present  in  the  form  of  phosphates.  The  phosphatic 
nodules  found  on  the  bottom  of  the  sea  are  considered  farther  on  in 
this  chapter. 

Arsenic. — Detected  by  Daubree.  A.  Gautier 8 found  its  quantity 
to  range  from  0.01  to  0.08  milligram  per  liter. 

Silicon. — According  to  J.  Murray  and  R.  Irvine,9  sea  water  con- 
tains silica.  The  proportion  is  from  1 part  in  220,000  to  1 in  460,000, 
or  even  less.  The  siliceous  organisms  which  abound  in  the  ocean 
probably  take  their  silica  from  clayey  matter  in  mechanical  sus- 
pension. Small  amounts  of  such  matter  are  carried  far  and  wide 
by  currents,  often  to  a great  distance  from  land.  E.  Raben  10  found 
sea  water  to  contain  from  0.2  to  1.4  milligrams  of  silica  per  liter. 

Boron. — Present  in  sea  water  and  in  the  ashes  of  marine  plants. 
J.  A.  Veatch,11  who  examined  water  from  the  coast  of  California, 
found  boric  acid  almost  exclusively  in  samples  collected  over  a sub- 
marine ridge,  parallel  with  the  land  but  30  to  40  miles  away.  He 
suggests  for  it  a volcanic  origin  from  submerged  sources. 

Lithium. — Reported  in  sea  water  by  L.  Dieulafait.12  Also  detected 
spectroscopically  by  G.  Bizio  in  water  from  the  Adriatic. 

1 Compt.  Rend.,  vol.  158,  1914,  p.  1631. 

2 Idem,  vol.  144, 1907,  pp.  437,  1240. 

a Idem,  vol.  81, 1875,  p.  619. 

* Annales  chim.  phys.,  5th  ser.,  vol.  14,  1878,  p.  380.  Dieulafait  mentions  earlier  work  by  Marchand 

and  Boussingault. 

& Contributions  a l’6tude  de  la  chimie  agricole,  in  Fremy’s  Encyclopedic  chimique,  1888. 

e Proc.  Roy.  Soc.  Edinburgh,  vol.  17, 1889,  p.  89. 

i Monatsh.  Chemie,  vol.  14, 1893,  p.  675;  vol.  15, 1894,  p.  596;  vol.  16, 1895,  p.  591;  vol.  20, 1899,  p.  1.  See 
also  E.  Raben,  Wissenschaftliche  Meeresuntersuchungen,  vol.  11,  Kiel,  1910,  p.  303.  Many  determina- 
tions are  given,  also  a full  summary  of  earlier  work. 

8 Compt.  Rend.,  vol.  137, 1903,  pp.  232,  374. 

9 Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1891,  p.  229. 

Wissenschaftliche  Meeresuntersuchungen,  vol.  11,  Kiel,  1910,  p.  311. 

“ Proc.  California  Acad.  Sci.,  vol.  2, 1859,  p.  7. 

12  Annales  chim.  phys.,  5th  ser.,  vol.  17,  1879,  p.  377.  See  also  Thorpe  and  Morton’s  analysis  of  water 
from  the  Irish  Sea,  1871,  cited  on  p.  123. 


THE  OCEAN. 


121 


Rubidium. — Found  in  sea  water  by  Sonstadt.1  Determined  quan- 
titatively by  Schmidt,  whose  analyses  will  be  cited  later. 

Caesium. — Also  found  by  Sonstadt.1 

Barium  and  strontium. — Can  be  detected  by  ordinary  methods. 
Also  found  in  the  ashes  of  seaweeds  and  in  boiler  scale.2 

Aluminum  and  iron. — Easily  detected  by  direct  methods. 

Manganese. — Easily  detected.  Noted  by  Forchhammer  and  also 
by  Dieulafait.3  Concretions  of  manganese  oxide  are  abundant  over 
portions  of  the  sea  bottom.  Reported  by  E.  Maumene  4 in  the  ashes 
of  Fucus  serratus. 

Nickel  and  cobalt. — Found  in  the  ashes  of  marine  plants. 

Copper. — Repeatedly  detected  in  sea  water,  especially  by  Dieula- 
fait.5 Also  in  the  ashes  of  seaweeds  and  in  certain  corals. 

Zinc. — Reported  in  sea  water  by  Dieulafait.6  Also  found  in  the 
ashes  of  seaweeds. 

Lead. — Found  by  Forchhammer  in  a coral. 

Silver. — Repeatedly  observed.  Forchhammer,  in  the  coral  above 
noted,  found  one  part  of  silver  to  eight  of  lead.  Malaguti,  Durocher, 
and  Sarzeaud  7 found  silver  to  the  amount  of  0.5  milligram  in  50 
liters  of  water  and  detected  copper  and  lead.  According  to  A. 
Liversidge,8  silver  is  present  in  sea  water  to  the  extent  of  1 to  2 grains 
per  ton. 

Gold. — The  fact  that  sea  water  contains  gold  was  first  established 
by  E.  Sonstadt 9 in  1872.  Its  presence  has  since  been  repeatedly 
verified.  In  1892  C.  A.  Munster  10  examined  water  from  the  Kris- 
tiania  Fjord,  Norway,  and  found  in  it  5 to  6 milligrams  of  gold,  with 
19  to  20  of  silver,  per  ton.  In  each  analysis  he  used  100  liters  of 
water.  LN  ersidge 11  found  the  gold  in  Australian  waters  to  range 
from  0.5  to  1.0  grain  per  ton.  At  either  rate,  gold  is  present  in  the 
ocean  in  thousands  of  millions  of  tons.  Liversidge  12  also  detected 
gold  in  kelp,  rock  salt,  and  a number  of  saline  minerals,  such  as 
sylvine,  kainite,  carnallite,  and  Chilean  niter.  In  one  sample  of  kelp 
he  found  22  grains  of  gold  per  ton,  and  in  a bittern,  5.08  grains. 
J.  R.  Don  13  examined  both  ocean  water  and  oceanic  sediments.  In 


1 Chem.  News.,  vol.  22, 1870,  p.  25. 

2 On  strontium  in  sea  water  see  Dieulafait,  Compt.  Rend.,  vol.  84, 1877,  p.  1303. 

3 Idem,  vol.  96, 1883,  p.  718. 

* Idem,  vol.  98,  1884,  p.  1417. 

5 Annales  chim.  phys.,  5th  ser.,  vol.  18,  1879,  p.  359. 

e Idem,  vol.  21,  1880,  p.  266. 

7 Idem,  3d  ser.,  vol.  28, 1850,  p.  129. 

8 Proc.  Roy.  Soc.  New  South  Wales,  vol.  29,  1895,  pp.  335, 350.  See  also  F.  Field,  Proc.  Roy.  Soc.,  vol.  8, 
1856,  p.  292. 

9 Chem.  News,  vol.  26,  1872,  p.  159. 

10  Jour.  Soc.  Chem.  Ind.,  vol.  11,  1892,  p.  351.  From  Norsk  Tekn.  Tidsskr. 

11  Proc.  Roy.  Soc.  New  South  Wales,  vol.  29,  1895,  pp.  335, 350. 

12  Jour.  Chem.  Soc.,  vol.  71,  1897,  p.  298. 

13  Trans.  Am.  Inst.  Min.  Eng.,  vol.  27,  1897,  p.  615. 


122 


THE  DATA  OF  GEOCHEMISTRY. 


the  former  he  detected  0.071  grain  of  gold  per  metric  ton,  but  the 
sediments  were  barren.  In  waters  collected  near  the  Bay  of  San 
Francisco  L.  Wagoner  1 found,  also  per  metric  ton,  11.1  milligrams 
of  gold  and  169.5  of  silver.  In  a later  paper  he  gives  larger  figures, 
namely,  16  milligrams  of  gold  and  1.9  grams  of  silver.  According  to 
J.  W.  Pack  2 sea  water  contains  about  0.5  grain  of  gold  per  ton.  In 
deep-sea  dredgings  Wagoner 3 detected  even  larger  quantities  of 
both  precious  metals. 

Radium. — Ocean  water,  sea  salt,  and  oceanic  sediments  are  all 
more  or  less  radioactive.  From  measurements  of  this  radioactivity 
the  amount  of  radium  is  inferred.4  According  to  Joly,  1 cubic 
centimeter  of  sea  water,  on  the  average,  contains  0.017  XlO-12  gram 
of  radium.  This  represents  a total  of  about  20,000  metric  tons  of 
radium  in  the  entire  ocean.  But  is  this  radioactivity  due  solely  to 
radium  ? 

COMPOSITION  OF  OCEANIC  SALTS. 

In  order  to  determine  the  composition  of  ocean  salts,  innumerable 
analyses  have  been  made,  representing  water  collected  in  all  quarters 
of  the  globe.  The  older  investigations,  down  to  and  including  the 
work  of  Forchhammer,  are  well  summarized  by  Both  and  it  is  not 
necessary  to  recapitulate  them  here.  With  a few  exceptions  I shall 
confine  myself  to  the  more  recent  analyses,  which  are  numerous 
enough  and  varied  enough  for  all  present  purposes.  They  show  a 
striking  uniformity  in  the  composition  of  sea  salts,  the  only  great 
variable  being  that  of  concentration.  As  this  factor  is  large,  com- 
pared with  the  salinity  of  lakes  and  rivers,  I shall  express  it  generally 
in  percentages  rather  than  in  parts  per  million.  The  analyses  them- 
selves I have  reduced  to  ionic  form,  ignoring  bicarbonates,  as  in  the 
tables  given  in  the  preceding  chapter.  The  selected  data  are  as 
follows:  5 

1 Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  807. 

2 Min.  and  Sci.  Press,  vol.  77,  1898,  p.  154. 

3 Trans.  Am.  Inst.  Min.  Eng.,  vol.  38, 1907,  p.  704.  P.  De  Wilde  (Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  19, 
1905,  p.  559)  and  A.  Wiesler  (Zeitschr.  angew.  Chemie,  1906,  p.  1795)  have  published  good  summaries  rela- 
tive to  the  detection  of  gold  in  sea  water  and  have  discussed  the  possibility  of  its  economic  recovery. 

4 See  It.  J.  Strutt,  Proc.  Roy.  Soc.,  vol.  78A,  1907,  p.  151;  A.  S.  Eve,  Philos.  Mag.,  6th  ser.,  vol.  18,1909, 
p.  102;  J.  Joly,  idem,  vol.  15, 1908,  p.  385;  vol.  18,  1909,  p.  396.  In  a volume  entitled  “Radioactivity  and 
geology, ” London,  1909,  pp.  45-58,  Joly  sums  up  the  relations  of  the  ocean  to  radium.  See  also  S.  J. 
Lloyd,  Am.  Jour.  Sci.,  4th  ser.,  vol.  39,  1915,  p.  580.  His  estimate  of  radium  in  sea  water  is  only 
1.2 XlO-12  gram  per  liter,  or  1,400  tons  in  the  ocean. 

5 Other  analyses  of  Atlantic  water,  taken  off  the  coast  of  Brazil,  with  analyses  of  water  from  the  mouths 
of  the  Amazon,  are  given  by  F.  Katzer,  in  Sitzungsb.  K.  bohm.  Gesell.  Wiss.  1897,  No.  17.  These  repre- 
sent mixtures  of  sea  and  river  water.  For  special  determinations  of  bromine  in  sea  water,  and  its  ratio  to 
the  chlorine,  see  E.  Berglund,  Ber.  Deutsch.  chem.  Gesell.,  vol.  18,  1885,  p.  2888.  An  analysis  of  water 
from  the  Ionian  Sea,  by  F.  Wibel,  is  printed  in  Ber.  Deutsch.  chem.  Gesell.,  vol.  6,  1873,  p.  184.  One  by 
A.  Vierthaler  (Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  56, 1867,  p.  479),  of  Adriatic  water  taken  nearSpalato, 
shows  abnormally  low  sodium  and  high  calcium,  presumably  due  to  admixtures  of  water  from  the  land. 
See  also  W.  Skey,  Third  Ann.  Rept.  Colonial  Mus.  and  Lab.,  New  Zealand,  1868,  for  seven  analyses  of 
sea  water  taken  near  that  island;  C.  J.  White,  Proc.  Roy.  Soc.  New  South  Wales,  vol.  41,  1907,  p.  55,  one 
analysis  of  water  taken  off  Coogee;  A.  Burada,  Ann.  sci.  Univ.  Jassy,  vol.  5,  1909,  p.  251,  one  analysis  of 
water  from  the  Black  Sea.  On  salinity  of  the  Persian  Gulf,  Annalen  d.  Hydrographic,  vol.  7,  1908,  p.  293. 
Two  recent  analyses  of  Adriatic  water  are  reported  by  V.  Gegenbauer,  Min.  pet.  Mitt.,  vol.  29, 1910,  p.  357. 


THE  OCEAN, 


123 


Analysis  of  oceanic  salts. 

A.  Mean  of  77  analyses  of  ocean  water  from  many  localities,  collected  by  the  Challenger  expedition. 
W.  Dittmar,  analyst.  Challenger  Kept.,  Physics  and  chemistry,  vol.  1,  1884,  p.  203.  Salinity  3.301  to 
3.737  per  cent. 

B.  Atlantic  water,  mean  of  22  samples  collected  on  a voyage  from  the  Cape  of  Good  Hope  to  England. 

C.  J.  S.  Makin,  Chem.  News,  vol.  77,  1898,  pp.  155, 171.  Salinity,  average,  3.631  per  cent. 

C.  The  Atlantic  near  Dieppe.  Analysis  by  T.  Schloesing,  Compt.  Rend.,  vol.  142, 1906,  p.  320.  Salinity 
32.420  grams  per  liter. 

D.  The  Irish  Sea.  Analysis  by  T.  E.  Thorpe  and  E.  H.  Morton,  Liebig’s  Annalen,  vol.  158,  1871,  p.  122. 
The  small  amounts  of  Fe2C>3,  NH3,  and  N2O5  are  here  added  together.  A trace  of  lithium  was  also  reported. 

E.  The  Baltic  Sea  between  Oeland  and  Gothland.  Analysis  by  C.  Schmidt,  Bull.  Acad.  St.  Peters- 
burg, vol.  24, 1878,  p.  231.  In  all  Schmidt’s  analyses  the  bicarbonates  given  by  him  have  been  here  reduced 
to  normal  salts.  The  quantities  of  Fe,  PO4,  and  Si02  found  by  Schmidt  are  so  small  that  I have  added 
them  together.  Salinity  of  this  sample,  0.7215  per  cent. 

F.  The  Atlantic  at  Bahia  Blanca,  coast  of  Argentina.  Mean  of  two  samples,  taken  at  low  and  high 
tide.  Analyses  by  E.  H.  Ducloux,  An.  Soc.  cient.  Argentina,  vol.  54,  1902,  p.  62.  Salinity,  3.365  per  cent. 
Another  pair  of  analyses  is  given  of  water  taken  at  the  mouth  of  Rio  Negro. 

G.  The  Gulf  of  Mexico,  off  Loggerhead  Key,  near  Florida.  Analysis  by  G.  Steiger,  laboratory  of  the 
U.  S.  Geological  Survey,  1910.  Salinity,  3.549  per  cent. 

H.  From  near  Beaufort,  North  Carolina.  Mean  of  five  analyses  of  samples  taken  under  varying  con- 
ditions, by  A.  S.  Wheeler,  Jour.  Am.  Chem.  Soc.,  vol.  32, 1910,  p.  646.  Salinity,  3.179  to  3.607  per  cent. 
Wheeler  cites  an  analysis  by  C.  Herbst  of  Mediterranean  water. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

55.  292 

55. 185 

55.  04 

55.  21 

55.  01 

54.  62 

55.  24 

55.  25 

Br 

. 188 

. 179 

. 19 

. 19 

. 13 

. 17 

S04 

7.  692 

7.  914 

7.  86 

7.  69 

8.  00 

8.  01 

7.  54 

7.  56 

CO, 

. 207 

. 213 

. 18 

. 09 

. 14 

. 27 

. 34 

. 37 

0 

Na 

30.  593 

30.  260 

30.  71 

30.  82 

30.  47 

30.  20 

30.  80 

30.  76 

K 

1. 106 

1. 109 

1.  06 

1. 16 

. 96 

2. 10 

1. 10 

1. 14 

Eb 

.04 

Ca 

1. 197 

1.  244 

1.  27 

1.  21 

1.  67 

1.  36 

1.  22 

1.  22 

Mg 

3.  725 

3.  896 

3.  69 

3.  61 

3.  53 

3.  36 

3.  59 

3.  70 

Fe,  Si02.  P04 

.05 

Fe,  NH4;  N03 

.02 

(Fe,Al)oO,,  SiOo 

.08 

100.  000 

100.  000 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

124 


THE  DATA  OF  GEOCHEMISTRY. 


Analysis  of  oceanic  salts — Continued. 

I.  The  north  Atlantic  between  Norway,  the  Faroe  Islands,  and  Iceland,  and  northward  to  Spitzbergen. 
Mean  of  51  incomplete  analyses  by  L.  Schmelck,  Den  Norske  N ordhavs-Expedition,  pt.  9, 1882,  p.  1 . Soda 
and  carbonic  acid  estimated  by  calculation,  not  directly  determined.  Salinity,  3.37  to  3.56  per  cent. 

J.  The  White  Sea.  Average  of  three  analyses  by  C.  Schmidt.  Bull.  Acad.  St.  Petersburg,  vol.  24, 1878, 
p.  231.  Salinity,  2.598  to  2.968  per  cent. 

K.  The  Arctic  Ocean  between  the  White  Sea  and  Nova  Zembla.  Mean  of  two  analyses  by  Schmidt, 
loc.  cit. 

L.  The  Siberian  Ocean.  Water  collected  by  the  Vega  expedition.  Mean  of  four  analyses  by  Forsberg, 
Vega  Exped.  Rept.,  vol.  2, 1883,  p.  376.  Salinity,  1.378  to  3.457  per  cent. 

M.  The  Mediterranean  near  Carthage.  Analysis  by  T.  Schloesing,  Compt.  Rend.,  vol.  142,  1906,  p.  320. 
Salinity,  38.9744  grams  per  liter. 

N.  The  Mediterranean,  midsea,  between  Bizerta  and  Marseille.  Salinity,  38.789  grams  per  liter.  Analy- 
sis by  Schloesing,  loc.  cit. 

O.  The  eastern  Mediterranean,  waters  collected  during  the  voyages  of  the  Austrian  steamer  Pola.  Ana- 
lyst, K.  Natterer,  Monatsh.  Chemie,  vol.  13,  1892,  pp.  873,  897;  vol.  14,  1893,  p.  624;  vol.  15,  1894,  p.  530. 
Three  hundred  samples  of  water  were  examined,  some  only  for  gases.  The  figures  given  here  are  the  aver- 
age from  42  analyses  which  were  fairly  complete.  Salinity,  3.836  to  4.115  per  cent. 

P.  The  Sea  of  Marmora.  Natterer,  Monatsh.  Chemie,  vol.  16, 1895,  p.  405;  44  partial  analyses.  Natterer 
gives  the  figures  here  utilized  as  averages  of  varying  numbers  of  determinations.  Mg,  Na,  and  K not 
determined.  Salinity,  2.310  to  4.061  per  cent. 


I 

J 

K 

L 

M 

N 

O 

P 

Cl 

\55.  46 

55.  22 

55.  30 

155.  45 

55.  53 

55.11 

55.  30 

55.  45 

Br 

/ 

. 14 

. 14 

j 

. 18 

.19 

.16 

. 17 

S04 

7.  59 

7.  88 

7.  78 

7.  79 

7.  74 

7.  89 

7.  72 

7.  67 

C03 

. 30 

. 10 

. 07 

. 19 

. 20 

. 19 

. 28 

Na 

30.  53 

30.  65 

30.  85 

30.  41 

30.  37 

30.  64 

30.  51 

K 

1. 12 

. 93 

. 89 

1. 17 

1.  09 

1.  09 

1. 12 

Rb... 

. 04 

. 04 

Ca 

1.  21 

1.  21 

1. 16 

1. 18 

1.  26 

1.  23 

1. 19 

1.  22 

Mg 

3.  79 

3.  75 

3.  69 

3.  82 

3.  64 

3.  65 

3.  81 

Fe,  Si02,  P04 ^ . 

. 08 

. 08 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

THE  OCEAN. 


125 


Analysis  of  oceanic  salts — Continued. 

Q.  The  Black  Sea.  Average  of  six  analyses  by  S.  Kolotoff,  Jour.  Russ.  Phys.  Chem.  Soc.,  vol.  24,  1893, 
p.  82.  Salinity,  1.826  to  2.223  per  cent. 

R.  The  Suez  Canal  at  Ismailia.  Analysis  by  C.  Schmidt,  Bull.  Acad.  St.  Petersburg,  vol.  24, 1878,  p.  231. 
Salinity,  5.103  per  cent.  For  other  data  on  the  Suez  Canal,  see  L.  Durand-Claye,  Annales  chim.  phys., 
5th  ser.,  vol.  3,  1874,  p.  188.  Very  high  salinities  were  noted.  For  a recent,  incomplete  analysis  of  Red 
Sea  water,  see  J.  B.  Coppock,  Chem.  News,  vol.  96,  1907,  p.  212. 

S.  The  Red  Sea  near  the  middle.  Analysis  by  Schmidt,  loc.  cit.  Salinity,  3.976  per  cent. 

T.  The  Red  Sea.  Average  of  four  analyses  by  Natterer,  Monatsh.  Chemie,  vol.  20,  1899,  p.  1;  vol.  21, 
1900,  p.  1037.  Water  collected  in  the  Suez  Canal,  the  Timsah  Lake,  and  the  two  Bitter  Lakes.  Many 
other  partial  analyses  are  given.  The  salinity  of  these  particular  samples  ranged  from  5.085  to  5.854  per 
cent. 

U.  The  Straits  of  Malacca.  Salinity,  2,7965  per  cent. 

V.  The  China  Sea.  Salinity,  3.208  per  cent. 

W.  The  Indian  Ocean,  mean  of  two  analyses,  salinity  3.5534  to  3.6681  per  cent.  Analyses  U,  V,  W,  by 
C.  Schmidt,  Mel.  phys.  chim.,  vol.  10,  p.  594.  Also  Jahresb.  Chemie,  1877,  p.  1370.  Schmidt’s  rubidium 
determinations  need  verification. 

X.  The  “Mare  Morto,”  an  inclosed  body  of  water  on  the  island  Lacromo  in  the  Adriatic,  having  under- 
ground connection  with  the  sea.  Salinity,  3.1744  per  cent.  Analysis  by  W.  Loebisch  and  L.  Sipocz,  Min. 
Mitt.,  1876,  p.  171. 


Q 

R 

s 

T 

U 

V 

W 

X 

Cl 

55. 12 

55.  59 

55.  60 

55.  96 

55.  46 

55.  43 

55.  41 

54.78 

Br 

. 18 

. 14 

.13 

. 18 

. 13 

. 13 

. 13 

.26 

S04 

7.  47 

7.  67 

7.  65 

7.  49 

7.  91 

7.  76 

7.  79 

7.  60 

C03 

.46 

.01 

.02 

. 13 

.04 

.03 

.05 

. 72 

Na. 

30.  46 

31.  21 

30.  81 

30.  31 

30.  23 

30.  67 

30.  89 

30.  57 

K 

1. 16 

.64 

.97 

1.  06 

.94 

.97 

.85 

1. 11 

Rb  

. 03 

.04 

.03 

. 04 

. 03 

Ca 

1.  41 

1.  05 

.89 

1.  22 

1. 19 

1. 19 

1. 16 

1.  25 

Mg 

3.74 

3.  64 

3.  87 

3.  65 

4.  03 

3.  75 

3.  67 

3.  71 

Fe,  S102,  P04 

. 02 

.02 

. 04 

. 03 

. 02 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Some  of  the  differences  between  the  foregoing  figures  are  no  larger 
than  can  be  ascribed  to  differences  in  analytical  methods  or  in  the 
atomic-weight  factors  used  for  calculation.  The  waters  of  the  Baltic 
and  Black  Seas,  with  their  very  low  salinity,  show  the  effect  of  dilu- 
tion by  fresh  water,  which  appears  in  the  slightly  higher  percentage 
of  calcium.  Still,  allowing  for  all  possible  sources  of  divergence, 
the  essential  uniformity  in  composition  of  ocean  salts  is  perfectly 
clear.  The  mass  of  the  ocean  is  so  great,  and  the  commingling  of  its 
waters  by  winds  and  currents  is  so  thorough,  that  the  local  changes 
produced  by  the  influx  of  rivers  are  exceedingly  small.  The  salinity 
may  range  from  less  than  1 to  over  4 per  cent,  but  the  saline  composi- 
tion remains  practically  the  same. 

For  the  composition  of  ocean  salts  in  general,  Dittmar’s  average 
should  be  taken  as  the  standard  of  comparison.  It  represents  the 
largest  number  of  complete  analyses  and  the  greatest  refinement  of 
methods;  the  samples  examined  covered  the  widest  geographic  range 
and  were  drawn  from  various  depths  of  water.  Some  were  surface 
specimens,  others  from  the  bottom  of  the  sea,  and  still  others  from 


126 


THE  DATA  OF  GEOCHEMISTRY. 


points  between,  and  all  the  results  lead  to  the  same  general  conclusion 
of  nearly  uniform  composition,  in  spite  of  variable  salinity.  The 
individual  analyses  vary  but  little  from  the  mean.  The  salinity  is 
shown  to  be  a function  of  temperature,  pressure,  and  density;  and  the 
last  factor  is  represented  by  J.  Y.  Buchanan’s  elaborate  determina- 
tions, which  appear  in  the  same  volume  with  Dittmar’s  analyses.1 
In  general,  according  to  the  summary  given  in  the  “Narrative”  of 
the  Challenger  expedition,2  the  density  and  therefore  the  salinity  of 
ocean  water  diminishes  from  the  surface  to  a depth  of  800  to  1,000 
fathoms,  and  then  increases  to  the  bottom.  Toward  both  poles  there 
are  areas  of  concentration  due  to  the  formation  of  ice,  a process  which 
removes  water  from  liquid  circulation,  leaving  a large  part  of  its  salts 
behind.  Freezing,  as  O.  Pettersson  3 has  shown,  modifies  the  compo- 
sition of  salt  water,  so  that  the  brine  formed  from  melting  ice  differs 
notably  from  the  parent  solution.  Two  analyses  by  Forsberg  4 serve 
to  illustrate  this  point.  Both  are  here  reduced  to  standard  form  in 
order  to  facilitate  comparison  with  those  of  normal  sea  water. 


Analyses  of  brine  from  melting  ice. 

A.  Liquid  intermingled  with  snow,  collected  on  Arctic  ice  at  — 32°. 

B.  Another  sample  free  from  snow,  also  collected  at  — 32°. 


A 

B 

Cl+Br 

62.  47 

63.  52 

S04 

1.  26 

. 82 

Na 

25.  88 

27.  85 

K 

. 97 

1.  06 

Ca 

2.  00 

1.  51 

Mr 

7.  42 

5.  24 

100.  00 

100.  00 

The  elimination  of  sulphates  and  the  increase  of  chlorides  is  here 
clearly  indicated,  and  if  we  refer  back  to  the  tables  previously  given 
we  shall  see  that  the  Arctic  waters  are  all  slightly  higher  in  sulphates 
than  Dittmar’s  average  for  the  great  oceans. 

In  one  sense  the  salinity  of  sea  water  is  a function  of  climate,  at 
least  so  far  as  surface  waters  are  concerned.  Where  the  rainfall  is 
slight  and  the  evaporation  rapid,  concentration  occurs;  where  the 
atmosphere  is  saturated  with  moisture  the  reverse  is  true.  The  Bed 
Sea  shows  the  maximum  effect  of  evaporation  and  the  highest 

1 Natterer  also,  in  the  memoirs  already  cited,  discusses  the  relations  between  density  and  salinity.  So, 
too,  does  H.  Tomoe  in  Den  Norske  Nordhavs-Expedition,  1880.  See  also  memoirs  by  A.  Bouquet  de  la 
Grye,  Annales  chim.  phys.,  5th  ser.,  vol.  25, 1882,  p.  433;  and  A.  Chevallier,  Compt.  Rend.,  vol.  140, 1905, 
p.  902.  On  this  theme  there  is  an  extensive  literature,  but  physical  problems  can  be  only  incidentallycon- 
sidered  in  the  present  memoir. 

2 Vol.  2, 1882,  pp.  948-1003. 

8 Vega  Exped.  Rept.,  vol.  2, 1883,  pp.  349-380. 

* See  O.  Pettersson,  op.  cit.,  1883,  p.  376. 


THE  OCEAN. 


127 


salinity;  the  Mediterranean  is  next  in  order.  West  of  the  Nile  no 
large  rivers  enter  the  Mediterranean;  the  evaporation  along  the 
African  shore  is  very  great,  and  the  salinity  is  therefore  excessive. 
Furthermore,  rainfall  serves  to  dilute  the  superficial  layers  of  the 
ocean,  and  the  same  effect  is  produced  by  the  influx  of  streams.  The 
Black  Sea,  for  instance,  is  diluted  by  the  Danube,  and  its  average 
salinity  barely  exceeds  2 per  cent.  When  a river  enters  the  ocean  its 
waters  tend  to  flow  upon  the  surface,  and  its  influence  may  be  detected 
at  great  distances,  sometimes  hundreds  of  miles  from  land.  Salinity, 
in  short,  is  the  product  of  many  agencies,  and  the  commingling  of 
waters  is  never  quite  complete.  In  view  of  conditions  like  these 
the  nearly  uniform  composition  of  sea  salts  is  all  the  more  striking. 

It  is  commonly  assumed  that  the  salts  of  the  ocean  are  derived 
from  the  decomposition  of  rocks  by  flowing  and  percolating  waters, 
which  finally  deposit  their  burden  in  the  great  general  reservoir. 
That  this  opinion  is  in  a very  large  measure  correct  is  unquestion- 
able; whether  it  is  wholly  true,  without  qualification,  is  another 
matter.  We  have  already  seen,  in  the  preceding  chapter,  that  an 
enormous  mass  of  soluble  salts  is  annually  discharged  by  rivers  into 
the  sea,  but  its  composition  is  very  different  from  that  of  the  saline 
substances  which  we  are  now  considering.  In  the  one  class  of  waters 
carbonates  and  calcium  prevail;  in  the  other  we  find  mainly  chlo- 
rides and  sodium.  If,  then,  ocean  water  is  continually  receiving 
water  unlike  itself,  its  composition  must  be  slowly  changing,  but  the 
gains,  although  large  in  themselves,  are  relatively  small  in  compari- 
son with  the  vast  accumulations  of  saline  matter  into  which  they 
diffuse.  Whatever  changes  may  take  place  must  proceed  very 
slowly,  and  no  known  methods  of  analysis  are  delicate  enough  to 
detect  them,  even  were  the  observations  to  be  continued  through 
many  centuries.  For  instance,  calcium  is  one  of  the  minor  con- 
stituents of  sea  water,  and  yet  J.  Murray  and  K.  Irvine  1 estimate 
that  the  discharge  of  rivers  would  require  680,000  years  to  make  up 
the  total  oceanic  amount.2 

Practically,  then,  the  composition  of  the  ocean  is  very  nearly  con- 
stant and  has  been  so  for  long  periods  of  time.  We  can  not,  by 
means  of  analysis,  measure  the  changes  in  it,  but  we  can  observe 
some  of  them  in  operation,  and  see  whither  they  tend.  They  are  due 
either  to  gains  or  losses  of  material,  and  both  conditions  have  been 
noted  in  the  preceding  pages.  The  gains  from  rivers  and  from  rain- 
fall are  obvious;  the  losses  by  precipitation  we  shall  examine  presently. 
Some  salts,  as  we  observed  in  studying  the  atmosphere,  are  lifted 
from  the  ocean  to  fall  again,  partly  upon  the  land,  in  rain.  Much  of 

1 Proc.  Roy.  Soc.  Edinburgh,  vol.  17, 1889,  pp.  100-101. 

2 For  a statistical  paper  on  the  mineral  matter  in  the  sea,  see  R.  D.  Salisbury,  Jour.  Geology,  vol.  13,  . 
1905,  p.  469.  See  also  A.  C.  Lane,  Jour.  Geology,  vol.  14, 1906,  p.  221,  and  A.  B.  Macallum,  Trans.  Canadian 
Inst.,  vol.  7,  1903,  p.  535. 


128 


THE  DATA  OF  GEOCHEMISTRY. 


this  material  returns  into  the  sea,  but  we  can  not  assume  that  all  of  it 
is  regained.  This  loss,  however,  is  trifling,  and  needs  no  further 
consideration  here.  Streams  bring  more  chlorine  and  more  sodium 
into  the  ocean  than  it  loses  through  the  mechanical  action  of  the  air. 
For  these  constituents  a small  net  gain  may  safely  be  taken  for  granted. 
As  for  the  changes  in  composition  produced  in  sea  water  by  freezing, 
they  are  local  and  transitory  in  character.  When  the  ice  melts,  its 
saline  contents  are  restored  to  oceanic  circulation,  although  not  always 
at  the  point  from  which  they  were  withdrawn.  To  the  slight  change 
thus  produced  in  Arctic  waters  reference  has  already  been  made. 

CARBONATES  IN  SEA  WATER. 

Although  calcium  and  carbonic  acid  are  subordinate  constituents 
of  sea  water,  their  importance  can  hardly  be  overestimated.  They 
are  the  chief  additions  made  by  rivers  to  the  ocean,  and  they  are 
the  substances  most  largely  withdrawn  from  it  by  living  organisms. 
Removed  from  solution,  they  form  calcium  carbonate,  and  that  is  the 
principal  material  of  corals  and  shells. 

Normal  calcium  carbonate  is  nearly  but  not  quite  insoluble  in 
water.  Upon  this  point  many  observations  have  been  made.  Ac- 
cording to  T.  Schloesing,1  whose  data  appear  to  be  trustworthy,  a 
liter  of  water  at  16°  can  dissolve  0.0131  gram  of  CaC03.  With  respect 
to  sea  water,  however,  the  different  varieties  of  the  carbonate  behave 
differently.  This  has  been  shown  by  R.  Irvine  and  G.  Young,2  who 
found  that  amorphous  calcium  carbonate  is  more  soluble  than  the 
crystalline  forms.  To  dissolve  1 part  of  the  former  1,600  parts  of 
sea  water  are  required,  as  compared  with  8,000  parts  for  the  crystal- 
line carbonate.  This  difference  bears  directly  upon  the  theory  of 
coral  reefs.  The  living  animal  secretes  amorphous  carbonate,  but 
after  decomposition  a partial  change  to  crystalline  carbonate  occurs. 
Without  this  molecular  rearrangement  the  coral  would  much  more 
largely  dissolve  and  its  stability  would  be  greatly  diminished.  Some 
re-solution,  however,  occurs,  especially  where  the  waves  have  beaten 
the  coral  into  sand,  and  this  subject  has  been  well  studied  by 
J.  Murray  and  R.  Irvine.3  They  find  that  the  porous  corals  dissolve 
more  readily  than  the  compact  varieties. 

In  presence  of  free  carbonic  acid,  the  solubility  of  calcium  carbonate 
is  increased  many  fold.  If  we  disregard  ionization  we  may  say  that 
calcium  bicarbonate,  CaH2C206,  is  then  formed,  a compound  which  is 
chiefly  known  in  solution.  Of  this  salt,  as  shown  by  F.  P.  Treadwell 

1 Compt.  Rend.,  vol.  74,  1872,  p.  1552. 

2 Proc.  Roy.  Soc.  Edinburgh,  vol.  15, 1888,  p.  316.  For  other  data  on  the  solubility  of  calcium  carbonate 
in  sea  water,  see  W.  S.  Anderson,  Proc.  Roy.  Soc.  Edinburgh,  vol.  16, 1889,  p.  318;  and  J.  Thoulet,  Compt, 
Rend.,  vol.  110, 1890,  p.  652. 

8 Proc.  Roy.  Soc.  Edinburgh,  vol.  17, 1889,  p.  79. 


THE  OCEAN. 


129 


and  M.  Reuter,1  a liter  of  pure  water  at  15°  can  dissolve  0.3850  gram, 
a quantity  which  may  he  considerably  increased  by  an  excess  of 
carbon  dioxide  in  the  water.  In  sea  water  this  solubility  is  modified 
by  the  presence  of  other  compounds.  E.  Cohen  and  M.  Raken,2 
experimenting  with  an  artificial  sea  water,  found  that  at  15°  it  was 
saturated  by  55.6  milligrams  of  fixed  C02  per  liter,  equivalent  to  0.1264 
gram  of  CaC03.  According  to  G.  Linck,3  the  maximum  solubility 
of  calcium  carbonate  in  sea  water  at  17Q-18°  is  0.191  gram  per  liter. 
The  total  quantity  of  calcium  carbonate  in  average  sea  water,  as 
shown  by  Dittmar’s  analyses,  and  upon  the  assumption  that  all  of  the 
C03  radicle  is  thus  combined,  is  not  far  from  0.121  gram  per  liter. 
This,  which  is  a maximum,  is  even  below  the  saturation  figure  given 
by  Cohen  and  Raken,  and  much  lower  than  that  of  Linck.  It  would 
be  diminished  by  the  formation  of  other  carbonates,  and  it  must  vary 
with  fluctuations  in  the  free  or  half-combined  carbonic  acid  of  the 
water.  The  latter  constituent  of  sea  water  does  ^not  appear  in  the 
analyses  of  dried  oceanic  salts. 

Calcium  bicarbonate  is  very  unstable  and  can  be  broken  down  to 
normal  carbonate  and  free  carbon  dioxide  by  evaporation,  by  rise  of 
temperature,  or  by  mechanical  agitation.4  Under  certain  conditions 
the  carbonate  thus  produced  may  assume  the  solid  form  and  be  pre- 
cipitated as  a sort  of  calcareous  ooze.  This,  however,  can  take  place 
only  in  very  shallow  waters,  and  especially  near  the  mouths  of  streams 
which  carry  carbonates  in  maximum  amount.  Such  a deposition  of 
calcium  carbonate,  forming  a crystalline  limestone,  was  long  ago 
observed  in  the  delta  of  the  Rhone;  and  a similar  reaction  is  taking 
place  among  the  Florida  keys.  Sea  water,  however,  is  not  saturated 
with  carbonates,  and  a precipitate  forming  on  the  surface  of  the  open 
ocean  would  be  redissolved  before  it  could  settle  to  the  bottom. 
Even  shells  undergo  solution,  and  in  sufficiently  deep  water  they  may 
entirely  disappear.  In  the  reports  of  the  Challenger  expedition  there 
is  much  valuable  information  on  this  point.5 6  Pteropod  remains  were 
never  found  on  the  ocean  floor  at  depths  below  1,500  fathoms,  but 
the  more  resistant  globigerina  was  collected  at  2,500  fathoms.  These 
animals  live  at  or  near  the  surface;  after  death  the  shells  slowly  sink, 
and,  while  sinking,  partially  or  wholly  dissolve.  The  decay  of  their 
organic  matter  generates  abundant  carbonic  acid,  and  this  aids  in 
effecting  solution.  Be  this  as  it  may,  the  Challenger  investigations 
show  that  the  quantity  of  calcium  carbonate  on  the  bottom  of  the 

1 Zeitschr.  anorg.  Chemie,  vol.  17,  1898,  p.  170. 

2 Proc.  Sec.  Sci.,  Amsterdam  Acad.,  vol.  3, 1901,  p.  63. 

3 Neues  Jahrb.,  Beil.  Bd.  16,  1903,  p.  505.  A recent  paper  on  the  solubility  of  calcium  carbonate,  by 

J.  Kendall,  is  in  Philos.  Mag.,  ser.  6,  vol.  23, 1912,  p.  958. 

* W.  Dittmar,  Challenger  Rept.,  Physics  and  chemistry,  vol.  1,  1884,  p.  211. 

6 See  summary  in  vol.  2 of  the  Narrative,  1882,  pp.  948  et  seq. 

97270°— Bull.  616—16 9 


130 


THE  DATA  OE  GEOCHEMISTRY. 


ocean  depends  in  great  measure  upon  the  depth  of  water.  Beyond 
the  limits  indicated  little  calcium  carbonate  is  found,  a fact  which 
will  be  considered  more  in  detail  presently. 

Calcium  carbonate,  then,  takes  part  in  a great  system  of  cnanges 
whose  magnitude  and  direction  can  hardly  be  estimated.  It  enters 
the  sea  in  fresh  waters;  part  of  it  is  withdrawn  by  living  animals  to 
form  coral  or  shell;  some  of  the  material  thus  used  is  redissolved, 
but  much  of  it  is  permanently  deposited  in  limestones  or  calcareous 
shales.  Limestone  formations  of  marine  origin,  in  all  quarters  of  the 
globe,  testify  to  the  importance  of  these  processes.  Living  animals 
secrete  more  calcium  carbonate  than  is  redissolved,1  but  the  inflow 
of  fresh  waters  tends  to  supply  the  loss.  Whether  a balance  is  pre- 
served it  is  impossible  to  say.  The  problem  is  complicated  by  the 
fact  that  the  erosion  of  limestones  laid  down  in  former  geologic  pe- 
riods now  supplies  material  to  streams,  thus  returning  to  the  ocean 
carbonates  which  were  once  withdrawn  from  it.2 

In  this  system  of  gains  and  losses  some  otherwise  unimportant 
constituents  of  sea  water  play  an  interesting  part.  Radiolarians, 
diatoms,  and  siliceous  sponges  extract  silica  from  the  ocean;  this 
material  is  finally  deposited  upon  the  sea  floor,  and  does  not  redissolve, 
or  at  least  not  readily.3  The  silica  brought  in  by  rivers  is  partly  dis- 
posed of  in  this  way.  Phosphates  are  also  withdrawn,  but  the  bony 
parts  of  marine  creatures,  after  the  death  of  the  latter,  go  to  a great 
extent  into  solution  again.  Iron,  silica,  and  some  potassium  are  laid 
down  in  the  form  of  glauconite;  and  the  substances  dredged  up  from 
the  bottom  of  the  ocean  tell  us  of  still  other  reactions  which  are  not 
easy  to  explain. 

OCEANIC  SEDIMENTS.4 

On  the  subject  of  oceanic  sediments  there  is  a voluminous  literature. 
A great  part  of  it  relates  to  what  may  be  called  mechanical  deposits, 
like  gravel,  sand,  river  silt,  and  so  on — a class  of  substance  that  does 
not  concern  us  now.  Their  chemical  character  will  be  discussed  else- 
where, with  reference  to  their  origin.  Near  land,  and  especially  at  the 
mouths  of  rivers,  the  sea  bottom  is  covered  mainly  by  mechanical 
sediments,  or  by  the  remains  of  marine  animals;  in  mid-ocean  the 
deposits  are  of  a very  different  type. 

An  entire  volume  of  the  Challenger  reports,  by  J.  Murray  and 
A.  F.  Renard,  is  devoted  to  the  subject  of  “ Deep-sea  deposits,”  and 


1 See  J.  Murray  and  R.  Irvine,  Proc.  Roy.  Soc.  Edinburgh,  vol.  17, 1889,  p.  79. 

2 On  the  circulation  of  calcium  carbonate,  and  its  relation  to  the  age  of  the  earth,  see  E . Dubois,  Proc.  Sec. 
Sci.,  Amsterdam  Acad.,  vol.  3, 1901,  pp.  43, 116. 

a The  insolubility  of  silica  in  sea  water  is  great  but  not  absolute.  J.  Murray  and  A.  F.  Renard  (Chal- 
lenger Rept.,  Deep-sea  deposits,  1891,  p.  288)  find  that  some  silica  can  be  dissolved  out  from  diatomaceous 
ooze. 

* A recent  treatise  by  L.  W.  Collet  (Les  depots  marins,  Paris,  1908)  deals  with  this  subject  quite  fully. 


THE  OCEAN. 


131 


special  attention  is  paid  to  substances  formed  by  chemical  action  on 
the  ocean  floor.1  The  larger  deposits  may  be  classified  as  follows: 


Deposits  on  the  ocean  floor. 


Name. 

Average  depth 
in  fathoms. 

Percentage  of 
CaC03. 

Red  clay 

2,  730 
2,  894 
1, 477 
2,049 
1,044 

6.  70 
4.  01 
22.  96 
64.  47 
79.  25 

Radiolarian  ooze 

Diatom  ooze 

Globigerina  ooze 

Pteropod  ooze 

The  oozes  derive  their  names  from  the  characteristic  organic 
remains  which  they  contain,  and  they  merge  by  slight  gradations 
one  into  another.  The  classification  is  obviously  approximate,  not 
absolute.  If  we  consider  them  together,  and  include  the  coral  muds, 
the  average  percentage  of  calcium  carbonate  upon  the  sea  bottom  at 
various  depths  is  as  follows: 


Variation  of  calcium  carbonate  with  depth. 


Per  cent. 


Under  500  fathoms 86.  04 

500  to  1,000  fathoms 66.  86 

1,000  to  1,500  fathoms 70.  87 

1,500  to  2,000  fathoms 69.  55 


Per  cent. 


2.000  to  2,500  fathoms 46.  73 

2.500  to  3,000  fathoms 17.  36 

3.000  to  3,500  fathoms 88 

3.500  to  4,000  fathoms None- 


The  disappearance  of  carbonates  with  increasing  depth  is  thus 
clearly  shown. 

Of  all  these  deposits,  the  red  clay,  which  covers  about  51,500,000 
square  miles,  is  the  most  extensive,  and  from  a chemical  point  of  view, 
the  most  interesting.  It  is  universally  distributed  in  the  oceanic 
basins,  but  is  typical  only  at  depths  ranging  from  2,200  to  4,000 
fathoms  and  far  from  land.  Various  theories  have  been  proposed  to 
account  for  its  formation;  but  Murray  and  Renard  look  on  it  as  essen- 
tially a chemical  deposit,  produced  by  the  decomposition  of  silicates 
of  volcanic  origin.  Remnants  of  volcanic  rocks  are  found  on  nearly 
all  parts  of  the  ocean  floor,  and  fragments  of  pumice  are  particularly 
common.  Some  of  these  doubtless  came  from  ordinary  subaerial  vol- 
canoes, either  as  direct  flows  into  the  ocean,  or  as  volcanic  dust  borne 
long  distances  by  currents  of  air.  Other  fragments  represent  sub- 
marine volcanoes.  Some  of  the  specimens  studied  by  Murray  and 
Renard  were  quite  fresh,  others  were  largely  decomposed;  and  in  a 
number  of  them  zeolites  had  been  formed  by  subaqueous  alteration. 
Crystals  of  phiflipsite  were  repeatedly  identified.  The  color  of  the 
clay  is  due  to  ferric  oxide  or  hydroxide,  which  is  easily  removable  by 


1 See  also  J.  Murray,  Geog.  Jour.,  vol.  19, 1902,  p.  691;  on  material  collected  in  1901  by  S.  S.  Britannia. 


132 


THE  DATA  OF  GEOCHEMISTRY. 


means  of  strong  acids.  In  all  essential  respects  the  clay  resembles 
the  residues  formed  by  the  decay  of  igneous  rocks.  Its  composition, 
as  shown  by  many  analyses,  is  extremely  variable. 

That  sea  water  will  attack  and  dissolve  silicates  is  well  known, 
although  its  efficiency  is  less  than  that  of  fresh  water.  On  this 
subject  the  experiments  of  J.  Thoulet 1 have  been  often  quoted  and 
A.  Johnstone  2 has  shown  that  even  so  refractory  a mineral  as  talc  is 
slowly  but  perceptibly  soluble.  The  process  of  change  is  of  course 
almost  inconceivably  slow;  but  in  the  quiet  depths  of  the  ocean  it  has 
doubtless  been  going  on  throughout  all  geological  time.  It  began 
when  the  first  volcanic  eject  amenta  entered  the  sea,  if  such  a moment 
can  be  imagined,  and  has  been  operative  continuously  to  the  present 
day.  Cosmic  and  other  dusts  have  contributed  something  to  the 
formation  of  the  clay,  and  so,  too,  have  animal  remains;  but  volcanic 
matter  seems  to  have  been  the  chief  starting  point.  This  is  the  view 
of  Murray  and  Renard,  and  it  is  the  opinion  best  sustained  by  chemical 
evidence.  Possibly,  however,  submarine  volcanoes  must  also  be 
taken  into  account. 

In  addition  to  the  widespread  formations  mentioned  in  the  fore- 
going paragraphs,  the  sea  bottom  yields  many  interesting  products 
of  a sporadic  or  local  character.  Among  them  are  the  well-known 
manganese  and  phosphatic  nodules  and  glauconite;  and  these  we 
may  briefly  consider  in  regular  order. 

Manganese, . as  oxide  or  hydroxide,  exists  in  all  deep-sea  deposits, 
sometimes  as  grains  in  the  clay  or  ooze,  sometimes  as  a coating  upon 
pumice,  coral,  shells,  or  fragments  of  bone,  and  often  in  the  form  of 
nodular  concretions  made  up  of  concentric  layers  about  some  other 
substance  as  a nucleus.3  Even  in  shallow  waters,  as  in  Loch  Fyne  in 
Scotland,  these  nodules  have  been  found,4  but  they  seem  to  be  more 
characteristic  of  the  deeper  ocean  abysses,  whence  the  dredge  often 
brings  them  up  in  great  numbers. 

The  origin  or  mode  of  formation  of  the  manganese  nodules  is  still 
in  doubt.  Murray  5 regards  the  manganese  as  derived,  like  the  red 
clay,  from  the  subaqueous  decomposition  of  volcanic  debris.  C.  W. 
Giimbel 6 attributes  the  nodules  to  submarine  springs  holding  manga- 
nese in  solution,  which  is  precipitated  on  contact  with  sea  water. 
Buchanan  7 invokes  the  reducing  agency  of  organic  matter,  which 
transforms  the  sulphates  of  sea  water  to  sulphides,  precipitating  iron 

1 Compt.  Rend.,  vol.  108, 1889,  p.  753.  See  also  recent  work  by  J.  Joly,  in  Compt.  rend.  Vni.  Cong.  g6oL 
internat.,  1900,  p.  774. 

2 Proc.  Roy.  Soc.  Edinburgh,  vol.  16, 1889,  p.  172. 

2 For  full  description  see  Challenger  Rept.,  Deep-sea  deposits,  1891,  pp.  341-378.  See  also  J.  Murray  and 
R.  Irvine,  Trans.  Roy.  Soc.  Edinburgh,  vol.  37, 1895,  p.  721. 

4 J.  Y.  Buchanan,  Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1890,  p.  19. 

b Proc.  Roy.  Soc.  Edinburgh,  vol.  9, 1876,  p.  255. 

6 See  abstract  in  Neues  Jahrb.,  1878,  p.  869. 

7 Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1890,  p.  17. 


THE  OCEAN. 


133 


and  manganese  in  the  latter  form  to  be  subsequently  oxidized.  This 
view  was  contested  by  R.  Irvine  and  J.  Gibson,1  who  showed  that 
manganese  sulphide  was  decomposed  by  sea  water,  the  manganese 
redissolving  as  bicarbonate.  J.  B.  Boussingault 2 holds  that  the  man- 
ganese was  derived  from  carbonates  carried  in  solution  by  oceanic 
waters  and  a similar  explanation  has  been  offered  by  L.  Dieulafait.3 
The  oxidation  of  the  carbonates  is  supposed  to  take  place  at  the  sur- 
face, through  atmospheric  contact,  after  which  the  precipitated  oxide 
falls  to  the  bottom  of  the  sea. 

Of  all  these  theories,  that  of  Murray  seems  to  be  the  best  substan- 
tiated. The  manganese  can  easily  be  derived  from  the  alteration  of 
rock  fragments,  as  it  is  by  weathering  on  land;  it  goes  into  solution 
as  carbonate,  is  oxidized  by  the  dissolved  oxygen  of  the  sea  water, 
and  is  precipitated  near  its  point  of  derivation  around  any  nuclei 
which  happen  to  be  at  hand.  The  nodules  occur  in  close  association 
with  altered  volcanic  materials,  and  most  abundantly  in  connection 
with  the  red  clay  of  similar  origin;  furthermore,  their  impurities  are 
of  the  kind  which  the  suggested  mode  of  formation  would  lead  us  to 
expect.  In  composition  the  nodules  vary  widely,  ranging  from  4.16 
to  63.23  per  cent  of  manganese  oxide.  The  analysis  by  J.  Gibson  4 
is  the  most  complete  one  among  the  many  which  were  made,  and  is 
therefore  selected  as  representative.  The  entire  sample  contained — 


Water 29.  65 

Aqueous  extract 5 2.  44 

Insoluble  residue 17.  93 

Portion  soluble  in  HC1 49.  97 


99.  99 


1 Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1890,  p.  54. 

2 Annales  chim.  phys.,  5th  ser.,  vol.  27,  1882,  p.  289. 

s Compt.  Rend.,  vol.  96, 1883,  p.  718. 

4 Challenger  Rept.,  Deep-sea  deposits,  1891,  pp.  417-423. 

6 Saline  matter  unavoidably  inclosed  in  the  nodules.  Gibson  gives  its  composition  in  detail. 


134 


THE  DATA  OF  GEOCHEMISTRY. 


The  insoluble  and  soluble  portions,  recalculated  separately,  are 
represented  in  the  subjoined  statement: 


Analysis  of  manganese  nodule. 


Portion  soluble 
in  HC1. 

Insoluble 

portion. 

Si02 

74.  58 

Ti(>2  

. 72 

A1203 

6.  34 

12.  93 

Fe203 

26.  97 

4.  79 

mAk 

4.  60 

CaO 

4.  02 

1. 45 

SrO 

. 11 

BaO 

.67 

MnO 

42.  94 

NiO 

1.  96 

CoO 

. 56 

ZnO 

.20 

CuO 

. 74 

PbO 

. 10 

TLO 

.06 

Na^jO 

3.  62 

K20 

.95 

P90, 

.22 

.11 

VXb 

. 14 

Mo03 

.20 

so3 

.94 

co2 

.58 

Peroxide  oxygen 

9.  42 

99.  99 

99.  93 

If  we  include  in  this  analysis  the  water  of  the  original  material  we 
see  that  it  represents  a mixture  of  manganese,  iron,  and  aluminum 
hydroxides,  soluble  in  hydrochloric  acid,  with  an  insoluble  residue  of 
silicates.  The  specimen  came  from  a depth  of  2,375  fathoms. 

The  phosphatic  concretions  found  on  the  ocean  floor  offer  a sim- 
pler problem  for  solution.  As  Murray  and  Renard  1 show,  they  are 
directly  derived  from  the  “ decaying  bones  of  dead  animals,  upon 
wdiich  carbonic  acid  exerts  a powerful  solvent  action.”  They  form, 
like  the  manganese  nodules,  around  various  nuclei,  but  preferably 
upon  organic  centers,  such  as  shells.  In  many  cases  the  phosphatic 
matter  was  first  deposited  in  cavities  of  shells,  around  which  the 
nodules  continued  to  grow,  inclosing  various  muddy  impurities. 
Probably  the  ammoniacal  salts  which  are  generated  by  the  decompo- 
sition of  organic  matter  in  the  bone  play  some  part  in  the  precipita- 
tion of  the  calcium  phosphate.  The  following  analyses,  by  Klement, 
show  the  composition  of  these  bodies.  A was  from  a depth  of  150 
and  B from  1,900  fathoms. 


1 Challenger  Rept.,  Deep-sea  deposits,  1891,  pp.  397-400.  On  the  phosphatic  nodules  of  the  Agulhas 
Bank,  see  L.  W.  Collet,  Proc.  Roy.  Soc.  Edinburgh,  vol.  25,  1905,  p.  862;  and  L.  Cayeux,  Bull.  Soc.  gdol. 
France,  4th  ser.,  vol.  5,  1906,  p.  750. 


THE  OCEAN. 


135 


Analyses  of  phosphatic  concretions  from  sea  bottom. 


A 

B 

p0o, 

19.  96 

23.  54 

co2 

12.  05 

10.  64 

so3 

1.  37 

1.39 

Si02 

1.  36 

2.  56 

CaO 

39.  41 

40.  95 

MgO 

.67 

.83 

Feo0,  

2.54 

2.  79 

A1,0,  

1. 19 

1. 43 

Loss  on  ignition 

Undet. 

3.  65 

Insoluble  residue 

17.  34 

11.  93 

95.  89 

99.  71 

Analyses  of  the  insoluble  residue  gave  the  following  results : 
Analyses  of  insoluble  residue  from  phosphatic  concretions. 


A 

B 

Si02 

77.  43 

76.  58 

A1203 

12.40 

13.  85 

Fe903 

7.  91 

7.  93 

CaO 

1.  07 

1.  27 

MgO 

1.  02 

1. 18 

99.  83 

100.  81 

The  concretions,  then,  consist  mainly  of  calcium  phosphate  and 
carbonate,  mixed  with  sand  and  clay. 

The  last  of  the  oceanic  deposits  which  we  need  to  consider  in  this 
connection  is  glauconite,  a hydrated  silicate  of  potassium  and  ferric 
iron.  It  is  widely  disseminated  upon  the  sea  bottom,  but  most  abun- 
dantly in  comparatively  shallow  waters  and  near  the  mud  line  sur- 
rounding continental  shores — that  is,  it  is  formed  “just  beyond  the 
limits  of  wave  and  current  action,  or,  in  other  words,  where  the  fine 
muddy  particles  commence  to  make  up  a considerable  portion  of  the 
deposits.’’1  It  is  developed  principally  in  the  interior  of  shells,  but 
its  mode  of  formation  is  obscure.  Murray  and  Renard  argue  that 
after  the  death  of  the  organism  the  shell  first  becomes  filled  with  fine 
mud,  upon  which,  in  presence  of  the  sulphates  of  sea  water,  the 
organic  matter  of  the  animal  may  act.  The  iron  of  the  mud  is  re- 
duced to  sulphide,  which  afterwards  oxidizes  to  ferric  hydroxide, 
alumina  being  at  the  same  time  removed  in  solution  and  colloidal 
silica  set  free.  The  latter,  reacting  upon  the  hydroxide,  in  presence 
of  potassium  salts  derived  from  adjacent  minerals,  finally  generates 


1 Murray  and  Renard,  Challenger  Rept.,  Deep-sea  deposits,  1891,  p.  383. 


136 


THE  DATA  OF  GEOCHEMISTRY. 


glauconite.  This  theory  is  supported  by  the  observation  that  the 
glauconitic  shells  are  always  associated  with  the  detritus  of  terrigenous 
rocks,  containing  orthoclase,  muscovite,  and  other  minerals  from 
which  the  necessary  potassium  could  be  obtained.  In  a later  portion 
of  this  work  we  shall  have  to  examine  the  subject  of  glauconite  more 
fully.  An  elaborate  discussion  of  it  would  be  out  of  place  now. 

Oceanic  deposits,  then,  whether  of  shell,  coral,  red  clay,  manganese 
nodules,  or  glauconite,  are  in  a sense  the  fossil  records  of  chemical 
reactions  which  have  taken  place  in  the  depths  of  the  sea.  They 
represent  both  additions  to  and  withdrawals  of  matter  from  the 
waters  of  the  ocean,  with  the  formation  of  new  substances  by  chemical 
change.1 * 

The  relative  quantities  of  the  chemical  sediments  thus  annually 
formed  can  be  approximately  estimated.  For  this  purpose  we  may 
first  compare  in  detail  the  actual  amount  of  each  radicle  poured 
into  the  ocean  in  one  year  with  the  total  accumulation  of  saline 
matter  in  the  ocean  itself.  The  data  are  given  in  the  following  table: 

Comparison  of  oceanic  and  Jluviatile  salts. 

A.  The  annual  addition  of  each  radicle,  by  rivers,  computed  from  the  data  already  given  in  the  preced- 
ing chapter. 

B.  The  saline  matter  in  the  ocean,  computed  from  Dittmar’s  analyses,  with  Karstens’s  value  for  the 
volume  of  the  ocean,  1,285,935,211  cubic  kilometers,  and  a mean  density  of  1.026. 


A 

B 

Annual  from  rivers 

In  ocean 

(metric  tonsXlO3). 

(metric  tonsXlO12). 

co3 

961,  350 
332,  030 
155, 350 

95.  6 

so4 

3,  553.  0 
25,  538.  0 
86.8 

Cl 

Br 

no3 

24,  614 
258,  357 
57,  982 
557,  670 
93,  264 
75,  213 
319, 170 

Na 

14, 130.  0 
510.  8 

K 

Ca 

552.  8 

Mg 

1, 721.  0 

Si02 

Sum 

2,  735,  000  X103 

46, 188.0X1012 

If  from  each  of  the  quantities  in  column  A we  subtract  the  amount 
annually  retained  in  solution  by  the  sea,  the  difference  will  represent 
the  amount  precipitated.  To  do  this,  an  assumption  must  be  made 
as  to  the  age  of  the  ocean;  but  whatever  figure  is  assumed,  the  results 
will  be  of  the  same  order  of  magnitude.  For  example,  the  ocean 
contains  552.8 X 1012  metric  tons  of  dissolved  calcium;  which  quan- 
tity, divided  by  the  assumed  age,  gives  the  annual  increment.  If 


1 E.  J.  Jones  (Jour.  Asiatic  Soc.  Bengal,  vol.  56,  pt.  2, 1887,  p.  209)  has  described  another  class  of  marine 

nodules.  They  were  dredged  up  in  675  fathoms  of  water  off  Colombo,  Ceylon,  and  contained  about  75  per 

cent  of  barium  sulphate. 


THE  OCEAN. 


137 


the  age  of  the  ocean  is  100,000,000  years,  the  annual  addition  of 
calcium  has  been  5,528,000  tons;  if  only  50,000,000  years  it  is 

11.056.000  tons.  Subtracting  these  quantities  from  the  total  cal- 
cium of  the  river  waters  the  remainders  become  552,142,000  and 

546.614.000  tons,  respectively;  the  difference  being  less  than  the 
actual  uncertainties  of  the  computation.  Calculating  upon  both 
assumptions  the  annual  precipitation  of  chemical  sediments  is  as 
follows,  in  metric  tons : 


Age  of  ocean  (years) 

100,000,000 

50,000,000 

so4 

296, 500, 000 
552, 142,  000 
76,  054,  000 
52,  874,  000 
75,  213,  000 
319, 170,  000 

260,  970, 000 
546,  614,  000 
58,  844,  000 
47,  766,  000 
75,  213,  000 
319, 170,  000 

Ca 

Mg 

K. 

Si02 

If  we  assume  that  all  the  calcium  and  magnesium  are  precipitated 
as  carbonates  and  the  sesquioxides  as  hydrates,  the  total  amount 
of  chemical  sediments  annually  deposited,  including  coral  reefs 
and  calcareous  oozes,  is  somewhere  between  2,200,000,000  and 
2,400,000,000  metric  tons.  A little  lime  undoubtedly  goes  down  as 
sulphate,  although  gypsum  or  anhydrite  is  found  in  oceanic  sedi- 
ments only  in  very  small  proportions.  Probably  much  of  the 
sulphuric  radicle  is  reduced  by  organic  matter,  forming  sulphides. 
The  potassium  is  partly  taken  up  by  the  clay  substances  of  oceanic 
silt  and  partly  goes  to  form  glauconite,  but  there  are  no  data  from 
which  to  determine  its  actual  distribution.  Silica  is  assumed  to  be 
wholly  thrown  down,  the  trifling  residue  held  in  solution  being 
negligible.  Chlorine  and  sodium  are  held  to  remain  dissolved. 

The  figures  given  above  for  the  quantities  of  the  chemical  pre- 
cipitates are,  of  course,  by  no  means  accurate.  They  are  merely 
rough  approximations  to  the  truth,  but  they  tell  something  of  the 
relative  magnitudes.  Even  if  we  knew  precisely  the  age  of  the  ocean 
it  would  not  be  practicable  to  reckon  backward  and  so  to  determine 
the  total  mass  of  deposits  formed  during  geological  time.  The 
figures  tell  us  what  is  happening  to-day,  but  are  inapplicable  to  the 
past.  The  reason  for  this  statement  is,  that  apparently  the  different 
deposits  have  formed  at  different  rates.  In  the  beginning  of  chemical 
erosion  fresh  rocks  were  attacked,  and  relatively  more  silica  and  less 
lime  passed  into  solution.  At  present,  limestones  laid  down  in  pre- 
vious geologic  ages  are  being  dissolved,  and  calcium  is  added  to  the 
ocean  more  rapidly  than  in  pre-Cambrian  time.  This  is  not  mere 
speculation.  A study  of  river  waters  with  reference  to  their  origin, 
whether  from  crystalline  or  sedimentary  rocks,  fully  justifies  my 
assertions. 


138 


THE  DATA  OF  GEOCHEMISTRY. 


So  much  for  the  annual  precipitation.  J.  Joly,* 1  by  a different 
method,  has  calculated  that  the  total  mass  of  chemical  sediments  in 
the  ocean  is  about  19.5  XlO16  metric  tons.  This  estimate  is  not 
inconsistent  with  the  foregoing  computations.  Purely  mechanical 
sediments,  such  as  river  silt,  volcanic  ejectamenta,  or  dust  brought 
by  the  atmosphere  from  the  land,  are  obviously  left  out  of  considera- 
tion here.  Their  sum  total  could  hardly  be  estimated,  at  least  not 
with  existing  data.2 

POTASSIUM  AND  SULPHATES. 

In  seeking  to  balance  the  gains  and  losses  of  the  ocean  some  account 
must  be  taken  of  potassium  and  of  sulphates.  The  latter  have 
already  been  mentioned  as  partly  reduced  by  organic  matter,  a 
change  which  is  counterbalanced  to  some  extent  by  reoxidation 
under  other  circumstances.  On  the  whole,  sulphates  seem  to  accu- 
mulate in  the  ocean,  but  the  figures  are  not  wholly  concordant  or 
satisfactory.  The  extent  of  their  precipitation  is  by  no  means  clear, 
although  they  are  found  in  all  the  clays  and  oozes  in  trivial  propor- 
tions. 

With  potassium  other  conditions  hold,  and  river  and  ocean  water 
are  not  at  all  alike.  In  river  waters,  on  an  average,  the  proportion 
of  potassium  is  about  one-fourth  that  of  the  sodium; 3 but  in  sea 
water  it  is  only  one-thirtieth.  In  the  igneous  rocks  sodium  and 
potassium  are  nearly  equal;  they  pass  unequally  into  the  streams, 
and  in  the  ocean  the  difference  is  still  further  increased.  What 
becomes  of  the  potassium  ? 

The  answer  to  this  question  is  simple.  Hydrous  silicates  of  alumi- 
num, the  clays,  are  able  to  take  up  considerable  proportions  of 
potassium  and  to  remove  its  salts  from  solutions.  According  to  J.  M. 
van  Bemmelen,4  ordinary  soils  will  extract  more  potassium  than 
sodium  from  solutions  in  which  the  salts  of  both  metals  are  present, 
even  where  the  sodium  is  in  excess.  Potassium,  then,  is  removed 
from  natural  waters  as  they  percolate  through  the  soil,  or  else  by  the 
suspended  silt  carried  by  streams.  The  sodium  is  not  so  largely  with- 
drawn, and  therefore  its  relative  proportion  tends  steadily  to  increase. 
One  metal  is  deposited  with  the  sediments,  the  other  remains  in 
solution. 


1 Radioactivity  and  geology,  pp.  57,  58. 

1 In  an  interesting  but  not  altogether  conclusive  paper  (Jour.  Geology,  vol.  2,  1894,  p.  318)  J.  A.  Udden 
has  endeavored  to  show  that  the  dust  carried  by  the  atmosphere  is  of  greater  amount  than  the  silt  trans- 
ported by  rivers.  See  also  E.  E.  Free,  Science,  vol.  29, 1909,  p.  423.  In  Bull.  Bur.  Soils  No.  68,  U.  S.  Dept. 
Agr.,  1911,  Free  gives  an  elaborate  discussion  of  the  movement  of  the  soil  by  wind,  and  a full  bibliography 

of  the  subject. 

a Many  of  the  analyses  of  river  water,  as  published,  show  no  potassium,  but  this  only  means  that  they 
are  incomplete.  In  such  cases  the  alkalies  were  weighed  together  and  in  calculation  the  potassium  was 
ignored.  This  is  especially  true  of  boiler-water  analyses. 

* Landw.  Versuchs-Stationen  (Berlin),  vol.  21, 1877,  p.  135.  The  adsorption  of  potassium  has  been  estab- 
lished by  the  work  of  many  investigators. 


THE  OCEAN. 


139 


These  observations  are  confirmed  in  part  by  analyses  of  oceanic 
deposits,  although  the  evidence  is  often  incomplete.  The  larger 
number  of  analyses  given  for  clay,  mud,  and  ooze  in  the  Challenger 
report  contain  no  mention  of  alkalies,  but  when  the  latter  are  noted 
the  potassium  is  commonly,  not  always,  in  excess.1  In  glauconite  and 
phillipsite  deposits  potassium  always  predominates.  L.  Schmelck,2  in 
his  analyses  of  clays  from  the  northern  Atlantic,  records  no  alkalies, 
but  K.  Natterer,3  in  sediments  from  the  eastern  Mediterranean  and 
the  Red  Sea,  found  small  quantities  of  potash  and  soda,  and  in  nearly 
every  instance  potash  was  the  more  abundant  of  the  two.  In  short, 
if  the  recorded  analyses  are  correct,  the  clays  and  oozes  of  the  deep 
sea  have  been  partly  leached  of  their  alkalies;  but  some  of  the 
potassium  from  the  original  volcanic  material,  with  less  sodium,  has 
been  retained  in  the  production  of  zeolites.  Nearer  to  land  potassium 
has  been  used  in  the  formation  of  glauconite,  and  still  nearer,  where 
mechanical  sediments  appear,  a similar  discrimination  is  evident. 
Sodium  dissolves,  but  potassium  is  held  back.  Potassium  salts  are 
also  absorbed  by  some  seaweeds  in  large  quantities.  This  has  been 
recently  shown  by  D.  M.  Balch,4  who  finds  that  the  giant  algse  of  the 
California  coast  are  remarkably  rich  in  potassium  chloride. 

THE  CHLORINE  OF  SEA  WATER. 

It  is  not  possible  at  present  to  trace  all  of  the  changes  which  take 
place  in  ocean  water,  nor  to  account  with  certainty  for  the  difference 
between  sea  salts  and  the  material  received  from  streams.  In  chem- 
ical character,  fresh  and  salt  water  are  opposites,  as  a brief  inspection 
of  the  data  will  show.  In  ocean  water,  C1>S04>C03;  in  average 
river  water,  C03>S04>C1.  So  also  for  the  bases — in  the  first  case, 
Na  >Mg  >Ca;  in  the  other,  Ca  >Mg  >Na — a complete  reversal  of  the 
order.  We  can  understand  the  accumulation  of  sodium  in  the  ocean, 
and  some  of  the  losses  are  accounted  for,  but  the  great  excess  of 
chlorine  in  sea  water  is  not  easily  explained.  In  average  river  water 
sodium  is  largely  in  excess  of  chlorine;  in  the  ocean  the  opposite  is 
true,  and  we  can  not  well  avoid  asking  whence  the  halogen  element 
was  derived.  Here  we  enter  the  field  of  speculation,  and  the  evi- 
dence upon  which  we  can  base  an  opinion  is  scanty  indeed.5 

To  the  advocates  of  the  nebular  hypothesis  the  problem  is  compara- 
tively simple.  If  our  globe  was  formed  by  cooling  from  an  incan- 

1 This  conclusion  is  confirmed  by  a recent  and  very  complete  analysis  of  the  “red  clay,”  conducted  in 
the  laboratory  of  the  United  States  Geological  Survey.  These  sediments  will  be  considered  more  fully  in 
another  chapter. 

2 Den  Norske  Nordhavs-Expedition,  pt.  9,  1882,  p.  35. 

s Monatsh.  Chemie,  vol.  14,  1893,  p.  624;  vol.  15, 1894,  p.  530;  vol.  20,  1899,  p.  1. 

* Jour.  Indust,  and  Eng.  Chem.,  vol.  1, 1909,  p.  777. 

5 On  the  ratio  between  sodium  and  chlorine  in  the  salts  carried  by  rivers  to  the  sea,  see  E.  Dubois,  Proc. 
Sec.  Sci.,  Amsterdam  Acad.,  vol.  4, 1902,  p.  388.  On  the  ratio  between  Cl  and  SO*  in  sea  water,  see  E.  Rup- 
pin,  Zeitschr.  anorg.  Chemie,  vol.  69, 1910,  p.  232. 


140 


THE  DATA  OF  GEOCHEMISTRY. 


descent  mass,  its  primitive  atmosphere  and  ocean  must  have  been 
quite  unlike  the  present  envelopes,  and  we  may  fairly  suppose  that 
they  contained  large  quantities  of  acid  substances.  Hydrochloric 
acid  in  the  atmosphere  would  imply  a solution  of  hydrochloric  acid 
in  the  sea,  which  might  in  time  be  neutralized  by  the  bases  dissolved 
from  rocks  and  poured  by  rivers  into  the  common  reservoir.  This 
argument  has  been  especially  developed  by  T.  Sterry  Hunt,1  who 
shows  that,  if  his  premises  are  sound,  the  primeval  ocean  must  have 
been  much  richer  in  calcium  and  magnesium  than  the  sea  is  to-day. 
The  richness  of  some  artesian  waters  of  Canada  in  lime  salts,  waters 
which  Hunt  regards  as  fossil  remainders  from  the  early  sea,  may  be 
cited  in  support  of  his  views. 

On  the  other  hand,  R.  A.  Daly 2 has  cited  paleontological  data  in 
favor  of  the  view  that  the  pre-Cambrian  ocean  was  nearly  free  from 
lime.  The  absence  of  fossils  from  rocks  of  an  age  immediately  pre- 
ceding a period  rich  in  highly  developed  calcareous  forms  is  taken  as 
evidence  that  the  earliest  life  was  essentially  shcll-less  and  soft- 
bodied,  in  consequence  of  a deficiency  of  lime  salts  in  its  environment. 
It  is  possible,  however,  that  the  pre-Cambrian  animals  were  developed 
under  conditions  which  favored  the  formation  of  aragonitic  rather 
than  calcitic  exoskeletons.  Aragonitic  shells  dissolve  much  more 
readily  than  those  formed  of  calcite,  and  therefore  rarely  appear  as 
fossils. 

Another  group  of  writers,  seeking  to  avoid  the  nebular  hypothesis, 
conceive  the  earth  as  having  been  built  up  by  the  slow  aggregation  of 
small,  solid,  and  cold  meteoric  bodies.3  Each  of  these,  it  is  supposed, 
carried  with  it  entangled  or  occluded  atmospheric  material.  In 
course  of  time  central  heat  was  developed  by  pressure,  and  a partial 
expulsion  of  gas  followed,  thus  forming  an  atmosphere  derived  from 
within.  When  the  atmosphere  became  adequate  to  retain  solar  heat, 
and  so  to  raise  the  surface  temperature  of  the  globe  above  the  freezing 
point,  the  hydrosphere  came  into  existence;  but  of  its  chemical  nature 
at  the  beginning  nothing,  so  far  as  I am  aware,  has  been  said  by  the 
advocates  of  this  doctrine.  There  is,  however,  an  analogy  which  may 
be  utilized.  Meteoric  iron  frequently  incloses  anhydrous  ferrous 
chloride,  or  lawrenceite,  a fact  of  which  the  curators  of  collections 
are  painfully  aware.  The  ferrous  chloride  deliquesces,  the  liquid 
formed  then  undergoes  oxidation,  ferric  hydroxide  is  deposited,  and 
acid  solutions  are  developed  which  still  further  attack  the  iron. 


1 Am.  Jour.  Sei.,  2d  ser.,  vol.  39,  1865,  p.  176;  and  various  papers  in  his  Chemical  and  geological  essays. 
See  also  J.  Joly,  on  the  geologic  age  of  the  earth,  in  Trans.  Roy.  Dublin  Soc.,  2d  ser.,  vol.  7, 1899,  p.  23;  and 
R.  A.  Taylor,  Proc.  Manchester  Lit.  Philos.  Soc.,  vol.  50.  1906,  p.  ix. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  23, 1907,  p.  93.  Also  a later  paper  in  Bull.  Geol.  Soc.  America,  vol.  20, 1909, 
p.  153. 

3 See  T.  C.  Chamberlin,  Jour.  Geology,  vol.  5,  1897,  pp.  653  et  seq.;  also  H.  L.  Fairchild,  Am.  Geologist, 
vol.  23, 1899,  p.  94. 


THE  OCEAN. 


141 


Through  this  process  of  corrosion  certain  meteoric  irons  have  crum- 
bled into  masses  of  rust  and  disappeared  as  specimens  from  museums. 
If,  now,  the  earth  was  formed  from  meteoric  masses,  some  of  them 
doubtless  contained  this  annoying  impurity,  and  chlorine  from  that 
source  may  have  reached  the  primeval  ocean.  In  fact,  A.  Daubree  1 
found  lawrenceite  in  the  terrestrial  native  iron  from  Ovifak.  The 
planetesimal  hypothesis  is  evidently  not  inconsistent  with  the  excess 
of  oceanic  chlorine.  It  is  also  in  harmony  with  the  idea  advanced  by 
E.  Suess,2  that  the  ocean  has  received  large  accessions  from  volcanic 
sources.  Hydrochloric  acid  and  volatile  chlorides  exist  in  volcanic 
emanations  and  must,  to  some  extent,  reach  the  sea.  G.  F.  Becker 
has  recently 3 discussed  this  phase  of  the  problem  and  has  shown  that 
a comparatively  moderate  emission  of  volcanic  chlorine  would  fully 
account  for  the  excess  of  that  element  in  the  ocean.  But  if,  as  has 
often  been  suggested,  the  volcanic  gases  were  first  derived  from 
oceanic  infiltrations,  they  represent  no  gain  to  the  ocean,  and  this 
question  is  still  at  issue. 

THE  DISSOLVED  GASES. 

Up  to  this  point  we  have  considered  only  the  saline  matter  of  the 
ocean;  but  the  dissolved  gases  are  almost  equally  important  and  have 
been  the  subject  of  exhaustive  investigations.  The  earlier  researches 
were  not  altogether  satisfactory,  and  we  need  therefore  examine  only 
the  more  recent  data,  first  as  to  the  air  and  then  as  to  the  carbonic 
acid  of  sea  water. 

The  solubility  of  a gas  in  water  varies  with  its  nature  and  with  the 
temperature,  being  greatest  in  the  cold  and  diminishing  as  the  sol- 
vent becomes  warmer.  The  Arctic  Ocean,  therefore,  dissolves  more 
air  than  the  waters  of  tropical  regions,  and  it  also  seems  to  carry  a 
greater  proportion  of  oxygen.  We  have  already  seen,  in  studying 
the  atmosphere,  that  water  exercises  a selective  function  in  the  solu- 
tion of  air,  so  that  the  dissolved  gaseous  mixture  is  enriched  in  oxy- 
gen. Ordinary  air  contains  by  volume  only  about  one  part  in  five  of 
oxygen;  dissolved  air  contains,  roughly,  one  part  in  three;  although, 
as  we  shall  see,  the  proportion  changes  as  conditions  vary..  Even  the 
salinity  of  the  ocean  must  probably  be  taken  into  account,  for  the 
reason  that  some  if  not  all  gases  are  less  soluble  in  salt  than  in  fresh 
water.  According  to  the  experiments  by  F.  Clowes  and  J.  W.  H. 
Biggs,4  salt  water  dissolves  only  82.9  per  cent  as  much  oxygen  as  is 
absorbed  by  fresh  water.  So  large  a difference  can  not  well  be 
ignored. 

1 Etudes  synth4tiques  de  g4ologie  experiment  ale,  1879,  p.  557. 

2 Geog.  Jour.,  vol.  20,  1902,  p.  520.  See  also  C.  Doelter,  Sitzungsb.  Akad.  Wien,  vol.  112,  1903,  p.  704. 

3 Smithsonian  Misc.  Coll.,  vol.  56,  No.  6, 1910. 

4 Jour.  Soc.  Chem.  Ind.,  vol.  23, 1904,  p.  358. 


142 


THE  DATA  OF  GEOCHEMISTRY. 


To  illustrate  the  difference  in  solubility  between  the  two  principal 
atmospheric  gases,  we  may  use  the  data  given  by  O.  Pettersson  and 
K.  Sonden.1  In  pure  water  the  gases  dissolve  unequally,  and  the  fol- 
lowing table  shows  their  solubility  throughout  a fair  range  of  atmos- 
pheric temperatures.  The  figures  represent  the  number  of  cubic  cen- 
timeters of  each  gas,  at  760  millimeters  pressure,  required  to  saturate 
1 liter  of  water;  and  the  last  column  gives  the  percentage  of  oxygen 
in  the  dissolved  mixture,  when  N + 0 = 100. 

Solubility  of  nitrogen  and  oxygen  in  water  at  various  temperatures. 


Tempera- 

ture. 

Nitrogen 

absorbed. 

Oxygen 

absorbed. 

Percentage 
of  oxygen. 

°C. 

CTO3. 

CTO®. 

0 

19.  53 

10.  01 

33.  88 

6.  00 

16.  34 

8.  28 

33.  60 

6.  32 

16.  60 

8.  39 

33.  55 

9. 18 

15.  58 

7.  90 

33.  60 

13.  70 

14. 16 

7. 14 

33.  51 

14. 10 

14. 16 

7.  05 

33.  24 

When  we  recall  the  fact  that  ordinary  air  contains  only  21  per  cent 
of  oxygen,  the  magnitude  of  the  change  produced  by  solution  becomes 
manifest. 

In  sea  water  the  same  relation  holds  approximately,  but  the  enrich- 
ment is  slightly  greater.  H.  Tomoe,2  assisted  by  S.  Svendsen,  made 
94  analyses  of  air  extracted  from  the  water  of  the  North  Atlantic 
and  found  the  oxygen  in  the  mixture  N + O to  range  from  a minimum 
of  31  to  a maximum  of  36.7  per  cent.  Between  70°  and  80°  lati- 
tude the  average  was  35.64  per  cent;  below  70°  it  was  34.96.  At  the 
surface  the  mean  percentage  of  oxygen  was  35.3,  and  it  diminished 
with  the  depth  from  which  the  samples  were  taken  down  to  300 
fathoms,  when  the  proportion  was  reduced  to  32.5.  Below  300 
fathoms  the  percentage  of  oxygen  was  nearly  constant.  O.  Jacobsen,3 
analyzing  dissolved  air  from  the  water  of  the  North  Sea,  obtained 
a range  of  25.20  to  34.46  per  cent,  the  surface  average  being  33.95. 

Still  more  elaborate  are  the  data  published  by  W.  Dittmar,4  whose 
samples  of  dissolved  air  came  from  many  points  in  the  Atlantic, 
Pacific,  Indian,  and  Antarctic  oceans.  The  maximum  amount  was 
found  in  the  Antarctic — 28.58  cubic  centimeters  of  air  to  the  liter  of 

1 Ber.  Deutsch.  chem.  Gesell.,  vol.  22, 1889,  p.  1489.  See  also  R.  W.  Bunsen,  Gasometrische  Methoden; 
W.  Dittmar,  in  his  Challenger  report;  and  A.  Hamberg,  Bihang  K.  Svensk.  Vet.-Akad.  Handl.,  vol.  10, 
No.  13, 1884. 

2 Den  Norske  Nordhavs-Expedition,  Chemistry,  1880,  pp.  1-23.  Tomoe  in  this  memoir  gives  a good 
summary  of  the  earlier  investigations. 

2 Die  Ergebnisse  der  Untersuchungsfahrten  S.  M.  Knbt.  Drache,  Berlin,  1886.  An  earlier  memoir  by 
Jacobsen  is  printed  in  Liebig's  Annalen,  vol.  167, 1873,  pp.  1 et  seq. 

* Challenger  Kept.,  Physics  and  chemistry,  vol.  1, 1884.  For  the  table  cited  below,  see  p.  224.  Also  for  a 
summary  of  the  results  obtained,  see  the “ Narrative”  of  the  expedition. 


THE  OCEAN. 


143 


water,  containing  35.01  per  cent  of  oxygen.  The  minimum,  13.73 
cubic  centimeters  and  33.11  per  cent,  was  obtained  at  a point  south- 
east of  the  Philippine  Islands.  The  general  conclusions  as  to  the 
solubility  of  nitrogen  and  oxygen  in  sea  water  at  different  tempera- 
tures appear  in  the  table  following. 


Solubility  of  nitrogen  and  oxygen  in  sea  water  at  various  temperatures. 


Temperature. 

Dissolved 

nitrogen.® 

Dissolved 

oxygen.® 

Percentage 
of  oxygen. 

°C. 

cm.3 

cm.3 

0 

15.  60 

8.  18 

34.  40 

5 

13.  86 

7.  22 

34.  24 

10 

12.  47 

6.45 

34.  09 

15 

11.  34 

5.  83 

33.  93 

20 

10.  41 

5.  31 

33.  78 

25 

9.  62 

4.  87 

33.  62 

30 

8.  94 

4.  50 

33.  47 

35 

8.  36 

4. 17 

33.  31 

a Supposed  to  be  measured  dry,  at  0°  C.  and  760  millimeters  pressure;  in  other  words,  the  normal  volumes 
in  cubic  centimeters  in  1 liter  of  sea  water  at  the  given  temperatures.  The  “nitrogen”  of  course  includes 

argon. 


No  argument  is  needed  to  show  the  importance  of  the  facts  thus 
developed.  The  dissolved  oxygen  plays  a double  part  in  the  activities 
of  the  ocean — first  in  maintaining  the  life  of  marine  organisms,  and 
second  in  oxidizing  dead  matter  of  organic  origin.  By  the  latter 
process  carbon  dioxide  is  generated,  and  that  compound,  as  we  have 
already  seen,  helps  to  hold  calcium  carbonate  in  solution.  Its  other 
function  as  a possible  regulator  of  climate  will  be  considered  presently. 

Free  or  half-combined  1 carbonic  acid  is  received  by  the  ocean  from 
various  sources.  It  may  be  absorbed  directly  from  the  atmosphere  or 
brought  down  in  rain;  it  enters  the  sea  dissolved  in  river  water;  it  is 
derived  from  decaying  organic  matter,  and  submarine  volcanic 
springs  contribute  a part  of  the  supply.  The  free  gas  is  also  liberated 
from  bicarbonates  by  the  action  of  coral  and  shell  building  animals, 
which  assimilate  the  normal  calcium  salt.  Carbonic  acid  is  continu- 
ally added  to  the  ocean  and  continually  lost,  either  to  the  atmosphere 
again  or  in  the  maintenance  of  marine  plants,  and  we  can  not  say  how 
nearly  the  balance  between  accretions  and  losses  may  be  preserved. 
The  equilibrium  is  probably  far  from  perfect;  it  may  be  disturbed  by 
changes  in  temperature  or  by  the  agitation  of  waves,  and  every  varia- 
tion in  it  leads  to  important  consequences.  It  is  estimated  that  the 
ocean  contains  from  eighteen  to  twenty-seven  times  as  much  carbon 
dioxide  as  the  atmosphere,  and  that  it  is  therefore,  as  T.  Schloesing  2 
has  pointed  out,  the  great  regulative  reservoir  of  the  gas. 

1 A much  used  but  inexact  expression.  It  describes  tbe  second  molecule  of  carbonic  acid  which  converts 

the  normal  salts  into  bicarbonates. 

* Compt.  Rend.,  vol.  90,  1880,  p.  1410.  See  also  A.  Krogh,  Meddelelser  om  Groenland,  vol.  26,  1904, 
pp.  333, 409. 


144 


THE  DATA  OF  GEOCHEMISTRY. 


Nearly  all  of  the  authorities  thus  far  quoted  with  reference  to  the 
dissolved  air  of  sea  water  have  also  studied  the  omnipresent  carbonic 
acid.  Jacobsen,  Hamberg,  Tomoe,  Buchanan,  Dittmar,  Natterer,  and 
others  have  made  numerous  determinations  of  its  amount,  and  as  a 
general  rule  the  quantities  found  were  insufficient  to  transform  all  of 
the  normal  calcium  carbonate  into  the  acid  salt.  Tornoe,  as  the  aver- 
age of  78  sea-water  analyses,  found  52.78  milligrams  to  the  liter  of 
fully  combined  carbon  dioxide,  and  in  addition  43.64  milligrams  avail- 
able for  the  formation  of  bicarbonates.  Results  of  the  same  order 
were  obtained  by  Natterer  in  his  examination  of  waters  from  the 
Mediterranean.  Normal  carbonate  and  bicarbonate  are  both  present 
in  sea  water,  although  in  a few  exceptional  determinations  during  the 
Challenger  expedition  the  carbonic  acid  was  clearly  in  excess.  Such 
instances,  however,  are  rare,  and  are  ascribable  to  purely  local  and 
unusual  conditions. 

The  carbonic-acid  determinations  of  the  Challenger  voyage  were 
conducted  partly  by  J.  Y.  Buchanan  on  shipboard,  and  partly  by 
W.  Dittmar  on  land.1  The  combined  acid  has  already  been  accounted 
for  in  the  analyses  given  for  sea  salts;  the  “ loose,”  free,  or  half-com- 
bined  acid,  is  more  variable.  Its  average  amount,  in  milligrams  to 
the  liter,  at  different  temperatures  appears  in  the  following  table: 


Average  amount  of  free  carbonic  acid  in  sea  water  at  various  temperatures. 


25°  to  28.7°C 
20°  to  25°C. . 
15°  to  20°C  . . 


[Milligrams  per  liter.] 


35.  88 
37. 18 
42.  68 


10°  to  15°C 

5°  to  10°C 

-1.4°  to  +3.2°C 


43.  50 
47.  21 
53.  31 


That  is,  the  ocean  contains  less  free  carbonic  acid  in  warm  than  in 
cold  latitudes.  Its  average  quantity  is  estimated  by  Murray  at  45 
milligrams  per  liter,  which  is  equivalent  to  a layer  of  carbon  3.45 
centimeters  thick  over  the  entire  oceanic  area.  For  different  depths 
of  water  the  variations  in  carbonic  acid  are  less  pronounced,  as  may 
be  seen  from  the  subjoined  averages: 


Average  amount  of  free  carbonic  acid  in  sea  water  at  various  depths. 


Surface 

25  fathoms. . 
50  fathoms.. 
100  fathoms 
200  fathoms 


[Milligrams  per  liter.] 


42.6 

33.7 

48.8 
43.6 
44.  6 


300  fathoms 

400  fathoms 

800  fathoms 

More  than  800  fathoms 
Bottom 


44.  0 

41. 1 

42.2 
44.6 
47.4 


The  figures  are  derived  from  195  determinations  by  Buchanan,  and 
the  individual  numbers  range  from  19.3  to  96  milligrams  to  the  liter. 


i See  vol.  1 of  the  report  on  physics  and  chemistry  and  part  2 of  the  “Narrative,”  p.  979;  also  J.  Y. 
Buchanan,  in  Proc.  Roy.  Soc.,  vol.  22,  1874,  pp.  192,  483.  The  tables  cited  are  from  the  “Narrative.” 


THE  OCEAN. 


145 


In  15  determinations  the  carbonic  acid  was  in  excess  of  the  amount 
necessary  to  form  bicarbonates;  in  only  22  was  it  sufficient  to  fully 
convert  the  normal  into  the  acid  salt. 

In  the  light  of  the  evidence  just  presented,  and  speaking  from  the 
point  of  view  of  the  modern  theory  of  solutions,  we  may  say  that  the 
water  of  the  ocean  contains  not  only  the  normal  carbonic  ions,  C03, 
but  also  a considerable  proportion  of  the  bicarbonic  ions  HC03. 
The  latter  ions  are  unstable,  and  their  existence  is  conditional  on 
temperature,  so  that  although  they  are  continually  forming  they  are 
as  continually  being  decomposed.  That  is,  between  the  ocean  and 
the  atmosphere  there  is  an  interchange  of  carbonic  acid,  which  is 
released  from  the  water  in  warm  climates  and  absorbed  again  in  the 
cold.  The  atmospheric  supply  of  carbon  dioxide  is  thus  alternately 
enriched  and  impoverished,  and  the  conditions  affecting  equilibrium 
are  of  several  kinds.  This  problem  has  been  elaborately  discussed 
by  C.  F.  Tolman,  jr.,1  from  the  standpoint  of  the  physical  chemist, 
and  his  memoir  should  be  consulted  for  the  detailed  argument.  The 
essential  features  of  the  evidence  upon  which  a theoretical  discussion 
can  be  based  are  already  before  us.  We  have  considered  the  oceanic 
losses  and  gains  of  carbon  dioxide,  and  it  remains  to  correlate  them 
with  the  corresponding  changes  in  the  atmosphere.  This  can  not  be 
done  quantitatively,  for  the  rates  of  consumption  and  supply  are  not 
measurable.  In  particular,  the  carbon  dioxide  from  volcanoes  and 
volcanic  springs  is  not  a determinable  quantity. 

That  the  surface  of  the  earth  has  been  subjected  to  climatic  alterna- 
tions, to  glacial  periods  and  epochs  of  greater  warmth,  is  a common- 
place of  geology.  To  account  for  such  changes,  various  astronomical 
and  physical  theories  have  been  proposed,  and  with  these,  of  course, 
chemistry  has  nothing  to  do.  Whether,  for  example,  the  solar  con- 
stant of  radiation  is  really  a constant  or  not  is  a question  which  the 
chemist  can  not  attempt  to  answer.  The  chemical  portion  of  the 
problem  is  all  that  concerns  us  now;  and  that  relates  to  the  variable 
carbonation  of  the  atmosphere. 

The  researches  of  Arrhenius  on  the  possible  climatic  significance  of 
carbon  dioxide  were  cited  and  criticized  in  a previous  chapter,  and  we 
then  saw  that  its  variation  in  the  atmosphere  might  be  attributed  to 
fluctuating  volcanic  activity.  A varying  supply  of  the  gas  was 
postulated,  and  its  influence  on  atmospheric  temperatures  was  shown 
to  offer  a plausible,  but  not  well-sustained,  explanation  of  alternating 
climates.  A variable  consumption  of  carbon  dioxide  would  obviously 
produce  much  the  same  effect,  and  it  is  therefore  evident  that  supply 

i Jour.  Geology,  vol.  7, 1899,  p.  585.  See  also  memoirs  by  C.  J.  J.  Fox,  Trans.  Faraday  Soc.,  vol.  5, 1909, 
p.  68;  J.  Stieglitz,  Pub.  107,  Carnegie  Inst,  of  Washington,  1909,  p.  235;  E.  Ruppin,  Zeitschr.  anorg.  Chemie, 
vol.  66, 1910,  p.  122.  Ruppin  discusses  especially  the  alkalinity  of  sea  water. 

97270°— Bull.  616—16 10 


146 


THE  DATA  OF  GEOCHEMISTRY. 


and  loss  must  be  considered  together.  Disregarding  for  the  moment 
the  doubtful  Validity  of  Arrhenius’s  hypothesis,  we  may  consider  the 
interesting  work  of  T.  C.  Chamberlin,1  who  has  sought  to  show  that 
the  ocean  is  the  prime  agent  in  producing  the  observed  changes. 
The  supplies  of  carbon  dioxide  are  drawn  from  the  storehouse  of  the 
ocean,  they  are  consumed  in  the  decomposition  of  silicates  on  land, 
and  they  are  regenerated  by  the  action  of  lime-secreting  animals, 
which  set  carbonic  acid  free,  as  well  as  by  changes  in  temperature. 

According  to  Chamberlin,  an  important  factor  in  climatic  varia- 
tion is  the  fluctuating  elevation  of  the  land.  During  periods  of 
maximum  elevation,  when  the  largest  land  surfaces  are  exposed  to 
atmospheric  action,  the  consumption  of  carbon  dioxide  in  rock 
weathering  is  great  and  the  air  becomes  impoverished.  When  depres- 
sion occurs  and  the  oceanic  area  enlarges,  a smaller  quantity  of  sili- 
cates is  decomposed  and  less  carbonic  acid  disappears.  The  first 
change  is  thought  to  produce  a lowering  of  temperature,  which  is 
increased  by  the  consequent  greater  absorbability  of  carbon  dioxide  in 
sea  water;  the  second  causes  a relative  rise,  intensified  by  a release  of 
the  gas  from  solution.  Enlargement  of  land  area  implies  a low  tem- 
perature, whereas  a decrease  is  conducive  to  warmth,  both  conditions 
hinging  on  the  variability  produced  in  the  atmospheric  supply  of  car- 
bonic acid  and  its  effectiveness  as  a retainer  of  solar  radiations. 

But  this  is  not  all  of  the  story.  A depression  of  the  land  is  ac- 
companied by  an  increased  area  of  shoal  water  in  which  lime- 
secreting  organisms  can  flourish,  and  they  liberate  carbon  dioxide 
from  bicarbonates.  A period  of  limestone  formation  is  therefore 
correlated  with  an  enrichment  of  the  atmosphere,  and  consequently 
with  the  maintenance  of  a mild  climate.  The  ocean  is  the  great 
reservoir  of  carbonic  acid,  and  upon  its  exchanges  with  the  atmos- 
phere the  variations  of  climate  are  supposed  partly  to  depend.  This 
argument  does  not  exclude  consideration  of  the  volcanic  side  of  the 
problem,  but  the  oceanic  factor  seems  to  be  the  larger  of  the  two. 

Chamberlin’s  theory  is  ingenious,  but  may  perhaps  carry  more 
weight  if  stated  in  somewhat  different  form.  C.  G.  Abbot  and  F.  E. 
Fowle,2  who  have  studied  the  influence  of  the  atmosphere  upon  solar 
radiations  with  great  care,  show  that  in  the  lower  regions  of  the  atmos- 
phere water  vapor  is  present  in  such  quantities  as  almost  completely  to 
extinguish  the  radiation  from  the  earth  irrespective  of  the  presence 
of  carbon  dioxide.  They  therefore  say  that  “it  does  not  appear 
possible  that  the  presence  or  absence  or  increase  or  decrease  of  the 
carbonic  acid  contents  of  the  air  are  likely  to  appreciably  influence 
the  temperature  of  the  earth’s  surface.” 

i Jour.  Geology,  vol.  5, 1897,  p.  653;  vol.  6, 1898,  pp.  459,  609;  vol.  7,  1899,  pp.  545,  667,  751.  Chamberlin’s 
views  are  criticized  by  A.  Krogh  in  Meddelelser  om  Greenland,  vol.  26, 1904,  pp.  333, 409. 

* Annals  Astrephys.  Observ.,  vol.  2, 1908,  pp.  172,  175. 


THE  OCEAN. 


147 


Water  vapor,  then,  is  the  chief  agent  in  the  atmospheric  regulation 
of  climate,  and  to  this  conclusion  Chamberlin’s  theory  may  be 
adjusted.  When  the  area  of  land  surface  increases,  evaporation 
from  the  ocean  diminishes,  and  vice  versa.  The  climatic  conditions 
may  vary  as  Chamberlin  claims,  hut  the  relative  dryness  or  wetness 
of  the  atmosphere  may  be  the  true  cause  of  fluctuating  temperatures, 
rather  than  the  carbon  dioxide. 

INFLUENCE  OF  LIVING  ORGANISMS  ON  THE  OCEAN. 

One  other  important  factor  in  marine  chemistry  remains  to  be 
considered — namely,  the  influence  of  living  organisms.  These,  both 
plants  and  animals,  are  almost  incredibly  abundant  in  the  ocean,1 
and  their  vital  processes  play  a great  part  in  its  chemical  activities. 
This  fact  has  already  been  noted  on  what  might  be  called  its  inor- 
ganic side — that  is,  with  reference  to  the  function  of  marine  organ- 
isms in  secreting  phosphate  and  carbonate  of  lime.  Coral  reefs  and 
the  submarine  oozes  are  made  up  of  animal  remains,  calcareous  or 
siliceous,  and  their  aggregate  amount  is  something  enormous. 

The  living  animals,  however,  do  much  more  than  to  secrete  inor- 
ganic material.  In  developing  they  absorb  large  quantities  of  car- 
bon, hydrogen,  nitrogen,  and  oxygen,  the  principal  constituents  of 
their  soft  tissues.  These  elements,  in  one  form  of  combination  or 
another,  are  released  again  by  decomposition  after  the  organism 
dies,  and  they  are  also  eliminated  to  a certain  extent  by  the  vital 
processes  of  the  living  creatures.  Where  life  is  abundant  there  car- 
bon dioxide  is  abundant  also,  and  its  activity  as  a solvent  of  calcium 
carbonate  is  greatest.2  The  relations  of  the  ocean  to  carbon  dioxide 
can  not  be  completely  studied  without  taking  into  account  both 
plant  and  animal  life. 

When  marine  animals  die  they  may  become  food  for  others,  the 
scavengers  of  the  sea,  or  they  may  simply  decompose.  The  latter 
fate,  obviously,  most  often  befalls  creatures  whose  soft  parts  are 
protected  by  hard  shells.  Water,  carbon  dioxide,  and  ammoniacal 
salts  are  the  chief  products  of  decomposition,  and  ammonium  car- 
bonate, thus  formed,  acts  as  a precipitant  of  calcium  compounds.3 
The  calcium  carbonate  thus  thrown  down  is  in  a finely  divided  con- 
dition, and  therefore  peculiarly  available  for  absorption  by  coral 
and  shell  builders.  The  ammonium  salts  also,  as  shown  by  Murray 
and  Irvine,  are  food  for  the  marine  flora,  and  on  that  some  portions 
of  the  fauna  subsist. 


1 The  abundance  of  life  in  the  ocean  is  admirably  stated  by  W.  K.  Brooks,  in  Jour.  Geology,  vol.  2, 1894, 
p.  455.  Its  chemical  significance  can  hardly  be  exaggerated. 

2 See  W.  L.  Carpenter  in  C.  Wyville  Thomson’s  Depths  of  the  sea,  1874,  pp.  502-511.  Where  CO2  was 
abundant  in  bottom  waters,  the  dredge  brought  up  a good  haul  of  living  forms.  Where  it  was  deficient, 
the  hauls  were  poor. 

8 See  J.  Murray  and  R.  Irvine,  Proc.  Roy.  Soc.  Edinburgh,  vol.  17,  1889,  p.  89, 


148 


THE  DATA  OF  GEOCHEMISTRY. 


But  this  is  not  all.  Decomposing  organic  matter  reduces  the 
sulphates  of  sea  water  to  sulphides,  which  by  reaction  with  carbonic 
acid  yield  sulphureted  hydrogen.  This  process,  as  shown  by  Murray 
and  Irvine,1  is  particularly  effective  in  bottom  waters  in  contact 
with  “blue  mud,”  and  by  it  local  changes  are  produced  in  the 
composition  of  the  waters  themselves.  Bacteria  also  assist  in  the 
process,  and  according  to  N.  Androussof,2  this  H2S  fermentation  is 
especially  conspicuous  in  the  Black  Sea.  Some  of  the  hydrogen 
sulphide  passes  into  the  atmosphere  and  is  lost  to  the  ocean;  some 
of  it  reacts  upon  the  iron  silicates  of  the  sea  floor,  to  form  pyrite  or 
marcasite;  and  some  is  reoxidized  to  produce  sulphates  again. 
From  all  of  these  considerations  we  see  that  the  biochemistry  of  the 
ocean  is  curiously  complex,  and  that  its  processes  are  conducted 
upon  an  enormous  scale.  The  magnitude  of  their  influence  can  not 
be  expressed  in  any  quantitative  terms,  and  must  long  remain  an 
unmeasured  factor  in  marine  statistics.  In  all  probability  the  cir- 
culation and  distribution  of  carbon  in  the  ocean  is  as  much  influ- 
enced by  living  beings  as  by  exchanges  between  the  sea  and  the 
atmosphere. 

AGE  OF  THE  OCEAN. 

The  facts  that  we  can  estimate,  with  some  approach  to  exactness, 
the  absolute  amount  of  sodium  in  the  sea,  and  that  it  is  added  in  a 
presumably  constant  manner  without  serious  losses,  have  led  to  va- 
rious attempts  toward  using  its  quantity  in  geological  statistics.3 
The  sodium  of  the  ocean  seems  to  furnish  a quantitative  datum  from 
which  we  can  reason,  whereas  calcium,  magnesium,  silica,  potassium, 
etc.,  are  more  or  less  deposited  from  solution,  and  so  become  una- 
vailable for  the  discussion  of  such  problems  as  that  of  geologic  time. 

Nearly  200  years  ago  Edmund  Halley  4 suggested  that  the  age  of 
the  earth  might  be  ascertained  by  measuring  the  rate  at  which  rivers 
delivered  salt  to  the  sea.  The  suggestion  was  of  course  fruitless  for 
the  time  being,  because  the  data  needed  for  such  a computation  were 
undetermined,  but  it  was  nevertheless  pertinent,  and  it  now  seems 
to  be  approaching  realization.  For  reasons  already  given,  the 
method  proposed  for  estimating  geologic  time  can  as  yet  be  only 
applied  provisionally,  the  data  still  being  imperfect  although  rapidly 
accumulating.  The  present  state  of  the  problem  is  worth  consider- 
ing now. 

1 Trans.  Roy.  Soc.  Edinburgh,  vol.  37,  1895,  p.  481.  See  also  Challenger  Rept.,  Deep-sea  deposits,  1891, 
p.  254;  W.  N.  Hartley,  Proc.  Roy.  Soc.  Edinburgh,  vol.  21, 1897,  p.  25;  and  Murray  and  Irvine,  idem,  p.  35. 

2 Guide  des  excursions  du  VII  Cong.  gdol.  internat..  No.  29. 

8 See,  for  example,  Chapter  I of  the  present  volume,  where  the  relative  volumes  of  the  sedimentary  rocks 
are  estimated. 

* Philos.  Trans.,  vol.  29, 1715,  p.  296.  See  an  abstract  in  G.  F.  Becker’s  Age  of  the  earth;  Smithsonian 
Misc.  Coll.,  vol.  56,  No.  6, 1910;  also  in  Science,  vol.  31, 1910,  p.  459. 


THE  OCEAN. 


149 


The  first  really  serious  attempt  to  measure  geologic  time  by  the 
annual  additions  of  sodium  to  the  ocean  seems  to  have  been  made  by 
J.  Joly  1 in  1899.  Joly,  with  Murray’s  figures  for  rainfall,  run-off,  and 
the  average  composition  of  river  water,  combined  with  Dittmar’s 
analyses  of  oceanic  salts  and  an  estimate  of  the  mass  of  the  ocean, 
deduced  an  uncorrected  value  for  the  age  of  the  ocean  of  97,600,000 
years.  The  calculation  is  very  simple,  and  by  the  following  equation: 


Na  in  ocean 
Annual  Na  in  rivers 


= Age  of  ocean. 


Joly’s  data,  however,  were  much  less  satisfactory  than  the  data 
now  at  hand,  as  given  in  this  and  the  preceding  chapter.  With  them 
the  equation  now  becomes 


14,130X10  12 
158,357X10  3 


89,222,900; 


the  crude  age  of  the  ocean  to  which  certain  corrections  are  yet  to  be 
applied.2  The  first  of  these  to  be  studied  tends  to  increase  the  quo- 
tient, others  to  diminish  it. 

A part  of  the  sodium  found  in  the  discharge  of  rivers  is  the  so- 
called  “ cyclic  sodium”;  that  is,  sodium  in  the  form  of  salt  lifted 
from  the  sea  as  spray  and  blown  inland  to  return  again  to  its  source 
in  the  drainage  from  the  land.3  Near  the  seacoast  this  cyclic  salt  is 
abundant;  inland  its  quantity  is  small.  The  table  given  in  Chapter 
II  illustrates  the  way  in  which  the  amount  falls  off  as  we  recede  from 
the  shore,  and  the  isochlors  of  the  New  England  “ chlorine  maps” 
show  the  same  thing  most  conclusively.  Joly  estimates  that  the  cor- 
rection for  cyclic  salt  may  be  10  per  cent;  but  Becker  in  his  paper 
on  the  age  of  the  earth  has  discussed  the  isochlor  evidence  mathe- 
matically, and  found  that  6 per  cent  is  a more  trustworthy  value. 
By  Ackroyd  the  significance  of  the  correction  is  enormously  overesti- 
mated. Adopting  Becker’s  figure,  and  deducting  6 per  cent  from  the 
total  river  load  of  sodium,  the  remainder  becomes  148,846,000  metric 


1 Trans.  Roy.  Dublin  Soc.,  2d  ser.,  vol.  7, 1899,  p.  23,  and  with  later  corrections,  Rept.  British  Assoc.  Adv. 
Sci.,  1900,  p.  369.  Criticized  by  W.  Mackie,  Trans.  Edinburgh  Geol.  Soc.,  vol.  8, 1902,  p.  240;  and  O.  Fisher, 
Geol.  Mag.,  1900,  p.  124.  See  also  V.  von  Lozinski,  Mitt.  K.-k.  geog.  Gesell.  Wien,  vol.  44, 1901,  p.  74.  He 
cites  a paper  by  E.  von  Romer,  Kosmos,  vol.  25,  1900,  p.  1,  which  I have  not  seen.  Related  memoirs  are 
by  E.  Dubois,  Proc.  Sec.  Sci.,  Amsterdam  Acad.,  vol.  3, 1901,  pp.  43, 116;  vol.  4,  1902,  p.  388.  The  presi- 
dential address  of  W.  J.  Sollas  (Quart.  Jour.  Geol.  Soc.,  vol.  65, 1909,  p.  xli)  is  mainly  devoted  to  this  theme. 
For  more  details  see  F.  W.  Clarke,  Smithsonian  Misc.  Coll.,  vol.  56,  No.  5, 1910,  and  G.  F.  Becker,  idem, 
No.  6. 

2 These  figures  differ  from  those  given  in  my  Preliminary  study  of  chemical  denudation.  In  that  I used 
Dole’s  data  for  American  rivers,  in  which  all  the  alkalies  were  reckoned  as  sodium  alone.  The  new  compu- 
tation is  based  on  Palmer’s  determinations  of  potassium,  which  must  be  subtracted  from  the  former  sum. 
The  latter  gave  175,040,000  metric  tons  Na  (+K),  as  against  the  158,357,000  Na  now  employed. 

3 For  the  quantities  of  salt  thus  transported  see  the  table  given  in  Chapter  II.  For  a discussion  of  the 
significance  of  the  correction  for  cyclic  sodium,  see  J.  Joly,  Geol.  Mag.,  1901,  pp.  344, 504;  Chem.  News,  vol. 
83,  p.  301;  and  British  Assoc.  Report,  1900,  p.  369.  Also  W.  Ackroyd,  Geol.  Mag.,  1901,  pp.  445, 558;  Chem. 
News,  vol.  83, 1901,  p.  265;  vol.  84,  1901,  p.  56. 


150 


THE  DATA  OF  GEOCHEMISTRY. 


tons,  which,  divided  into  the  sodium  of  the  ocean,  gives  a quotient  of 
94,712,000  years.  Joly’s  correction  of  10  per  cent  is  very  nearly 
equivalent  to  the  assumption  that  the  entire  run-off  of  the  globe, 
6,524  cubic  miles,  according  to  Murray,  carries  on  an  average  one  part 
per  million  of  chlorine.  The  chlorine  maps,  so  far  as  they  have  been 
made,  show  this  figure  to  be  excessive. 

The  foregoing  correction  for  “cyclic  salt”  is,  however,  not  final.  It 
has  already  been  suggested  that  the  wind-borne  salt  is  only  in  part 
restored  to  the  ocean,  at  least  within  reasonable  time.  Some  of  it  is 
retained  by  the  soil,  if  not  permanently,  at  least  rather  tenaciously; 
and  the  portion  which  falls  into  depressions  of  the  land  may  remain 
undisturbed  almost  indefinitely.  In  arid  regions,  like  the  coasts  of 
Peru,  Arabia,  and  parts  of  western  Africa,  a large  quantity  of  cyclic 
salt  must  be  so  retained  in  hollows  or  valleys  which  do  not  drain  into 
the  sea.  Torrential  rains,  which  occur  at  rare  intervals,  may  return 
a part  of  it  to  the  ocean  but  not  all.  Some  writers,  Ackrovd 1 for 
example,  have  attributed  the  saline  matter  of  the  Dead  Sea  to  an 
accumulation  of  wind-borne  salt,  an  assumption  which  contains 
elements  of  truth  but  is  probably  extreme.  A more  definite  instance 
of  the  sort  is  furnished  by  the  Sambhar  salt  lake  in  northern  India, 
as  studied  by  T.  H.  Holland  and  W.  A.  K.  Christie.2  This  lake, 
situated  in  an  inclosed  drainage  basin  of  2,200  square  miles  and  over 
400  miles  inland,  appears  to  receive  the  greater  part,  if  not  all  of  its 
salt  from  dust-laden  winds  which,  during  the  four  hot,  dry  months, 
sweep  over  the  plains  between  it  and  the  arm  of  the  sea  known  as  the 
Rann  of  Cutch.  Analyses  of  the  ah  during  the  dry  season  showed 
a quantity  of  salt  so  carried  which  amounted  to  at  least  3,000  metric 
tons  over  the  Sambhar  Lake  annually,  and  130,000  tons  into  Rajpu- 
tana.  These  quantities  are  sufficient  to  account  for  the  accumulated 
salt  of  the  lake,  which  the  authors  were  unable  to  explain  in  any 
other  way. 

Examples  like  this  of  the  Sambhar  Lake  are  of  course  exceptional. 
In  a rainy  region  salt  dust  is  quickly  dissolved  and  carried  away  in 
the  drainage.  Only  in  a dry  period  can  it  be  transported  as  dust 
from  its  original  point  of  deposition  to  points  much  farther  inland. 
It  appears,  however,  that  some  salt  is  so  withdrawn,  at  least  for  an 
indefinitely  long  time,  from  the  normal  circulation,  and  should,  if  it 
could  be  estimated,  be  added  to  the  amount  now  in  the  ocean.  Such 
a correction,  however,  would  doubtless  be  quite  trivial,  and,  there- 
fore, negligible;  and  the  same  remark  must  apply  to  all  the  visible 
accumulations  of  rock  salt,  like  those  of  the  Stassfurt  region,  which 
were  once  laid  down  by  the  evaporation  of  sea  water.  The  saline 
matter  of  the  ocean,  if  concentrated,  would  represent  a volume  of 


Chem.  News,  vol.  89, 1904,  p.  13. 


* Records  Geol.  Survey  India,  vol.  38,  1909,  p.  154. 


THE  OCEAN.  151 

over  4,800,000  cubic  miles;  a quantity  compared  with  which  all  beds 
of  rock  salt  become  insignificant. 

But  although  the  visible  accumulations  of  salt  are  relatively  insig- 
nificant, it  is  possible  that  there  may  be  quantities  of  disseminated 
salt  which  are  not  so.  The  sedimentary  rocks  of  marine  origin  must 
contain,  in  the  aggregate,  vast  amounts  of  saline  matter,  widely  dis- 
tributed, but  rarely  determined  by  analysis.  These  sediments,  laid 
down  from  the  sea,  can  not  have  been  completely  freed  from  adherent 
salts,  which,  insignificant  in  a single  ton  of  rock,  must  be  quite  appre- 
ciable when  cubic  miles  are  considered.  The  fact  that  their  presence 
is  not  shown  in  ordinary  analyses  merely  means  that  they  were  not 
sought  for.  Published  analyses,  whether  of  rocks  or  of  waters,  are 
rarely  complete,  especially  with  regard  to  those  substances  which 
may  be  said  to  occur  in  “traces.” 

It  is  perhaps  not  possible  to  evaluate  the  quantity  of  this  dissem- 
inated salt,  and  yet  a maximum  limit  may  be  assigned  to  it.  In 
Chapter  I it  was  shown  that  84,300,000  cubic  miles  1 of  the  average 
igneous  rock  would  yield,  upon  decomposition,  all  the  sodium  of 
the  ocean  and  the  sedimentaries.  The  volume  of  the  sandstones 
would  be  approximately  15  per  cent  of  this  quantity,  or  12,645,000 
cubic  miles.  Assume  now  that  the  sandstones,  the  most  porous 
of  rocks,  contain  an  average  pore  space  of  20  per  cent,  or  2,529,000 
cubic  miles,  and  that  all  of  it  was  once  filled  with  sea  water,  repre- 
senting 118,730,000,000,000  metric  tons  of  sodium.  If  all  of  that 
sodium  were  now  present  in  the  sandstones,  and  chemical  erosion 
began  at  the  rate  assigned  to  the  rivers,  namely,  158,357,000  tons 
of  sodium  annually,  the  entire  accumulation  would  be  removed 
in  about  750,000  years.  This,  compared  with  the  crude  estimate 
already  reached  for  geologic  time  is  almost  a negligible  quantity. 
The  correction  for  disseminated  salt  is  therefore  small,  and  not 
likely  to  exceed  1 per  cent. 

The  foregoing  calculations,  so  far  as  they  relate  to  the  age  of  the 
ocean,  imply  the  assumption  that  the  rivers  have  added  sodium  to 
the  sea  at  an  average  uniform  rate,  slight  accelerations  being  offset 
by  small  temporary  retardations.  For  the  moment  let  us  consider 
one  phase  of  this  suggested  variability.  The  present  rate  of  discharge 
has  been  hastened  during  modern  times  by  human  agency,  and  that 
acceleration  may  be  important  to  take  into  account.  The  sewage 
of  cities,  the  refuse  of  chemical  manufactures,  etc.,  is  poured  into 
the  ocean,  and  so  disturbs  the  rate  of  accumulation  of  sodium  quite 
perceptibly.  The  change  due  to  chemical  industries,  so  far  as  it 
is  measurable,  is  wholly  modern,  and  that  due  to  human  excretions 
is  limited  to  the  time  since  man  first  appeared  upon  the  earth.  Its 


1 This  quantity,  it  must  be  remembered,  is  a maximum.  The  true  value  is  probably  very  much  less, 
by  10  per  cent  or  even  more. 


152 


THE  DATA  OF  GEOCHEMISTRY. 


exact  magnitude,  of  course,  can  not  be  determined,  but  its  order 
seems  to  be  measurable,  as  follows: 

According  to  the  best  estimates,  about  14,500,000  metric  tons  of 
common  salt  are  annually  produced,  equivalent  to  5,700,000  tons  of 
sodium.  If  all  of  that  was  annually  returned  to  the  ocean,  it  would 
amount  to  a correction  of  about  3.25  per  cent  on  the  total  addition  of 
sodium  to  the  sea.  The  fact  that  much  of  it  came  directly  or  indi- 
rectly from  the  ocean  in  the  first  place  is  immaterial  to  the  present 
discussion;  the  rate  of  discharge  is  affected.  All  of  this  sodium, 
however,  is  not  returned;  much  of  it  is  permanently  fixed  in  manu- 
factured articles.  The  total  may  be  larger,  because  of  other  additions, 
excretory  in  great  part,  which  can  not  be  estimated,  but  we  may 
assume,  nevertheless,  a maximum  of  3 per  cent  as  the  correction  to 
be  applied.  Allowing  6 per  cent,  as  already  determined,  to  cyclic  or 
wind-borne  sodium,  and  1 per  cent  to  disseminated  salt  of  marine 
origin,  the  total  correction  is  10  per  cent.  This  reduces  the 
158,357,000  tons  of  river  sodium  to  142,521,000  tons,  and  the  quo- 
tient representing  crude  geologic  time  becomes  99,143,000  years. 

The  corrections  so  far  considered  are  all  in  one  direction,  and 
increase,  by  a roughly  evaluated  amount,  the  apparent  age  of  the 
ocean.  Other  corrections,  whose  magnitudes  are  more  uncertain, 
tend  to  compensate  the  former  group.  The  ocean  may  have  con- 
tained primitive  sodium,  over  and  above  that  since  contributed  by 
rivers.  It  receives  some  sodium  from  the  decomposition  of  rocks  by 
marine  erosion,  which  is  estimated  by  Joly  as  a correction  of  less  than 
6 per  cent  and  more  than  3 per  cent  on  the  value  assigned  to  geologic 
time.  Sodium  is  also  derived  from  volcanic  ejectamenta,  from 
“juvenile”  waters,  and  possibly  from  submarine  rivers  and  springs. 
The  last  possibility  has  been  considered  by  Sollas,1  but  no  numerical 
correction  can  be  devised  for  it.  These  four  sources  of  sodium  in  the 
sea  may  be  grouped  together  as  nonfluviatile,  and  reduce  the  numera- 
tor of  the  fraction  which  gives  the  age  of  the  ocean.  Whether  they 
exceed,  balance,  or  only  in  part  compensate  the  other  corrections  it 
is  impossible  to  say. 

From  the  foregoing  computations  it  is  to  be  inferred  that  the  age  of 
the  ocean,  since  the  earth  assumed  its  present  form,  is  somewhat  less 
than  100,000,000  years.  If,  however,  any  serious  change  of  rate  in 
the  supply  of  sodium  to  the  sea  has  taken  place  during  geologic 
time,  the  estimate  must  be  correspondingly  altered.  This  side  of  the 
question  has  been  studied  by  G.  F.  Becker  in  the  memoir  already 
cited,  who  has  shown  that  the  rate  was  probably  greater  in  early 
times  than  now,  and  has  steadily  tended  to  diminish.  Wlien  erosion 
began,  the  waters  had  fresh  rocks  to  work  upon.  Now,  three-fourths 


Presidential  address.  Quart.  Jour.  Geol.  Soc.,  May,  1909. 


THE  OCEAN. 


153 


of  the  land  area  of  the  globe  are  covered  by  sedimentary  rocks  or  by 
detrital  and  alluvial  material,  from  which  a large  part  of  the  sodium 
has  been  leached.  The  accessible  supply  of  sodium  has  decreased, 
and  it  may  be  supposed  that  at  some  remote  time  in  the  future  it  will 
be  altogether  exhausted.  From  considerations  of  this  order  Becker 
has  developed  an  equation  representing  the  supply  of  sodium  to  the 
ocean  during  past  time  by  a descending  exponential,  and  has  shown 
that  the  age  of  the  ocean,  as  deduced  from  the  data  already  given, 
must  lie  somewhere  between  50  and  70  millions  of  years.  The  higher 
figure,  he  thinks,  is  closer  to  the  truth  than  the  lower  one.  If  the 
ocean  was  initially  saline  the  estimate  of  its  age  would  be  still  further 
reduced.  Becker’s  conclusions  are  fairly  accordant  with  the  results 
derived  from  physical,  astronomical,  and  paleontological  evidence, 
although  the  study  of  radioactivity  among  minerals  has  led  to 
much  higher  figures  for  the  age  of  the  earth.  The  latter  line  of 
evidence  will  be  considered  in  another  chapter,  but  it  seems  that  the 
rate  of  chemical  erosion  offers  a more  tangible  and  definite  mode  of 
attack  upon  the  problem  of  geologic  time.  The  problem  can  not  be 
regarded  as  definitely  solved,  however,  until  all  available  methods  of 
estimation  shall  have  converged  to  one  common  conclusion.1 


1 For  persistent  criticisms  of  the  chemical  method  of  computing  geological  time,  see  H.  S.  Shelton,  Chem. 
News,  vol.  99, 1909,  p.  253,  vol.  102,  1910,  p.  75;  vol.  112,  1915,  p.  85;  Jour.  Geology,  vol.  18,  1910,  p.  190; 
Sci.  Progress,  vol.  9, 1914,  p.  55.  The  criticisms  are  based  upon  a belief  that  the  analyses  of  river  waters 
are  inaccurate,  especially  in  the  determination  of  Na  and  SO4;  that  is,  the  skill  and  accuracy  of  many 
reputable  chemists  are  questioned.  On  this  subject,  see  the  rejoinder  by  R.  B.  Dole,  Chem.  News,  vol. 
103, 1911,  p.  289.  Mr.  Shelton  also  claims  that  he  has  found  a discrepancy  between  the  SO4  determina- 
tions in  waters  and  the  amounts  found  in  igneous  rocks.  In  making  this  claim  he  has  compared  the  mean 
percentage  of  S in  the  great  mass  of  igneous  rocks  with  that  of  the  soluble  matter  leached  from  a thin  film 
of  surficial  deposits.  The  two  quantities  are  not  commensurable. 


CHAPTER  V. 

THE  WATERS  OF  CLOSED  BASINS. 

PRELIMINARY  STATEMENT. 

In  dealing  with  the  ocean  and  its  tributary  rivers  we  have  studied 
the  hydrosphere  in  its  larger  sense,  the  waters  all  forming  part  of 
one  great  system  of  circulation  which  can  be  treated  as  a unit. 
But  on  all  the  continents  there  are  isolated  areas  from  which  the 
drainage  never  reaches  the  sea.  Streams  originate  in  the  higher 
portions  of  such  areas,  resembling  in  all  respects  those  tributary  to 
the  ocean.  Their  waters  gather  in  depressions  and,  ultimately,  by 
the  concentration  of  their  saline  constituents  form  salt  or  alkaline 
lakes  or  even  dry  beds  of  solid  residues.  The  latter  condition  is 
developed  in  small  areas  of  great  aridity,  where  evaporation  is  so 
rapid  that  no  large  body  of  water  can  accumulate;  but  the  more  im- 
portant closed  basins  are  characterized  by  the  formation  of  permanent 
reservoirs,  such  as  the  Caspian,  the  Great  Salt  Lake,  and  the  Dead 
Sea.  Each  basin  exhibits  individual  peculiarities  of  more  or  less 
local  origin,  and  therefore  each  one  must  be  studied  separately. 
No  such  uniformity  as  that  shown  by  the  ocean  is  manifested  here, 
although  in  some  lakes  we  can  recognize  a curious  approximation 
in  chemical  character  to  that  of  the  open  sea. 

THE  BONNEVILLE  BASIN. 

To  American  students  the  most  accessible  and  therefore  the  most 
interesting  of  these  isolated  regions  is  that  known  as  “the  Great 
Basin”  in  the  western  part  of  the  United  States.  This  area  is  fully 
described  in  two  monographs  of  the  Geological  Survey,1  in  which  it 
is  represented  as  having  been  formerly  the  seat  of  two  great  lakes, 
Bonneville  and  Lahontan,  of  which  only  the  remnants  now  exist. 
The  Great  Salt  Lake  of  Utah  is  the  chief  remainder  of  Lake  Bonneville 
and,  with  its  accessory  waters,  may  well  occupy  our  attention  first. 

The  water  of  Great  Salt  Lake  has  been  repeatedly  analyzed — on 
the  whole  with  fairly  concordant  results,  except  in  regard  to  salinity. 
The  latter  varies  with  changes  in  the  level  of  the  lake,  but  is  always 
several  times  greater  than  that  of  sea  water.  An  early,  incomplete 
analysis  by  L.  D.  Gale  and  a questionable  one  by  H.  Bassett  are 
hardly  worth  reproducing.2  The  other  available  data,  expressed  in 
percentages  of  total  salts,  are  as  follows : 

1 G.  K.  Gilbert,  Lake  Bonneville:  Mon.  U.  S.  Geol.  Survey,  vol.  1, 1890.  I.  C.  Russell,  The  geological 
history  of  Lake  Lahontan:  Mon.  U.  S.  Geol.  Survey,  vol.  11, 1885. 

2 They  are  cited  in  Gilbert’s  monograph.  Bassett’s  analysis  is  very  high  in  potassium. 

154 


THE  WATERS  OF  CLOSED  BASINS. 


155 


Analyses  of  water  from  Great  Salt  Lake. 

A.  By  O.  D.  Allen,  Kept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2,  1877,  p.  433.  Water  collected  in  1869.  A 
trace  of  boric  acid  is  also  reported,  in  addition  to  the  substances  named  in  the  table.  Allen  also  gives 
analyses  of  a saline  soil  from  a mud  flat  near  Great  Salt  Lake.  It  contained  16.40  per  cent  of  soluble  matter 
much  like  that  of  the  lake  water. 

B.  By  Charles  Smart.  Cited  in  Resources  and  attractions  of  the  Territory  of  Utah,  Omaha,  1879. 
Analysis  made  in  1877. 

C.  By  E.  von  Cochenhausen,  for  C.  Ochsenius,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  34,  1882,  p.  359. 
Sample  collected  by  Ochsenius  April  16,  1879.  Ochsenius  also  gives  an  analysis  of  the  salt  manufactured 
from  the  water  of  Great  Salt  Lake. 

D.  By  J.  E.  Talmage,  Science,  vol.  14, 1889,  p.  445.  Collected  in  1889.  An  analysis  of  a sample  taken 
in  1885  is  also  given. 

E.  By  E.  Waller  j,  School  of  Mines  Quart.,  vol.  14, 1892,  p.  57.  A trace  of  boric  acid  is  also  reported. 

F.  By  W.  Blum.  Collected  in  1904.  Recalculated  to  100  per  cent.  Reported  by  Talmage  in  Scottish 
Geog.  Mag.,  vol.  20, 1904,  p.  424.  An  earlier  paper  by  Talmage  on  the  lake  is  in  the  same  journal,  vol.  17, 

1901,  p.  617. 

G.  By  W.  C.  Ebaugh  and  K.  W illiams,  Chem.  Zeitung,  vol.  32, 1908,  p.  409.  Collected  in  October,  1907. 

H.  By  R.  K.  Bailey,  in  the  laboratory  of  the  U.  S.  Geological  Survey.  Sample  collected  by  H.  S.  Gale, 
October  24, 1913. 


A 

B 

C 

D 

E 

F 

G 

H 

Cl 

55.  99 

56.  21 

55.  57 

56.  54 

55.  69 

55.  25 

55. 11 

55.  48 

Hr  

Trace. 

Trace. 

Trace. 

so4 

6. 57 

6.  89 

6.  86 

5.  97 

6.  52 

6.  73 

6.  66 

6.  68 

co,  

.07 

.09 

Li 

Trace. 

.01 

Trace. 

Na 

33. 15 

33.  45 

33. 17 

33.  39 

32.  92 

34.  65 

32.  97 

33. 17 

K 

1.  60 

(?) 

.20 

1.  59 

1.  08 

1.  70 

2.  64 

3. 13 

1.  66 

Ca 

. 17 

.21 

.42 

1.  05 

. 16 

. 17 

.16 

Mg 

2.  52 

3. 18 

2.  60 

2.  60 

2. 10 

.57 

1.  96 

2.  76 

Fe,Oo,  AloO,,  SiOo 

.01 

Salinity,  per  cent 

100.  00 
14.  994 

100.  00 
13.  790 

100.  00 
15.  671 

100.  00 
19.  558 

100.  00 
°23.036 

100.  00 
27.  72 

100.  00 
22.  99 

100.  00 
20.  349 

a More  correctly,  230.355  grams  per  liter. 


Although  the  salinity  of  the  lake  is  very  variable  and  from  four  to 
seven  times  as  great  as  that  of  the  ocean,  its  saline  matter  has  nearly 
the  same  composition.  The  absence  of  carbonates,  the  higher  sodium, 
and  the  lower  magnesium  are  the  most  definite  variations  from  the 
oceanic  standard;  but  the  general  similarity,  the  identity  of  type,  is 
unmistakable.  Gilbert  estimates  the  quantity  of  sodium  chloride 
contained  in  the  lake  at  about  400  millions  and  the  sulphate  at  30 
millions  of  tons. 

For  the  waters  tributary  to  Great  Salt  Lake  many  analyses  are 
available.1  The  following  table  relates  to  some  of  the  streams,  except 
that  Sevier  Lake,  an  outlying  remnant  of  Lake  Bonneville,  is  included 
as  a matter  of  convenience.  The  analyses  are  all  reduced  to  standard 
form,  with  bicarbonate  radicles  recalculated  to  normal  C03.  Salinity 
is  stated  in  parts  per  million. 

1 In  addition  to  the  data  given  here,  see  analyses  by  J.  T.  Kingsbury,  of  City,  Red  Butte,  Farmington, 
Emigration,  Parleys,  Big  Cottonwood,  and  Littlo  Cottonwood  creeks,  cited  by  G.  B.  Richardson  in  Water- 
Supply  Paper  U.  S.  Geol.  Survey  No.  157,  1906,  p.  30;  analyses  made  in  1882  and  1884.  Field  Operations 
Bur.  Soils,  U.  S.  Dept.  Agr.,  1903,  p.  1138,  contains  analyses  of  Provo  River,  Spanish  Fork,  American  Fork 
and  Dry,  Payson,  Santaquln,  Currant,  and  Warm  creeks,  but  the  analyst  is  not  named.  Other  analyses 
of  Great  Salt  Lake,  complete  and  partial,  are  given  by  W.  C.  Ebaugh  and  W.  Macfarlane  in  Science,  vol. 
32, 1910,  p.  568. 


156 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  waters  tributary  to  Great  Salt  Lake. 

A.  Bear  River  at  Evanston,  Wyoming.  Analysis  By  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  9, 
1884,  p.  30. 

B.  Bear  River  at  Corinne,  Utah,  near  its  mouth.  Analysis  received  from  the  Southern  Pacific  Railroad. 

C.  Jordan  River  at  intake  of  Utah  and  Salt  Lake  canal.  Analysis  by  F.  K.  Cameron,  Rept.  No.  64, 
Bur.  Soils,  U.  S.  Dept.  Agr.,  1900,  p.  108. 

D.  Jordan  River  near  Salt  Lake  City.  Analysis  by  Cameron,  loc.  cit. 

E.  City  Creek,  Utah.  Analysis  by  T.  M.  Chatard,  Bull.  U.  S.  Geol.  Survey  No.  9, 1884,  p.  29. 

F.  Ogden  River  at  Ogden,  U tah. 

G.  Weber  River  at  mouth  of  canyon.  Analyses  F and  G made  under  the  direction  of  F.  K.  Cameron, 
Field  Operations  Div.  Soils, U.  S.  Dept.  Agr.,  1900,  p.  226. 

H.  Sevier  Lake.  Analysis  by  Oscar  Loew,  Rept.  U.  S.  Geog.  Surveys  W.  100th  Mer.,  vol.  3, 1875, p.  114. 
Sample  taken  in  1872. 


A 

B 

C 

D 

E 

F 

G 

H 

Cl 

2.  68 

32.  36 

35.54 

34.  76 

5.  38 

23.  21 

13.  73 

52.  66 

so4 

5.  76 

8. 16 

26.  54 

30.  68 

2.  87 

5.  65 

9.  25 

10.  88 

CO,  

52.  68 

21.53 

2.  67 

Trace. 

52.  57 

33.  68 

40.  00 

Na 

1 4.49 

120.  54 

126. 13 

123.04 

1 3.  74 

11.  31 

8.  37 

33.  33 

K 

/ 

/ 

/ 

/ 

/ 

4. 16 

4. 19 

Ca 

23.  69 

10. 12 

7.59 

10.  26 

24. 19 

16.  05 

18. 19 

.12 

Mg 

6.  86 

4.  76 

1.  53 

1.  26 

7. 15 

5.  94 

6.  27 

3.  01 

Si02 

3.  84 

3.  69 

(A1  Fe)oO, 

2.  53 

.41 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per 

million 

185 

637 

892 

1,  090 

243 

444 

455 

86,  400 

Utah  Lake,  at  the  head  of  Jordan  River,  has  furnished  material  for 
a most  instructive  series  of  analyses,  as  follows : 

Analyses  of  water  from  Utah  Lake. 

A.  By  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  9, 1884,  p.  20. 

B.  By  F.  K.  Cameron,  1899. 

C.  By  B.  E.  Brown,  1903. 

D.  Mean  of  three  analyses  by  A.  Seidell,  1904.  Samples  taken  in  May. 

E.  By  B.  E.  Brown,  1904.  Collected  August  31.  For  analyses  B,  C,  D,  and  E,  see  F.  K.  Cameron,  Jour. 
Am.  Chem.  Soc.,  vol.  27,  1905,  p.  113.  All  are  here  reduced  to  terms  of  normal  carbonates. 


A 

B 

c 

D 

E 

Cl 

4.  04 

35.  48 

26.  23 

24.  75 

26.  87 

so4 

42.  68 

26.  53 

28.  49 

28.  25 

30. 14 

C03 

19.  88 

2.  66 

10.  23 

12.  35 

8.  48 

Li 

.06 

Na 

| 5.81 

| 26.  20 

19.  28 

18. 19 

18.  34 

K 

2.  34 

2. 17 

1.  75 

Ca 

J 18.24 

7.  58 

6.  25 

5.  90 

5.  34 

Sr 

. 15 

Mg 

6.  08 

1.  55 

7. 18 

6. 18 

6.  85 

Si02 

3.  27 

2.00 

2.  23 

Salinity,  parts  per  million 

100.  00 
306 

100.00 

892 

100.  00 
1,  281 

100.00 
1, 165 

100.  00 
1,  254 

Although  the  foregoing  analyses  are,  in  one  respect  or  another, 
incomplete,  they  tell  an  intelligible  story.  Bear  River  at  Evanston 
is  a normal  river  water,  which  upon  evaporation  would  yield  mainly 
calcium  carbonate,  and  so,  too,  is  City  Creek.  Bear  River,  near  its 


THE  WATERS  OF  CLOSED  BASINS. 


157 


mouth,  has  changed  its  character  almost  completely  and  has  evidently 
taken  up  large  quantities  of  sodium  chloride  from  the  soil.  Utah 
Lake,  in  the  20  years  intervening  between  the  earliest  and  latest 
analyses,  has  undergone  a thorough  transformation,  and  its  salinity 
has  more  than  quadrupled.  From  a fresh  water  of  the  sulphate  type 
it  has  become  distinctly  saline,  and  this  change  is  probably  a result 
of  irrigation.  Its  natural  supplies  of  water  have  been  diverted  into 
irrigating  ditches,  and  at  the  same  time  salts  have  been  leached  out 
from  the  soil  and  washed  into  the  lake.  To  some  extent,  these  salts 
have  been  brought  to  the  surface  as  a result  of  cultivation,  so  much 
so  that  considerable  areas  of  land  bordering  upon  the  lake  have  ceased 
to  be  available  for  agriculture.  Its  outlet,  Jordan  River,  exhibits 
the  same  peculiarities.  As  for  Sevier  Lake,  which  is  now  reduced  to 
a mere  pool  in  consequence  of  irrigation  along  its  sources,  its  water 
resembles  that  of  Great  Salt  Lake,  except  that  at  the  time  the  analysis 
was  made  it  was  only  about  half  as  saline. 

All  of  the  waters  tributary  to  Great  Salt  Lake,  so  far  as  they  have 
been  examined,  contain  notable  quantities  of  carbonates,  which  are 
absent  from  the  lake  itself.  These  salts  have  evidently  been  precipi- 
tated from  solution,  and  evidence  of  this  process  is  found  in  beds  of 
oolitic  sand,  composed  mainly  of  calcium  carbonate,  which  exist  at 
various  points  along  the  lake  shore.1  The  strong  brine  of  the  lake 
seems  to  be  incapable  of  holding  calcium  carbonate  in  solution. 

THE  LAHONTAN  BASIN. 

The  Quaternary  Lake  Lahontan,  which  once  covered  an  area  of 
8,400  square  miles  in  northwestern  Nevada,  is  now  represented  by  a 
number  of  relatively  small,  scattered  sheets  of  water  and  many 
alkaline  or  saline  beds.  Instead  of  one  large  basin  there  are  now 
several  basins,  and  each  one  is  fed  by  independent  sources  of  fresh 
water.  Each  lake,  therefore,  has  its  own  individual  peculiarities,  as 
the  various  analyses  show.  Some  of  the  lakes  exist  only  during  the 
humid  season,  when  large  areas  are  covered  by  a thin  layer  of  water; 
others  are  permanent  sheets  of  considerable  depth.  Our  data  relate 
only  to  the  latter,  with  their  sources  of  supply. 

In  the  statement  of  some  analyses  precision,  in  a certain  sense,  has 
been  sacrificed  to  uniformity.  In  strongly  alkaline  waters  the  radicle 
Si03  may  possibly  exist  instead  of  the  colloidal  Si02.  In  no  case, 
however,  is  the  silica  high  enough  to  cause  a serious  error  in  this 
respect,  and  a fraction  of  1 per  cent  will  cover  the  uncertainty.  A 
graver  criticism  might  be  based  upon  the  representation  of  all  the  car- 
bonates as  normal,  for  bicarbonates  are  undoubtedly  present  in  some 
of  the  waters,  which  on  evaporation  deposit  trona  in  large  quantities. 
If,  however,  we  regard  the  analyses  as  representing  the  percentage 


1 See  analyses  by  R.  W.  Woodward,  cited  in  Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2,  1877,  p.  435, 
Also  an  analysis  by  T.  M.  Chatard,  in  Bull.  U.  S.  Geol.  Survey  No.  228, 1904,  p.  331, 


158 


THE  DATA  OF  GEOCHEMISTRY. 


composition  of  ignited  residues,  the  suggested  objection  no  longer 
holds.  We  can  compare  our  data  upon  the  uniform  basis  adopted 
hitherto,  and  leave  the  question  of  bicarbonates  for  separate  con- 
sideration later.  The  divergent  character  of  the  analyses  seems  to 
render  some  such  procedure  necessary.  It  is  only  by  ehminating 
variables  that  we  can  obtain  comparable  results. 

In  the  next  table  two  groups  of  analyses  appear.  Lake  Tahoe,  a 
typical  mountain  lake  of  great  purity,  empties  through  Truckee 
River,  which  terminates  in  Winnemucca  and  Pyramid  lakes.  These 
waters  are  included  in  the  first  group.  The  second  comprises 
Walker  River  and  Walker  Lake.  The  individual  analyses,  which, 
except  when  otherwise  stated,  are  recalculated  from  the  laboratory 
records  of  the  Survey,  are  as  follows : 

Analyses  of  Lahontan  waters — I. 

A.  Lake  Tahoe,  California.  Analysis  by  F.  W.  Clarke. 

B.  Truckee  River,  Nevada.  Mean  of  two  concordant “boiler-water  analyses  ” received  from  the  South- 
ern Pacific  Railroad. 

C.  Pyramid  Lake,  Nevada.  Mean  of  four  concordant  analyses  by  Clarke. 

D.  Winnemucca  Lake,  Nevada.  Analysis  by  Clarke. 

E.  Walker  River,  Nevada.  Analysis  by  Clarke. 

F.  Walker  Lake,  Nevada.  Mean  of  two  analyses  by  Clarke.  For  analyses  A,  C,  D,  E,  and  F,  see  Bull. 
U.  S.  Geol.  Survey  No.  9,  1884. 


A 

B 

C 

D 

E 

F 

Cl 

3. 18 

7.59 

41.  04 

47.  88 

7.  50 

23.  77 

S04 : 

7.  47 

12.  87 

5.  25 

3.  76 

16. 14 

21.  29 

co3 

38.  73 

33.  30 

14.  28 

7.  93 

30.  34 

17.  34 

Na 

10. 10 

1 17.  26 

33.84 

36.  68 

\ 18.  07 

\ 34.83 

K 

4.  56 

J 

2. 11 

1.  94 

j 

} 

Ca 

12.  86 

11.02 

.25 

.55 

12.  96 

.90 

Mg 

4. 15 

3. 49 

2.  28 

.49 

2.  21 

1.  56 

Si02 

(Al,Fe)oO. 

18.  95 

} 14.  47 

.95 

.77 

12.  78 

.31 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million  .... 

73 

153 

3, 486 

3,602 

180 

2,  500 

The  changes  shown  by  these  waters  1 are  elaborately  discussed  by 
Russell  in  his  work  on  Lake  Lahontan.  Ordinary  fresh  waters  rich 
in  carbonates  and  in  calcium  are  concentrated,  and  the  lime  salts  are 
finally  thrown  out  in  the  form  of  tufa.  The  tufa,  however,  instead  of 
being  an  oolitic  or  granular  deposit,  as  in  the  Bonneville  basin,  is  in 
the  form  of  crystals,  “ thinolite,”  pseudomorphous  after  some 
unknown  mineral,  which  may  have  been  a calcium  chlorocarbonate. 
This  peculiar  variety  of  tufa  is  characteristic  of  the  Lahontan  basin; 
but  the  mode  of  its  formation  is  uncertain.2 


1 Except  that  of  analysis  B,  which  is  more  recent. 

2 See  discussion  by  E.  S.  Dana,  in  Bull.  U.  S.  Geol.  Survey  No.  12,  1884.  Calcite  pseudomorphs,  simi- 
lar to  thinolite  and  called  pseudogay lussite,  have  been  discussed  by  F.  J.  P.  van  Calker  (Zeitschr.  Kryst. 
Min.,  vol.  28,  1897,  p.  556)  and  C.  O.  Trechmann  (idem,  vol.  35, 1902,  p.  283).  The  Australian  glendonite 
is  calcite  pseudomorphous  after  glauberite  and  sometimes  forms  crystals  15  to  20  inches  long.  See  T.  W.  E. 
David,  Rec.  Geol.  Survey  New  South  Wales,  vol.  8, 1905,  p.  162. 


THE  WATERS  OF  CLOSED  BASINS. 


159 


Four  more  analyses  of  Lahontan  waters  remain  to  be  considered, 
as  follows: 

Analyses  of  Lahontan  waters — II. 

G.  Humboldt  River,  Nevada.  Analysis  by  T.  M.  Chatard. 

H.  Humboldt  Lake,  Nevada.  Analysis  by  O.  D.  Allen,  Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2, 
1877,  p.  743. 

I.  The  large  Soda  Lake,  Ragtown,  Nevada.  Surface  sample.  Analysis  by  Chatard. 

J.  The  large  Soda  Lake,  sample  from  a depth  of  30.5  meters.  Analysis  by  Chatard.  For  these  analyses 
of  Chatard’s  see  Bull.  U.  S.  Geol.  Survey  No.  9,  1884.  An  earlier  analysis  of  Soda  Lake  by  O.  D.  Allen 
is  given  in  the  Fortieth  Parallel  report,  vol.  2,  1877,  p.  748.  It  is  less  complete  than  Chatard’s,  but  other' 
wise  not  very  different.  This  water  contains  bicarbonates.  Specific  gravity,  1.101. 


G 

H 

I 

J 

Cl  

2. 19 

31.  82 

36.  51 

35.  38 

so4 

13.  92 

3.  27 

10.  36 

10.  50 

co3  

39.  55 

21.  57 

13.  78 

15.  89 

PO.  

.07 

BXL 

.25 

.26 

Na 

13.  63 

29.  97 

36.  63 

35.  38 

K 

2.  92 

6.54 

2.  01 

2. 13 

Ca 

14.  28 

1.  35 

My 

3.  62 

1.  88 

.22 

.21 

Si02 

9.  51 

3.  53 

.24 

.25 

ai2o3 

.38 

Salinity,  parts  per  million 

100.  00 
361 

100.  00 
929 

100.  00 
113,  700 

100.  00 
113, 700 

The  first  two  of  these  analyses  show  the  change  from  river  to 
lake  water  very  clearly.  There  is  a concentration  of  chlorides  and 
a relative  loss  in  silica,  magnesium,  and  calcium.  The  water  of  Soda 
Lake  is  more  than  three  times  as  concentrated  as  sea  water,  and  of 
an  entirely  different  type.  It  has  no  visible  supply  of  water  except 
from  springs  near  its  margin,  and  at  certain  times  it  deposits  trona 
and  also  gaylussite  in  notable  quantities.  Gaylussite  is  a carbonate 
of  calcium  and  sodium,  but  no  calcium  is  shown  by  Chatard’s  analy- 
ses. It  must,  therefore,  be  deposited  by  the  lake  about  as  rapidly 
as  it  is  received.  The  tributary  springs  have  not  been  investigated. 

The  Lahontan  waters,  then,  are  distinctly  alkaline,  whereas  the 
lakes  of  the  Bonneville  basin  are  salt.  The  cause  of  the  difference 
must  be  sought  in  the  sources  from  which  the  waters  are  derived, 
and  one  distinction  is  clear.  Great  Salt  Lake  is  fed  by  streams  and 
springs  which  flow  in  great  part  through  sedimentary  formations. 
Its  saline  matter  is  a concentration  of  old  salts  which  were  laid  down 
long  ago.  The  Lahontan  lakes,  on  the  other  hand,  are  supplied  with 
water  from  areas  of  igneous  rocks,  in  which  rhyolites  and  andesites 
are  especially  abundant  and  from  which  the  alkalies  may  be  obtained. 
They  represent,  therefore,  a primary  concentration  of  leached  mate- 
rial, as  contrasted  with  the  secondary  origin  of  the  Bonneville  brine. 
The  difference  is  easily  recognized,  but  it  does  not  explain  all  of  the 
phenomena.  To  account  for  the  large  amounts  of  chlorine  in  the 


160 


THE  DATA  OF  GEOCHEMISTRY. 


waters,  particularly  in  that  of  Great  Salt  Lake,  is  not  so  easy  a 
matter.  So  far  as  I am  aware,  no  plausible  solution  of  the  latter 
problem  has  yet  been  suggested.  The  cosmological  speculations, 
which  help  us  in  the  case  of  the  ocean,  hardly  seem  to  be  applicable 
here. 

LAKES  OF  CALIFORNIA. 

In  California  there  are  a number  of  alkaline  lakes  having  a gen- 
eral resemblance  to  those  of  the  Lahontan  basin.  The  following 
analyses  are  available,  and  in  them,  as  usual,  bicarbonates,  if  reported, 
have  been  reduced  to  normal  form. 


Analyses  of  water  from  alkaline  lakes  in  California. 


A.  Mono  Lake.  Analysis  by  T.  M.  Chatard,  Bull.  U.  S.  Geol.  Survey  No.  60,  1890,  p.  53.  Sample 
taken  in  1882.  Specific  gravity,  1.045.  An  improbable  analysis  of  Mono  Lake  water,  by  Winslow  Ander- 
son, is  given  in  his  Mineral  springs  and  health  resorts  of  California,  San  Francisco,  1892,  p.  198.  In  it  the 
calcium  salts  predominate  over  all  others. 

B.  Owens  River  at  Charlies  Butte.  Mean  of  36  ten-day  composite  samples,  taken  between  December 
31,  1907,  and  December  31, 1908.  Average  analysis  by  W.  Van  Winkle  and  F.  M.  Eaton,  Water-Supply 
Paper  U.  S.  Geol.  Survey  No.  237,  p.  121.  A similar  annual  average  is  given  for  the  water  at  Round  Valley 
farther  upstream. 

C.  Owens  Lake.  Analysis  by  Chatard,  op.  cit.,  p.  58.  Specific  gravity,  1.062.  For  an  early  analysis 
of  Owens  Lake  see  O.  Loew,  Ann.  Rept.  Geog.  Surveys  W.  100th  Mer.,  1876,  p.  190. 

D.  Owens  Lake.  Analysis  by  C.  H.  Stone,  cited  by  W.  T.  Lee  in  Water-Supply  Paper  U.  S.  Geol. 
Survey  No.  181, 1906,  p.  22.  Sample  taken  in  August,  1905. 

E.  Owens  Lake.  Analysis  by  W.  B.  Hicks  in  the  laboratory  of  the  U.  S.  Geological  Survey.  Specific 
gravity,  1.0977.  An  analysis  by  J.  G.  Smith  is  given  in  Bull.  Dept.  Agr.  No.  61, 1914,  p.  80. 

F.  Black  Lake,  near  Benton,  Mono  County.  Analysis  by  Loew,  op.  cit.,  p.  191. 

G.  Tulare  Lake  in  1889.  Analysis  by  E.  W.  Hilgard,  Appendix  to  Rept.  Univ.  California  Exper. 
Sta.,  1900.  This  lake  has  an  outlet  during  floods,  but  not  at  other  times.  An  analysis  of  water  collected 
in  1880  is  also  given. 

H.  Borax  Lake.  Analysis  by  W.  H.  Melville,  published  by  G.  F.  Becker  in  Mon.  U.  S.  Geol.  Survey, 
vol.  13, 1888,  p.  265.  In  addition  to  the  substances  named  in  the  table,  the  original  residue  contained  4.5, 
per  cent  of  organic  matter. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

23.  34 

9.  49 

25.  67 

24.  82 

25.  40 

7.  68 

20.  26 

32.  27 

Br 

Trace. 

.04 

I 

Trace. 

S04 

12.  86 

15.  53 

9.  95 

9.  93 

9.  89 

13.  24 

20.  77 

.13 

co3 

23.  42 

29.  84 

32.  51 

24.  55 

22.  70 

37.  73 

19.  55 

22.  47 

P04 

. 11 

Trace. 

.02 

b4o7 

.32 

.48 

. 14 

1.  89 

Trace. 

5.  05 

NO, 

.48 

.45 

Li 

.03 

Trace. 

Na 

37.  93 

119.  83 

37.  83 

38.  09 

37.  83 

39.  05 

35.  79 

38. 10 

K 

1.  85 

/ 

2. 18 

1.  62 

2.  09 

2.  03 

2.44 

1.  52 

Rb,  Cs 

Trace. 

Ca 

.04 

8.  92 

.02 

.02 

.28 

.03 

Mg 

. 10 

3.  45 

.01 

.01 

.26 

.35 

Si02 

.14 

12.  37 

.29 

.14 

.20 

.27 

.65 

.01 

A1203 

Trace. 

.04 

} .04 

1 

Fe203 

Trace. 

.09 

.02 

l .01 

Mn203 

) 

J 

As203 

.05 

100.  00 

100.00 

100.  00 

100.00 

100.  00 

100.00 

100.00 

100.00 

Salinity,  parts  per 

million 

51, 170 

339 

72,  700 

213,700 

118,  830 

18,  500 

4,  910 

76,  560 

THE  WATERS  OF  CLOSED  BASINS. 


161 


Like  Soda  Lake,  Owens  and  Mono  lakes  both  yield  trona  on  evapo- 
ration, and  at  Owens  Lake  it  has  been  prepared  on  a commercial  scale.1 
Soda  Lake  was  also  utilized  at  one  time  for  the  same  purpose. 
Borax  Lake,  according  to  Becker,  derives  its  boron  from  neighboring 
hot-  springs.  It  deposits  some  calcareous  sinter. 

NORTHERN  LAKES. 

The  region  of  alkaline  lakes  continues  northward  from  Nevada  and 
California,  and  a number  of  the  waters  have  been  analyzed.  The 
more  important  analyses  are  given  in  the  following  tables.  Those 
made  by  W.  Van  Winkle  are  recalculated  from  the  figures  published 
in  Water-Supply  Paper  No.  363,  1914,  with  bicarbonates  reduced 
to  normal  salts. 

Analyses  of  water  from  northern  alkaline  lakes. 

A.  Summer  Lake,  Oregon.  Analysis  by  Van  Winkle,  who  cites  two  other  analyses.  Specific  gravity, 

1.0162  at  15°. 

B.  Ana  River,  a feeder  of  Summer  Lake.  Van  Winkle  analyst.  One  other  analysis  is  cited. 

C.  Abert  Lake,  Oregon.  Analysis  by  T.  M.  Chatard,  U.  S.  Geol.  Survey  Bull.  No.  60, 1890,  p.  55.  An 
earlier  analysis  by  F.  W.  Taylor  is  not  in  accord  with  this.  Specific  gravity  1.03117,  at  19.8°. 

D.  Abert  Lake.  Analysis  by  Van  Winkle,  who  cites  other  analyses.  Sample  taken  in  February,  1912. 

E.  Chewaucan  River,  the  chief  feeder  of  Abert  Lake.  Van  Winkle,  analyst.  Average  of  37  analyses  of 
composite  samples  of  water,  taken  between  August  11, 1911,  and  August  14, 1912. 

F.  Harney  Lake,  Oregon.  Analysis  by  G.  Steiger  in  the  laboratory  of  the  U.  S.  Geological  Survey. 
Sample  taken  August  5, 1902. 

G.  Harney  Lake.  Van  Winkle,  analyst.  Collected  March  10, 1912.  Specific  gravity,  1.0209. 

H.  Malheur  Lake,  Oregon.  Van  Winkle,  analyst.  An  analysis  of  Silver  Lake,  in  the  same  general 
region,  is  also  given  and  one  of  Donner  and  Blitzen  River,  a feeder  of  Malheur  Lake. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

18.  27 

7.  07 

36.  04 

36.  23 

0.  66 

27.  50 

30.  40 

4.  55 

so4 

4. 18 

5.  21 

1.  90 

1.  91 

5.  99 

7.  67 

8.  62 

7.  64 

co3 

35.  57 

32.  73 

20.  67 

20.  82 

28.  79 

25.  87 

19.  77 

44.  63 

P04 

Trace. 

. 33 

b4o7 

. 92 

Present. 

Present. 

4 w V 

NOo 

.02 

.13 

Trace. 

.46 

. 01 

. 50 

Na 

39.  48 

\25.  08 

39.  33 

38.  78 

9.  06 

35.  78 

39.  43 

24. 17 

K 

1.  59 

/ 

1.  44 

1.  69 

3.  33 

1.  91 

1.  50 

5.  58 

Ca 

Trace. 

3. 15 



Trace. 

10. 13 

None. 

.03 

5.  58 

Mg 

Trace. 

2.  83 

Trace. 

2.  54 

. 07 

Trace. 

4. 13 

Si02 

.62 

23.  79 

.62 

.36 

38.  64 

! 28 

.14 

2.  89 

ALO, 

. 27 

. 21 

None. 

. 10 

Trace. 

Fe203 

Trace. 

.01 

Trace. 

.40 

None. 

Trace. 

Trace. 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100. 00 

Salinity,  parts  per 

million 

16,  633 

156 

39, 172 

29,  564 

75 

10,  427 

22,  383 

484 

1 See  Chatard’s  memoir  on  “natural  soda”  in  Bull.  U.  S.  Geol.  Survey  No.  60, 1890.  The  nature  of  the 
product  will  be  considered  later  in  the  chapter  on  saline  residues. 

97270°— Bull.  616—16 11 


162 


THE  DATA  OF  GEOCHEMISTBY. 


Analyses  of  water  from  northern  alkaline  lakes — Continued. 

I.  Silvies  River,  the  chief  feeder  of  Malheur  Lake.  Van  Winkle,  analyst.  Average  of  23  analyses  of 
composite  samples  of  water,  collected  between  October  12, 1911,  and  August  14, 1912. 

J.  Pelican  Lake,  Oregon.  Van  Winkle,  analyst. 

K.  Bluejoint  Lake,  Oregon.  Van  Winkle,  analyst.  Pelican  and  Bluejoint  Lakes  are  in  the  Warner 
Lake  basin.  Analyses  are  also  given  of  Crump,  Hart,  and  Flagstaff  Lakes,  all  in  the  same  group. 

L.  Silver  Lake,  in  Christmas  Lake  basin,  Oregon.  Analysis  by  Van  Winkle. 

M.  Soap  Lake,  Washington.  Analysis  by  George  Steiger,  U.  S.  Geol.  Survey  Bull.  No.  113, 1893,  p.  113. 
Another  analysis  by  H.  G.  Knight  is  given  in  the  previous  editions  of  this  work. 

N.  Moses  Lake,  Washington.  Analysis  by  H.  G.  Knight,  Ann.  Rept.  Washington  Geol.  Survey,  vol. 
1, 1901,  p.  295. 

O.  Omak  Lake,  Colville  Indian  Reservation,  Washington.  Analysis  by  Steiger  in  the  laboratory  of 
the  Survey.  Specific  gravity,  1.004,  at  25°. 

P.  Goodenough  Lake,  a shallow  pond  28  miles  north  of  Clinton,  British  Columbia.  Analysis  by  F.  G. 
Wait,  Ann.  Rept.  Geol.  Survey  Canada,  new  ser.,  vol.  11, 1898,  p.  48  R. 


Cl... 

so4.. 

co3.. 

P04.. 

b4o7. 

no3-. 

Na... 

K. . . 

Ca 

Mg... 

Si02.. 

AI2O3. 


Salinity,  parts  per 
million 


2.  88 
7.  35 
34.  76 


.92 
10.  42 
2.  45 
12.  88 
3. 13 
25. 13 


.08 


100.  00 
163 


7.  97 
22.  09 
30.  87 
.07 
Present. 
.05 
29.  25 
3.  58 
2.  27 
2.  62 
1.  21 


.02 


100.  00 
1,  983 


13.  85 
5.  67 
38.  68 
.05 
Present. 
.02 
37.  70 
2.  26 
.57 
.63 
.55 


.02 


100.  00 
3,  640 


0.  87 
2.  43 
47.  48 


.06 
^16.  36 

11.07 
6.  59 
15.  04 


10 


100.  00 
379 


M 


13.  28 
16.  44 
30.  22 


J39.  60 

Trace. 

.04 

.42 


100.  00 
28, 195 


3.  88 
2.  87 
51.  56 


19.  86 


8.  41 
7.  25 
5. 06 

1. 11 


100.  00 
2, 966 


2.  96 
21. 12 
36.  75 


None. 


32.  60 
4.  52 
.23 
1.  82 


100.  00 
5, 704 


7.  64 
7. 08 
41.  41 
.62 
Trace. 


36. 17 
6.  65 
.02 
.04 
.04 
.33 


100. 00 

103, 470 


All  of  these  waters  contain  bicarbonates.  Goodenough  Lake 
deposits  natron,  Na2CO3.10H2O,  of  which  an  analysis  is  given.1 

A few  saline  lakes  situated  east  of  the  Kocky  Mountains  have  been 
studied  to  some  extent.  The  analyses  are  as  follows: 

1 Analyses  by  J.  G.  Smith  of  Summer,  Christmas,  Fossil,  North  Alkali,  Middle  Alkali,  and  South  Alkali 
Lakes,  all  in  Oregon,  are  given  in  Bull.  U.  S.  Dept.  Agr.,  No.  61, 1914,  p.  80. 


THE  WATERS  OF  CLOSED  BASINS. 


163 


Analyses  of  water  from  saline  lakes  east  of  the  Rocky  Mountains. 

A.  Wilmington  Lake,  Wyoming.  Analysis  by  E.  E.  Slosson,  Bull.  Wyoming  Exper.  Sta.  No.  49, 1901. 

B.  Big  Lake. 

C.  Track  Lake. 

D.  Red  Lake.  These  three  lakes  are  known  as  the  Laramie  or  Union  Pacific  Lakes  of  Wyoming.  They 
are  usually  dry,  but  in  1888  were  filled  with  water.  Analyses  by  H.  Pemberton  and  G.  P.  Tucker,  Jour. 
Franklin  Inst.,  vol.  135,  1893,  p.  52. 

E.  Lake  De  Smet,  Wyoming.  Analysis  by  W.  T.  Schaller  in  the  laboratory  of  the  U.  S.  Geol.  Survey. 
An  analysis  of  its  feeder,  Shell  Creek,  was  also  made.  See  Water-Supply  Paper  No.  364,  1914,  p.  17. 

F.  Devils  Lake,  North  Dakota.  Analysis  by  H.  W.  Daudt,  Quart.  Jour.  Univ.  North  Dakota,  vol.  1, 
1911,  p.  225.  Reduced  to  standard  form.  Ca,  0.04;  Si02, 12.2;  R2O3,  4.0  parts  per  million. 

G.  Old  Wives  or  Chaplin  Lake,  Saskatchewan,  Canada.  Analysis  by  F.  J.  Alway  and  R.  A.  Gortner, 
Am.  Chem.  Jour.,  vol.  37,  1907,  p.  3.  Recalculated  to  100  per  cent  from  the  original  summation  of  98.55. 


A 

B 

C 

D 

E 

F 

G 

Cl 

10.  78 

8.  85 

2.  74 

3.  06 

0.  90 

10.  45 

4.  98 

so4 

16.  62 

58. 16 

64.  30 

64.  57 

64. 15 

54.  07 

61.  86 

co3 

32.  75 

5. 14 

4.  24 

1.  54 

b4o7 

2.  03 

1. 14 

. 57 

■^4^7  ------------- 

Na 

39.  85 

27.  00 

30.  20 

29.  89 

20.  85 

25.  88 

30.  65 

K 

1.  27 

Trace. 

Ca 

.93 

.53 

.59 

1. 10 

Trace. 

Trace. 

Mg 

3.  03 

1.  09 

1.  32 

6.  32 

5.  36 

.97 

Si02 

.22 

} .05 

) 

Trace. 

Trace. 

A1203 

Trace. 

Trace. 

Fe203 

Salinity,  parts  per 
million 

100.  00 
0 119,  700 

100.  00 
«52,  600 

100.  00 
®77,  300 

100.  00 
«93, 100 

100. 00 
6,  708 

100.  00 
11,  278 

100. 00 
27,  300 

a These  figures  for  salinity  of  the  Laramie  Lakes  have  little  or  no  significance,  because  the  "lakes”  vary 
from  dry  masses  of  salts  to  solutions  of  varying  concentration.  For  additional  information  about  them  see 
L.  C.  Ricketts,  Ann.  Rept.  Territorial  Geologist  Wyoming,  1888,  p.  45;  and  A.  R.  Schultz,  Bull.  U.  S.  Geol. 
Survey  No.  430,  p.  570. 


Five  of  these  lakes  are  essentially  solutions  of  sodium  sulphate,  and 
resemble  certain  bodies  of  water  on  the  Russian  steppes. 


164 


THE  DATA  OF  GEOCHEMISTRY, 


CENTRAL  AND  SOUTH  AMERICA. 

For  the  saline  waters  of  Central  and  South  America  the  chemical 
data  are  very  scanty.  Six  analyses,  however,  may  be  cited  here : 

Analyses  of  saline  waters  from  Central  and  South  America. 

A.  Lake  Chichen-Kanab  (“little  sea”),  Yucatan.  Analysis  by  J.  L.  Howe  and  H.  D.  Campbell,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  2, 1896,  p.  413.  Two  samples  were  analyzed,  and  that  from  the  middle  of  the  lake 
is  given  below.  The  water  deposits  gypsum. 

B.  Lake  Parinacochas,  Peru.  Analysis  by  G.  S.  Jamieson  and  H.  Bingham,  Am.  Jour.  Sci.,  ser.  4,  vol. 
34,  p.  12, 1912. 

C.  Lake  Huacachima,  Peru.  Analysis  by  E.  Pozzi-Escot,  Bull.  Soc.chim.,  4th  ser.,  vol.  15,  1914,  p.  97. 
Traces  of  bromides,  iodides,  and  thiosulphates  are  also  reported.  The  analysis  is  obscurely  stated,  and  the 
recalculation  here  is  therefore  somewhat  uncertain. 

D.  Lagoon  of  Tamentica,  Chile.  See  F.  J.  San  Rom&n,  Desierto  i cordilleras  de  Atacama,  vol.  3,  Santiago 
de  Chile,  1902,  p.  199. 

E.  Rio  Saladillo,  Argentina.  Analysis  by  Siewert,  reported  by  A.  W.  Stelzner,  Beitrage  zur  Geologie 
und  Palaeontologie  der  argentinischen  Republik,  1885.  Sample  taken  at  Puente  del  Monte.  The  river 
empties  into  the  Laguna  de  los  Porongos.  It  is  salt  during  drought,  nearly  fresh  in  th  e rainy  season.  Stelz- 
ner estimates  that  it  carries  into  the  laguna,  annually,  584,566,200  kilograms  of  salts.  Stelzner  also  gives 
analyses  by  Doering  of  the  Saladillo  between  Salta  and  Jujuy,  and  of  Arroyo  Salado  in  Patagonia. 

F.  Laguna  de  Epecuen,  Argentina.  Analysis  by  M.  M.  Leguizam<5n,  Trabajos  Cuarto  Cong,  cient.  Pan- 
Americano,  vol.  4,  Santiago,  1910,  p.  258. 


A 

B 

c 

D 

E 

F 

Cl 

8. 14 

46.  87 

11.18 

50.  44 

56.  74 

42.  96 

so4 

58.  64 

10.  59 

16.  95 

9.17 

4.  82 

17. 19 

co3 

2.16 

29.  33 

2. 13 

no3 

.40 

Trace. 

2. 14 

P04 

.05 

Trace. 

b4o7 

1.  36 

s 

. 12 

Na 

11.  99 

32.  64 

36.  54 

35.  35 

36.40 

37.  72 

K 

.43 

3.  83 

4.  52 

2.  29 

Ca 

13.  49 

1. 18 

.01 

1.  63 

Me 

7.  31 

.82 

.34 

.60 

.41 

Si02 

.07 

. 63 

A1203 

.39 

Fe90, 

.03 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  parts  per  million 

4,446 

12,  059 

(?) 

285,  500 

108,  250 

285, 000 

THE  WATERS  OF  CLOSED  BASINS. 


165 


CASPIAN  SEA  AND  SEA  OF  ARAL. 

The  greatest  of  all  the  closed  basins  is  that  of  the  Caspian  Sea, 
which  was  formerly  connected,  through  the  Black  Sea,  with  the  gen- 
eral oceanic  circulation.  It  is  also  probable  that  the  Sea  of  Aral  was 
at  some  time  a part  of  the  same  great  body  of  water,  and  therefore  the 
two  sheets  are  properly  to  be  considered  together.  Many  smaller 
saline  lakes  are  scattered  through  the  Caspian  depression,  some  of 
them  being  recent  concentrations  from  overflows,  while  others  are  of 
much  older  origin.1 

The  Caspian  Sea,  however,  is  something  more  than  a segregated 
remnant  of  the  ocean.  Its  water  is  diluted  by  the  influx  of  the 
Volga,  the  Ural,  arid  other  important  streams,  so  that  its  composition 
is  intermediate  between  that  of  a river  and  that  of  the  open  sea. 
Its  salinity  is  relatively  low  and  very  variable.  At  the  north  end, 
near  the  mouth  of  the  V olga,  the  water  is  only  brackish ; in  the  deeper 
southern  portions  it  is  much  salter.  On  the  eastern  side  of  the  Cas- 
pian there  is  a large  gulf,  the  Karaboghaz,  into  which  a current 
continually  flows,  through  a shallow  channel,  with  no  compensating 
return.  This  current,  it  is  estimated,  carries  daily  into  the  gulf 
350,000  tons  of  salt;  and  therefore  the  salinity  of  the  Karaboghaz  is 
steadily  increasing.  Its  waters  no  longer  support  animal  life,  and 
saline  deposits  are  forming  upon  its  bottom.  Near  its  margin 
gypsum  crystals  are  formed;  toward  the  center  of  the  gulf  sodium 
sulphate  is  deposited.2  The  latter  substance  is  thrown  down  only 
during  the  winter  months,  for  at  summer  temperatures  the  Karabo- 
ghaz brine  is  an  unsaturated  solution.  In  cold  weather  it  is  saturated 
with  respect  to  sodium  sulphate,  but  not  for  the  chloride,  and  the 
latter  remains  dissolved.3  The  separation  of  salts  by  fractional 
crystallization  is  thus  well  exemplified. 


1 For  analyses  of  some  of  these  waters,  the  Bogdo,  Indersk,  and  Stepanova  lakes,  see  Roth,  Allgemeine 
und  chemische  Geologie,  vol.  1,  p.  469.  Modern  and  complete  analyses  are  much  to  he  desired;  the  old 
ones  are  unsatisfactory. 

2 See  S.  Kusnetsoff,  Zeitschr.  prakt.  Geologie,  1898,  p.  26. 

3 See  N.  S.  Kurnakoff,  Verhandl.  Russ.  k.  min.  Gesell.,  2d  ser.,  vol.  38,  1900,  p.  26  of  the  proceedings. 
For  a long  paper  on  the  Karaboghaz,  also  known  as  the  Karabugas  or  Adschi-darja,  see  W.  Stahl,  Natur. 
Wochenschr.,  vol.  20, 1905,  p.  689.  Tin's  paper  is  based  on  an  official  Russian  report  by  Spindler  and  Lebo- 
dintzeff,  published  in  1902.  For  an  analysis  of  water  from  Lake  Durun  in  Transcaspia  see  A.  Stachmann, 
Jahresb.  Chemie,  1887,  p.  2531. 


166 


THE  DATA  OF  GEOCHEMISTRY. 


To  illustrate  the  composition  of  the  Caspian  and  allied  waters,  a 
few  analyses  must  suffice.  The  older  data  can  be  found  in  the  works 
of  Bischof  and  Both.  The  following  examples  are  fairly  typical: 

Analyses  of  Caspian  and  allied  waters. 

A.  Caspian  Sea.  Mean  of  five  analyses  by  C.  Schmidt,  Bull.  Acad.  St.  Petersburg,  vol.  24, 1878,  p.  177. 

B.  Caspian  Sea.  Analysis  by  A.  LebedintzefE,  cited  by  W.  Stahl,  Natur.  Wochenschr.,  vol.  20,  1905, 
p.  689. 

C.  Karaboghaz  Gulf.  Analysis  by  Schmidt,  loc.  cit. 

D.  Karaboghaz  Gulf.  Analysis  by  LebedintzefE,  cited  by  Stahl,  loc.  cit. 

E . Tinetzky  Lake,  a residue  of  concentration  from  the  Caspian.  Analysis  by  Schmidt,  loc.  cit. 

F.  Sea  of  Aral.  Analysis  by  Schmidt,  cited  from  Roth,  Allgemeine  und  chemische  Geologie,  vol.  1,  p.  465. 
Schmidt’s  analyses  report  bicarbonates,  which  are  here  reduced  to  normal  salts.  I have  also  consolidated 
the  insignificant  quantities  of  silica,  phosphoric  acid,  and  ferric  oxide,  which  were  determined  separately. 

G.  Sea  of  Aral.  Analysis  by  Stepanow,  cited  by  S.  Sowetow,  Ann.  Hydjog.  und  Marit.  Meteorolog., 
1910,  p.  658.  Other  recent  analyses  are  also  mentioned,  probably  from  the  monograph  by  L.  Berg  on  the 
Sea  of  Aral,  published  by  the  Russian  Geographical  Society,  a work  which  I have  not  seen. 

H.  The  River  Atrek,  a western  tributary  of  the  Caspian.  Mean  of  two  analyses  by  F.  K.  Otten,  Jahresb. 
Chemie,  1881,  p.  1442.  Analyses  of  the  tributary  rivers  Sumbar  and  Tschandyr  are  also  given. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

' 42.04 

41.  78 

53.  32 

50.  26 

47.  99 

35.  40 

35.  63 

19.  33 

Br 

. 05 

. 05 

.06 

. 08 

. 13 

.03 

S04 

23.  99 

23.  78 

17.  39 

15.  57 

21.  25 

30.  98 

31.  27 

43.  09 

co3 

. 37 

. 93 

. 13 

. 85 

. 10 

6.  09 

Na 

1 24.  70 

24.  49 

11.  51 

25.  51 

18.  46 

22.  62 

22.  05 

19.  03 

K 

. 54 

. 60 

1.  83 

. 81 

. 24 

. 54 

1.  07 

Rb 

.02 

.06 

.01 

.02 

Ca 

2.  29 

2.  60 

. 57 

.01 

4.  02 

4.  48 

5.  98 

Mg 

5.97 

5.  77 

15.  83 

7.07 

11.  91 

5.  50 

5.40 

5.40 

Si09,  PCX,  FeoO, 

.03 

. 04 

1.  08 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

100.00 

Salinity,  per  cent 

[ 1.294 

1.  267 

28.  50 

16.  396 

28.  90 

1.084 

1.  067 

1.  495 

Analyses  C and  D show  that  the  Karaboghaz  varies  from  time  to 
time,  both  in  composition  and  in  concentration. 

With  the  exception  of  the  Atrek  and  two  other  small  streams, 
analyses  of  the  rivers  which  feed  the  Caspian  seem  to  be  wanting ; at 
least,  I have  found  none  recorded.  They  must  have  carried  large 
amounts  of  calcium  and  of  carbonic  acid,  which  have  been  almost 
entirely  eliminated.  The  falling  off  of  sulphates  and  the  concentration 
of  magnesium  in  the  more  saturated  waters  is  clearly  brought  out  by 
the  table,  an  order  of  change  which  will  be  considered  more  fully 
somewhat  later.  Both  the  Caspian  Sea  and  the  Sea  of  Aral  differ 
chemically  from  the  ocean  in  their  higher  proportions  of  calcium, 
magnesium,  and  sulphates.1 

i Bergstrasser,  In  Petermann’s  Mittheilungen,  1858,  pp.  104-105,  has  brought  together  38  old  analyses  of 
salts  from  the  lakes  of  Astrakhan  and  the  mouth  of  the  V olga.  For  an  analysis  of  water  from  Lake  Tinaksk, 
Astrakhan,  see  N.  W.  Sokoioff,  Jour.  Chem.  Soc.,  vol.  100,  ii,  1911,  p.  502,  abstract  from  Jour.  Russian 
Phys.-Chem.  Soc.,  vol.  43,  p.  436. 


THE  WATERS  OF  CLOSED  BASINS. 


167 


THE  DEAD  SEA. 

In  the  water  of  the  Dead  Sea  some  of  the  phenomena  of  saline 
concentration  are  exhibited  to  an  extreme  degree.  Sodium  com- 
pounds have  been  largely  eliminated,  and  the  remaining  brine  resem- 
bles in  many  respects  the  mother  liquor  left  by  ocean  water  after 
the  extraction  of  salt.  It  is  rich  in  magnesium,  calcium,  and  bromine ; 
the  sulphates  have  been  reduced  to  an  insignificant  amount,  and  car- 
bonates are  almost  entirely  lacking.  The  original  solutions,  how- 
ever, from  which  the  Dead  Sea  was  formed  were  probably  not  iden- 
tical in  composition  with  those  which  produced  the  salinity  of  the 
ocean,  and  so  the  bittern  of  sea  water  differs  from  the  brine  that  we 
are  now  considering.  The  two  are  similar,  but  not  quite  the  same. 

The  water  of  the  Dead  Sea  has  been  repeatedly  analyzed  and  the 
older  data  are  reproduced  in  the  works  of  Bischof  and  Roth.  The 
best  series  of  analyses  is  due  to  A.  Terreil,1  and  of  his  eight,  six  are 
given  below  in  reduced  form.  They  represent  samples  collected  from 
different  depths  and  different  parts  of  the  lake,  and  they  show  its 
variable  character. 


Analyses  of  water  from  Dead  Sea  and  River  Jordan. 

A . Surface  water , north  end  of  lake . Terreil . 

B.  At  depth  of  20  meters,  5 miles  east  of  Wady  Mrabba.  Terreil. 

C.  At  depth  of  42  meters,  near  Has  Mersed.  Terreil. 

D.  At  depth  of  120  meters,  5 miles  east  of  Has  Feschkah.  Terreil. 

E.  Same  locality  as  D,  at  depth  of  200  meters.  Terreil. 

F.  Same  locality  as  B,  at  depth  of  300  meters.  Terreil. 


A 

B 

c 

D 

E 

F 

Cl 

65.  81 

70.  25 

68. 16 

67.  66 

67.  84 

67.  30 

Br 

2.  37 

1.  55 

1.  99 

1.  98 

1.  75 

2.  72 

S04 

. 31 

. 21 

. 22 

. 22 

.22 

. 24 

C03 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Na 

11.  65 

6.  33 

10.  21 

10.  20 

10.  00 

5.  50 

K 

1.  85 

1.  70 

1.  00 

1.  62 

1.  79 

1.  68 

Ca 

4.  73 

5.  54 

1.  53 

1.  51 

1.  68 

6.  64 

Mg 

13.  28 

14.  42 

16.  89 

16.  81 

16.  72 

15.  92 

Si02 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Salinity,  per  cent 

100.  00 
19.  215 

100.  00 
20.  709 

100.  00 
24.  263 

100.  00 
24.  573 

100.  00 
25. 110 

100.  00 
25.  998 

1 Compt.  Rend.,  vol.  62, 1866,  p.  1329  Terreil  also  made  an  analysis  of  the  water  of  the  River  Jordan,  but 
stated  it  obscurely.  In  addition  to  the  substances  named  in  the  table,  Terreil  reports  traces  of  hydrogen 
sulphide,  ammonia,  alumina,  ferric  oxide,  and  organic  matter  in  the  water  of  the  Dead  Sea. 


168 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  water  from  Dead  Sea  and  River  Jordan — Continued. 

G.  Analysis  by  J.  B.  Boussingault,  Annales  chim.  phys.,  3d  ser.,  vol.  48,  1856,  p.  129.  Boussingault 
cites  the  earlier  analyses  of  Dead  Sea  water. 

H.  Analysis  by  F.  A.  Genth,  Liebig’s  Annalen,  vol.  110,  1859,  p.  240. 

I.  Analysis  by  Roux,  Compt.  Rend.,  vol.  57,  1863,  p.  602. 

J.  Analysis  by  H.  Fleck,  Jour.  Chem.  Soc.,  vol.  42,  1882,  p.  24,  abstract.  Probably  surface  water. 

K.  Analysis  by  A.  Stutzer  and  A.  Reich,  Chem.  Zeitung,  vol.  31, 1907,  p.  845. 

L.  Analysis  by  A.  Friedmann,  Chem.  Zeitung,  vol.  36,  p.  147,  1912.  Specific  gravity  1.1298.  Mean  of  2 
analyses. 

M.  Analysis  by  H.  Fresenius,  Zeitschr.  angew.  Chem.,  1912,  p.  1991.  Specific  gravity  1.1555  at  15°.  The 
trace  of  iodine  is  0.000247  gram  per  kilo,  and  of  iron,  0.0007586  gram. 

N.  The  Jordan  near  Jericho.  Analysis  by  R.  Sachsse,  Inaug.  Diss.,  Erlangen,  1896.  Analyses  of  several 
smaller  streams  are  given.  Organic  matter  not  included  in  the  following  table.  An  earlier  analysis  by 
Anderson  is  cited  in  the  first  edition  of  this  book  (Bulletin  330). 


G 

H 

I 

1 

J 

K 

L 

M 

N 

Cl 

65.  80 

65.  22 

65.  43 

65.  74 

64.49 

63.40 

65.  86 

41.47 

Br 

1.  37 

2.  08 

1.  54 

1.48 

1.  45 

1.  69 

1. 13 

I 

Trace. 

S04 

. 13 

.29 

.20 

.33 

.45 

.42 

.39 

7.22 

co3 

. 01 

Trace. 

. 02 

13. 11 

no3 

Trace. 

Na 

11.  22 

13.  39 

11.  70 

11.  60 

15.  75 

13.  49 

13.  73 

18. 11 

K 

3.  70 

2.  37 

3.  53 

3.  40 

3.  24 

3.  24 

2.  36 

1.14 

NII4 

Trace. 

Trace. 

Ca 

5.  69 

4.  79 

5.  60 

5.  02 

4.  09 

5.  74 

4. 19 

10.  67 

Mg 

12.  09 

11.  85 

11.  85 

12.  42 

10.  53 

12.02 

12.  32 

4.88 

Si02 

1.  95 

(Al,  Fe)203 

Trace. 

Trace. 

.15 

Trace. 

Trace. 

Trace. 

1.45 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Salinity,  per  cent 

22.  7697 

22.  2834 

20.  590 

21.  977 

22.  030 

23.  8906 

18.  8453 

0.  770 

From  the  foregoing  analyses  we  see  that  the  water  of  the  Dead  Sea 
differs  widely  from  all  the  other  waters  that  we  have  examined.  The 
composition  of  its  main  feeder,  the  Jordan,  is  also  unusual.  When  it 
enters  the  Dead  Sea,  its  carbonates,  and  gypsum  are  precipitated,  and 
its  contribution  to  the  lake  brine  is  composed  almost  entirely  of 
chlorides.  The  valley  of  the  Jordan  and  the  regions  roundabout  the. 
Dead  Sea  contain  many  beds  of  rock  salt  and  gypsum,  and  the  neigh- 
boring Cretaceous  strata  are  impregnated  with  the  same  substances. 
From  these  sources  the  river  derives  its  chlorides  and  sulphates,  and 
so  returns  to  the  lake  some  products  of  its  former  concentration.  Hot 
springs,  also,  as  L.  Lartet 1 and  others  have  shown,  contribute  to  the 
salinity  of  the  waters.  To  some  extent,  probably,  there  is  atmospheric 
transportation  of  salts  from  the  Mediterranean,  and  W.  Ackroyd  2 
regards  this  as  a most  important  agency,  although  its  influence  is 
probably  overestimated.  Whatever  may  have  been  the  origin  of  the 
Dead  Sea,  its  water  is  now  essentially  a bittern,  relatively  low  in 
sodium,  high  in  magnesium,  and  remarkably  rich  in  bromine.  The 


Bull.  Soc.  g6ol.  France,  2d  ser.,  vol.  23,  1866,  pp.  719-760. 


2 Chem.  News,  vol.  89, 1904,  p.  13. 


THE  WATERS  OF  CLOSED  BASINS. 


169 


brine  from  300  meters  depth  carries  over  7 grams  of  bromine  to  the 
liter,  but  only  a trace  of  iodine  has  been  detected  in  it.1 

OTHER  RUSSIAN  AND  ASIATIC  LAKES. 

Mother  liquors  having  a general  similarity  to  the  Dead  Sea  brine 
are  also  furnished  by  the  Elton  Lake,  in  southern  Russia,  and  the 
Red  Lake,  near  Perekop,  in  the  Crimea.  Their  analyses,  recalculated 
from  the  figures  given  by  Roth,  appear  in  the  next  table.  The  com- 
position of  the  Elton  water  varies  with  the  season  of  the  year,  and 
I have  selected  an  analysis  which  represents  its  concentration  in 
August.  In  spring  its  tributaries,  swollen  by  melting  snow,  bring  in 
much  sodium  chloride  and  alter  its  character  materially.  Analyses 
of  water  from  several  Asiatic  lakes  are  included  with  these  in  the 
table  following. 

Analyses  of  Russian  and  Asiatic  waters. 

A.  Elton  Lake,  Russia.  Analysis  by  Erdmann,  cited  by  Roth,  Allgemeine  und  chemische  Geologie, 
vol.  1,  p.  469. 

B.  Red  Lake,  Perekop,  Crimea.  Analysis  by  Hasshagen,  from  Roth,  op.  cit.,  p.  471.  Roth  gives  anal- 
yses of  several  other  Crimean  salt  lakes.  Analyses  of  four  Crimean  lakes  are  given  by  A.  Goebel,  M61- 
chim.  phys.,  vol.  5,  1864,  p.  326. 

C.  Lake  Van,  Armenia.  Analysis  by  E.  de  Chancourtois,  Compt.  Rend.,  vol.  21,  1845,  p.  1111.  Car- 
bonates reduced  to  normal  salts. 

D.  Lake  Urmi  or  Urmiah,  Persia.  Analysis  by  R.  T.  Gunther  and  J.  J.  Manley,  Proc.  Roy.  Soc.,  vol. 
65,  1899,  p.  312. 

E.  Salt  Lake  near  Shiraz,  Persia.  Analysis  by  K.  Natterer,  Monatsh.  Chemie,  vol.  16,  1895,  p.  658. 

F.  Gaukhane  Lake,  southern  Persia.  Analysis  by  A.Heider,  published  by  Natterer,  op.  cit.,  p.  673. 

G.  Koko-Nor,  Tibet.  Analysis  by  C.  Schmidt,  Bull.  Acad.  St.  Petersburg,  vol.  24,  1878,  p.  177.  Bicar- 
bonates reduced  to  normal  salts.  Sample  taken  in  autumn,  1872. 

H.  Koko-Nor,  Tibet.  Analysis  by  Schmidt,  M41.  chim.  phys.,  St.  Petersburg,  vol.  11,  1881,  p.  487. 
Sample  taken  in  the  winter  of  1880,  from  under  thick  ice.  For  analyses  of  three  saline  lakes  in  Central 
Asia,  see  Schmidt,  idem,  vol.  12,  1887,  p.  547. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

64.  22 

66.  82 

27.  08 

57.  33 

58. 17 

59.  67 

40.  05 

41.  69 

Br  

.03 

.01 

.04 

.04 

I 

. 11 

S~04 

6.  82 

11.  95 

5.  06 

3.  48 

1.  29 

17.  84 

16.  30 

CO, 

. 04 

20.  71 

. 23 

5.  55 

6.  66 

vv3*  * * * * 

Na 

11.  27 

19.  32 

37.  65 

33.  98 

35.  51 

37.  38 

30.  60 

28.  64 

K 

.58 

1. 19 

.78 

.29 

1.  08 

. 81 

Rb 

.04 

.04 

NH4  ..  . 

.01 

Trace. 

Ca 

. 10 

2.  01 

.32 

.46 

.82 

1.  77 

.04 

Mg 

17.  55 

11. 13 

.57 

2.  53 

1.  84 

. 83 

2.  90 

5.  66 

Si02 

. 85 

.01 

.09 

.08 

Fe<,Oo 

Trace. 

.02 

.02 

P04 

.02 

.02 

Salinity,  per  cent 

100.  00 
26.  50 

100.  00 
30.  01 

100.  00 
2. 10 

100.  00 
14.  85 

100.  00 
7.  77 

100.  00 
25.  88 

100.  00 
1. 11 

100.  00 
1.  30 

1 The  following  references  to  original  authorities  on  the  water  of  the  Dead  Sea  are  worth  recording:  J. 
Apjohn,  Proc.  Roy.  Irish  Acad.,  vol.  1, 1841,  p.  287;  B.  Silliman,  jr.,  Am.  Jour.  Sci.,  1st  ser.,  vol.  48,  1845, 
p.  10;  T.  J.  and  W.  Herapath,  Jour.  Chem.  Soc.,  vol.  2,  1849,  p.  337;  A.  F.  Boutron-Charlard  and  O.  Henry, 
Jour,  pharm.  chim.,  March,  1852;  R.  M.  Murray,  Proc.  Glasgow  Philos.  Soc.,  vol.  3, 1852,  p.  242;  J.  C.  Booth 
and  A.  Muckle,  Am.  Jour.  Sci.,  2d  ser.,  vol.  19, 1855,  p.  149;  F.  Moldenhauer,  Liebig’s  Annalen,  vol.  97, 1856, 
p.  357;  Schwarzenbach,  Mitt,  naturforsch.  Gesell.  Berne,  1870,  p.  47.  An  analysis  by  J.  H.  Salisbury  (Am. 
Polytech.  Jour.,  vol.  2,  1853,  p.  374)  of  what  purported  to  be  Dead  Sea  water  was  evidently  of  ocean  water. 
The  earlier  analyses  by  A.  Marcet,  Klaproth,  Gay-Lussac,  and  C.  G.  Gmelin  have  only  historical  interest. 
A recent  analysis  by  Mitchell  (Berg-  u.  hiittenm.  Zeitung,  1902,  p.  225)  is  of  doubtful  value. 


170 


THE  DATA  OF  GEOCHEMISTRY. 


The  general  resemblance  of  analyses  A and  B to  those  of  Dead  Sea 
water  is  evident.  Elton  Lake,  however,  contains  a notable  propor- 
tion of  sulphates,  which  are  entirely  wanting  in  the  Crimean  water. 
Lake  Van  is  alkaline,  and  its  saline  composition  is  much  like  that  of 
Mono  Lake  in  California,  except  that  it  is  less  concentrated.  Lake 
Urmi  is  of  the  same  type  as  Great  Salt  Lake,  and  the  two  other 
Persian  waters  are  similar.  The  Koko-Nor  belongs  in  the  same  class 
with  the  Caspian  and  the  Sea  of  Aral,  but  it  contains  a much  larger 
proportion  of  carbonates. 

In  the  neighborhood  of  Minussinsk  and  Abakansk,  government  of 
Yeniseisk,  Siberia,  there  are  a number  of  saline  lakes  or  ponds  which 
have  been  studied  by  F.  Ludwig.1  The  reduced  analyses,  arranged 
in  the  order  of  their  chlorine,  are  as  follows: 

Analyses  of  water  from  saline  lakes  of  Yeniseisk,  Siberia. 

A.  The  Kisil-Kul. 

B.  Lake  Schunett,  water  collected  in  1899.  Another  analysis,  of  a sample  collected  in  1898,  gave  similar 
hut  somewhat  different  results,  and  showed  much  greater  concentration.  This  latter  sample  had  a salinity 
of  25.35  per  cent,  and  its  salts  contained  0.19  per  cent  of  bromine. 

C.  LakeTagar. 

D.  LakeBeisk. 

E.  Bitter  Lake. 

F.  Lake  Altai. 

G.  Lake  Biljo.  This  is  the  largest  of  the  lakes  and  measures  about  60  kilometers  in  circumference. 

H.  Lake  Domoshakovo. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

48.  28 

38. 89 

29.  52 

22.  79 

20.  02 

14.  38 

9.  91 

3.  71 

Br 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

S04 

14.  55 

32. 19 

34.  99 

42.  32 

43.  83 

50. 14 

52.  33 

63.  62 

co3 

.22 

.31 

1.  55 

.61 

1.  53 

1. 12 

6.  22 

.08 

NO, 

1. 07 

. 07 

Na 

34.  01 

16. 12 

28. 41 

31.  32 

31.  78 

32.  83 

21.  83 

30.  61 

K 

.35 

.33 

1.  01 

1. 01 

1.  38 

.52 

.87 

.59 

Ca 

.69 

.44 

.27 

.07 

.15 

.05 

.43 

. 58 

Mg 

1.  86 

11.  67 

4. 12 

1.  86 

1.  28 

.90 

7.  28 

.74 

Si02 

.04 

.01 

.04 

.01 

.03 

.03 

.03 

Trace. 

ALO, 

.04 

.09 

.01 

Trace. 

.02 

.03 

Trace. 

Fe90, 

Trace. 

Trace. 

.01 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

100.00 

100.  00 

Salinity,  per  cent 

10.  87 

15. 19 

2.09 

10. 47 

5.  90 

10.  88 

.88 

14.  55 

The  last  analysis  in  this  table,  that  of  Lake  Domoshakovo,  repre- 
sents essentially  a solution  of  sodium  sulphate,  with  very  little  else. 
It  is  the  extreme  type  of  a sulphate  water.  The  other  waters  upon 
evaporation,  yield  mixtures  of  chlorides  and  sulphates,  sodium  being 
the  dominant  electropositive  radicle.  In  one  analysis  only  is  magne- 
sium high;  in  two  others  it  is  important.  The  calcium  is  insignificant 
throughout  the  series. 


1 Zeitschr.  prakt.  Geologie,  vol.  11,  1903,  p.  401.  Ludwig  also  gives  analyses  of  sediments  and  saline 
deposits  from  these  waters. 


THE  WATERS  OF  CLOSED  BASIE'S. 


171 


A number  of  other  Siberian  lakes  have  been  investigated  by  C. 
Schmidt,  from  whose  memoirs  the  subjoined  analyses,  reduced  to 
standard  form,  have  been  selected.1 

Analyses  of  water  from  Siberian  lakes. 

A.  Issyk-Kul.  Mel.  phys.  chim.,  St.  Petersburg,  vol.  11, 1882,  p.  623. 

B.  Iletsk  salt  lake,  government  of  Orenberg.  Op.  cit.,  vol.  11,  1882,  p.  608.  Average. 

C.  Barchatow  bitter  lake,  300  versts  southwest  of  Barnaul,  government  of  Tomsk.  Op.  cit.,  vol.  11, 
1882,  p.  609. 

D.  Buluktii-Kul  or  Fish  Lake,  Kirghiz  Steppe.  Op.  cit.,  vol.  12,  1883,  p.  37. 


A 

B 

C 

D 

Cl 

15.  64 

60.  26 

45. 05 

37.  96 

Br 

.03 

Trace. 

. 11 

.04 

S04 

55.  94 

.47 

20. 23 

27.  39 

C03 

1.  26 

.98 

P04 

.02 

Na 

11.  76 

38. 86 

28. 01 

23.  29 

K 

1. 85 

Trace. 

.26 

.32 

Ca 

.94 

.33 

5.  28 

Mg 

12.  50 

.08 

5. 84 

4.  68 

Fe 

Trace. 

Si02 

.06 

.06 

S,  sulphide.. 

.50 

Salinity,  parts  per  million 

100. 00 

3, 574 

100. 00 
155, 230 

100. 00 
13, 308 

100.  00 
11, 458 

i In  M6m.  Acad.  St.  Petersburg,  vol.  20,  No.  4,  1873,  Schmidt  gives  analyses  of  14  bitter,  salt,  and  fresh 
lakes  on  the  line  from  Omsk  to  Petropavlovsk,  and  thence  to  Prasnowskaja. 


172 


THE  DATA  OF  GEOCHEMISTRY. 


MISCELLANEOUS  LAKES. 

In  the  next  table  I give  reduced  analyses  of  several  European  lakes 
of  widely  varying  character.  They  are  as  follows: 

Analyses  of  water  from  European  lakes. 

A.  Lake  Laach,  Germany.  Analysis  by  G.  Bischof,  Lehrbuch  der  chemischen  und  physikalischen 
Geologie,  2d  ed.,  vol.  1,  1863,  p.  316.  This  lake  occupies  the  crater  of  an  extinct  volcano,  and  its  water  is 
fresh.  It  is,  nevertheless,  an  alkaline  water  and  yields  sodium  carbonate  on  evaporation. 

B.  Palic  Lake,  Banat,  Hungary.  Analysis  by  K.  von  Hauer,  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  7, 
1856,  p.  361.  Iron,  magnesium,  and  calcium  are  held  in  solution  as  bicarbonates,  and  are  precipitated  on 
boiling.  Free  carbonic  acid  and  organic  matter  are  also  present. 

C.  Illyes  or  Medve  Lake,  near  Szovata,  Hungary.  Analysis  by  B.  von  Lengyel,  Foldt,  Kozl.,  vol.  28, 
1898,  p.  280.  Recently  formed  by  a sinking  of  the  ground.  The  neighboring  country  contains  salt  deposits. 

D.  Lake  Ruszanda,  Hungary.  Analysis  by  J.  Schneider,  cited  by  A.  Kaleczinzky,  Foldt,  Kozl.,  vol.  28, 
1889,  p.  284.  The  data  as  published  show  discrepancies  which  detract  from  their  value.  Organic  matter 
omitted. 

E.  Lake  Tekir-Ghiol,  Roumania.  Analysis  by  Popovici,  Saligny,  and  Georgesco,  cited  by  P.  Bujor, 
Ann.  sci.  Univ.  Jassy,  vol.  1, 1901,  p.  158.  A lake  of  about  1,140  hectares,  situated  only  300  to  400  meters 
from  the  Black  Sea.  The  published  summation  of  the  analysis  is  not  in  accord  with  the  individual  figures. 

F.  Lacu  Sarat,  Roumania.  Analysis  by  Carnot,  cited  by  Bujor,  op.  cit.,  p.  176.  In  winter  this  lake 
deposits  crystallized  sodium  sulphate,  mirabilite,  Na2SO4.10H2O.  In  a memoir  entitled  “Apergu  geolo- 
gique  sur  les  formations  saliferes  et  les  gisements  de  sel  en  Roumanie,”  Bucharest,  1902,  L.  Mrazec  and 
W.  Teisseyre  cite  analyses  of  Lacu  Sarat,  Lacu  Fundata,  Lacu  Amara,  and  Lacu  Ianca.  They  also  give 
analyses  of  Roumanian  salt. 


Cl... 

Br... 

S04.. 

co3. 

no3. 

P04. 

nh4. 

Na.. 

K... 

Ca... 

Mg.. 


Fe203 

Si02. 


Salinity,  parts  per  million. 


4.  99 


2.97 
50.  97 


27.  05 


9.  90 
2.  77 


1.  35 


100.  00 
218 


15.  68 


2.  92 
41.  02 


35.  75 


.66 

3. 35 


. 35 
.27 


100.  00 
2,215 


60. 18 
Trace. 
.44 
.04 


39.  02 


.25 

.03 


Trace. 

.04 


100.00 

233, 747 


19.  07 


22.56 

19.22 


.52 


37.07 
. 1.19 
.20 
.15 

Traces. 

.02 


100.  00 
6, 276 


60.  53 
.18 
.67 
Trace. 
Trace. 


Trace. 
34.  78 
1.  68 
.28 
1.  84 

j*  .03 

.01 


28.  25 

37*  i2 
.27 


31.  75 

”*.*39 
2. 16 

.02 

.04 


100.  00 
70, 877 


100.  00 
58, 038 


Illyes  Lake  and  the  neighboring  Black  Lake  are  essentially  strong 
solutions  of  common  salt,  formed  by  the  leaching  of  salt  beds.  Ac- 
cording to  A.  Kaleczinzky,1  they  have  warm  layers  under  a fresh- 
water surface,  which  owe  their  increased  temperature  to  the  absorp- 
tion of  solar  heat  and  to  the  fact  that  brine  has  a lower  specific  heat 
than  water.  The  surface  layer  of  Black  Lake  has  a temperature  of 
21°;  the  warm  layer  below  reaches  56°.  These  lakes,  therefore,  are 
accumulators  of  heat. 

With  the  analyses  of  six  more  lake  waters,  the  present  tabulation 
must  close.  They  are  as  follows: 

1 Ueber  die  ungarischen  warmen  und  heissen  Kochsalz-Seen,  etc.,  Budapest,  1902.  An  analysis  by 
Hanko  of  the  Black  Lake  is  given.  It  is  practically  identical  with  that  of  Illyes  Lake;  the  salinity  is  19.53 
percent.  See  also  F.  Schafarzik,  Foldt.  Kozl.,  vol.  38,  1908,  p.  437. 


THE  WATERS  OF  CLOSED  BASINS. 


173 


Analyses  of  saline  lakes  in  Africa,  India,  and  Australia. 

A.  Natron  Lake,  near  Thebes,  Egypt.  Analysis  by  E.  Willm,  Compt.  Rend.,  vol.  54, 1862,  p.  1224.  No 
bromine,  iodine,  nitrates,  or  sulphates  were  detected. 

B.  Salt  lake  32  kilometers  north  of  Pretoria,  Transvaal.  Described  by  E.  Cohen,  Min.  pet.  Mitt.,  vol.  15, 
1895,  pp.  1,  194.  Analysis,  incomplete,  by  H.  Hopmann.  This  lake  or  salt  pan  is  about  400  meters  in 
diameter  and  occupies  a funnel-shaped  depression  in  granite. 

C.  The  Katwee  salt  lake,  north  of  Albert  Edward  Nyanza,  central  Africa.  Analysis  by  A.  Pappe  and 
H.  D.  Richmond,  Jour.  Soc.  Chem.  Ind.,  vol.  9, 1890,  p.  734. 

D.  Sambhar  Salt  Lake,  Rajputana,  India.  Analysis  by  W.  A.  K.  Christie,  Rec.  Geol.  Survey  India, 
vol.  38,  1909,  p.  167.  Traces  of  NIL,  Fe,  S,  BO3,  PO4,  and  I were  also  found.  For  the  origin  of  the  salt 
in  this  lake  see  ante,  p.  150. 

E.  Lonar  Lake,  Berar  district,  Central  Provinces,  India.  Analysis  by  T.  H.  D.  La  Touche  and  W.  A. 
K.  Christie,  Rec.  Geol.  Survey  India,  vol.  41,  1912,  p.  266.  Traces  of  borates  detected. 

F.  Lake  Corongamite,  Victoria,  Australia.  Analysis  by  A.  W.  Craig  and  N.  T.  M.  Wilsmore,  Fourth 
Rept.  Australasian  Assoc.  Adv.  Sci.,  1892,  p.  270. 


A 

B 

C 

D 

E 

F 

Cl 

26.00 

43.47 

36.67 

52. 96 
.04 
5.85 

40. 76 

59.32 

.22 

1.65 

Br 

SO* 

.03 

12. 33 

1.48 

.01 

17.63 

39.60 

.11 

.01 

Trace. 

Trace. 

.40 

S 

C03 

32.90 

31.05 

15.17 

41.33 

10.42 

33.46 

7.09 

Trace. 

Trace. 

2.19 

38.86 

.09 

Trace. 

.01 

Undet. 

35.07 

.84 

.13 

2.77 

Na 

K 

Ca 

3.57 

3.62 

1.50 

1.36 

Mg 

(Al,  Fe)203 

SiO  2 

.03 

Trace. 

Salinity,  parts  per  million.  . . . 

100.  00 
4,  407 

100. 00 
211, 400 

100. 00 
310, 000 

100.  00 

(?) 

100. 00 
82,  872 

100. 00 
46,  039 

SUMMARY. 

With  the  evidence  now  before  us  it  is  easy  to  see  that  the  waters  of 
salt  and  alkaline  lakes  may  be  classified  in  a few  fairly  well  defined 
groups.  First,  we  have  a group  of  chloride  waters,  characterized 
mainly  by  sodium  chloride,  which  may  be  regarded  as  belonging  to  an 
oceanic  type.  In  the  following  table  these  waters  are  summed  up  in 
the  order  of  diminishing  chlorine,  only  the  main  constituents  being 
given : 

Principal  constituents  of  chloride  waters. 


Lake  Tekir-Ghiol 

Iletsk  Lake 

Illyes  Lake 

Gaukhane  Lake 

Lake  Corongamite 

Lake  near  Shiraz 

Lake  Urmi 

Rio  Saladillo 

Great  Salt  Lake  (average) 

Ocean 

Sambhar  Lake 


Cl,  Br. 

S04. 

C03. 

Na,  K. 

Ca. 

Mg. 

60.71 

0.67 

Trace. 

36.46 

0. 28 

1.84 

60.26 

.47 

38.86 

.33 

.08 

60. 18 

.44 

0.04 

39.02 

.25 

.03 

59.67 

1.29 

37.38 

.82 

.83 

59.  54 

1.65 

(?) 

35.  91 

.13 

2.  77 

58. 18 

3.48 

.23 

35.80 

.46 

1.84 

57.33 

5.06 

34.  76 

.32 

2.  53 

56.74 

4.82 

36.40 

1.63 

.41 

55.73 

6.61 

Trace. 

35. 16 

.32 

2.28 

55.48 

7.  69 

.21 

31.70 

1.20 

3.72 

53.00 

5.  85 

2. 19 

38.95 

.01 

174 


THE  DATA  OF  GEOCHEMISTRY. 


These  analyses  suggest,  if  they  do  not  actually  prove,  a similarity 
of  origin  for  all  these  bodies  of  water,  and  a possible  derivation, 
direct  or  indirect,  from  a primitive  ocean.  Some  of  the  lakes  were 
formed  by  leaching  masses  of  oceanic  salts  which  were  deposited  in 
earlier  geologic  ages;  others  are  doubtless  remnants  of  oceanic  over- 
flows or  segregations.  In  the  leaching  process  the  alkaline  chlorides 
dissolved  more  freely  than  other  salts,  and  so  became  concentrated  in 
the  newer  waters.  K.  Natterer,1  in  his  discussion  of  the  Persian 
salt  lakes,  suggests  that  differing  diffusibility  may  have  played  a 
part  in  the  concentration  of  sodium  chloride.  As  the  leaching  waters 
percolated  through  the  soil,  the  more  diffusible  alkaline  chlorides 
would  he  partially  separated  from  the  less  active  calcium  and  mag- 
nesium salts,  and  would  reach  the  lake  reservoir  in  larger  quantities. 
The  composition  of  Lake  Tekir-Ghiol,  which  is  closely  adjacent  to 
the  Black  Sea,  would  seem  to  emphasize  this  suggestion.  In  it  the 
alkaline  chlorides  are  concentrated,  while  the  other  constituents  of 
sea  water  are  present  in  much  less  than  the  normal  amounts. 

In  direct  relation  to  waters  of  the  preceding  group  are  the  derived 
waters  of  the  bittern  type.  In  these,  by  prolonged  evaporation, 
magnesium  salts  are  concentrated,  sodium  chloride  having  crystal- 
lized out.  The  three  waters  available  for  comparison  are  as  follows: 


Principal  constituents  of  natural  bitterns. 


Cl,  Br,  I. 

S04. 

C03. 

Na,  K. 

Ca. 

Mg. 

Dead  Sea  (average) 

Red  Lake 

68.15 
66.96 
64. 22 

0.28 

Trace. 

13.55 

19.90 

11.27 

4.37 

2.01 

.10 

13.62 

11.13 

17.55 

Elton  Lake 

6.82 

.04 

From  the  chloride  waters  we  pass  by  slow  gradations  to  the  sul- 
phate type,  as  shown  in  the  following  condensed  analyses.  Between 
the  two  groups  there  is  no  distinct  line  of  demarcation. 

Principal  constituents  of  chloro-sulphate  waters. 


Sevier  Lake 

Tamentica  Lagoon 

Kisil-Kul 

Lake  Parinacochas 

Lagoon  of  Epecuen 

Lake  Tagar 

Lacu  Sarat 

Lake  Beisk 

Bitter  Lake 

Lake  Altai 

Old  Wives  Lake 

Laramie  Lakes  (average) 
Lake  Domoshakovo 


Cl,  Br. 

S04. 

co3. 

Na,  K. 

Ca. 

Mg. 

52.  66 

10. 88 

33.  33 

0. 12 

3.  01 

50. 44 

9. 17 

37.  64 

.01 

.60 

48.  28 

14.  55 

0.  22 

34.  36 

.69 

1.  86 

46.  87 

10.  59 

2. 16 

36.  47 

1. 18 

.82 

42.  96 

17. 19 

2. 13 

37.  72 

29.  52 

34.  99 

1.  55 

29. 42 

.27 

4. 12 

28.  25 

37. 12 

.27 

31.  75 

.39 

2. 16 

22.  79 

42.  32 

.61 

32.  33 

.07 

1.  86 

20.  02 

43.  63 

1.  53 

33. 16 

.15 

1.  28 

14.  38 

50. 14 

1. 12 

33.  35 

.05 

.90 

4.  98 

61.  86 

1.54 

30.  65 

.97 

4.  88 

62.  34 

29.  03 

.68 

1.  81 

3.  71 

63.  62 

oo 

o 

31.  20 

.58 

. 74 

i Monatsh.  Chemie,  vol.  16,  1895,  p.  666, 


THE  WATERS  OF  CLOSED  BASINS. 


175 


Some  of  these  waters  have  been  modified  by  human  agency,  which 
utilized  them  as  sources  of  salt.  They  form,  nevertheless,  a natural 
series,  in  which  the  alkaline  radicles  are  nearly  constant  in  propor- 
tion, while  the  chlorides  and  sulphates  vary  reciprocally.  Lake  De 
Smet,  a sulphate  water  from  which  chlorides  are  nearly  absent, 
might  be  placed  at  the  end  of  this  series  were  it  not  for  the  small 
proportion  of  carbonates  that  it  contains. 

A slightly  different  composition  is  represented  by  a subgroup  of 
sulphato-chloride  waters,  as  shown  by  the  analyses  of  the  Caspian, 
the  Sea  of  Aral,  and  two  smaller  lakes. 


Principal  constituents  of  sulphato-chloride  waters. 


Cl,  Br. 

so4. 

co3. 

Na,K. 

Ca. 

Mg. 

Barchatow  bitter  lake 

45. 16 

20.  23 

28.  27 

5.  84 

Caspian  Sea 

41.  96 

23.  88 

0.*65 

25. 16 

2.44 

5.  87 

Biiluktii-Kul 

38.  00 

27.  39 

.98 

23.  61 

5.  28 

4.  68 

Sea  of  Aral 

35.  43 

30.  98 

.85 

23. 18 

4.  02 

5.  50 

Here  we  have  a dilution  of  oceanic  water  by  sulphate-bearing  tribu- 
taries, with  a falling  off  of  the  alkaline  metals  and  an  increase  in 
calcium  and  magnesium.  The  bitterns  derived  from  these  waters 
differ  from  the  normal  bitterns  in  respect  to  their  proportion  of  sul- 
phates, but  otherwise  they  represent  the  same  order  of  changes.  I 
include  with  them  the  Schunett  Lake  of  Siberia,  which  has  analo- 
gous composition,  and  also  the  Issyk-Kul. 


Principal  constituents  of  sulphato-chloride  bitterns . 


Cl,  Br. 

S04. 

C03. 

Na,  K. 

Ca. 

Mg. 

Karaboghaz  Gulf  (average) 

51.  86 

16.  48 

0. 07 

18.  33 

0.  28 

11.  45 

Tinetzky  Lake 

48. 12 

21.  25 

18.  70 

. 01 

11.  91 

Schunett  Lake 

38.  89 

32. 19 

.31 

16.  45 

.44 

11.  67 

Issyk-Kul 

15.  67 

55.94 

1.  26 

13.  61 

.94 

12.  50 

The  water  of  Lake  Chichen-Kanab  in  Yucatan  is  also  a sulphato- 
chloride  water,  but  it  stands  alone  as  the  only  known  member  of  a 
distinct  subgroup.  Its  dominant  kation  is  calcium. 

The  alkaline  lakes  that  contain  notable  quantities  of  carbonates 
are  less  easy  to  classify  than  the  foregoing  waters,  and  yet  some 


176 


THE  DATA  OF  GEOCHEMISTRY. 


analogies  are  clear.  First,  we  have  a number  of  analyses  in  which 
the  carbonates  are  largely  in  excess  of  all  other  salts,  as  follows : 


Principal  constituents  of  carbonate  waters . 


Cl,  Br. 

SO*. 

co3. 

Na,  K. 

Ca. 

Mg. 

Silver  Lake 

0.  87 

2. 43 

47.48 

16.  36 

11.  07 

6.  59 

Moses  Lake 

3.  88 

2.  87 

51.  56 

19.  86 

8.  41 

7.  25 

Malheur  Lake 

4.  55 

7.  64 

44.  63 

29.  75 

5.  58 

4. 13 

Lake  Laach 

4.  99 

2.  97 

50.  97 

27.  05 

9.  90 

2.  77 

Goodenough  Lake 

7.  64 

7.  08 

41.  41 

42.  82 

.02 

.04 

Black  Lake 

7.  68 

13.  24 

37.  79 

41.  08 

Palic  Lake 

15.  68 

2.  92 

41.  02 

35.  75 

.66 

3.  35 

In  the  next  group  of  waters  carbonates  and  chlorides  predomi- 
nate, with  sulphates  in  subordinate  quantity. 

Principal  constituents  of  carbonate-chloride  waters. 


Bluejoint  Lake 

Summer  Lake 

Natron  Lake 

Harney  Lake  (average) . 

Humboldt  Lake 

Borax  Lake 

Abert  Lake  (average)... 

Lonar  Lake 

Pyramid  Lake 

Salt  Lake  near  Pretoria. 
Winnemucca  Lake 


Cl,  Br. 

SO*. 

co3. 

13.  85 

5.67 

38.  68 

18.  27 

4. 18 

35.  57 

26.  00 

32.  90 

28.  95 

8. 14 

22.  82 

31.82 

3.  27 

21.  57 

32.  31 

.13 

22.  47 

36. 13 

1.  90 

20.  73 

40.  76 

1.48 

17.  63 

41.  04 

5.  25 

14.  28 

43.  47 

.03 

15. 17 

47.  88 

3.  76 

7.  93 

Na,  K. 

Ca. 

Mg. 

39.  96 

0.  57 

0.  63 

41.  07 

Trace. 

Trace. 

31.05 

3.  57 

3.  62 

39.  31 

.01 

.04 

36.  51 

1.35 

1.88 

- 39.  62 

.03 

.35 

40.  62 

Trace. 

Trace. 

39.  71 

.01 

Trace. 

35.  95 

.25 

2.  28 

41.  33 

38.  62 

.55 

.49 

Borax  Lake,  which  also  contains  5.05  per  cent  of  B407  in  its  saline 
residue,  might  well  be  put  in  a class  by  itself ; but  extreme  subdivision 
is  not  now  desirable. 

Two  of  the  waters  are  conveniently  classed  as  sulphato-carbonates, 
as  follows: 

Principal  constituents  of  sulphato-carbonate  waters. 


Cl,  Br. 

SO4. 

co3. 

Na,  K. 

Ca. 

Mg. 

Omak  Lake 

2.  96 

21. 12 

36.  75 

37. 12 

0.  23 

1.  82 

Pelican  Lake 

7.  97 

22.  09 

30.  87 

32.  83 

2.  27 

2.  62 

In  the  following  waters,  which  are  of  the  “ triple”  type,  chlorides, 
sulphates,  and  carbonates  are  all  present  in  notable  quantities : 


THE  WATERS  OF  CLOSED  BASINS. 


177 


Principal  constituents  of  “ triple ” waters. 


Cl,  Br. 

SO*. 

1 

CO3. 

Na,  K. 

Ca. 

Mg. 

Wilmington  Lake 

10.  78 

16.  62 

32.  75 

39.  85 

Soap  Lake 

13.  28 

16.  44 

30.  22 

39.  60 

Trace. 

0.  04 

Lake  Huacachima 

11. 18 

16.  95 

29.  33 

41.  06 

. 34 

Owens  Lake  (average) 

25.  30 

9.  92 

23.  59 

39.  88 

0.  02 

.01 

Mono  Lake 

23.  34 

12.  86 

23.  42 

39.  78 

.04 

.10 

Lake  Van 

27.  08 

11.  95 

20.  71 

38.  84 

. 57 

Tulare  Lake 

20.  26 

20.  77 

19.  55 

38.  21 

.28 

.26 

Lake  Ruszanda 

19.  07 

22.  56 

19.  22 

38.  26 

.20 

.15 

Walker  Lake 

23.  77 

21.  29 

17.  34 

34.  83 

.90 

1.  56 

Soda  Lake  (average) 

35.  95 

10.  42 

14.  83 

36.  00 

. 22 

Katwee  Salt  Lake 

36.  67 

12.  33 

10.  42 

40.  55 

Finally  there  are  three  waters  which  might  be  classed  with  the  sul- 
phato-chlorides,  were  it  not  for  their  moderately  alkaline  character. 


Principal  constituents  of  water  of  Lake  Biljo,  Devils  Lake , and  Koko-Nor. 


Cl,  Br. 

SO4. 

C03. 

Na,  K. 

Ca. 

Mg. 

Lake  Biljo 

9.  91 

52.  33 

6.  22 

22.  70 

0.  43 

7.  28 

Devils  Lake 

10.  45 

54.  07 

4.  24 

25.  88 

Trace. 

5.  36 

Koko-Nor 

40.  09 

17.  84 

5.  55 

31.  72 

1.  77 

2.  90 

In  general,  as  was  pointed  out  in  discussing  the  Lahontan  waters, 
alkaline  lakes  are  representative  of  volcanic  regions,  while  saline 
lakes  are  associated  with  sedimentary  deposits.  That  is,  from  a 
chemical  point  of  view  the  alkaline  waters  are  the  newest,  and  exhibit 
the  nearest  relationship  to  rivers  and  springs.  By  the  weathering 
of  rocks  carbonates  are  first  formed,  as  is  seen  in  most  rivers  near 
their  sources.  Under  favorable  conditions  these  salts  accumulate 
and  they  are  transformed  into  or  replaced  by  other  compounds  only 
after  a long  and  slow  series  of  chemical  reactions.  In  recently 
formed  bodies  of  water,  derived  from  igneous  rocks,  carbonates  are 
abundant;  but  as  salinity  or  concentration  increases,  the  slightly 
soluble  calcium  carbonate  is  thrown  down,  leaving  sulphates  and 
chlorides  in  solution.  If  more  calcium  is  available,  gypsum  is  pre- 
cipitated, and  the  final  result  is  a water  containing  little  except 
chlorides.  The  carbonate  waters  form  the  beginning,  the  chloride 
waters  the  end  of  the  series.  When  calcium  is  deficient  in  quantity, 
then  mixed  waters  are  produced,  in  which  alkaline  sulphates,  car- 
bonates, and  chlorides  may  coexist  in  almost  any  relative  propor- 
tions. Waters  of  mixed  type  may  also  be  formed  by  the  blending  of 
supplies  from  different  sources,  and  the  contributions  of  two  tribu- 
taries may  be  very  unlike.  The  fresh  decomposition  products  from 
97270°— Bull.  616—16 12 


178 


THE  DATA  OF  GEOCHEMISTRY. 


a volcanic  rock  and  the  leachings  of  sedimentary  beds  are  widely 
dissimilar;  but  the  chemical  changes  consequent  upon  their  com  min  - 
gling  will  follow  the  order  just  laid  down.  This  order  can  not  be 
stated  in  quantitative  terms,  for  the  conditions  of  equilibrium  in 
complex  mixtures  are  not  definitely  known.  The  solubility  of  a salt 
in  pure  water  is  one  thing;  its  solubility  in  the  presence  of  other 
compounds  is  something  quite  different;  and  when  the  number  of 
possible  substances  is  great  the  problem  becomes  hopelessly  com- 
plicated. Each  substance  influences  every  other  substance,  in  a 
manner  which  depends  partly  upon  temperature  and  partly  upon 
concentration,  and  no  known  equations  can  cover  the  whole  field. 

Qualitatively,  however,  the  conditions  governing  the  deposition 
of  salts  can  be  simply  and  intelligibly  stated.  Suppose  we  consider 
a solution  so  dilute  that  it  contains  ions  capable  of  forming  the  chlo- 
rides, sulphates,  and  carbonates  of  sodium,  calcium,  and  magnesium, 
which  are  the  chief  salts  derivable  from  natural  waters.  Upon  con- 
centration, the  difficultly  soluble  carbonates  of  calcium  and  magne- 
sium will  be  precipitated  first,  to  be  followed  by  the  slightly  soluble 
gypsum.  Next  in  order  sodium  sulphate  and  carbonate  will  form, 
and  these  salts  are  deposited  by  many  saline  or  alkaline  waters. 
Later,  sodium  chloride  and  magnesium  sulphate  may  crystallize  out, 
leaving  at  last  a bittern  containing  the  very  soluble  chlorides  of  cal- 
cium and  magnesium.  This  is  the  observed  order  of  concentration, 
but  every  step  is  not  necessarily  taken  in  every  instance.  All  of  the 
calcium  may  be  eliminated  as  carbonate,  leaving  none  for  the  forma- 
tion of  other  salts.  All  of  the  sulphuric  ions  may  be  taken  to  produce 
gypsum,  and  then  no  sodium  sulphate  can  form.  In  short,  the  actual 
changes  which  take  place  during  the  concentration  of  a specified  water 
depend  on  the  proportions  of  its  constituents,  and  vary  from  case  to 
case.  The  proposed  order  of  deposition  is  simply  the  general  order, 
which  conforms  to  the  facts  of  observation  and  to  the  known  solubil- 
ities of  the  several  salts.  The  least  soluble  possible  salt  will  form 
first;  the  most  soluble  will  remain  longest  in  solution.  The  formation 
of  double  salts  will  be  considered  in  another  chapter. 


CHAPTER  VI. 

MINERAL  WELLS  AND  SPRINGS. 

DEFINITION. 

Between  the  so-called  “ mineral  waters”  and  waters  of  ordinary 
character  no  sharp  line  of  demarcation  can  be  drawn.  In  fact,  some 
of  the  springs  having  the  greatest  commercial  importance  yield 
waters  of  exceptionally  low  mineral  content  and  owe  their  value  to 
their  remarkable  purity.  They  are  simply  potable  waters  carrying  a 
minimum  of  foreign  matter  in  solution.  Other  springs,  on  the  con- 
trary, are  characterized  by  excessive  salinity,  and  between  the  two 
extremes  nearly  every  intermediate  condition  may  be  observed. 

In  the  chapter  on  lakes  and  rivers  a number  of  springs  were  con- 
sidered which  represent  the  ordinary  or  common  type  of  water  sup- 
ply. Rain  water,  charged  with  carbonic  acid,  percolates  through 
the  soil  or  through  relatively  thin  layers  of  rock  and  emerges  with  a 
moderate  load  of  dissolved  impurities.  Upon  evaporation  such 
waters  give  a residue  consisting  most  commonly  of  calcium  carbonate, 
calcium  sulphate,  or  silica,  with  minor  amounts  of  alkaline  chlorides, 
and,  blending  with  rain  or  seepage  waters,  they  form  the  beginnings 
of  streams.  Sometimes  sulphates  predominate,  sometimes  carbon- 
ates, but  chlorides  are  present  much  less  conspicuously.  Calcium  is 
the  dominating  metal,  and  sodium  occupies,  as  a rule,  a subordinate 
place.  To  the  vast  majority  of  spring  waters  these  statements  apply, 
but  here  and  there  exceptions  are  encountered  which,  by  their  peculiar 
characters,  attract  attention  and  are  known  as  “ mineral”  wells  or 
springs.  Speaking  broadly,  all  springs  are  mineral  springs,  for  all 
contain  mineral  impurities;  but  in  a popular  sense  the  term  is 
restricted  to  waters  of  abnormal  or  unusual  composition.  A mineral 
water,  then,  is  merely  a water  which  differs,  either  in  composition  or 
in  concentration,  from  the  common  potable  varieties.  The  term  is 
loose  and  indefinite,  but  it  has  a certain  convenience,  and  we  may  use 
it  without  danger  of  being  led  astray. 

To  put  the  case  differently,  a mineral  spring  may  be  described 
as  one  which  owes  its  character  to  local  as  distinguished  from  wide- 
spread or  general  conditions;  and  the  peculiarities  thus  acquired 
may  result  from  a great  variety  of  causes.  One  water,  rising  from 
beds  of  salt,  is  charged  with  sodium  chloride;  another  represents  the 
solution  of  gypsum;  a third  may  carry  substances  derived  from  the 
sulphides  of  metalliferous  veins,  and  so  on  indefinitely.  Any  soluble 

179  * 


180 


THE  DATA  OF  GEOCHEMISTRY. 


matter  existing  in  the  crust  of  the  earth  may  find  its  way  into  the 
waters  of  a spring  and  give  to  the  latter  some  distinguishing  peculiar- 
ity. Even  in  their  gaseous  contents  spring  waters  differ  widely. 
Some  are  heavily  charged  with  carbonic  acid  and  effervesce  upon 
reaching  the  air,  and  others  contain  hydrogen  sulphide  in  sufficient 
quantities  to  be  recognized  by  the  smell.  Some  waters  are  strongly 
acid,  some  alkaline,  and  some  neutral;  waters  emerging  from  beds 
of  pyritiferous  shale  are  often  rendered  astringent  by  salts  of  alumi- 
num or  iron;  one  spring  is  boiling  hot  while  its  neighbors  are  ice 
cold;  in  short,  every  difference  of  origin  may  be  reflected  in  some 
peculiarity  of  composition  or  character.  In  recent  years  many  min- 
eral springs  have  been  found  to  contain  appreciable  quantities  of 
argon,  helium,  and  the  other  inert  gases,  a fact  which  bears  upon  the 
radioactivity  exhibited  by  natural  waters.  For  example,  G.  Massol,1 
in  the  gas  from  the  thermal  spring  of  Uriage,  France,  found  0.932 
per  cent  of  helium,  together  with  krypton  and  xenon.  Argon  was 
detected  in  the  hot  springs  of  Bath,  England,  shortly  after  the  ele- 
ment was  discovered.2  In  the  boric  acid  sojjioni  of  Tuscany,  helium 
and  argon  were  found  by  R.  Nasini,  F.  Anderlini,  and  R.  Salvadori.3 
Many  French  springs  have  been  studied,  with  similar  results,  by 
C.  Moureu  and  R.  Biquard.4  These  minor  characteristics  of  natural 
waters  can  not  be  dwelt  upon  more  fully  here. 

CLASSIFICATION. 

The  classification  of  waters  can  be  based  on  a variety  of  considera- 
tions. It  may  be  geologic,  correlating  the  springs  with  their  geologic 
origin,  or  as  ancient  or  modern,  or  by  dividing  them  into  classes 
according  to  their  derivation  from  rain  water  or  from  sources  deep 
within  the  earth;  it  may  be  physical,  drawing  a chief  distinction 
between  cold  and  thermal  springs;  or  chemical,  in  which  case  differ- 
ences of  composition  determine  the  place  which  each  water  shall 
occupy.  To  a great  extent  the  three  systems  of  classification  over- 
lap, and  each  one  depends  more  or  less  on  the  others;  but  for  the 
purposes  of  this  memoir,  which  deals  with  chemical  phenomena, 
the  chemical  method  is  obviously  the  most  appropriate.  The  other 
considerations  must,  of  course,  be  taken  into  account;  but  chemical 
composition  is,  for  us,  the  determining  factor.  From  this  point  of 
view  the  classification  of  springs  is  comparatively  simple  and  follows 
the  lines  laid  down  in  the  preceding  chapters.  Waters  are  classed 
according  to  their  negative  radicles,  as  chloride,  sulphate,  carbonate, 

1 Compt.  Rend.,  vol.  151, 1910,  p.  1124. 

2 See  Rayleigh  and  Ramsay,  Zeitschr.  phys.  Chemie,  vol.  16,  1895,  p.  362.  Also  Rayleigh,  Proc.  Roy. 
Soc.,  vol.  59, 1896,  p.  198. 

s Gazz.  chim.  ital.,  vol.  28,  1898,  p.  81. 

* Compt.  Rend.,  vol.  143, 1906,  p.  795;  vol.  146, 1908,  p.  435.  See  also  Moureu,  idem,  vol.  142, 1906,  p.  1155, 
and  in  Revue  sci.,  1914,  p.  65,  for  a thorough  review  of  the  whole  subject. 


MINERAL  WELLS  AND  SPRINGS. 


181 


or  acid  waters,  with  various  mixed  types  and  occasional  examples  in 
which  unusual  combinations,  such  as  nitrates,  borates,  sulphides,  or 
silicates,  appear.  The  classification,  however,  can  not  be  rigid,  and 
to  a great  extent  convenience  must  govern  and  modify  the  usual 
rules.  Mixtures  such  as  we  have  now  to  consider  can  not  be  arranged 
according  to  any  hard-and-fast  system,  but  must  be  dealt  with  some- 
what loosely.  The  general  relationships  are  simple  and  evident,  but 
the  exceptional  cases  are  common  enough  to  modify  any  formal 
scheme  of  arrangement  that  might  be  adopted. 

CHLORIDE  WATERS. 

The  literature  relating  to  mineral  springs  is  extremely  volumi- 
nous, and  the  recorded  analyses  are  numbered  by  thousands.  From 
such  a mass  of  material  only  typical  or  striking  examples  can  be  util- 
ized here  in  order  to  show  the  variations  in  composition  which  have 
been  observed.  As  the  chloride  waters  form  perhaps  the  most  con- 
spicuous group,  we  may  properly  begin  with  them,  and  consider  first 
the  solutions  which  upon  evaporation  yield  principally  sodium  chlo- 
ride. Waters  of  this  class  are  very  common,  and  range  from  potable 
springs  to  brines  resembling  sea  water  in  saline  composition.  From 
such  brines  common  salt  is  commercially  obtained,  and  the  sub- 
joined table  gives  analyses  of  several  important  examples.1  The 
figures  represent  the  composition  of  the  anhydrous  saline  matter  con- 
tained by  the  several  waters,  each  analysis  being  reduced  from  the 
original  form  of  statement  to  percentages  of  ions. 

1 In  Ann.  Kept.  Geol.  Survey  Canada,  vol.  15, 1902-3,  p.  236  S,  G.  C.  Hoffman  gives  12  analyses  of  brines 
from  Manitoba.  A brine  from  a well  1,920  feet  deep,  at  Sand  Beach,  Michigan,  analyzed  by  S.  P.  Duffield 
(Geol.  Survey  Michigan,  vol.  5,  pt.  2, 1895,  p.  82),  is  unusually  rich  in  bromine.  J.  W.  Turrentine,  U.  S. 
Dept.  Agric.,  Bur.  Soils  Bull.  No.  94, 1914,  gives  many  analyses  of  American  brines  and  bitterns.  For  the 
brines  of  Silver  Peak  Marsh,  Nevada,  see  R.  B.  Dole,  U.  S.  Geol.  Survey  Bull.  No.  530,  pp.  331-345, 1913. 


182 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  natural  brines. 

A.  Brine  from  Syracuse,  New  York.  Average  of  four  analyses  by  C.  A.  Goessmann,  published  in  Dana’s 
System  of  mineralogy,  6th  ed.,  p.  156. 

B.  Brine  from  Warsaw,  New  York.  Analysis  by  F.  E.  Engelhardt,  Bull.  New  York  State  Mus.  No.  11, 
1893,  p.  38.  Many  other  analyses  are  given  in  this  publication. 

C.  Brine  from  East  Saginaw,  Michigan.  Well  806  feet  deep.  Analysis  by  Goessmann,  Geol.  Survey 
Michigan,  vol.  3, 1873-1876,  p.  183. 

D.  Brine  from  Pomeroy,  Ohio.  - Analysis  by  C.  W.  Foulk,  Bull.  Ohio  Geol.  Survey  No.  8, 1906,  p.  27. 
The  trace  of  iodine  represents  0.004  gramme  Nal  per  liter. 

E.  Humboldt  salt  well,  Minnesota.  Analysis  by  C.  F.  Sidener,  Ann.  Rept.  Geol.  Survey  Minnesota, 
vol.  13, 1884,  p.  101. 

F.  Brine  from  Hutchinson,  Kansas.  Analysis  by  E.  H.  S.  Bailey  and  E.  C.  Case,  Univ.  Kansas  Geol, 
Survey,  vol.  7, 1902,  p.  79. 

G.  Artesian  well,  Abilene,  Kansas.  Analysis  by  E.  H.  S.  Bailey  and  F.  B.  Porter,  Univ.  Kansas  Geol. 
Survey,  vol.  7, 1902,  p.  130.  WeU  1,260  feet  deep. 

H.  Bryan’s  well,  Bistineau,  Louisiana.  Analysis  by  M.  Bird,  Report  on  geology  of  Louisiana,  1902, 
p.  40.  Many  other  analyses  of  salines  are  given  in  this  volume.  The  brines  are  of  Cretaceous  origin. 


Cl. 

Br. 

I.. 


S04 

C03 

P04 

Na 

K 

Ca 

Sr 

Ba 

Mg 

Mn 

Fe" 

Fe203 

A1203 

Si02 

Other  solids . 


Salinity,  per  cent. 


58.  85 

.01 


2.  29 

.01 


37.  29 
.03 
1.28 


.23 

.'6i' 


100.  00 
16.  84 


59.  71 


1. 19 


38.  38 
’*.*67 


.05 


100.  00 
26.  34 


61.  27 


.52 


32.  76 
’4.'25' 


1.  20 


100.  00 
20.  24 


61.  59 
.13 
Trace. 
None. 


31.  51 
.06 
4.  91 
.14 
.21 
1.  36 


55.  96 


.08 

.01 


100.  00 
10.  52 


4. 18 
1.  68 
Trace. 
32.  56 
.66 
2.  71 


1.  80 


.02 

.07 

.36 


100.  00 
5.  72 


59.  60 


1.  33 


38.  38 


.55 


11 


03 


100.  00 
29.  31 


61.  65 
.29 
Trace. 
.07 


31.  57 
Trace. 
4.  85 


1.  52 
Trace. 
. 05 


Trace, 


100.  00 
17.  89 


59.  96 


37.  20 


.94 


29 


63 

98 


100.  00 
8.  93 


Most  if  not  all  of  the  foregoing  brines  were  formed  by  solution 
from  beds  of  rock  salt.  The  latter  undoubtedly  originated  from  the 
evaporation  of  salt  lakes  or  sea  water,  and  in  geological  age  they 
range  from  the  Cretaceous  down  to  the  upper  Silurian.  The  New 
York  brines  are  from  Silurian  deposits.  The  Humboldt  well  is 
nearest  to  ocean  water  in  composition,  although  it  is  nearly  twice  as 
concentrated.  In  general,  the  proportion  of  sodium  chloride  is 
greater  than  in  sea  salts,  for  the  reason  that  that  compound  redis- 
solves more  readily  than  the  gypsum  which  was  deposited  with  it. 
The  process  of  deposition  and  re-solution  thus  tends  to  separate  the 
constituents  of  the  original  water;  and  so  the  composition  of  the 
ancient  lake  or  ocean  is  not  exactly  reproduced. 

The  following  analyses  also  represent  the  salts  from  chloride  waters 
in  which  sodium  is  largely  the  predominant  base: 


MINERAL  WELLS  AND  SPRINGS, 


183 


Analyses  of  chloride  waters — I. 

A.  Cincinnati  artesian  well,  Cincinnati,  Ohio.  Analysis  by  E.  S.  Wayne,  cited  by  A.  C.  Peale,  in  Bull. 
U.  S.  Geol.  Survey  No.  32,  1886,  p.  133.  This  water  contains  considerable  quantities  of  free  H2S  and  C02. 

B.  Upper  Blue  Lick  Spring,  Kentucky.  Analysis  by  J.  F.  Judge  and  A.  Fennel,  cited  by  Peale,  op.  cit., 
p.  111.  Also  rich  in  H2S  and  C02.  I represent  here  by  X an  indeterminate  mixture  of  Ca3P208,  A1203,  and 
Fe203.  For  later  analyses  of  the  Blue  Lick  springs,  by  R.  and  A.  M.  Peter,  and  for  analyses  of  other 
mineral  waters  in  Kentucky,  see  Chase  Palmer,  Water-Supply  Paper  U.  S.  Geol.  Survey  No.  233,  1909, 
pp.  184-215. 

C.  Montesano  Springs,  Missouri.  Analysis  by  P.  Schweitzer,  Geol.  Survey  Missouri,  vol.  3,  1892,  p.  77. 
This  volume  contains  many  analyses  of  Missouri  mineral  waters. 

D.  Deep  well  at  Brunswick,  Missouri.  Depth  1,505  feet.  Analysis  by  Schweitzer,  op.  cit.,  p.  97. 

E.  Utah  Hot  Springs,  8 miles  north  of  Ogden,  Utah.  Temperature  55°  C.  Analysis  by  F.  W.  Clarke. 
Bull.  U.  S.  Geol.  Survey  No.  9,  1884,  p.  30. 

F.  Spring  at  Pahua,  New  Zealand.  Analysis  by  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  10,  1877,  p. 
423.  This  spring  is  notable  from  the  fact  that  it  contains  free  iodine.  According  to  J.  A.  Wanklyn  (Chem. 
News,  vol.  54,  1886,  p.  300)  the  water  of  Woodhull  Spa,  near  Lincoln,  England,  has  the  same  peculiarity. 
The  iodine  colors  the  water  brown  and  can  be  extracted  by  carbon  bisulphide. 

In  analyses  D and  F the  bicarbonates  of  the  original  statement  have  been  reduced  to  normal  salts. 


A 

B 

C 

D 

E 

F 

Cl 

55.  83 

53.  08 

57.  38 

52.  74 

58.  79 

60.  78 

Br 

.04 

. 51 

.31 

Trace. 

Trace. 

I,  combined 

.03 

.02 

. 04 

I,  free 

. 11 

S04 

3. 12 

6.03 

5.  37 

8.  36 

. 94 

. 15 

co3 

2.  63 

2.  34 

1.  88 

.61 

. 17 

P04 

. 05 

Na 

33.  09 

31.  47 

28. 17 

30. 15 

30.  38 

34.  81 

K 

.27 

.96 

.15 

3.  76 

.02 

Li 

Trace. 

Ca 

3.  72 

3.  56 

6. 15 

4.  74 

4.  90 

3. 14 

Mg 

1. 13 

1.  57 

2.  30 

2.  09 

.40 

. 60 

A1 

.01 

A1203 

.02 

Fe// 

Trace. 

FeoCb 

.06 

Si02 

.08 

. 16 

.17 

.04 

.20 

.12 

X 

.30 

Salinity,  parts  per  million 

100.  00 
10,  589 

100.  00 
11,  068 

100.  00 
8,  509 

100.  00 
15,  905 

100.  00 

23,  309 

100.  00 
21,  060 

184 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  chloride  waters — I — Continued. 

G.  Water  of  Salsomaggiore,  Italy.  Analysis  by  R.  Nasini  and  F.  Anderlini,  Gazz.  chim.  ital.,  vol.  30, 
i,  1900, 305.  Contains  in  1,000  grams  0.00223  gram  Mn  and  0.00792  gram  B4O7.  These  are  less  than  0.01  per 
cent  of  the  total  solids. 

H.  The  Marienquelle,  Bavaria.  Analysis  by  A.  Lipp,  Ber.  Deutsch.  chem.  Gesell.,  vol.  30,  1897,  p.  309. 
Contains  also  much  free  C02. 

I.  The  Kochbrunnen,  Wiesbaden,  Germany.  Analysis  by  C.  R.  Fresenius,  Jahrb.  Nassau.  Ver.  Natur- 
kunde,  vol.  50,  1897,  p.  20.  This  water  also  contains  0.000013  gram  iodine,  0.00002  gram  PO4,  and  0.00016 
gram  ASO4  to  the  liter,  each  recorded  here  as  a “ trace.”  For  other  analyses  of  Wiesbaden  waters  see  the 
same  journal,  vol.  49, 1896,  pp.  22,  23. 

J.  Water  of  Arva-Polhora,  Hungary.  Analysis  by  W.  Kalmann  and  M.  Glaser,  Min.  pet.  Mitt.,  vol. 
18, 1898-99,  p.  443.  Organic  matter,  about  0.15  per  cent,  is  excluded  from  the  reduced  statement  here  given. 

K.  Old  sulphur  well,  Harrogate,  England.  Analysis  by  T.  E.  Thorpe,  Jour.  Chem.  Soc.,  vol.  39,  1881, 
p.  500.  The  memoir  contains  some  other  analyses. 

L.  Chloride  of  Iron  Spa,  Harrogate.  Analysis  by  C.  H.  Bothamley,  Jour.  Chem.  Soc.,  vol.  89,  1881,  p. 
502.  The  same  author,  in  vol.  63,  1883,  p.  685,  gives  analyses  of  waters  from  Askem,  Yorkshire. 


G 

H 

I 

J 

K 

L 

Cl 

61.  09 

52.  72 

56.  58 

58.  76 

58.  81 

60.  83 

Br 

. 15 

.42 

.04 

. 37 

. 19 

.07 

I 

.03 

.54 

Trace. 

. 14 

.01 

Trace. 

F 

Trace. 

S04 

.18 

Trace. 

.78 

.12 

.02 

S 

. 23 

CO, 

7.  66 

3. 13 

1.  07 

2. 12 

1.  23 

P04 

Trace. 

Trace. 

.02 

Trace. 

As04 

Trace. 

B407 

Trace. 

Trace. 

.72 

bo2 

. 01 

Na 

34.04 

33.  08 

32.  60 

36. 18 

33.  61 

23.  45 

K 

Trace. 

1. 16 

.42 

.48 

. 35 

Li 

. 07 

Trace. 

.04 

.22 

.01 

Trace. 

nh4 ; 

. 12 

. 07 

.03 

.03 

Ca 

3.  21 

4.15 

4.  05 

1. 10 

2.  65 

7.  28 

Sr 

.24 

. 12 

.34 

Trace. 

. 07 

Ba 

. 01 

. 08 

. 42 

. 76 

Mg 

.82 

1.  34 

. 61 

.29 

1.  37 

3. 12 

Mn 

. 10 

Fe" 

.03 

}>  . 04 

) 

.14 

2.  39 

Fe203 

. 09 

A1 

.01 

Trace. 

Trace. 

Cu 

Trace. 

Si02 

.01 

.76 

.03 

.07 

.30 

Salinity,  parts  per  million 

100.00 
159,  000 

100.  00 

2,  970 

100.00 

8,  241 

100.00 
30, 150 

100.00 
14,  800 

100.00 
6,  617 

Although  sodium  chloride  is  the  principal  salt  obtainable  from  the 
waters  represented  by  the  preceding  analyses,  they  owe  their  interest 
to  other  things.  They  have  been  selected  from  the  great  mass  of 
published  material  in  order  to  show  the  extent  to  which  substances 
like  bromine,  iodine,  sulphur,  lithium,  barium,  strontium,  and  iron 
occur  in  waters  of  this  class.1 

To  these  minor  constituents  the  therapeutic  value  of  mineral  waters 
is  commonly  ascribed,  but  to  considerations  of  that  sort  no  attention 

1 For  the  common  occurrence  of  Sr,  Ba,  Mn,  As,  etc.,  in  mineral  springs  see  J.  C.  Gil,  Rev.  Acad,  ci 
Madrid,  vol.  8,  1909,  p.  131.  On  selenium  in  mineral  waters  see  F.  Taboury,  Bull.  Soc.  chim.,  4th  ser., 
vol.  5, 1909,  p.  865. 


MINERAL  WELLS  AND  SPRINGS. 


185 


can  be  paid  here.  The  last  analysis  given,  that  of  the  Chloride  of 
Iron  Spa  at  Harrogate,  is  interesting  as  marking  a transition  to 
another  group  of  chloride  waters,  in  which  the  proportion  of  sodium 
is  decreased  and  large  quantities  of  calcium  appear.  Sometimes 
magnesium  is  also  abundant;  for  example,  in  salts  from  the  group 
of  springs  at  Kapouran,  Java,  S.  Meunier1  found  54.2  per  cent  of 
calcium  chloride  and  40.65  per  cent  of  magnesium  chloride.  The 
following  analyses  are  characterized  by  the  presence  of  calcium  in 
large  proportion : 2 

Analyses  of  chloride  waters — II. 

A.  Brine  from  well  2,667  feet  deep  at  Conneautsville,  Pennsylvania.  Analysis  by  A.  E.  Robinson  and 
C.  F.  Mabery,  Jour.  Am.  Chem.  Soc.,  vol.  18, 1896,  p.  915.  A little  H2S  is  present. 

B.  Well  at  Bowerman’s  mills,  Whitby,  Canada.  Analysis  by  T.  Sterry  Hunt,  Geology  of  Canada,  1863, 
p.  547.  Analyses  of  other  waters  are  given  in  this  memoir. 

C.  Water  from  well  192  feet  deep,  Manitoulin  Island,  Lake  Huron.  Analysis  by  T.  Sterry  Hunt,  Chem- 
ical and  geological  essays,  1875,  p.  158. 

D.  Water  from  the  Silver  Islet  mine,  Lake  Superior.  Analysis  by  F.  D.  Adams,  Ann.  Rept.  Geol. 
Survey  Canada,  new  ser.,  vol.  1,  1885,  p.  17  M. 

E.  Water  from  the  lower  level  of  the  Quincy  mine,  Hancock,  Michigan.  Analysis  by  G.  Steiger  in  the 
laboratory  of  the  United  States  Geological  Survey. 

F.  Waterfrom  boring  on  Kanab  Creek,  near  Port  Haney,  British  Columbia.  Analysis  by  F.  G.  Wait, 
Ann.  Rept.  Geol.  Survey  Canada,  vol.  5,  ii,  new  ser.,  1890-91,  p.  22  R. 

G.  Boiling  spring  at  Savu-Savu,  Fiji.  Analysis  by  A.  Liversidge,  Proc.  Roy.  Soc.  New  South  Wales, 
vol.  14, 1880,  p.  147.  Part  of  the  aluminum  in  this  water  is  reported  as  A1C13  and  part  as  A1203. 

H.  W ater  from  People’s  N atural  Gas  W ell,  8 miles  southwest  of  Imperial,  W ashington  County,  Pennsyl- 
vania. Specific  gravity,  1.211.  Depth  of  well  when  sample  was  taken,  6,300  feet.  Analysis  by  G.  Steiger 
in  the  laboratory  of  the  Survey. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

62.  31 

64.  43 

64.  15 

61.  57 

63.  55 

63.  39 

57.  91 

61.  38 

Br 

.53 

.41 

. 26 

I 

.01 

Trace. 

Present 

Trace. 

so4. . 

.03 

. 13 

.01 

None. 

3.  38 

. 02 

C03 

.27 

.09 

.48 

. 01 

Trace. 

None. 

P04... 

None. 

Trace. 

J-  V4.  - 

Na 

18.  35 

16. 17 

8.  71 

18.  33 

5.  63 

5.  27 

16.  65 

24.  50 

K 

1.  55 

Trace. 

1.92 

.67 

None. 

.42 

.93 

1.  97 

Li 

.04 

nh4 

.23 

Ca 

13.  86 

13.  68 

20.  67 

17.  46 

30.  78 

30.  89 

18.  34 

9.  56 

Sr 

Trace. 

1.  31 

Mg 

2.  53 

5.  22 

4.  25 

1.  21 

.01 

.03 

.04 

.94 

A1 

.02 

None. 

None. 

. 43 

A1203 

. 54 

Fe" 

.25 

Trace. 

None. 

None. 

Trace. 

.06 

Fe203 

Mn,  Co 

Trace. 

None. 

Si02 

.02 

.15 

.01 

1.  78 

Salinity,  parts  per 
million 

100.  00 
309, 175 

100.  00 
46,  300 

100.  00 
21,  660 

100.  00 
36,  000 

100.  00 

212,  300 

100.  00 
48,  500 

100.  00 
7,  813 

100.  00 
263,  640 

1 Compt.  Rend.,  vol.  103,  1886,  p.  1205. 

2 See  also  the  analysis  of  brinefrom  a well  at  Alma,  Michigan,  by  C.  F.  Chandler  and  C.  E.  Pellew,  Geol. 
Survey  Michigan,  vol.  5,  pt.  2, 1894,  p.  46.  Also  one  of  water  from  the  Freda  well,  Keweenaw  Point,  Michi- 
gan, by  G.  A.  Konig,  Rept.  State  Board  Geol.  Survey  Michigan,  1903,  p.  165.  In  the  deep-seated  waters 
around  Lake  Superior  calcium  chloride  seems  to  be  an  important  constituent.  These  waters  have  been 
carefully  studied  by  A.  C.  Lane,  Jour.  Canadian  Min.  Inst.,  vol.  12,  1909,  p.  114,  and  Proc.  Lake  Superior 
Min.  Inst.,  1908,  p.  63. 


186 


THE  DATA  OF  GEOCHEMISTRY. 


The  water  represented  by  analysis  H is  remarkable  for  its  high  pro- 
portion of  strontium — 3.55  grams  per  kilogram,  equivalent  to  6.8 
grams  of  SrCl2  per  liter.  A trace  of  barium  was  also  detected  in  the 
water. 

The  next  table  contains  analyses  of  waters  belonging  to  the  chloride 
group,  but  in  which  notable  quantities  of  other  acid  radicles  are  also 
present.  The  chlorine,  however,  predominates. 

Analyses  of  chloride  waters — III. 

A.  Congress  Spring,  Saratoga,  New  York.  Analysis  by  C.  F.  Chandler,  cited  by  A.  C.  Peale  in  Bull. 
U.  S.  Geol.  Survey  No.  32, 1886,  pp.  38, 39. 

B.  Hathom  Spring,  Saratoga,  New  York.  Analysis  by  Chandler,  loc.  cit.  For  recent  analyses  of  the 
Hathom  and  twelve  other  Saratoga  waters,  see  J.  K.  Haywood  and  B.  H.  Smith,  Bull.  Bur.  Chemistry 
No.  91,  U.  S.  Dept.  Agr.,  1905.  For  5 more  analyses  see  L.  R.  Milford,  Jour.  Ind.  Eng.  Chem.,  vol.6, 
1914,  p.  207. 

C.  Franklin  artesian  well,  Ballston,  New  York.  Analysis  by  Chandler,  op.  cit.,  p.  33.  These  waters 
(A,  B,  and  C)  are  all  reported  as  containing  bicarbonates,  which  in  the  present  tabulation  are  reduced  to 
normal  salts.  They  all  effervesce  because  of  their  large  content  in  free  C02.  The  P04  in  A and  C amounts 
to  0.01  grain  per  gallon. 

D.  Artesian  well  at  Louisville,  Kentucky.  Analysis  by  J.  Lawrence  Smith,  cited  by  Peale,  op.  cit., 
p.  115.  Bicarbonates  reduced  to  normal  salts.  Lithium  is  reported  as  0.02  grain  per  gallon. 

E.  Steamboat  Springs,  Nevada.  Analysis  by  W.  H.  Melville,  given  by  G.  F.  Becker  in  Mon.  LT.  S. 
Geol.  Survey,  vol.  13, 1888,  p.  349.  Bicarbonates  reduced  to  normal  salts.  The  “ trace”  of  iron  represents 
0.14  part  per  million.  From  a geological  point  of  view  this  water  is  out  of  its  proper  classification.  It  is 
a volcanic  water,  whereas  the  other  waters  in  the  table  are  of  sedimentary  origin. 

F.  Lansdowne  well,  Cheltenham,  England.  Analysis  by  T.  E.  Thorpe,  Join.  Chem.  Soc.,  vol.  65, 
1894, p.772.  The  “trace”  of  bromine  is  0.3part  and  that  ofiron  0.1  part  per  million. 

G.  The  Stanislawaquelle,  near  Karlsdorf,  Galicia.  Analysis  by  Von  Dunin-Wasowicz  and  J.  Horowitz, 
Chem.  Centralbl.,  1899,  pt.  2,  p.  491.  Bicarbonates  reduced  to  normal  salts.  The  N03  amounts  to  0.02 
part  per  million.  One  kilogram  of  this  water  contains  2.157232  grams  of  free  C02  and  0.10665  gram  of 
organic  matter. 


A 

B 

c 

D 

E 

F 

G 

Cl 

42.  00 

42.  42 

41.  95 

48.  03 

35.  00 

38.  01 

34.  60 

Br 

1. 13 

. 16 

. 37 

.05 

Trace. 

I 

.02 

.02 

. 02 

.04 

Trace. 

\ .02 

F. .. 

Trace. 

Trace. 

Trace. 

) 

S04. . 

. 08 

. 04 

14.  93 

4.  58 

20.  89 

.82 

s 

.22 

co3 

18.  59 

19.  28 

18.  66 

.49 

5.  08 

4.  22 

19.  96 

no3 

Trace. 

P04 

Trace. 

Trace. 

Trace. 

.09 

.03 

Trace. 

b4o7 

Trace. 

Trace. 

Trace. 

8.  88 

Na 

27.  62 

27.  29 

28.  84 

29.  84 

30.  35 

32.  80 

37.  29 

K 

. 78 

.68 

1.  83 

.41 

3.  79 

.72 

.53 

Li 

.08 

.16 

.07 

Trace. 

.27 

Trace. 

.01 

Ca 

6.03 

5.  69 

5.  04 

3.  75 

.25 

1.  85 

3.64 

Sr 

Trace. 

Trace. 

Trace. 

1.  44 

Ba 

. 09 

. 12 

.06 

.82 

Mg 

3.  41 

3.  92 

2.  95 

2. 19 

.01 

1.  37 

Mn 

Trace. 

.01 

Fe" 

Trace. 

Trace. 

Fe203 

. 03 

. 07 

. 07 

. 02 

. 17 

A1 

.06 

Trace. 

A1203 

Trace. 

.02 

. 03 

.01 

As 

. 10 

Sb 

.02 

Trace. 

Sif>2 

. 14 

.17 

.07 

.10 

11.41 

.14 

.69 

100.  00 

100. 00 

100.  00 

100.  00 

100.  00 

100.00 

100.00 

Salinity,  parts  per 

million 

12,  022 

15,  238 

20,  315 

15,700 

2,  850 

8,  870 

7,  639 

MINERAL  WELLS  AND  SPRINGS. 


187 


SULPHATE  WATERS. 

The  sulphate  waters,  or  the  waters  in  which  S04  is  the  principal 
negative  ion,  fall,  like  the  chloride  waters,  into  several  groups,  which 
shade  one  into  another  by  imperceptible  gradations.  Among  potable 
waters  of  this  class,  those  which  upon  evaporation  yield  chiefly  cal- 
cium sulphate  are  by  far  the  most  common.  Many  examples  of  such 
waters  were  cited  among  the  analyses  of  rivers.  As  a rule,  on  account 
of  the  slight  solubility  of  gypsum,  their  salinity  is  relatively  low. 
Waters  of  this  type  are  frequently  found  in  so-called  mineral  springs. 
Other  waters  of  medicinal  significance  are  essentially  solutions  of 
magnesium  sulphate  or  sodium  sulphate;  still  others  contain  sul- 
phates of  aluminum  or  iron,  and  a small  group  of  waters,  derived 
from  the  oxidation  of  sulphides,  carry  heavy  metals  in  considerable 
quantity.  Examples  of  these  different  classes  are  given  below,  and 
some  sulphate  waters  which  contain  free  acids  will  be  considered  in 
a special  group  later.  The  following  analyses  are  sufficient  for  pres- 
ent purposes : 

Analyses  of  suljphate  waters. 

A.  Abilena  well,  14  miles  northwest  of  Abilene,  Kansas,  130  feet  deep.  Analysis  by  E.  H.  S.  Bailey, 
Univ.  Geol.  Survey  Kansas,  vol.  7,  1902,  p.  166.  The  ‘‘traces”  refer  to  4 parts  N03  and  3.2  parts  Fe  per 
million  of  water. 

B.  Spring  near  Denver,  Colorado.  Analysis  by  L.  G.  Eakins,  Bull.  U.  S.  Geol.  Survey  No.  60,  1890, 
p.  174.  Contains  210  parts  of  free  CO2  per  million. 

C.  Cottage  well,  Cheltenham,  England.  Analysis  by  T.  E.  Thorpe,  Jour.  Chem.  Soc.,  vol.  65, 1894,  p.  772. 
Contains  0.2  part  of  Fe  per  million. 

D.  Bitter  spring  at  Laa,  Austria.  Analysis  by  A.  Kauer,  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  20, 1870, 
p.  118.  Contains  free  CO2. 

E . Water  from  Cruzy,  Hdrault,  France.  Analysis  published  by  Braconnier,  Annales  des  mines,  8th  ser., 
vol.  7, 1885,  p.  143.  From  a well  14  meters  deep  in  an  old  gypsum  quarry.  The  fissures  around  the  well 
are  lined  with  fibrous  epsomite. 

F.  St.  Lorenzquelle,  Leuk,  Switzerland.  Analysis  by  G.  Lunge  and  R.  E.  Schmidt,  Zeitschr.  anal. 
Chemie,  vol.  25, 1886,  p.  309.  Contains  0.06  part  Li,  0.05  part  NIL,  0.05  part  Fe,  and  0.11  part  Mn  per  mil- 
lion—in  each  case  less  than  0.01  per  cent  of  the  total  solids. 


A 

B 

C 

D 

E 

F 

Cl 

0.  48 

2.  62 

6.  56 

0.  57 

3.  73 

0.  34 

so4 

66.  28 

72.  56 

57.  42 

69.  87 

74. 16 

65.  86 

co3 

. 60 

6.  48 

4.  75 

.03 

3.  74 

no3 

Trace. 

.02 

PO, 

Trace. 

As 

Trace. 

Na 

30.  46 

11.23 

13.  51 

2.  99 

4.  50 

1.  50 

K 

1.08 

.22 

.48 

.35 

.03 

. 30 

Li 

Trace. 

Trace. 

Trace. 

nh4 

. 01 

.22 

Trace. 

Ca 

.67 

.53 

8.33 

7.  63 

.02 

23.  55 

Sr 

. 05 

Ba 

Trace. 

Mg 

.41 

12.  79 

7.  03 

13. 18 

17.  45 

3.  07 

1 

Mn 

Trace. 

Trace. 

Fe" 

Trace. 

Trace. 

} *01 

Fe90o 

} .02 

.01 

) 

ALo, 

.03 

Al. 

Trace. 

) 

Cu 

Trace. 

Si02 

.02 

.05 

.16 

.42 

.07 

1.55 

Salinity,  parts  per  million 

100.  00 
74,  733 

100.  00 
60,  584 

100.  00 
5,  518 

100.  00 
62,  371 

100.  00 
101,  000 

100.  00 
1,  948 

188 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  sulphate  waters — Continued. 

G.  Spring  at  Srebrenica,  Bosnia.  Analysis  by  E.  Ludwig,  Min.  pet.  Mitt.,  vol.  11, 1889-90,  p.  303;  1.37 
per  cent  of  free  H2SO4  has  been  here  added  to  the  figure  for  the  SO4  radicle.  A little  organic  matter  (11.2 
parts  per  million)  is  also  present.  On  p.  308  of  the  same  volume  Ludwig  gives  an  analysis  of  an  acid  water 
rich  in  aluminum  sulphate  from  Biidos,  Transylvania.  Other  papers  in  the  volume  give  a number  of 
important  analyses  of  springs  in  Bosnia  and  Transylvania.  Some  waters  containing  unusual  amounts  of 
strontium  are  mentioned  in  Rept.  State  Board  Geol.  Survey  Michigan,  1905,  p.  555. 

H.  Alumweil,  Versailles,  Missouri.  Analysis  by  P.  Schweitzer,  Geol.  Survey  Missouri,  vol.  3, 1892,  p.  131. 

I.  Water  from  Roncegno,  southern  Tyrol.  Analysis  by  M.  Glaser  and  W.  Kalmann,  Ber.  Deutsch. 
chem.  Geseil.,  vol.  21, 1888,  p.  2879.  For  a later  analysis  of  Roncegno  water  see  R.  Nasini,  M.  G.  Levi,  and 
F.  Ageno,  Gazz.  chim.  ital.,  vol.  39  (2),  1909,  p.  481.  They  cite  another  analysis  by  P.  Spica. 

J.  Arsenical  spring,  S.  Orsola,  southern  Tyrol.  Analysis  by  C.  F.  Eichleiter,  Jahrb.  K.-k.  geol.  Reichs- 
anstalt,  vol.  57, 1907,  p.  529.  The  trace  of  Ni  is  0.003  per  cent. 

K.  Spring  on  Shoal  Creek,  4|  miles  west  of  Joplin,  Missouri.  Analysis  by  W.  F.  Hillebrand,  Bull.  U.  S. 
Geol.  Survey  No.  113, 1893,  p.  49.  Total  CO2,  free  and  combined,  120.5  parts  per  million.  A trace  of  lead 
is  also  reported.  The  water  of  Spring  River,  in  eastern  Kansas,  also  contains  zinc,  derived  from  the  drain- 
age of  adjacent  mines.  See  E.  H.  S.  Bailey,  U.  S.  Geol.  Survey  Water-Supply  Papers  Nos.  273,  351,  1911. 


Cl 

504.. .. 
C03... 
P04.... 
h3as04 
As02.  . 

Na 

K 

Li 

Ca 

Mg.... 

M11 

Fe"... 

Fe///... 

A1 

Co.... 

Ni.... 

Cd.... 

Zn.... 

Cu.... 

5109. . . 


Salinity,  parts  per  million . 


0.  48 
65.  33 


Trace. 


.41 
.31 
.32 
Trace. 
3.  00 
1.  48 
.12 
24.  98 


1.21 


.30 
.36 
1.  70 


100.  00 
1,723 


76.  57 


1. 19 


5.  82 
3.  39 


4.  28 
’7.' 36 


1.39 


100.  00 
3,  303 


0.  03 
70.  93 


.23 
1.  93 


1.25 

.23 


7.  08 
.93 
.78 
.03 
11.  09 
3.  09 
.17 
.41 


.06 
.15 
1.  61 


100.  00 
8, 150 


0. 33 
71.  84 


.75 


.14 

.21 

.10 


6. 32 
.97 
.24 
1.  76 
13.  09 
3.  05 


Trace. 


.01 

1. 19 


100.  00 
7,  683 


0.  48 
52.  76 
8.00 


.67 

.46 


11.32 

.71 

.42 

.11 

* . 08 


.10 

22.31 

.04 

2.54 


100.00 

540 


The  Roncegno  and  S.  Orsola  waters  evidently  derive  their  saline 
constituents  from  metallic  sulphides,  apparently  in  great  part  from 
arsenical  pyrites.  Arsenical  waters  are  not  uncommon,  and  some  of 
them  contain  enough  arsenic  to  be  poisonous.  The  water  from  Shoal 
Creek  represents  the  oxidation  of  zinc  blende,  together  with  some 
reaction  upon  the  adjacent  limestones,  from  which  its  calcium  and 
carbonic  ions  were  obtained.  It  is  essentially  the  same  thing  as  a 
mine  water,  although  it  is  not  derived  from  any  artificial  opening. 
For  comparison,  three  analyses  of  mine  waters,  carried  out  in  the 
laboratory  of  the  Geological  Survey,  are  appended.  Two  of  them  are 
zinc  waters;  the  third  is  a strong  solution  of  copper  sulphate.  Such 
waters  play  an  important  part  in  the  leaching  and  reprecipitation  of 
ores  and  will  be  more  fully  considered  later. 


MINERAL  WELLS  AND  SPRINGS. 


189 


Analyses  of  mine  waters.1 


A,  B.  Two  mine  waters  from  the  Missouri  zinc  region,  analyzed  by  H.  N.  Stokes.  Two  similar  waters 
from  the  same  region  were  analyzed  by  C.  P.  Williams,  Am.  Chemist,  vol.  7,  1877,  p.  246. 


C.  Water  from  the  Mountain  View  mine,  Butte,  Montana.  Analysis  by  W.  F.  Hillebrand.  Specific 
gravity,  1.1317  at  15°  C.  Contains,  in  parts  per  million,  3.5  Ni,  4.6  Co,  6.8  K,  and  1.5  PO4. 

A 

B 

C • 

Cl  

0. 16 

0.  03 

0.  01 

so4 

64.47 

63.  26 

60  29 

Pol 

Trace. 

As04  

Trace. 

Na  

1. 14 

.50 

.04 

K 

. 10 

Trace. 

Trace. 

Li 

Trace. 

None. 

Trace. 

Ca  

14.  38 

3.55 

.26 

Mr  

1.  36 

.26 

.13 

Mn 

.08 

.02 

.01 

Fe" 

6.49 

4.  88 

.04 

Ni 

Trace. 

Co 

Trace. 

Zn 

10.  74 

24.  80 

.37 

Cu 

Trace. 

.04 

38.  72 

Cd 

.02 

.09 

Al 

.20 

1.  46 

.07 

Si02  

.86 

1.11 

.06 

Salinity,  parts  per  million 

100.  00 
4,  232 

100.  00 

9,  754 

100.  00 
117,  850 

Two  other  examples  of  intermediate  waters,  containing  both  sul- 
phates and  chlorides,  but  with  the  former  in  excess,  may  be  cited 
here.  Both  are  from  Indiana,  and  the  analyses  are  by  W.  A.  Noyes. 

Analyses  of  sulphato-chloride  waters. 

A.  King’s  mineral  spring,  near  Dallas.  Twenty-sixth  Ann.  Kept.  Indiana  Dept.  Geology,  1901,  p.  32. 
Contains  traces  of  Al,  Fe,  Ba,  Sr,  Li,  Mn,  Ni,  Zn,  Br,  P.O4,  and  B4O7.  This  volume  contains  an  elaborate 
report  upon  the  mineral  waters  of  Indiana,  in  which  many  other  analyses  are  cited. 

B.  West  Baden  Spring.  Op.  cit.,  p.  109.  Contains  traces  of  Al,  Fe,  Ba,  Sr,  Li,  Br,  I,  PO4,  and  B4O7. 
Also  32.5  parts  of  H2S  per  million  of  water. 


A 

B 

Cl 

11. 10 

18. 19 

so4 

59.  68 

46.  66 

co3 

1.  67 

4. 11 

Na 

13.  89 

11.  72 

K 

.49 

. 78 

Ca 

2.  91 

13. 16 

Mr 

10. 19 

5.  21 

SiO., 

.07 

. 17 

Salinity,  parts  per  million 

100.  00 
15,  682 

100.  00 
4,  417 

For  other  analyses  of  mine  waters  see  Chapter  XV  of  this  memoir. 


190 


THE  DATA  OF  GEOCHEMISTKY. 


CARBONATE  WATERS. 

The  carbonate  waters,  those  in  which  C03  or  HC03  is  the  principal 
negative  ion,  fall  into  two  main  subdivisions,  calcium  being  the  im- 
portant base  in  one  and  sodium  in  the  other.  A large  number  of 
lake  and  river  waters,  as  we  have  already  seen,  belong  to  the  first  of 
these  groups,  and  so  do  many  springs  of  the  usual  potable  type; 
waters  of  the  second  group,  however,  are  not  uncommon.  In  most  of 
these  waters  the  carbonic  acid  present  is  sufficient  to  form  bicarbon- 
ates— a condition  which  renders  it  possible  for  calcium,  magnesium, 
and  iron  to  remain  in  solution.  Upon  evaporation  of  such  waters, 
CaC03  and  MgC03  are  deposited,  while  the  ferrous  bicarbonate  is 
broken  up,  and  insoluble  Fe203,  or  some  corresponding  hydroxide,  is 
formed  by  oxidation.  The  anhydrous  residue  in  such  cases  contains 
no  bicarbonates,  but  the  latter  may  exist  when  sodium  is  predomi- 
nant. The  salt  NaHC03  is  moderately  stable.  On  account  of  these 
peculiarities,  which  characterize  the  carbonate  waters,  it  seems  best 
to  state  their  analyses  in  two  ways — one  with  bicarbonate  ions  (when 
they  are  given)  in  terms  of  parts  per  million,  the  other  in  percentages 
of  anhydrous  residue,  as  in  all  the  preceding  tables.  Each  form  of 
statement  has  its  advantages,  but  the  second  method  gives  the  best 
comparison  between  different  waters.  The  following  analyses  repre- 
sent waters  of  the  carbonate  type:1 

1 Some  interesting  carbonate  waters  from  Colorado  are  described  by  W.  P.  Headden  in  Am.  Jour.  Sci., 
4th  ser.,  vol.  27,  1909,  p.  305. 


MINERAL  WELLS  AND  SPRINGS. 


191 


Analyses  of  carbonate  waters. 

A.  McClelland  well,  Cass  County,  Missouri.  Analysis  by  P.  Schweitzer,  Geol.  Survey  Missouri,  vol.  3, 

1892,  p.  181. 

B.  Artesian  water,  La  Junta,  Colorado.  Well  386feet  deep.  Analysis  by  W.  F.  Hillebrand  in  the  labo- 
ratory of  the  United  States  Geological  Survey. 

C.  Ojo  Caliente,  near  Taos,  New  Mexico.  Analysis  by  Hillebrand,  Bull.  U.  S.  Geol.  Survey  No.  113, 

1893,  p.  114.  Traces  of  As,  NO3,  Ba,  NH4,  and  possibly  I,  were  found.  For  the  geologic  relations  of  Ojo 
Caliente  see  W.  Lindgren,  Econ.  Geology,  vol.  5, 1910,  p.  22. 

D.  The  Grande-Grille,  Vichy,  France.  Analysis  by  J.  Bouquet,  Annales  chim.  phys.,  3d  ser.,  vol.  42, 
1854,  p.  304.  Analyses  of  other  Vichy  waters  and  their  sediments  are  given  in  this  memoir. 

E.  Spring  at  Hikutaia,  Puriri,  district  of  Auckland,  New  Zealand.  Analysis  by  W.  Skey,  Trans.  New 
Zealand  Inst.,  vol.  10,  1877,  p.  423. 

F.  Excelsior  Springs,  Missouri.  Analysis  by  W.  P.  Mason,  Chem.  News,  vol.  61,  1890,  p.  123.  This 
water  is  notable  for  the  relatively  large  amount  of  manganese  which  it  contains. 

G.  Spring  in  Pine  Creek  valley,  near  Atlin,  British  Columbia.  Analysis  by  F.  G.  Wait,  Ann.  Rept. 
Geol.  Survey  Canada,  1900,  p.  49  It.  This  water  deposits  hydromagnesite  and  calcareous  tufa. 

H.  Wilhelmsquelle,  Karlsbrunn,  Austrian  Silesia.  Analysis  by  E.  Ludwig,  Min.  pet.  Mitt.,  vol.  4, 1882, 

p.  182. 

I.— Parts  per  million  of  water. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

94 

66.9 

231.4 

324 

190.2 

11.  98 

1.  5 

1.  09 

I 

Trace. 

F 

5.2 

so4 

88 

71.1 

151.0 

197 

47.9 

2.  68 

60.2 

6.  48 

s 

1 

co3 

791.5 

i,  095.  9 

2,  392 

273.  75 

hco3 

1,  287 

5,  305.  8 
Present. 

6.  79 

6,  339. 1 
Trace. 

405. 18 

P04 

.2 

80 

.54 

As04 

Trace. 

2 

Trace. 

B407 

4.  2 

Trace. 

Na 

581 

668.  7 

995.  7 

1,  851 
151 

1,  897. 1 
31.  6 

9.51 

51.  9 

5.  24 

K 

6.4 

31.4 

3.  65 

12.0 

1.  76 

Li 

Trace. 

3.4 

Trace. 

Trace. 

Ca 

4 

4.4 

22.8 

120 

100.6 

145. 10 

116.8 

66.  27 

Sr 

1.4 

2 

Trace. 

Mg 

2 

2.5 

9.5 

58 

60.2 

15.  63 

1, 152.  3 

18.  85 

Mn 

Trace. 

4.  50 

.05 

Fe" 

2.4 

Trace. 

11.31 

6.  7 

46.  57 

Fe90, 

1.  6 

2 

A1203 

3.4 

. 5 

2. 10 

6.5 

. 30 

Si02 

12 

51.0 

60.2 

70 

39,6 

12.  00 

82.5 

69.  36 

2,  069 

1,  668.  3 

2,  614.  4 

5,  249 

7,  673. 1 

489.  00 

7,  829.  5 

621.  69 

192 


THE  DATA  OF  GEOCHEMISTRY. 


II.  Percentage  of  total  solids,  all  carbonates  normal. 


A 

B 

c 

D 

E 

F 

G 

H 

Cl 

6.  63 

4.  01 

8.  85 

6. 17 

3.  84 

2.  42 

0.  03 

0.  28 

I 

Trace. 

F 

. 19 

so* 

6.  21 

4.  26 

5.  77 

3.  75 

.98 

.54 

1.  31 

1.  68 

s. 

.06 

co3 

44.  76 

47.45 

41.  91 

45.  57 

52.  09 

55.  92 

67.  56 

38.  72 
. 14 

P04 

.01 

1.  52 

Present. 

Trace. 

As04 

.04 

Trace. 

B407 

. 16 

Trace. 

Na 

41.  07 

40.  09 

38.  08 

35.  27 

38.  39 

1.  92 

1. 13 

1.  36 

K 

.38 

1.  20 

2.88 

. 64 

.73 

.26 

. 46 

Li 

Trace. 

. 12 

Trace. 

Trace. 

Ca 

.30 

.27 

.87 

2.  29 

2.04 

29.  28 

2.  54 

17. 18 

Sr 

.05 

. 04 

Trace. 

Mg 

.12 

. 15 

. 41 

1. 11 

1.22 

3. 15 

25.  03 

4.  89 

Mn 

Trace. 

None. 

. 91 

.01 

Fe" 

.14 

Trace. 

2.  28 

Fe90o 

. 06 

.04 

. 21 

17.  24 

A1203 

. 20 

.02 

. 43 

. 14 

. 07 

Si02 

.85 

3.  05 

2.  30 

1.32 

o 

CO 

2.  42 

1.  79 

17.  97 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

The  water  of  Ojo  Caliente  is  noticeable  on  account  of  its  content  of 
fluorine.  This  element  is  rarely  determined  in  water  analyses,  but 
is  almost  invariably  present.  According  to  A.  Gautier  and  P. 
Clausmann,1  its  quantity  in  spring  waters  ranges  from  0.30  to  6.32 
milligrammes  per  liter,  being  highest  in  waters  issuing  from  areas  of 
eruptive  rocks.  The  highest  values  of  all  were  found  in  the  waters 
of  Vichy.2 


1 Compt.  Rend.,  vol.  158,  p.  1631, 1914. 

2 According  to  De  Gouvenain  (Compt.  Rend.,  vol.  76,  1873,  p.  1063),  Vichy  water  contains  7.6  parts  of 
fluorine  per  million.  In  the  water  of  Bourbon-rArchambault  2.68  parts  of  fluorine  were  found.  For 
other  examples  of  water  containing  fluorine  see  J.  C.  Gil,  Mem.  Acad.  Barcelona,  vol.  1, 1896,  p.  420;  A.  F. 
de  Silva  and  A.  d’Aguiar,  Bull.  Soc.  chim.  ,3d  ser.,  vol.  21, 1899,  p.  887;  C.  Lepierre,  Compt.  Rend.,  vol.  128, 
1899,  p.  1289;  J.  Casares,  Zeitschr.  anal.  Chemie,  vol.  34,  1895,  p.  546;  vol.  44,  1905,  p.  729;  and  P.  Carles, 
Compt.  Rend.,  vol.  144,  1907,  p.  37.  Carles  rarely  failed  to  detect  fluorine  in  mineral  waters,  commonly 
from  0.002  to  0.004  gram  per  liter.  In  one  Vichy  water  he  found  0.018  gram,  his  maximum.  This  is  18 
parts  per  million. 


MINERAL  WELLS  AND  SPRINGS. 


193 


WATERS  OF  MIXED  TYPE. 

The  following  analyses,  which  are  all  reduced  to  the  normal  stand- 
ard, represent  waters  of  mixed  type,  chlorides  with  carbonates;  sul- 
phates with  carbonates;  or  chlorides,  carbonates,  and  sulphates  all 
together.  Waters  of  this  character  are  very  common,  and  show 
almost  every  stage  of  intermediate  gradation. 

Analyses  of  waters  of  mixed  type. 

A.  The  Virginia  Hot  Springs,  Virginia.  Average  of  six  springs,  analyzed  by  F.  W.  Clarke,  Bull.  U.  S. 
Geol.  Survey  No.  9, 1884,  p.  33. 

B.  The  Life  well,  Fairhaven  Springs,  Missouri.  Analysis  by  P.  Schweitzer,  Geol.  Survey  Missouri,  vol.  3, 
892,  p.  174. 

C.  Deep  well,  Macomb,  Illinois.  Analyzed  by  G.  Steiger  in  the  laboratory  of  the  United  States  Geological 
Survey. 

D.  Cleopatra  Spring,  Yellowstone  National  Park.  Analysis  by  F.  A.  Gooch  and  J.  E.  Whitfield,  Bull. 
U.  S.  Geol.  Survey  No.  47,  1888,  p.  36.  Free  C02,  354  parts  per  million. 

E.  Orange  Spring,  Yellowstone  National  Park.  Analysis  by  Gooch  and  Whitfield,  op.  cit.,p.  38.  Free 
C02, 92  parts  per  million. 

F.  Konigsquelle,  Bad  Elster,  Saxony.  Analysis  by  R.  Flechsig,  cited  by  A.  Goldberg,  15.  Ber.  Naturw. 
Gesell.  Chemnitz,  1904,  pp.  74,  108.  This  memoir  is  a monograph  on  the  mineral  waters  of  Saxony  and 
contains  many  analyses.  Bicarbonates  reduced  to  normal  salts.  Free  C02  is  also  present. 

G.  The  Sprudel,  Carlsbad,  Bohemia.  Analysis  by  F.  Ragsky , cited  by  Roth,  Allgemeine  und  chemische 
Geologie,  vol.  1,  p.  569.  Contains  0.7604  gram  free  and  half-combined  C02  per  kilogram.  Also  traces  of  Br, 
I,  Li,  B,  Rb,  and  Cs. 

H.  Chalybeate  water,  Mittagong,  New  South  Wales.  Analysis  by  J.  C.  H.  Mingaye,  Proc.  Roy.  Soc. 
New  South  Wales,  vol.  26,  1892,  p.  73.  A very  unusual  water.  In  the  same  memoir,  Mingaye  gives  many 
other  analyses  of  Australian  spring,  artesian,  and  well  waters. 


A 

B 

C 

D 

E 

F 

G 

H 

Cl 

0.  64 

0.  06 

18.  02 

10.09 

10.  07 

20.  36 

11.52 

27.  34 

Br  

Trace. 

Trace. 

F 

. 03 

S04  

21.  73 

51.  54 

33.  22 

30.34 

32.  80 

31.  47 

31. 19 

C03 

40.  02 

16.  84 

13. 14 

21.  65 

20.  76 

10.  96 

19. 15 

30.  58 

P(L 

.01 

As04 

.26 

B/)7 

1.  46 

Undet. 

Na 

1.  81 

5.  33 

26.  88 

7.  50 

7.  65 

32.  51 

32.49 

7. 13 

K 

2.  04 

.79 

2.  95 

3.  78 

.45 

1.35 

8.  96 

Li 

. 13 

.10 

.23 

nh4 

. 03 

Ca 

23.  35 

16.  86 

5.  26 

17.  76 

17.  50 

1.40 

2.  23 

4.  25 

Sr 

. 01 

Mg 

5.  82 

6.  39 

2.  23 

4.  21 

4.  09 

.44 

. 65 

5.  89 

Mn 

. 19 

. 01 

Fe 

.79 

.59 

.02 

15.  85 

Fe90q 

.07 

A1 

Trace. 

A1203 

. 58 

. 04 

. 54 

. 13 

Si02 

4.  01 

2. 19 

.35 

2.  98 

3. 12 

1.  40 

1.  34 

Salinity,  parts  per 
million 

100.  00 
563 

100.  00 
1,  670 

100.  00 
3,  008 

100.  00 
1,  732 

100.  00 
1,  612 

100.  00 
4,  991 

100.  00 
5,  431 

•100.  00 
225 

97270°— Bull.  616—16 13 


194 


THE  DATA  OP  GEOCHEMISTRY. 


SILICEOUS  WATERS. 

Waters  characterized  by  a large  relative  proportion  of  silica  are 
common,  and  a number  of  examples  were  noted  among  river  waters, 
Uruguay  River  forming  an  extreme  case.  Springs  issuing  from 
feldspathic  rocks  are  likely  to  contain  silica  as  a chief  inorganic  con- 
stituent, but  the  absolute  amount  of  it  is  generally  small.  In  volcanic 
waters,  on  the  other  band,  and  especially  in  geyser  waters,  the  silica 
may  reach  half  a gram  to  the  liter,  and  sometimes  even  more.1  It  is 
usually  reported  as  Si02;  although  in  some  cases,  when  the  ordinary 
acid  radicles  are  insufficient  to  satisfy  the  bases,  it  becomes  necessary 
to  assume  the  existence  of  silicates,  even  if  their  precise  nature  is 
unknown.  For  such  waters  it  is  convenient  to  report  this  saline  silica 
in  the  form  of  the  metasilicic  radicle  Si03,  the  dried  residue  being 
supposed  to  contain  the  sodium  salt  Na2Si03;  but  this  is  hardly  more 
than  a convenient  device  for  evading  a recognized  uncertainty.  In 
solution,  according  to  L.  Kahlenberg  and  A.  T.  Lincoln,2  sodium 
metasilicate  is  hydrolyzed  into  colloidal  silica  and  sodium  hydroxide; 
and  this  conclusion  was  also  reached  by  F.  Kohlrausch  3 about  five 
years  earlier,  although  he  stated  it  in  a more  tentative  form.  In 
natural  waters,  then,  silica  is  actually  present  in  the  colloidal  state, 
and  not  in  acid  ions.  On  evaporation  to  dryness  the  silicate  may 
form,  but  only  when  there  is  a deficiency  of  other  acid  groups.  Such 
a deficiency  is  indicated  by  a pronounced  alkalinity  in  any  highly 
siliceous  water. 

For  convenience  the  silicic  waters  are  divided  below  into  two 
groups — first,  two  waters  are  given  which  are  probably  not  of  volcanic 
origin;  second,  a number  of  geyser  waters  appear  in  a table  by  them- 
selves. The  first  two  waters  are  rather  dilute. 


1 For  example,  the  Opal  Spring,  in  the  Yellowstone  National  Park,  carries  0.7620  gram  of  silica  per  kilo- 
gram of  water.  The  analyses  of  the  Yellowstone  Park  waters,  originally  published  in  U.S.  Geol.  Survey 
Bull.  No.  47,  are  also  reprinted  in  Water-Supply  Paper  No.  364. 

2 Join.  Phys.  Chem.,  vol.  2,  1898,  p.  77. 

3 Zeitschr.  physikal.  Chemie,  vol.  12,  1893,  p.  773. 


MINERAL  WELLS  AND  SPRINGS. 


195 


Analyses  of  silicic  waters  of  nonvolcanic  origin. 

A.  Big  Iron  Spring,  Hot  Springs  of  Arkansas.  Analysis  by  J.  K.  Haywood,  Rept.  to  U.  S.  Dept. 
Interior,  1902.  This  is  & typical  water,  selected  from  among  the  46  springs  which  were  analyzed.  All  the 
hot  springs  in  this  group  are  very  much  alike.  Haywood  reports  his  carbonates  wholly  as  bicarbonates, 
and  his  figures  are  here  restated  in  normal  form — that  is,  HC03  has  been  recalculated  into  the  proper  quan- 
tity of  C03  corresponding  to  the  normal  salts. 

B.  Cascade  Spring,  Olette,  eastern  Pyrenees.  One  of  six  analyses  by  E.  Willm,  Compt.  Rend.,  vol. 
104,  1887,  p.  1178.  Temperature,  79.4°  C.  In  this  water,  which  might  also  be  classed  as  a sulphur  water, 
the  radicle  Sa03  represents  the  presence  of  thiosulphates,  produced  by  the  partial  oxidation  of  sulphides. 
Thiosulphates  have  also  been  reported  in  other  waters,  and  several  examples  from  Indiana  are  cited  in 
Twenty-sixth  Ann.  Rept.  Indiana  Dept.  Geology,  1901,  pp.  76,  81,  86. 


A 

B 

Cl  

1.  27 

4.  38 

Br  I 

Traces. 

S04 

3.  93 

7.  28 

S„0,  

4.  81 

s 

3.  38 

co3 

41.  47 

12. 14 

NO, 

.23 

P04 

.03 

bo2  

. 64 

Na  

2.  38 

26.  09 

K 

. 80 

2.  00 

Li  

Trace. 

nh4 

. 03 

Ca 

23.  54 

i.oi 

Ba,  Sr 

Traces. 

Mr 

2.  56 

Trace. 

Mn 

. 17 

Fe,  A1 

. 10 

Si02 

22.  85 

38.  91 

Salinity,  parts  per  million 

100.  00 
a 199 

100.  00 
244 

J ) Jr  Ir 

a 284.8  in  the  original,  where  bicarbonates  are  included.  In  that  statement  HC03  forms  59.02  per  cent 
of  the  total  solids.  This  water  might  be  equally  well  classed  with  the  carbonate  waters. 


For  geyser  waters  and  waters  of  similar  character  the  data  are 
abundant  and  only  a few  examples  need  be  utilized  here. 


196 


THE  DATA  OF  GEOCHEMISTRY, 


Analyses  of  siliceous  geyser  waters. 

C.  Coral  Spring,  Norris  Basin,  Yellowstone  National  Park. 

D.  Echinus  Spring,  Norris  Basin. 

E.  Bench  Spring,  Upper  Geyser  Basin,  Yellowstone  National  Park. 

F.  Old  Faithful  Geyser,  Upper  Geyser  Basin. 

G.  Excelsior  Geyser,  Midway  Basin,  Yellowstone  National  Park.  Analyses  C to  G by  F.  A.  Gooch 
and  J.  E.  Whitfield,  Bull.  U.  S.  Geol.  Survey  No.  47,  1888.  A number  of  other  geyser  waters  were  ana- 
lyzed and  are  reported  in  this  memoir.  The  figures  given  here  vary  somewhat  from  the  original  state- 
ments, having  been  recalculated  on  a different  basis.  The  discrepancies,  however,  are  very  slight. 

H.  Great  Geyser,  Iceland.  Analysis  by  Sandberger,  Ann.  Chem.  Pharm.,  vol.  62,  1847,  p.  49. 

I.  Te  Tarata,  Rotorua,  New  Zealand.  The  water  which  formed  the  white  terrace  of  Rotomahana.  A 
large  excess  of  silica  over  bases,  represented  as  Si03. 

J.  Otukapuarangi,  Rotorua  geysers.  The  water  of  the  pink  terrace.  Excess  of  silica  very  small.  Anal- 
yses I and  J by  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  10,  1877,  p.  423.  Thirteen  other  analyses  are 
given  in  this  memoir.  J.  S.  Maclaurin,  in  Thirty-ninth  Ann.  Rept.  Colonial  Laboratory,  Mines  Dept., 
New  Zealand,  gives  23  analyses  of  mineral  springs  in  New  Zealand.  Several  of  them  are  very  high  in 
silica.  See  also  the  Forty-second  Report.  For  early  analyses  of  Yellowstone  waters  see  H.  Leffman, 
Am.  Jour.  Sci.,  3d  ser.,  vol.  25,  pp.  104,  351.  Analyses  of  several  Icelandic  geyser  waters  are  given  by 
A.  Damour  in  Annales  chim.  phys.,  3d  ser.,  vol.  19,  1847,  p.  470. 


C 

D 

E 

F 

G 

H 

I 

J 

Cl 

36.  61 

14.  93 

Trace. 

31.  64 

20.  91 

13.  52 

26.  82 

37.  52 

Br 

Trace. 

.25 

Trace. 

S04 

1.  84 

28.  65 

29.  22 

1.  30 

1.  31 

9.  01 

3.  60 

4.  96 

s 

. 32 

COo 

. 15 

8.  78 

25.  01 

10. 16 

P04 

None. 

Trace. 

Trace. 

As04 

. 08 

. 29 

. 24 

. 29 

B407 

2.  24 

2.  38 

1. 19 

1.  34 

Na 

21.44 

15.  65 

12. 15 

26.  42 

31.  34 

19.  71 

33.  94 

24.  22 

K 

4.  45 

4.  89 

2.  05 

1.  93 

2.  43 

1.  88 

1.  01 

.36 

Li 

.22 

Trace. 

Trace. 

.40 

. 15 

Trace. 

nh4 

. 02 

. 13 

Trace. 

Trace. 

.28 

Ca 

.39 

1.  42 

Trace. 

. 11 

. 17 

. 38 

2.  59 

Mg 

.08 

None. 

Trace. 

. 04 

. 17 

.08 

.09 

.19 

Mn 

Trace. 

Trace. 

Fe 

Trace. 

None. 

Trace. 

.13 

FeoCL 

| 5.  80 

. 20 

Trace. 

A12Os 

.76 

.12 

.17 

.01 

.35 

Al. 

. 33 

Si02 

31.  72 

31.  33 

50.  78 

27.  58 

16.  58 

45.04 

29.  81 

Si03 

33.  95 

Salinity,  parts  per 
million 

100.  00 
1,830 

100.  00 
808 

100.  00 
473 

100.  00 
1,388 

100.  00 
1,336 

100.  00 
1, 131 

100.  00 
2,  064 

100.  00 
2,  735 

NITRATE,  PHOSPHATE,  AND  BORATE  WATERS. 

Although  waters  containing  small  quantities  of  nitrates,  borates, 
or  phosphates  are  not  uncommon,  waters  in  which  these  compounds 
are  conspicuous  are  rare.  Melville’s  analysis  of  Steamboat  Springs 
has  already  been  cited,  and  the  salts  from  that  water  contain  nearly 
9 per  cent  of  the  radicle  B407,  corresponding  to  about  11.5  per  cent 
of  anhydrous  borax.1  Nitrates  are  usually  regarded  as  evidence  of 

i Boric  acid  in  natural  waters  has  been  discussed  by  L.  Dieulafait  in  Compt.  Rend.,  vol.  93, 1881,  p.  224; 
vol.  94,  1882,  p.  1352;  and  vol.  100,  1885,  pp.  1017,  1240.  According  to  L.  Kahlenberg  and  O.  Schreiner 
(Zeitschr.  physikal.  Chemie,  vol.  20,  1896,  p.  547),  the  group  B4O7  is  not  the  true  ion  of  the  borates.  It 
is  a convenient  expression,  however,  for  the  negative  radicle  of  borax. 


MINERAL  WELLS  AND  SPRINGS. 


197 


pollution  in  waters,  but  they  do  not  necessarily  indicate  pollution. 
In  arid  regions,  where  nitrification  goes  on  rapidly,  nitrates  may 
occur  in  considerable  amounts;  some  of  the  underground  waters  of 
Arizona  contain  as  high  as  160  parts  per  million  of  nitrogen  in  this 
form.®  The  following  analyses  probably  represent  extreme  examples 
of  phosphates,  borates,  and  nitrates  in  natural  waters :*  6 

Analyses  of  nitrate , phosphate , and  borate  waters. 

A.  Hot  spring  from  sulphur  hank  on  the  margin  of  Clear  Lake,  California.  Analysis  by  G.  E.  Moore, 
Geol.  Survey  California,  Geology,  1865,  p.  99.  In  the  original  the  carbonates  are  given  as  bicarbonates,  and 
ammonium  bicarbonate  is  reported  to  the  extent  of  107.76  grains  per  gallon.  So  great  a proportion  of 
ammonium  in  a water  is  extraordinary,  although  one  acid  water,  cited  later  (p.  199),  surpasses  it.  In  the 
tabulation  the  bicarbonates  are  reduced  to  normal  salts. 

B.  Hot  water  from  the  Hermann  shaft,  Sulphur  Bank,  California. 

C.  Hot  water  from  the  Parrott  shaft,  Sulphur  Bank.  Analyses  B and  C by  W.  H.  Melville,  cited  by 
G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  259.  Some  organic  matter,  a little  H2S,  and  a con- 
siderable amount  of  C02  are  reported  in  these  waters. 

D.  Phosphatic  water  from  Viry,  Seine-et-Oise,  France.  Analysis  by  Bourgoin  and  Chastaing;  abstract 
in  Jour.  Chem.  Soc.,  vol.  54, 1888,  p.  354.  The  water  issues  from  a gallery  cut  in  clay.  Bicarbonates  reduced 
to  normal  salts. 

E.  Spring  “ Valette,  ” at  Cransac,  Aveyron,  France.  One  of  nine  analyses  by  A.  Carnot,  Compt.  Rend., 
vol.  Ill,  1890,  p.  192.  These  springs  issue  below  beds  of  coal  and  carbonaceous  schists,  in  which  fires  have 
occurred.  The  nitrates  were  derived  from  the  oxidation  of  the  nitrogen  compounds  contained  in  the  coal. 

F.  The  holy  well  Zem-Zem,  at  Mecca.  Analysis  by  P.  Van  Romburgh,  Rec.  trav.  chim.,  vol.  5,  1886, 
p.  265.  For  a corroborative  analysis  see  M.  Greshoff,  idem,  vol.  16,  1897,  p.  354.  The  nitrates  of  this  water 
are  commonly  ascribed  to  pollution  by  human  agency;  but  it  is  not  certain  that  so  large  a quantity,  absolute 
or  relative,  could  be  derived  from  that  source. 


Cl... 

I.... 

so4.. 

co3.. 

no3.. 

b4o7. 

P04.. 

Na... 

K... 

Li... 

NH4. 

Ca... 


Mn.. 

Fe". 

Fe"7. 

A1203 

Si09. 


Salinity,  parts  per  million. 


16.  49 
.03 
Trace. 
21.  96 


25.  61 


24.  99 
Trace. 


7.  88 
Trace. 
Trace. 


.40 
2.  64 


100.  00 
c 5,  343 


13.  57 


.32 
22.  38 


27.  98 


33.  97 
.48 


.05 

.41 

.11 


.73 


100.  00 
5,  096 


14.  39 


10.  06 
4.  73 


40.  09 


28.  49 
.84 


.02 

.44 

.03 


.01 


.90 


100.  00 
4,  632 


5. 11 


7.  74 
19.  4§ 
6.  33 


22.41 
3.  32 
Trace. 
Trace. 


30.  38 
1.  21 


4.  04 


100.  00 
490 


5.  45 


27.  87 
2.  58 
36.  09 


3.  53 
.68 
Trace. 


15.  93 
5. 17 
.06 


.06 
2."  58 


100.  00 
1, 163 


16.  44 


14.  04 
12.  78 
24.  62 


12.  66 
6.  67 


8.  70 
2.  70 


1.  39 


]00.  00 
3,455 


a See  W.  W.  Skinner,  Bull.  Arizona  Exper.  Sta.  No.  46,  1903. 

6 The  mineral  water  of  Cherrydale,  Virginia,  is  also  reported  to  be  rich  in  nitrates.  See  analysis  by  J.  K. 
Haywood  and  B.  H.  Smith,  of  a commercial  bottled  sample,  in  Bull.  Bur.  Chemistry  No.  91,  U.  S.  Dept. 
Agr.,  1905,  p.  54.  Several  springs  in  Massachusetts,  reported  by  W.  W.  Skinner  (Bull.  Bur.  Chemistry 
No.  139, 1911),  are  also  remarkably  high  in  nitrates, 

c Reckoned  with  normal  carbonates.  With  bicarbonates  the  salinity  becomes  6,556  parts  per  million. 


198 


THE  DATA  OF  GEOCHEMISTRY. 


ACID  WATERS. 

The  last  group  of  waters  that  we  have  to  consider  are  those  which 
contain  free  acids,  sulphuric  or  hydrochloric.  They  may  be  classi- 
fied in  two  divisions — first,  acid  waters  derived  from  sedimentary 
rocks,  their  acidity  being  probably  due  to  the  oxidation  of  pyrites  or 
other  sulphides;  second,  waters  of  volcanic  origin.  Under  the  first 
heading  the  four  analyses  given  below  may  be  cited.  In  these  anal- 
yses it  seems  best  to  state  the  free  acids  as  such  and  not  in  the  form 
of  ions,  and  to  give,  instead  of  the  normal  “salinity,”  the  total 
inorganic  impurity  in  parts  per  million. 

Analyses  of  acid  waters  from  sedimentary  rocks. 

A.  The  Tuscarora  sour  spring,  9 miles  south  of  Brantford,. Canada.  Analysis  by  T.  Sterry  Hunt,  Geol. 
Survey  Canada,  1863,  p.  545. 

B.  Oak  Orchard  Spring,  Alabama,  Genesee  County,  New  York.  Analysis  by  W.  J.  Craw,  Am.  Jour. 
Sci.,  2d  ser.,  vol.  9,  1850,  p.  449.  The  free  acid  is  stated  in  the  original  as  S03;  it  is  here  recalculated  into 
H2S04. 

C.  Spring  9 miles  northwest  of  Jonesville,  Lee  County,  Virginia.  Analysis  by  L.  E.  Smoot,  Am.  Chem. 
Jour.,  vol.  19,  1897,  p.  234.  Acidity  low. 

D.  Rockbridge  Alum  Spring,  Virginia.  Analysis  by  M.  B.  Hardin,  Am.  Chemist,  vol.  4, 1873-74,  p.  247. 
This  water  and  that  analyzed  by  Smoot  might  be  equally  well  put  in  the  ordinary  sulphate  group  with 
other  “alum”  springs. 


A 

B 

C 

D 

H0SO4  free 

69.  62 

47.  87 

5.  82 

9.  37 

HN03  free 

.18 

Trace. 

Cl 

.43 

.32 

S04,  combined 

PCL 

22. 11 
Trace. 

36.  28 

75. 14 

68.  21 
Trace. 

Na 

. 26 

. 87 

1. 19 

.22 

K : 

.44 

.71 

.11 

Li 

.01 

Ca  

3.  70 

6.  39 

.38 

Ms  

. 50 

2.  06 

1. 11 

Fe" 

2. 17 

3.  06 

1. 19 

Ye'" 

2.  24 

Mn 

.69 

Ni 

.07 

Co 

.05 

Zn 

.08 

Cu 

Trace. 

A1 

1.  20 

1.  00 

12.  55 

11.  08 

Si02 

1.  33 

2.  88 

7. 11 

Total  inorganic  impurity,  parts  per  million 

100.  00 
6, 161 

100.  00 
a 5, 136 

100.  00 
3,  715 

100.  00 
464 

a 4,685  when  the  free  acid  is  reckoned  as  S03. 


Among  volcanic  waters  acidity  is  much  more  common,  and  many 
examples  of  it  are  known.  The  following  analyses  are  among  the 
most  typical,  and  are  stated  in  the  normal  percentage  form: 


MINERAL  WELLS  AND  SPRINGS. 


199 


Analyses  of  add  waters  of  volcanic  origin. 

A.  Devils  Inkpot,  Yellowstone  National  Park.  Analysis  by  F.  A.  Gooch  and  J.  E.  Whitfield,  Bull. 
U.  S.  Geol.  Survey  No.  47  .1888,  p.  80.  Acidity  slight.  This  water  is  unique  on  account  of  its  high  pro- 
portion of  ammonium  salts.  It  contains  NH4  equivalent  to  2.8  grams  of  ammonium  sulphate  per  liter,  or 
about  83  per  cent  of  the  total  impurity.  Contains  also  65  parts  of  free  C02  and  5 parts  of  H2S  per  million. 
As  an  ammoniacal  water  this  may  be  compared  with  the  borate  water  from  Clear  Lake,  California,  pre- 
viously cited. 

B.  Acid  Spring,  California  Geysers,  Sonoma  County,  California.  Temperature  60°  C.  Analysis  by 
Thomas  Price,  Trans.  Technical  Soc.  Pacific  Coast,  vol.  5,  1888,  p.  48.  Eleven  analyses  of  other  waters 
from  this  group  of  springs  are  also  given. 

C.  Water  from  Cove  Creek  sulphur  beds,  Utah.  Recalculated  from  the  analysis  by  W.  M.  Barr,  as  pub- 
lished by  W.  T.  Lee  in  Bull.  U.  S.  Geol.  Survey  No.  315, 1907,  p.  489.  The  water  issues  from  rhyolitic  tuffs, 
but  may  not  be  of  strictly  volcanic  origin. 

D.  Rio  Vinagre,  Colombia.  Analysis  by  J.  B.  Boussingault,  Annales  chim.  phys.,  5th  ser.,  vol.  2, 1874, 
p.  80.  Free  SO3  recalculated  into  H2SO4.  Boussingault  also  gives  analyses  of  several  saline  waters  from 
the  same  region.  On  p.  81  he  estimates  that  Rio  Vinagre  at  Purace  carries  each  day  46,873  kilograms  of 
H2SO4  and  42,150  kilograms  of  HC1.  These  figures  correspond  to  17,000  and  15,000  metric  tons  per  annum. 

E.  Hot  Spring,  Paramo  de  Ruiz,  Colombia.  Analyses  by  H.  Lewy,  cited  by  Boussingault,  op.  cit.,  p.  91. 
Free  SO3  recalculated  into  H2S04. 

F.  Solfatara  at  Pozzuoli,  Italy.  Analysis  by  S.  De  Luca,  Compt.  Rend.,  vol.  70, 1870,  p.  408. 

G.  Brook  finngi  Pait,  from  crater  of  Idjen  volcano,  Java.  Analysis  by  F.  A.  Fluckiger,  Jahresb. 
Chemie,  1862,  p.  820.  Acid  waters  are  not  uncommon  in  Java. 


A 

B 

c 

D 

E 

F 

G 

HG1  free 

0. 18 

35.  92 

5.  50 

43.  96 

H2S04  free 

1.29 

49.  71 

31.38 

1.89 

44. 17 

16.  62 

HoBO,  

2.  73 

Cl  

.81 

4.  75 

4.  96 

.34 

14.  95 

so4 

67.  66 

33.  92 

46.  95 

43.  97 

31.  71 

55.  08 

26.  96 

s 

. 04 

NO,  

. 02 

Na 

. 73 

.58 

1.  47 

3.08 

3.22 

Trace. 

1.  32 

K 

.24 

.10 

.57 

.39 

Li 

. 01 

nh4 

22.  85 

. 58 

Ca 

1. 18 

.41 

1.  62 

2.45 

1.21 

2.  91 

2.  05 

Ms  

.36 

5.  72 

2.  48 

2.31 

. 55 

.94 

Mn 

Trace. 

Fe" 

Trace. 

1.92 

5.  74 

1.  53 

3.47 

Fe"' 

8.22 

4.  66 

A1 

.10 

1.02 

None. 

7. 14 

3. 18 

7. 16 

4.  44 

As 

Trace. 

Si02 

2.  67 

6.  62 

1.27 

.80 

2.  21 

12.  72 

.33 

Total  impurity,  parts 
per  million 

100.  00 

3,  365 

100.  00 
5,  467 

100.  00 
9,  760 

100.  00 
2,  969 

100.  00 
8,  296 

100.  00 
2, 477 

100.  00 
18,  060 

200 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  acid  waters  of  volcanic  origin — Continued. 

H.  Hot  Lake,  White  Island,  Bay  of  Plenty,  New  Zealand.  Analysis  by  C.  Du  Ponteil,  Arm,  Chem. 
Pharm.,  vol.  96,  1855,  p.  193.  Practically  a 10  per  cent  solution  of  hydrochloric  acid. 

I.  Probably  the  same  water  as  that  of  H.  Analysis  by  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  10, 
1877,  p.  423.  In  a later  analysis  by  J.  S.  Haclaurin  (Proc.  Chem.  Soc.,  vol.  27, 1911,  p.  10),  the  presence  of 
pentathionic  acid  is  reported. 

J.  Cameron’s  Bath,  Rotorua  geyser  district,  New  Zealand.  Analysis  by  Skey,  loc.  cit.  Contains  6 
parts  per  million  of  H2S. 

K.  Yellow  lake  or  hot  pool,  crater  of  Taal  volcano,  Luzon,  Philippine  Islands. 

L.  Green  lake  or  pool,  crater  of  Taal  volcano.  Analyses  K and  L by  J.  Centeno,  Estudio  geologico  del 
volcan  de  Taal,  Madrid,  1885.  Obscurely  stated.  Recalculated  on  the  assumption  that  “fosfato  sodico” 
means  Na3P04,  and  that  sulphuric  acid  means  H2SO4  and  not  S03.  The  free  acid,  however,  should  prob- 
ably be  all  hydrochloric,  with  no  sulphuric  at  all.  In  this  matter  I have  simply  followed  the  author.  Com- 
pare citation  by  G.  F.  Becker,  Twenty-first  Ann.  Rept.  TJ.  S.  Geol.  Survey,  pt.  3, 1901,  p.  49.  For  recent 
analyses  of  these  Taal  waters,  see  R.  F.  Bacon,  Philippine  Jour.  Sci.,  vol.  1, 1906,  p.  433;  vol.  2, 1907,  p.  115. 
Unfortunately,  these  analyses,  which  corroborate  Centeno’s,  are  stated  in  such  form  that  I can  not  reduce 
them  to  the  uniform  standards. 


H 

I 

J 

K 

L 

HC1,  free 

65.42 

69.  99 

5.  60 

13.  04 

H2S04  free 

59. 11 

5.  87 

2.  48 

H3BO3 

Cl 

11.69 

9.  96 

47. 26 

44.  52 

so4 

10.  64 

11.  34 

20.  21 

9.  50 

6.40 

P04 

1.  91 

Trace. 

1.26 

.73 

B40- 

Trace. 

Na.l 

. 75 

1.  56 

8.  35 

24. 14 

20.  75 

K 

. 59 

.90 

.32 

1.  38 

3.03 

Ca 

2.  30 

. 50 

.47 

. 56 

.22 

Mr 

.34 

.09 

.22 

.98 

1.02 

Mn 

Trace. 

Fe" 

2.  86 

. 78 

1.  03 

Fe'" 

5. 98 

.33 

5. 35 

5. 55 

A1 

.35 

2.  62 

Trace. 

.55 

As 

Si09 

.03 

.18 

5.  39 

2.37 

1. 23 

Total  impurity,  parts  per  million 

100.  00 
158,  051 

100.  00 
194,  830 

100.  00 
1,  862 

100.  00 
26,  989 

100.  00 
60,  023 

Still  another  acid  water,  from  the  crater  of  Popocatepetl,  was 
partially  analyzed  by  J.  Lefort.1  It  contained  1 1 .009  grams  of  hydro- 
chloric acid  and  3.643  of  sulphuric  acid  in  1,000  parts,  together  with 
2.080  grams  of  alumina,  0.699  of  soda,  and  0.081  of  ferric  oxide. 
Lime,  magnesia,  silica,  and  arsenic  were  present  in  traces.  These 
data  are  too  incomplete  to  admit  of  systematic  discussion.  The 
total  dissolved  matter  amounted  to  17,512  parts  per  million. 

J.  B.  Boussingault,2  in  his  memoir  on  the  acid  waters  of  the  Colom- 
bian Andes,  discusses  at  some  length  the  question  of  their  origin. 
He  shows  that  hydrochloric  acid  may  he  generated  by  the  action  of 
steam  upon  a mixture  of  chlorides  and  silica,  and  also  that  hot  gas- 
eous hydrochloric  acid  will  liberate  sulphuric  acid  from  sulphates. 
Both  of  these  reactions  may  take  place  in  volcanoes.  Sulphuric  acid 


1 Compt.  Rend.,  vol.  56,  1863,  p.  909. 


2 A Tin  ales  chim.  pbys.,  5th  ser.,  vol.  2,  1874,  p.  76. 


MINERAL  WELLS  AND  SPRINGS. 


201 


may  also  be  formed  by  volcanic  heat,  sulphur,  either  free  or  derived 
from  sulphides,  first  burning  to  S02,  which  afterward,  in  presence 
of  moisture,  oxidizes  to  H2S04.  It  is  also  to  be  borne  in  mind  that 
aqueous  sulphuric  acid  will  decompose  chlorides,  with  liberation  of 
HC1,  and  this  reaction  also  probably  occurs.  The  acidity  of  a vol- 
canic water,  then,  may  be  due  to  a variety  of  causes,  which  operate 
under  varying  conditions  of  material  and  temperature.  We  may  not 
be  able  to  say  with  certainty  that  a given  water  of  this  class  origi- 
nated in  a given  way,  but  we  can  see  that  the  reactions  which  pro- 
duce it  are  neither  complex  nor  obscure. 

SUMMARY  OF  WATERS. 

From  the  evidence  before  us  the  classification  of  natural  waters 
according  to  their  negative  or  acid  ions  seems  to  be  fully  justified. 
This  question  has  been  partially  discussed  in  previous  chapters;  but 
the  greater  variety  of  composition  shown  by  mineral  springs  enables 
us  now  to  cover  the  ground  much  more  completely.  The  main 
divisions  and  subdivisions  are  as  follows: 

I.  Chloride  waters.  Principal  negative  ion  Cl. 

A.  Principal  positive  ion  sodium. 

B.  Principal  positive  ion  calcium. 

C.  Waters  rich  in  magnesium. 

II.  Sulphate  waters.  Principal  negative  ion  S04. 

A.  Principal  positive  ion  sodium. 

B.  Principal  positive  ion  calcium. 

C.  Principal  positive  ion  magnesium. 

D.  Waters  rich  in  iron  or  aluminum. 

E.  Waters  containing  heavy  metals,  such  as  zinc. 

III.  Sulphato-chloride  waters,  with  S04  and  Cl  both  abundant. 

IV.  Carbonate  waters.  Principal  negative  ion  C03  or  HC03. 

A.  Principal  positive  ion  sodium. 

B.  Principal  positive  ion  calcium. 

C.  Chalybeate  waters. 

V.  Sulphato-carbonate  waters.  S04  and  C03  both  abundant. 

VI.  Chloro-carbonate  waters.  Cl  and  C03  both  abundant. 

VII.  Triple  waters,  containing  chlorides,  sulphates,  and  carbonates  in  equally 
notable  amounts. 

VIII.  Siliceous  waters.  Rich  in  Si02. 

IX.  Borate  waters.  Principal  negative  radicle  B407. 

X.  Nitrate  waters.  Principal  negative  ion  N03. 

XI.  Phosphate  waters.  Principal  negative  ion  P04. 

XII.  Acid  waters.  Contain  free  acids. 

A.  Acid  chiefly  sulphuric. 

B.  Acid  chiefly  hydrochloric. 

This  classification  is  sufficient  for  all  practical  purposes,  although 
it  might  be  subdivided  still  further  in  order  to  cover  certain  excep- 
tional cases,  as,  for  example,  the  feebly  acid  ammonium  sulphate 
water  of  the  Devil’s  Inkpot.  Many  waters  are  obviously  interme- 


202 


THE  DATA  OF  GEOCHEMISTRY. 


diate  in  character,  like  the  brines  containing  both  calcium  and 
sodium,  or  the  sulphates  of  two  or  more  bases  in  something  like 
equally  important  quantities.  In  a classification  based  on  thera- 
peutic considerations  sulphur  waters  would  form  a distinct  group; 
but  sulphides  occur  in  subordinate  amounts,  and  from  a chemical 
point  of  view  are  merely  incidental  impurities.  It  has  already  been 
observed  that  mixtures  can  not  be  classified  rigorously,  a conclusion 
which  it  is  well  to  reiterate  now.  The  classification  of  natural 
waters  is  only  approximate,  and  a matter  of  convenience  rather  than 
of  fixed  principles. 

CHANGES  IN  WATERS. 

When  the  water  of  a spring  emerges  into  the  open  air  it  begins  to 
undergo  changes.  It  may  flow  into  other  waters  and  so  lose  its 
individuality;  it  may  simply  evaporate,  leaving  a saline  residue;  it 
may  react  upon  adjacent  material  and  so  produce  new  substances; 
or,  by  cooling,  it  may  deposit  some  one  or  more  of  its  constituents. 
The  first  of  these  contingencies  admits  of  no  systematic  discussion; 
the  third  will  be  considered  in  the  next  chapter;  the  others  can 
receive  attention  now. 

Alteration  by  loss  of  gaseous  contents  is  observed  in  two  impor- 
tant groups — the  sulphur  waters  and  those  containing  an  excess  of 
carbonic  acid.  Hydrogen  sulphide  partly  escapes  into  the  atmos- 
phere without  immediate  change,  and  part  of  it  is  oxidized,  with 
deposition  of  sulphur  and  the  formation  of  thiosulphates  and  finally 
sulphates,  which  remain  in  solution.  Deposits  of  finely  divided 
sulphur  are  common  around  those  springs  which  emit  hydrogen 
sulphide,  but  they  frequently  contain  other  substances,  such  as 
silica,  calcium  carbonate,  and  ocherous  matter.  Since,  however,  the 
sulphur  is  a product  of  partial  oxidation,  this  change  comes  more 
appropriately  under  the  heading  of  reaction  with  adjacent  material, 
the  latter,  in  this  case,  being  oxygen  derived  from  the  air.  The 
hydrogen  sulphide  itself  may  be  generated  by  the  action  of  acid 
waters  upon  other  sulphides,  but  it  is  more  commonly  produced  by 
the  reduction  of  sulphates  through  the  agency  of  organic  matter, 
and  the  subsequent  decomposition  of  the  resultant  alkaline  com- 
pounds by  carbonic  acid.  The  last  reaction,  however,  as  A.  Bechamp 1 
has  shown,  is  reversible.  Carbon  dioxide  decomposes  solutions  of 
calcium  hydrosulphide;  but,  on  the  other  hand,  hydrogen  sulphide 
can  partly  decompose  solutions  of  calcium  carbonate.  Bicarbonates 
and  sulphides,  therefore,  can  coexist  in  mineral  waters  in  a state  of 
unstable  equilibrium. 


i Annales  chim.  phys.,  4th  ser.,  vol.  16,  1869,  p.  202.  See  also  a recent  physicochemical  discussion  by 
F.  Auerbach,  Zeitschr.  physikal.  Chemie,  vol.  49,  1904,  p.  217. 


MINERAL  WELLS  AND  SPRINGS. 


203 


CALCAREOUS  SINTER. 

With  carbonated  waters  the  changes  due  to  escape  of  gas  are  more 
conspicuous,  at  least  when  calcium,  magnesium,  or  iron  happen  to  be 
the  important  basic  ions.  When  the  “bicarbonic”  ion  HC03  breaks 
up,  losing  carbon  dioxide  to  the  atmosphere,  the  normal  calcium  or 
magnesium  carbonate  is  formed  and,  being  insoluble,  is  precipitated. 
If  we  assume  calcium  bicarbonate  as  existent  in  solution,  the  reaction 
is  as  follows : 

CaH2C206  = CaC03  + H20  + C02 ; 

but  the  change  is  modified  by  other  substances  which  may  be  present, 
and  so  the  product  is  rarely  pure,  nor  is  the  precipitation  absolutely 
complete.  Calcareous  sinter,  tufa,  or  travertine  is  thus  produced, 
and  in  many  localities  it  is  an  important  deposit.  The  carbonate 
waters  of  the  Yellowstone  Park,  for  example,  form  large  bodies  of 
this  character,  and  many  analyses  of  it  have  been  made.  It  is  also 
abundant  in  the  Lahontan  and  Bonneville  basins,  as  mentioned  in 
the  preceding  chapter.  The  following  analyses  of  typical  American 
material  are  sufficient  to  show  its  usual  composition: 

Analyses  of  calcareous  sinters. 

A.  Travertine,  Terrace  Mountain,  Mammoth  Hot  Springs,  Yellowstone  National  Park.  Analysis  by 
E.  A.  Gooch,  Bull.  U.  S.  Geol.  Survey  No.  228,  1904,  p.  323. 

B.  Travertine,  near  Pulsating  Geyser,  Mammoth  Hot  Springs.  Analysis  by  J.  E.  Whitfield,  Bull. 
TJ.  S.  Geol.  Survey  No.  228,  1904,  p.  323.  Other  analyses  of  calcareous  deposits  are  given  in  the  same  publi- 
cation. See  also  W.  H.  Weed,  Ninth  Ann.  Kept.  U.  S.  Geol.  Survey,  1889,  p.  619. 

C.  Lithoid  tufa,  Lahontan  basin,  Nevada.  One  of  three  analyses  by  O.  D.  Allen,  cited  by  I.  C.  Russell, 
Mon.  U.  S.  Geol.  Survey,  vol.  11,  1885,  p.  203. 

D.  Calcareous  tufa,  main  terrace,  Redding  Spring,  Great  Salt  Lake  Desert.  Analysis  by  R.  W.  Wood- 
ward, Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  1,  1878,  p.  502. 


A 

B 

C 

D 

Insoluble 

! 

1.  70 

Si02 

0.  09 

} -11 
55.  37 
.35 
.04 

0.  05 

} -11 
52.  46 
.90 
.71 
.33 

8.  40 
1.  31 
Trace. 
46.  38 
3.  54 
.22 
.48 
Trace. 

ai203 

Fe203 

CaO 

} .25 

50.  48 
2.  88 

MgO 

k2o 

Na20 

Li20 

NaCl 

.10 

1.  45 

Cl 

Trace. 
Trace. 
41.85 
.30 
2.  07 

S03 

.44 
43. 11 

1.  82 
40.  88 

C02 

PXb 

38.  20 
Trace. 
1.  71 

±2Y5 

h2o 

.32 

.17 

1.  02 
.30 

C,  organic 

100. 10 

100.  03 

99.  53 

100.  24 

204 


THE  DATA  OE  GEOCHEMISTEY. 


Analyses  of  several  European  tufas  are  given  by  Roth,1  and  they 
exhibit  many  variations  in  composition.  Ten  calcareous  deposits 
from  the  springs  of  Vichy  were  analyzed  by  J.  Bouquet,2  who  found 
strontium  and  arsenic  in  them.  The  arsenic  ranged  from  a trace  to 
1.16  per  cent  of  As205.  In  the  Carlsbad  “Sprudelstein”  Blum  and 
Leddin  3 also  found  arsenic  to  the  extent  of  0.27  per  cent.  In  a tufa 
from  the  Doughty  Springs,  in  Delta  County,  Colorado,  W.  P.  Head- 
den  4 found  barium  sulphate  ranging  from  a small  amount  up  to  nearly 
95  per  cent.  This  tufa  or  sinter  was  distinctly  radioactive,  and 
probably  contained  traces  of  radium. 

The  commonest  companion  of  calcium  carbonate  in  sinter  is  mag- 
nesium carbonate,  which  is  rarely,  if  ever,  absent.  According  to 
H.  Leitmeier 5 the  springs  of  Lohitsch  in  Styria  deposit  hydrous  car- 
bonate of  magnesium.  The  presence  of  magnesium  salts  in  a water 
favors  the  deposition  of  calcium  carbonate  in  the  form  of  aragonite, 
as  shown  by  F.  Cornu6  and  F.  Vetter.7  Calcite,  however,  is  much 
more  common  in  sinters  than  aragonite.  In  rare  instances  fluorite 
is  deposited.8  Silica  and  ferric  hydroxide  are  also  frequent  con- 
taminations of  tufas.  In  short,  the  calcium  carbonate  precipitated 
from  natural  waters  may  carry  down  with  it  a great  variety  of 
impurities,  which  depend  upon  the  character  of  the  spring. 

OCHEROUS  DEPOSITS. 

When  ferrous  ions  are  present  in  a carbonate  water,  loss  of  carbonic 
acid  is  followed  or  accompanied  by  oxidation,  and  the  precipitated 
material  is  an  ocherous  ferric  hydroxide.  Around  chalybeate  springs 
these  deposits  of  iron  rust  are  always  noticeable.  With  substances 
of  this  character  calcium  and  magnesium  carbonates  are  often  thrown 
down,  and  also  silica,  so  that  the  ochers  from  iron  springs  vary  much 
in  composition.  Between  an  ocher  and  a calcareous  sinter  every 
intermediate  mixture  may  occur.  Sometimes  when  sulphates  have 
been  reduced  by  organic  matter  sulphides  of  iron  are  deposited,  and 
v a number  of  examples  of  this  kind  are  cited  by  Roth.9  The  following 
analyses  will  illustrate  the  usual  character  of  these  sediments. 


1 Allgemeine  und  chemische  Geologie,  vol.  1,  p.  539. 

2 Annales  chim.  phys.,  3d  ser.,  vol.  42, 1854,  p.  332.  For  later  analyses  of  Vichy  deposits,  see  C.  Girard 
and  F.  Bordas,  Compt.  Rend.,  vol.  132,  1901,  p.  1423. 

3 Ann.  Chem.  Pharm.,  vol.  73,  1850,  p.  217. 

4 Proc.  Colorado  Sci.  Soc.,  vol.  8, 1905,  pp.  1-30.  Analyses  of  six  of  the  springs  are  given  in  this  memoir, 
and  several  analyses  of  sinters.  On  the  coexistence  of  barium  and  sulphates  in  mineral  waters  see  P.  Carles, 
Jour.  Chem.  Soc.,  vol.  80  (abstracts),  pt.  2, 1901,  p.  506.  Alkaline  bicarbonates,  with  an  excess  of  CO2,  can 
hold  barium  in  solution,  notwithstanding  the  presence  of  sulphates.  R.  Delkeskamp,  in  Notizbl.  Ver. 
Erdkunde,  4th  ser.,  Heft  21,  p.  47,  has  discussed  the  occurrence  of  barium  in  natural  waters  and  tabulated 
a large  number  of  occurrences.  See  also  J.  White,  Jahresb.  Chemie,  1899,  p.  635,  on  barium  in  artesian 
waters  of  Derbyshire. 

5 Zeitschr.  Kryst.  Min.,  vol.  47,  1909,  p.  104. 

6 Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  vol.  55, 1907,  p.  596. 

7 Zeitschr.  Kryst.  Min.,  vol.  48, 1910,  p.  45. 

8 See  W.  Lindgren,  Econ.  Geology,  vol.  5, 1910,  p.  22. 

sAllgemeine  und  chemische  Geologie,  vol.  1,  pp.  599,  600. 


MINERAL  WELLS  AND  SPRINGS. 


205 


Analyses  of  ocherous  deposits. 

A.  Deposit  from  Driburg,  Germany.  Analysis  by  F.  J.  H.  Ludwig,  Jahresb.  Chemie,  1847-48,  p.  1012. 

B.  Deposit  from  Nauheim,  Germany.  Analysis  by  Ewald,  Jahresb.  Chemie,  1847-48,  p.  1012. 

C.  Deposit  from  Enclos  des  Celestins,  Vichy.  One  of  four  analyses  by  J.  Bouquet,  Annales  chim.  phys., 
3d  ser.,  vol.  42,  1854,  p.  336.  The  “quartz  and  mica,”  of  course,  do  not  belong  with  the  sediment,  but  are 
an  accidental  addition  to  it. 

D.  Deposit  from  Chalybeate  Spring,  Death  Gulch,  Yellowstone  National  Park.  Analysis  by  J.  E. 
Whitfield  in  the  laboratory  of  the  United  States  Geological  Survey.  For  an  analysis  of  water  from  Death 
Gulch,  see  G.  B.  Frankforter,  Jour.  Am.  Chem.  Soc.,  vol.  28,  1906,  p.  714. 


• 

A 

B 

0 

D 

Fe203 

57.  303 

49.  86 

47.  40 

63.  03 

Mn203 

.40 

Trace. 

ALO, 

.08 

CaO 

6.  683 

CaC03 

20.  81 

10.  85 

MgCO, 

6.03 

NaCl,  etc 

2.  59 

so3 

.543 

8.  35 

P90- 

Trace. 

As203 

.063 

AsoCL 

6.  96 

Soluble  Si02 

2.81 

1.  04 
} 25.  72 

1.  37 

H20 

23.  333 

23.53 

Organic  matter 

. 542 

1 26. 94 
J 

Sand 

5.  388 

J 

Quartz  and  mica 

2.  06 

C02  and  loss 

6. 145 

100.  000 

100.  00 

100.  06 

99.  77 

The  deposit  represented  by  analysis  D evidently  contains  an 
admixture  of  a basic  sulphate  of  iron.  A number  of  such  salts  are 
known  among  natural  minerals,  and  are  commonly  formed  by  deposi- 
tion from  chalybeate  solutions.  Their  consideration,  however,  does 
not  belong  in  this  chapter.  Ocherous  deposits  rich  in  manganese 
are  also  known.  For  example,  M.  Weibull1  has  described  a spring 
near  Lund,  in  Sweden,  which  contains  23  milligrams  of  MnO  to  the 
liter  of  water.  From  this,  by  the  action  of  the  organism  Crenothrix 
manganifera , the  manganese  oxide  is  precipitated  in  such  quantities 
as  to  clog  water  pipes. 

SILICEOUS  DEPOSITS. 

Siliceous  deposits  are  formed  by  all  waters  containing  silica,  but 
are  commonly  so  small  as  to  be  inconspicuous.  The  silica  then  ap- 
pears, as  in  the  preceding  tables  of  analyses,  as  an  impurity  in  some- 
thing else.  From  hot  springs,  however,  which  often  contain  silica 
in  large  quantities,  great  bodies  of  sinter  are  produced,  and  this  has 
a composition  approaching  that  of  opal.  Miner alogically,  siliceous 
sinter  is  classed  as  a variety  of  opal,  for  it  consists  mainly  of 

1 Jour.  Chem.  Soc.,  vol.  92,  pt.  2,  1907,  p.  888,  abstract. 


206 


THE  DATA  OF  GEOCHEMISTRY. 


hydrated  silica  with  variable  impurities.  According  to  W.  H.  Weed,1 
who  has  studied  the  formation  of  sinters  in  the  Yellowstone  Park, 
the  deposit  may  be  due  either  to  relief  of  pressure,  to  cooling,  to 
chemical  reactions  between  different  waters,  to  simple  evaporation, 
or  to  the  action  of  algae.  In  the  last  case  the  silica  forms  a gelatinous 
layer  upon  the  algous  growths,  and  this,  after  the  death  of  the  algae, 
gradually  hardens  to  sinter.  The  subjoined  analyses  (A  to  E)  of 
Yellowstone  Park  sinters  are  selected  from  among  fifteen  which  were 
made  by  J.  E.  Whitfield  in  the  laboratory  of  the  United  States  Geo- 
logical Survey.2 

Analyses  of  sinters  from  Yellowstone  Parle,  etc. 

A.  Incrustation,  Excelsior  Geyser  Basin. 

B.  Opal  deposit,  Norris  Basin. 

C.  Compact  sinter,  Old  Faithful  Geyser. 

D.  Deposit  from  Artemisia  Geyser. 

E.  Geyserite  incrustation,  Giant  group.  Upper  Basin. 

F.  Siliceous  sinter,  Steamboat  Springs,  Nevada.  Analysis  by  R.  W.  Woodward,  Rept.  U.  S.  Geol. 
Expl.  40th  Par.,  vol.  2,  1877,  p.  826. 


A 

B 

C 

D 

E 

F 

Si02 

94.40 
} _ .79 

93.  60 

89.  54 

83. 10 

72.  25 

92.  67 

A1203 

1.  06 

2. 12 

6.  02 

10.  96 

Fe90q 

Trace. 

Trace. 

Trace. 

. 7j6 

} . 80 

FeO  . 

.31 

) 

CaO 

None. 

. 50 

1.  71 

.80 

.74 

. 14 

MgO 

None. 

Trace. 

Trace. 

.21 

.10 

.05 

K20  

.30 

. 87 

1.  66 

. 18 

Na^O 

1. 12 

2. 18 

3.  55 

.75 

NaCl 

Trace. 

.36 

H20  « 

C 

5.  02 

4.  71 

5. 13 

6.  73 

9.  02 
.20 

5. 45 

so3 

Trace. 

.28 

.45 

s 

Trace. 

100.  21 

99.  87 

99.  92 

100. 19 

100.  36 

100.04 

a Loss  on  ignition. 


At  Steamboat  Springs  G.  F.  Becker3  found  the  deposits  to  contain 
also  sulphides  of  antimony,  arsenic,  lead,  copper,  and  mercury,  ferric 
hydroxide,  gold,  silver,  and  traces  of  zinc,  manganese,  cobalt,  and 
nickel. 

The  following  analyses  represent  sinters  from  foreign  localities  :4 


1 Am.  Jour.  Sci.,  3d  ser.,  vol.  37,  1889,  p.  351. 

2 Bull.  U.  S.  Geol.  Survey  No.  228,  1904,  pp.  298-299.  A very  exceptional  sinter,  from  a warm  spring  in 
Selangor,  Malay  States,  contains,  with  91.8  per  cent  of  Si02,  0.5  per  cent  of  SnC>2.  See  S.  Meunier,  Compt. 
Rend.,  vol.  110,  1890,  p.  1083.  According  to  W.  R.  Jones  (Geol.  Mag.,  1914,  p.  537),  the  water  of  this 
spring  contains  no  tin. 

3 Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  pp.  343-346. 

4 For  additional  analyses  see  Roth,  Allgemeine  und  chemische  Geologie,  vol.  1,  p.  593. 


MINERAL  WELLS  AND  SPRINGS. 


207 


Analyses  of  sinters  from  foreign  localities. 

G.  Geyserite,  Iceland.  Analysis  by  A.  A.  Damour,  Bull.  Soc.  gdol.  France,  2d  ser.,  vol.  5, 1847-48,  p.  160. 

H.  Deposits  from  the  Scribla  spring,  Icelandic  geysers.  Analysis  by  C.  Bickell,  Ann.  Chem.  Pharm., 
vol.  70,  1849,  p.  293. 

I.  Sinter  from  the  hot  springs  of  Taupo,  New  Zealand.  Analysis  by  J.  W.  Mallet,  Philos.  Mag.,  4th  ser., 
vol.  5,  1853,  p.  285. 

J.  Sinter  from  geysers  of  Rotorua,  New  Zealand.  Analysis  by  J.  E.  Whitfield,  discussed  by  W.  H. 
Weed,  Ninth  Ann.  Rept.  U.  S.  Geol.  Survey,  1889,  p.  619.  Two  other  analyses  are  given  in  this  report. 

K.  Sinter  from  the  Mount  Morgan  gold  mine,  Queensland.  Analysis  by  E.  A.  Schneider,  discussed  by 
W.  H.  Weed  in  Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  166.  This  sinter  is  impregnated  with  auriferous 
hematite.  In  sinters  from  the  geyser  district  of  New  Zealand,  according  to  J.  M.  Maclaren  (Geol.  Mag., 
1906,  p.  511),  there  are  also  appreciable  quantities  of  gold  and  silver. 


G 

H 

I 

j 

K 

SiOo 

87.  67 
} -71 

88.  26 

94.  20 

92.  47 

94.  02 
} 2.27 

ALOq 

. 69 

1.  58 

2.  54 

F e203 

3.  26 

.17 

MgO 

Trace. 

. 15 

Trace. 

CaO 

. 40 

. 29 

Trace. 

.79 

.07 

K20 

Trace. 

. 11 

Na20 

.82 

.11 

NaCl 

.85 

H20 

so, 

10.  40 

4.  79 
2.  49 

3.  06 

3.  99 

3.  36 



100.  00 

100.  00 

99.  86 

99.  94 

99.  72 

The  sinters,  however,  represent  only  the  simplest  form  of  deposit 
from  geysers  and  siliceous  springs.  A great  variety  of  intermediate 
substances,  mixtures  of  silica,  of  hydroxides,  of  carbonates,  sulphates, 
or  arsenates,  and  even  of  sulphur,  have  been  observed,  and  a number 
of  analyses  made  in  the  laboratory  of  the  United  States  Geological 
Survey  by  J.  E.  Whitfield  are  cited  below  as  illustrations  of  this 
fact.  All  the  samples  analyzed  were  collected  in  the  Yellowstone 
National  Park. 


208 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  spring  deposits  from  Yellowstone  Parle. 

A.  Deposit  from  spring  No.  75,  Norris  Basin.  Dried  at  104°. 

B.  Saline  deposit,  Shoshone  Geysers.  Dried  at  104°. 

C.  Sediment  from  Crater  Hill. 

D.  Black  coating,  Fairy  Springs.  Air  dried. 

E.  Deposit  from  Chrome  Spring,  Crater  Hill. 

F.  Sedimentary  deposit  from  Lamar  River. 

G.  Deposit  from  Constant  Geyser.  Described  by  Arnold  Hague  in  Am.  Jour.  Sci.,  3d  ser.,  vol.  34, 1887, 
p.  171.  Contains  scorodite. 

H.  Red,  ocherous  deposit,  Arsenic  Geyser.  Air  dried. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

54.  36 

50.  03 

54. 12 

21.  36 

68.  73 
} 3.66 

29.  23 

49.  83 

41.  20 

ALO, 

5.  90 

2. 15 

18.  03 

3. 11 

Trace. 

4.  74 

9.  53 

FeoO, 

25.  48 

Trace. 

.86 

9. 17 

1.  91 

18.  00 

19.  35 

MnO 

.33 

6. 19 

Mn02 

38.  65 

MgO 

. 17 

Trace. 

Trace. 

. 82 

.29 

.07 

CaO 

1.  86 

Trace. 

.32 

7.  50 

2. 14 

.50 

Na^jO 

1.  30 

24. 18 

.49 

K20 

1.  21 

. 32 

3.  82 

Li20 

None. 

. 24 

H20 

9.  60 

4.  78 

7. 12 

13.  02 

6. 15 

3.  03 

10.  62 

15.  70 

COo 

12.  92 

S03' 

5.  40 

15.  41 

.09 

.24 

s 

18.  79 

64.  29 

As205 

.28 

None. 

17.  37 

14.  08 

C,  organic 

1.  04 

100.  49 

100.  02 

100.  27 

99.  91 

99.  76 

100.  07 

100.  56 

100. 10 

Analyses  Gr  and  H are  especially  interesting,  for  they  represent 
the  deposition  of  scorodite,  FeAs04.2H20.  This  occurs  still  more  per- 
fectly at  Josephs  Coat  Springs,  in  the  Yellowstone  Park,  where  the 
mineral  has  been  separated  from  an  incrustation  and  identified. 1 
The  manganese  in  D and  the  sulphur  in  E and  F are  also  worthy  of 
notice.  When  we  consider  that  in  addition  to  these  precipitates 
many  saline  compounds  are  produced  by  the  simple  evaporation  of 
waters,  we  see  that  the  range  of  possibilities  must  be  very  great. 
When  a water  has  become  sufficiently  concentrated  to  begin  the 
deposition  of  solid  matter,  every  change  in  concentration  or  temper- 
ature introduces  a new  set  of  conditions  which  determine  the  nature 
of  the  compounds  to  be  formed.  The  complexity  of  the  problems 
which  thus  originate  will  become  more  evident  when  we  study  the 
subject  of  saline  residues.  It  is  clear,  from  the  nature  of  the  prod- 
ucts thus  far  considered,  that  in  a complex  water  several  reactions 
may  take  place  simultaneously,  a number  of  substances  being 
thrown  down  at  the  same  time.  If  a water  carrying  much  iron 
and  much  calcium  loses  hydrogen  sulphide  and  carbonic  acid,  then 
ferric  hydroxide,  calcium  carbonate,  and  sulphur  will  be  deposited 

i A.  Hague,  Am.  Jour.  Sci.,  3d  ser.,  vol.  34, 1887,  p.  171.  See  also  J.  E.  Whitfield,  Bull.  U.  S.  Geol.  Sur- 
vey No.  55,  18S9,  p.  65. 


MINERAL  WELLS  AND  SPRINGS. 


209 


together,  each  change  being  independent  of  the  others.  In  such 
cases  the  complexity  of  reaction  is  apparent  only  and  not  real. 
The  reactions  are  all  simple  and  easily  understood.  When  salts  are 
formed  by  evaporation  of  a water,  the  interpretation  of  the  phenomena 
is  more  difficult. 

REACTIONS  WITH  ADJACENT  MATERIAL. 

The  reactions  of  natural  waters  in  contact  with  adjacent  materials 
are  of  many  different  kinds.  We  have  already  seen  how  oxygen 
from  the  atmosphere  may  convert  ferrous  into  ferric  compounds  and 
sulphides  into  sulphates,  but  reducing  agents  also  must  be  taken  into 
account.  The  sulphates  of  a water,  by  accession  of  organic  matter, 
can  be  partly  or  entirely  reduced  to  sulphides,  and  carbonic  acid, 
acting  upon  the  latter,  may  expel  sulphureted  hydrogen  and  produce 
carbonates.  By  reactions  of  that  kind  a water  can  undergo  a com- 
plete change  of  type  and  pass  from  one  class  into  another. 

Acid  waters,  especially  when  hot,  act  vigorously  on  the  substances 
with  which  they  come  in  contact,  producing  soluble  chlorides  or  sul- 
phates according  to  their  character.  Hydrochloric  acid  forms  the 
one  set  of  salts,  sulphuric  acid  the  other.  The  extent  of  the  reactions 
will  of  course  depend  upon  the  kind  of  material  attacked,  for  some 
minerals  and  rocks  are  much  more  soluble  than  others.  The  carbon- 
ate rocks  are  naturally  the  most  attackable,  but  no  rock  is  entirely 
exempt  from  changes  of  this  order.  When  we  remember  that  even 
pure  and  cold  water  exerts  a solvent  action  upon  many  silicates,  we 
can  see  how  violently  corrosive  a hot,  acid,  volcanic  water  must  be. 
Wherever  waters  of  this  class  occur  the  surrounding  rocks  are  more 
or  less  decomposed,  calcium,  magnesium,  alkalies,  and  iron  being 
dissolved  out,  while  silica  and  hydrous  aluminum  silicates  remain 
behind.  As  the  water  cools  and  as  the  acid  becomes  neutralized  its 
activity  decreases,  and  its  peculiar  characteristics  gradually  disappear. 
An  ordinary  saline  or  astringent  water  is  the  product  of  these  changes, 
which  take  place  most  rapidly  when  the  active  solutions  are  concen- 
trated and  hot  and  more  slowly  in  proportion  as  they  are  diluted  or 
cooled. 

Waters  containing  free  sulphuric  or  hydrochloric  acid  are,  however, 
relatively  rare,  and  their  geological  importance  is  small  compared 
with  that  of  carbonated  solutions.  Meteoric  waters  carrying  free 
carbonic  acid  are  probably  the  most  powerful  of  agents  in  the  solution 
of  rocks,  although  their  chemical  activity  is  neither  violent  nor  rapid. 
Being  continually  replenished  from  the  storehouse  of  the  atmosphere, 
their  work  goes  on  unceasingly  over  a large  portion  of  our  globe. 
The  calcium  which  they  extract  from  rocks  is  carried  by  rivers  to  the 
sea  and  is  finally  deposited  in  the  form  of  limestones.  Springs  and 
97270°— Bull.  616—16 14 


210 


THE  DATA  OF  GEOCHEMISTRY. 


underground  waters  charged  with  carbonic  acid  exert  the  same  sol- 
vent action,  but  locally  and  in  different  degree.  We  have  seen  that 
many  springs  are  so  heavily  loaded  with  carbonic  acid  that  they 
effervesce  when  issuing  into  the  air,  and  such  waters  are  peculiarly 
potent  in  effecting  the  solution  of  limestones.  By  percolating  waters 
of  this  class  limestone  caverns  are  made,  and  part  of  the  substance 
dissolved  is  redeposited  as  stalactite  or  stalagmite.  In  reactions  of 
this  kind  the  general  character  of  a water  is  not  changed;  it  may  be 
a calcium  carbonate  water  throughout  its  course,  varying  only  in 
gaseous  content  and  in  concentration,  and  its  chemical  effectiveness 
is  shown  by  its  work  as  a carrier  in  transporting  from  one  point  to 
another  the  material  that  it  has  dissolved.1 

Alkaline  waters,  especially  thermal  waters  of  the  sodium  carbonate 
class,  are  also  active  solvents  of  mineral  substances.  Their  tendency, 
however,  is  opposite  to  that  of  the  acid  waters,  for  they  dissolve  silica 
rather  than  bases,  and  act  as  precipitants  for  magnesia  and  lime. 
When  solutions  of  calcium  sulphate  and  sodium  carbonate  are  com- 
mingled, calcium  carbonate  is  thrown  down  and  an  equivalent  amount 
of  sodium  sulphate  remains  dissolved.  Since  natural  waters  are 
rarely,  if  ever,  chemically  equivalent,  reactions  of  this  sort  between 
them  are  necessarily  incomplete,  and  the  blended  solutions  will  con- 
tain one  group  of  ions  in  excess  over  the  other.  Thus  a water  of 
mixed  type  is  produced,  but  the  mixture  is  not  an  average  of  the 
two  solutions,  for  part  of  their  original  load  has  been  removed.  This 
is  a simple  case  of  reaction,  but  it  may  be  complicated  in  various 
ways,  and  even  reversed.  For  instance,  a solution  of  sodium  sul- 
phate in  presence  of  free  carbonic  acid  will  dissolve  calcium  car- 
bonate, forming  sodium  bicarbonate  and  a precipitate  of  gypsum. 
E.  W.  Hilgard 2 has  investigated  this  transformation,  and  regards 
it  as  the  principal  source  of  alkaline  carbonate  solutions  in  nature. 
Furthermore,  mineral  substances  with  which  alkaline  waters  come  in 
contact  may  be  profoundly  modified,  as  at  the  thermal  springs  of 
Plombieres  in  France.  Here,  according  to  Daubree,3  the  brickwork 
and  masonry  of  the  ancient  Roman  baths  have  been  strongly  attacked 
with  the  production  of  hyalite  and  a number  of  zeolitic  minerals. 

Many  mineral  springs  contain  organic  matter,  presumably  in  the 
form  of  the  so-called  humus  acids,  but  the  influence  exerted  by  these 
substances  is  more  pronounced  in  swamp  and  river  waters.4  Their 

1 On  the  magnitude  of  erosion  by  subterranean  waters  see  H.  Schardt,  Bull.  Soc.  neuchateloise  sci. 
nat.,  vol.  33,  1907,  p.  168. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  2, 1896,  p.  100. 

3 Etudes  synthetiques  de  geologie  experimental,  1879,  pp.  179  et  seq.  Other  localities  at  which  similar 
changes  have  been  observed  are  also  described.  The  Plombieres  water  is  said  to  be  a very  dilute  solution 
of  alkaline  silicates,  but  its  exact  composition  is  not  given  by  Daubree.  Analyses  of  six  waters  from  Plom- 
bi&res  can  be  found  in  Les  eaux  m morales  de  la  France,  by  E.  Jacquot  and  E.  Willm,  Paris,  1894,  p.  224. 
They  confirm  Daubree ’s  statement. 

4 See  Chapter  III  for  details  on  this  subject.  Also  A.  A.  Julien,  Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  28, 
1879,  p.  311. 


MINERAL  WELLS  AND  SPRINGS. 


211 


supposed  solvent  action  upon  rocks  and  soils  has  already  been 
noticed,  as  well  as  their  alleged  efficiency  in  retaining  silica  in  solution. 
Against  these  suppositions  I may  cite  an  observation  by  C.  A.  Davis 
in  the  United  States  Geological  Survey,  that  the  peat  of  the  Dismal 
Swamp  contains  the  siliceous  skeletons  of  diatoms  whose  outlines 
are  still  perfectly  sharp,  without  the  slightest  trace  of  blurring.  This 
observation  has  been  confirmed  by  Chase  Palmer.  The  water 
saturating  the  peat  contains  much  dissolved  organic  matter,  which 
colors  it  strongly  brown,  and  also  contains  floating  diatoms. 

Furthermore,  iron  and  alumina  may  be  removed  from  sulphate  or 
chloride  waters  by  the  action  of  limestones.  If  the  iron  is  in  the 
ferrous  state,  it  must  first  be  oxidized  to  the  ferric  condition.  Then, 
by  means  of  calcium  carbonate,  both  of  the  bases  named  can  be  pre- 
cipitated, either  as  hydroxides  or  as  basic  sulphates.  Insoluble  com- 
pounds of  the  latter  class  are  often  formed  from  natural  waters,  and 
many  mineral  species  are  of  that  character.  It  is  quite  probable  that 
limestone  is  also  effective  in  removing  other  heavy  metals  from  their 
solutions;  copper,  for  example,  is  certainly  thrown  down,  but  these 
reactions  need  to  be  more  fully  investigated.  Their  consideration 
must  be  deferred  until  we  reach  the  subject  of  metalliferous  deposits. 

Finally,  the  character  of  a water  may  be  greatly  changed  by  simple 
percolation  through  the  soil.  That  potassium  is  thus  removed  from 
natural  waters  has  long  been  known,  and  reference  to  this  fact  was 
made  in  a previous  chapter.  Experiments  by  J.  T.  Crawley  and 
R.  A.  Duncan1  on  Hawaiian  soils  show  that  a layer  6 inches  thick 
will  fix  over  98  per  cent  of  the  potassium  in  a solution  of  potassium 
sulphate  which  is  allowed  to  filter  through  it,  and  the  retention  of 
phosphoric  acid  and  ammonia  is  even  more  complete.  According  to 
J.  M.  van  Bemmelen,2  basic  zeolitic  silicates  are  the  chief  agents  in 
effecting  the  retention  of  potassium,  exchanging  other  bases  for  it 
by  double  decomposition,  but  the  existence  of  such  compounds  in  the 
soil  is  not  well  established.  Hydrous  aluminum  silicates  may  be  the 
effective  absorbents,  or,  in  the  case  of  phosphoric  acid,  the  hydroxides 
of  aluminum  and  iron.  After  potassium  and  ammonium,  Van  Bem- 
melen finds  that  magnesium  is  most  readily  absorbed,  then  sodium, 
and  calcium  least  of  all.  It  is  clear,  however,  that  the  nature  of  the 
soil  must  be  taken  into  account.  A sandy  soil  or  an  impervious  clay 
would  be  less  effective  in  removing  saline  substances  from  water  than 
a loose  loam  rich  in  hydrous  basic  compounds.  The  fact  that  sub- 
stances are  taken  from  waters  by  soils  is  certain,  but  the  extent  of 
the  absorption  depends  upon  local  conditions.  It  is  also  certain  that 
potassium,  rather  than  sodium,  is  thus  withdrawn  from  aqueous 
circulation. 


1 Jour.  Am.  Chem.  Soc.,  vol.  25,  1903,  p.  47.  See  also  vol.  24, 1902,  p.  1114. 

2 Landw.  Versuchs-Stationen  (Berlin),  vol.  21,  p.  135. 


212 


THE  DATA  OF  GEOCHEMISTRY. 


A careful  consideration  of  all  the  evidence  concerning  mineral 
springs  will  show  that  it  is  exceedingly  difficult  to  generalize  on  rela- 
tions between  the  composition  of  a water  and  its  geological  history. 
Reactions  which  take  place  deep  within  the  earth  can  not  easily 
be  traced,  especially  as  a water  may  undergo  various  modifications 
before  it  reaches  the  surface.  A spring  may  be  a blend  from  different 
sources — either  a direct  mixture  or  a solution  from  which  ingredients 
have  been  removed — and  it  is  only  in  specific  cases  that  a simple 
interpretation  of  the  phenomena  can  be  found.  The  water  that  rises 
from  a salt  bed  or  from  gypsum  is  easily  understood,  and  so  also  is 
one  which  carries  sulphates  derived  from  pyritiferous  shales.  The 
Hunyadi  Janos  water  is  obtained  from  wells  sunk  near  a mass  of 
pyritiferous  dolomite,  and  therefore  its  high  proportion  of  mag- 
nesium sulphate  is  readily  intelligible.  We  can  see  that  a water  from 
granite  must  differ  greatly  from  one  issuing  out  of  limestone,  and 
Hanamann’s  analyses  of  the  Bohemian  rivers  illustrate  this  order  of 
dissimilarity.  Many  regularities  can  be  traced,  but  no  general  prin- 
ciple can  be  deduced  from  them.  For  example,  A.  De  Lapparent 1 
shows  that  solfataras  are  most  common  in  regions  of  highly  siliceous 
eruptive  rocks,  such  as  rhyolites,  andesites,  etc.,  a condition  which 
he  attributes  to  the  inferior  fluidity  of  the  volcanic  magmas  and  the 
consequently  greater  retention  of  gaseous  contents  by  them.  In  areas 
of  subsilicic  rock  solfataras  rarely  or  never  occur. 

Various  attempts  have  been  made  to  correlate  the  composition  of 
waters  with  the  geological  horizons  from  which  they  flow.  For 
spring  waters  such  attempts  are  of  little  value,  because  two  springs, 
side  by  side,  may  be  widely  different.  In  the  case  of  artesian  wells 
the  problem  is  perhaps  simpler,  for  there  the  horizon  can  be  de- 
termined. Artesian  waters  of  common  origin  often  show  a family 
likeness  to  one  another,  especially  in  their  minor  constituents,  one 
group  being  always  calciferous,  another  relatively  rich  in  bromine, 
and  so  on.2  But  no  law  can  be  framed  to  cover  even  these  regularities, 
for  the  exceptional  waters  are  too  numerous  and  too  confusing.  That 
waters  from  sedimentary  rocks  are,  as  a rule,  more  concentrated  and 
perhaps  more  complex  than  those  from  the  older  crystalline  forma- 
tions is  doubtless  true;  but  beyond  that  it  is  hardly  safe  to  generalize. 
It  is  better  to  discuss  each  water  by  itself,  and  so  seek  to  interpret 
its  individual  history. 

1 Compt.  Rend.,  vol.  108, 1889,  p.  149. 

2 A.  C.  Lane  (Water-Supply  Paper  U.  S.  Geol.  Survey  No.  31,  1899)  classifies  the  Michigan  waters  with 
reference  to  their  origin,  and  points  out  various  similarities  connected  with  identity  of  horizon.  On  the 
chemical  relations  between  spring  waters  and  the  rocks  from  which  they  issue,  see  M.  Dittrich,  Mitth. 
Badisch.  geol.  Landesanstalt,  vol.  4, 1901,  p.  199. 


MINERAL  WELLS  AND  SPRINGS. 


213 


YADOSE  AND  JUVENILE  WATERS.1 

Whether  it  is  possible  to  discriminate  between  waters  of  superficial 
or  vadose  origin  and  magmatic  or  deep-seated  waters  is  a question 
for  geology  to  answer.  Until  quite  recently  the  prevalent  opinion 
has  been  that  all  spring  waters,  including  those  emitted  by  geysers, 
were  originally  meteoric.  Modern  investigations  into  volcanism  and 
upon  the  subject  of  metalliferous  veins  have,  however,  led  to  a 
reopening  of  the  question.  E.  Suess,2  speaking  with  especial  refer- 
ence to  the  thermal  springs  of  Carlsbad,  has  advanced  strong  argu- 
ments to  show  that  waters  of  this  class  are  “ juvenile”  and  now  see 
the  light  of  day  for  the  first  time — that  is,  they  issue  from  deep 
within  the  earth,  from  the  fundamental  magma  itself,  and  bring  up 
veritable  additions  to  the  hydrosphere.  These  magmatic  waters, 
furthermore,  are  regarded  by  some  authorities  as  the  carriers  of 
metallic  salts,  by  which  certain  kinds  of  metalliferous  veins  have  been 
filled.3 

This  subdivision  of  springs  into  vadose,  or  those  which  represent 
original  infiltrations  of  surface  waters,  and  juvenile,  as  Suess  terms 
them,  has  had  wide  but  not  universal  acceptance.  A difficulty  in 
applying  the  proposed  nomenclature  arises  from  the  fact  that  it  is  not 
easy  to  determine  where  a given  water  belongs.  Armand  Gautier,4 
however,  has  pointed  out  several  criteria  which  may  make  discrimi- 
nation possible.  He  shows  that  vadose  waters,  or  waters  of  infiltra- 
tion, are  characterized  by  fluctuations  in  composition,  concentra- 
tion, and  rate  of  flow,  depending  upon  local  and  variable  conditions, 
such  as  abundant  rain  or  drouth.  They  also  contain,  as  a rule, 
carbonates  of  lime  or  magnesia,  chlorides,  and  sulphates.  Virgin  or 
juvenile  waters,  on  the  contrary,  are  fairly  constant  in  all  essential 
particulars,  and  carry  sodium  bicarbonate,  alkaline  silicates,  heavy 
metals,  etc.,  as  chief  constituents,  with  chlorides  or  sulphates  only 
as  accessories,  and  practically  no  carbonates  of  the  alkaline  earths. 
The  vadose  waters,  moreover,  issue  from  faults  having  no  relation  to-, 
the  metallic  veins  of  the  surrounding  territory — a lack  of  relation, 
which  is  conspicuous  as  regards  juvenile  springs.  Gautier  holds 

1 The  term  “connate”  is  also  used  to  some  extent  to  describe  buried  or  fossil  waters.  The  calcium 
chloride  waters  of  the  Lake  Superior  region  have  been  assigned  to  this  class. 

2 In  Verhandl.  Gesell.  Deutsch.  Naturforscher  und  Arzte,  1902.  Abstract  in  Geog.  Jour.,  vol.  20,  p.  520 
1902.  On  the  other  hand,  see  E.  H.  L.  Schwarz,  Geol.  Mag.,  1904,  p.  252;  and  J.  M.  Maclaren,  idem,  1906, 
p.  511.  These  writers  regard  the  hot  waters  of  Africa  and  New  Zealand  as  originally  vadose.  The  same 
conclusion  is  reached  by  Arnold  Hague  relative  to  the  geyser  waters  of  the  Yellowstone  National  Park. 
See  Scribner’s  Mag.,  May,  1904,  p.  513,  and  Trans.  Am.  Inst.  Min.  Eng.,  vol.  16,  1887,  p.  783;  also  his  presi- 
dential address  in  Bull.  Geol.  Soc.  America,  vol.  22, 1911,  p.  103,  and  Science,  vol.  33,  p.  555. 

3 See  for  example,  W.  Lindgren,  Eng.  and  Min.  Jour.,  vol.  79,  1905,  p.  460.  Also  A.  C.  Spencer,  Trans. 
Am.  Inst.  Min.  Eng.,  vol.  35,  1905,  p.  473;  vol.  36,  1906,  p.  364. 

4 Compt.  Rend.,  vol.  150,  1910,  p.  436.  Other  papers  bearing  on  this  subject,  and  on  the  origin  of  the 
carbon  dioxide  of  mineral  waters  are  by  R.  Delkeskamp,  Zeitschr.  gesammte  Kohlensaure-Industrie,  1906, 
Nos.  18-21;  L.  De  Launay,  Annales  des  mines,  10th  set.,  vol.  9,  1906,  p.  5;  F.  Henrich,  Zeitschr.  prakt. 
Geologie,  1910,  p.  85;  and  O.  Stutzer,  idem,  p.  346. 


214 


THE  DATA  OF  GEOCHEMISTRY. 


that  hydrogen  emitted  from  the  hot  interior  of  the  earth  acts  as 
a reducing  agent  upon  metallic  oxides  and  so  forms  the  magmatic 
water  of  the  springs.  With  the  water  thus  generated,  other  water, 
that  of  constitution  from  minerals  like  the  micas,  is  commingled. 

THERMAL  SPRINGS  AND  VOLCANISM. 

The  work  of  Gautier  just  cited  is  intimately  related  to  an  earlier 
memoir,1  in  which  the  close  connection  between  volcanism  and  the 
formation  of  thermal  springs  is  shown.  His  work  will  be  consid- 
ered more  in  detail  in  a later  chapter,  hut  his  general  conclusions 
may  be  cited  now.  When  a crystalline  rock,  like  granite,  is  heated 
to  redness  in  vacuo,  water  and  gases,  the  latter  identical  in  character 
with  the  volcanic  gases,  are  given  off.  For  instance,  to  cite  the  least 
significant  example,  1 cubic  kilometer  of  granite  can  yield  from  25 
to  30  millions  of  metric  tons  of  water,  which  at  1,100°  would  form 
160,000,000,000  cubic  meters  of  steam.  In  addition  to  this  enormous 
volume  of  vapor  28,000,000,000  cubic  meters  of  other  gases  would  be 
emitted.  Suppose,  now,  that  by  fissuring  and  subsidence  in  the  litho- 
sphere such  a mass  of  rock  were  carried  down  to  a depth  of  25,000  to 
30,000  meters.  It  would  then  be  in  the  heated  region,  and  the  evolu- 
tion of  vapors  under  great  pressures  would  occur.  To  some  such 
changes  Gautier  ascribes  the  phenomena  of  volcanism,  with  all  its 
development  of  solfataras  and  fumaroles.  Ordinary  thermal  springs 
may  be  formed  by  the  same  process,  operating,  perhaps,  less  violently, 
and  originate,  so  to  speak,  from  a sort  of  distillation  of  the  combined 
water  contained  in  the  depressed  masses  of  rock.  In  an  earlier 
memoir  2 Gautier  has  shown  that  granite,  heated  with  water  in  a 
sealed  tube  to  a temperature  between  250°  and  300°,  yields  solutions 
containing  sulphur  compounds  and  resembling  the  sulphur  waters  of 
hot  springs.  This  sulphur  he  ascribes,  not  to  the  decomposition  of 
metallic  sulphides,  but  to  reactions  upon  sulphosilicates,  a class  of 
compounds  represented  in  nature  by  hauynite  and  lazurite,3  and  also 
by  certain  artificial  substances  which  Gautier  himself  has  prepared. 
He  also  supposes  that  carbon  oxysulphide,  COS,  may  be  formed  in  the 
terrestrial  nucleus,  possibly  from  carbon  monoxide  generated  by  reac- 
tions between  oxides  and  metallic  carbides.  Here  he  enters  the  field 
of  speculation,  where  it  is  not  necessary  for  us  to  follow  him.  The 
reactions  which  he  has  experimentally  established  are  sufficiently 
suggestive,  and  his  broad  general  conclusions  are  entitled  to  the  most 
respectful  consideration. 

1 Annales  des  mines,  10th  ser.,  vol.  9, 1906,  p.  316.  A good  abstract  by  F.  L.  Ransome  is  given  in  Econ. 
Geology,  vol.  1,  1906,  p.  688. 

2Compt.  Rend.,  vol.  132,  1901,  p.  740. 

3 Helvite  and  danalite  are  other  natural  sulphosilicates  which  might  easily  take  part  in  the  supposed 
reactions. 


MINERAL  WELLS  AND  SPRINGS. 


215 


And  yet,  notwithstanding  all  that  has  been  written  on  the  subject, 
the  controversy  over  the  genesis  of  hot  springs  is  not  closed.  What 
is  the  origin  of  the  carbon  dioxide  with  which  so  many  mineral 
waters  are  heavily  charged?  In  some  instances,  doubtless,  it  is 
derived  from  the  decomposition  of  limestones,  but  in  others  this  expla- 
nation can  not  suffice.  Here  and  there  it  may  be,  to  use  Suess’s 
expression,  “juvenile,”  and  evidence  of  the  deep-seated  origin  of  a 
spring.1  Again,  whence  comes  the  sodium  chloride  of  waters  that 
flow  from  sources  where  it  could  not  have  been  previously  laid  down  ? 
These  questions  and  others  like  them  still  await  satisfactory  answers. 
With  mere  suppositions,  however  plausible  they  may  seem,  we  can  not 
be  content. 

A word  in  conclusion  on  the  radioactivity  of  spring  waters.  A very 
large  number  of  such  waters  possess  this  property,  but  no  distinction 
between  vadose  and  juvenile  waters  can  be  based  upon  the  observa- 
tions. Waters  of  both  classes  are  radioactive,  but  the  phenomenon 
is  perhaps  most  common  among  waters  of  volcanic  origin,  or  at  least 
among  thermal  springs.  In  the  United  States  the  Hot  Springs  of 
Arkansas  have  been  studied  by  B.  B.  Bolt  wood. 2 The  springs  of 
Missouri 3 and  the  Yellowstone  National  Park 4 were  investigated  by 
H.  Schlundt  and  B.  B.  Moore.  In  each  of  these  researches  radio- 
activity was  generally  detected,  but  with  varying  intensity  within  the 
same  group  of  springs.  On  the  radioactivity  of  European  waters 
there  is  a copious  literature. 

BIBLIOGRAPHIC  NOTE. 

The  following  collections  of  water  analyses  will  be  found  useful  for 
reference : 

F.  Raspe.  Heilquellen-Analysen,  Dresden,  1885.  A very  large  collection  of  analyses, 
mainly  of  European  mineral  waters. 

T.  E.  Thorpe.  Dictionary  of  applied  chemistry,  article  “Water,  ” vol.  3,  pp.  952-959, 
1893.  Tables  of  analyses  of  European  mineral  springs.  The  same  article  gives 
much  information  about  other  waters. 

J.  K.  Crook.  The  mineral  waters  of  the  United  States,  New  York  and  Philadelphia, 
1899. 

A.  C.  Peale.  The  mineral  springs  of  the  United  States:  Bull.  U.  S.  Geol.  Survey 
No.  32,  1886. 

F.  A.  Gooch  and  J.  E.  Whitfield.  Analyses  of  waters  of  the  Yellowstone  National 
Park:  Bull.  U.  S.  Geol.  Survey  No.  47,  1888. 

E.  Orton.  Rock  waters  of  Ohio:  Nineteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  4, 
1898,  p.  633.  Contains  many  analyses  of  deep  wells  from  various  horizons. 

W.  H.  Norton.  Artesian  wells  of  Iowa:  Iowa  Geol.  Survey,  vol.  6,  1896,  pp.  117-428. 


1 On  vadose  and  juvenile  carbonic  acid  in  waters,  see  an  elaborate  discussion  by  It.  Delkeskamp, 
Zeitschr.  prakt.  Geologie,  1906,  p.  33;  reviewed  by  W.  Lindgren,  Econ.  Geology,  vol.  1,  1906,  p.  602. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  20, 1905,  p.  168. 

3 Trans.  Am.  Electrochem.  Soc.,vol.8,  1905,  p.  291.  Schlundt,  Jour.  Phys.Chem.,  vol.  18,  p.663,1914, 
has  also  studied  the  radioactivity  of  Colorado  springs. 

* Bull.  U.  S.  Geol.  Survey  No.  395,  1909. 


216 


THE  DATA  OF  GEOCHEMISTRY. 


J.  H.  Shepherd.  Artesian  wells  of  South  Dakota:  Bull.  Agr.  Exper.  Sta.  South 
Dakota,  No.  41,  1895. 

J.  C.  Branner.  Mineral  waters  of  Arkansas:  Ann.  Kept.  Geol.  Survey  Arkansas, 
1891,  vol.  1. 

E.  H.  S.  Bailey  and  others.  The  mineral  waters  of  Kansas:  Kansas  Univ.  Geol. 
Survey,  vol.  7,  1902. 

P.  Schweitzer.  A report  on  the  mineral  waters  of  Missouri:  Geol.  Survey  Missouri, 
vol.  3,  1892. 

W.  S.  Blatchley.  The  mineral  waters  of  Indiana:  Twenty-sixth  Ann.  Kept.  Indiana 
Dept.  Geology  and  Nat.  Resources,  1901,  pp.  11-225. 

A.  C.  Lane.  The  mineral  waters  of  lower  Michigan:  Water-Supply  Paper  U.  S.  Geol. 
Survey  No.  31,  1899. 

S.  W.  McCallie.  Preliminary  report  on  the  mineral  springs  of  Georgia:  Bull.  Geol. 
Survey  Georgia  No.  20,  1913. 

W.  Anderson.  Mineral  springs  and  health  resorts  of  California,  San  Francisco,  1892. 

Contains  many  analyses,  the  greater  number  of  them  by  the  author. 

G.  A.  Waring.  Springs  of  California:  U.  S.  Geol.  Survey  Water-Supply  Paper  No. 
338,  1914. 

L.  De  Launay.  Recherche,  captage  et  amenagement  des  sources  thermominerales, 

Paris,  1899. 

A.  Carnot  and  others.  Analyses  of  French  and  colonial  mineral  waters:  Annales  des 
mines,  8th  ser.,  vol.  7,  1885,  p.  79;  9th  ser.,  vol.  6,  1894,  p.  355;  vol.  16,  1899, 
p.  33.  These  three  papers  contain  584  analyses. 

E.  Jacquot  and  E.  Willm.  Les  eaux  minerales  de  la  France,  Paris,  1894.  Many 
analyses  and  descriptions  of  the  springs. 

Guyon.  Etudes  sur  les  eaux  thermales  de  la  Tunisie,  Paris,  1864. 

M.  Hanriot.  Les  eaux  minerales  de  l’Algerie,  Paris,  1911. 

A.  Raimondi.  Aguas  minerales  del  Peru:  El  Peru,  estudios  mineralogicos  y geologicos, 
vol.  4,  19Q2,  pp.  235-394. 

L.  Darapsky.  Aguas  minerales  de  Chile,  Valparaiso,  1890. 

E.  H.  Ducloux.  Aguas  minerales  alcalinas  de  la  Republica  Argentina:  Revista 
Museo  de  la  Plata,  vol.  14,  pp.  9-52,  1907.  Other  analyses  are  in  vol.  16,  pp. 
51-120,  1909. 

E.  Abella  y Casariego  and  J.  De  Vera  y Gomez.  Estudio  descriptivo  de  algunas 
manantiales  minerales  de  Filipinas,  Manila,  1893. 

A.  Liversidge,  W.  Skey,  and  G.  Gray.  Rept.  Australasian  Assoc.  Adv.  Sci.,  1898, 
pp.  87-108.  A collection  of  analyses  of  Australasian  mineral  waters. 

R.  Ishiztj,  The  mineral  springs  of  Japan.  Tokyo,  1915. 

Deutsches  Baderbuch.  Leipzig,  1907.  A compendium  of  information  relative  to 
the  mineral  springs  of  Germany. 

Many  other  analyses  of  waters  are  scattered  through  the  periodical 
literature  of  chemistry,  geology,  pharmacy,  and  medicine,  and  the 
reports  of  geological  surveys.  The  publications  of  agricultural  experi- 
ment stations  also  contain  much  material  relative  to  artesian,  well, 
spring,  ground,  and  drainage  waters.  Daubree’s  three  volumes  on 
“Les  eaux  souterraines ” contain  few  analyses,  but  much  information 
upon  mineral  springs.  T.  Sterry  Hunt,  in  his  “Chemical  and  geolog- 
ical essays,”  also  has  much  to  say  upon  the  origin  of  natural  waters 
and  their  chemical  relations  to  one  another.  Bulletins  91  and  139 
of. the  Bureau  of  Chemistry,  United  States  Department  of  Agricul- 
ture, contain  many  analyses  of  American  mineral  waters. 


CHAPTER  VII. 

SALINE  RESIDUES. 

DEPOSITION  OF  SALTS. 

When  a natural  water  is  concentrated  by  evaporation  it  deposits 
its  saline  constituents  in  the  reverse  order  of  their  solubility,  the  least 
soluble  first,  the  most  soluble  last  of  all.  The  process,  however,  is 
not  so  simple  as  it  might  appear  to  be,  for  the  solubility  of  a salt  in 
pure  water  is  one  thing  and  its  solubility  in  the  presence  of  other 
compounds  is  another.  Each  substance  is  affected  by  its  associates, 
and  its  deposition  is  partly  a matter  of  concentration  and  partly  a 
question  of  temperature.  In  general,  the  character  of  a saline  deposit 
can  be  predicated  from  the  character  of  the  water  which  yields  it; 
a chloride  water  gives  chlorides,  a sulphate  water  sulphates,  and 
waters  of  mixed  type  furnish  mixtures  of  compounds  or  even  double 
salts.  The  more  complex  the  water  the  greater  becomes  the  range 
of  possibilities. 

We  have  already  seen,  in  our  studies  of  river,  sea,  and  spring 
waters  what  a variety  of  reactions  lead  to  the  deposition  of  insoluble 
sediments.  By  this  expression  I do  not  mean  sediments  of  suspended 
matter,  like  clays,  but  precipitates  from  solution,  such  as  sulphur, 
hydroxide  of  iron,  sinters,  tufas,  and  so  on.  These  substances  repre- 
sent something  more  than  the  results  of  simple  evaporation,  for  they 
are  produced  by  chemical  changes,  like  oxidation,  loss  of  carbonic 
acid,  etc.  We  have  now  to  consider  the  consequences  of  evaporation 
itself,  and  of  the  opposite  process,  re-solution,  in  which  nothing  is 
added  to  or  taken  away  from  the  reacting  system  but  water,  except 
in  so  far  as  the  soluble  salts  are  successively  deposited  and  so  removed 
from  the  sphere  of  chemical  change.  In  salt  and  alkaline  lakes  we 
can  recognize  several  stages  of  this  process — the  precipitation  of  the 
relatively  insoluble  calcium  sulphate,  then  of  salt  or  sodium  sulphate, 
the  production  of  bitterns,  like  the  water  of  the  Dead  Sea,  and  finally 
of  solid  beds  of  various  saline  materials.  What  are  these  saline  resi- 
dues, and  what  conditions  govern  their  formation? 

The  most  important  of  these  substances,  considering  the  magnitude 
of  the  deposits,  are  sodium  chloride  and  calcium  sulphate,  and  their 
most  probable  origin  is  the  evaporation  of  sea  water  or  its  equivalent 
in  either  ancient  or  modern  times.  The  two  compounds  are  commonly 
associated  the  one  with  the  other,  but  not  invariably,  for  gypsum  is 

217 


218 


THE  DATA  OF  GEOCHEMISTRY. 


sometimes  derived  from  other  sources,  and  rock  salt  may  be  dissolved 
and  washed  away  from  a given  locality,  perhaps  to  he  redeposited 
elsewhere.  Still,  the  concentration  of  salt  water,  either  from  the 
ocean  or  from  lakes,  is  the  principal  source  of  these  deposits,  and 
that  phenomenon  we  may  well  consider  in  detail.  The  process  has 
been  going  on  from  Cambrian  time  down  through  all  the  intervening 
ages  to  the  present  day,  and  it  can  be  observed  in  actual  operation  in 
many  accessible  localities.  A salt  lake  dries  up,  or  a body  of  water 
is  cut  off  from  the  sea  by  a bar,  and  so  permitted  to  evaporate,  and 
a bed  of  salt  is  formed.  Such  beds  are  lenticular  in  form — thick  at 
the  centers,  where  the  water  was  deepest,  and  thinning  out  toward 
the  edges ; and  they  show,  as  a rule,  the  same  alternation  of  material, 
hut  with  variations  in  regard  to  completeness.  In  general,  the  fol- 
lowing alternations  are  observed : First,  precipitates  are  formed,  such 
as  were  considered  in  our  discussion  of  mineral  springs;  then  calcium 
sulphate  is  deposited,  then  salt,  and  finally,  under  exceptionally 
favorable  conditions,  layers  of  the  more  soluble  compounds  which 
characterize  ordinary  bitterns.  This  order,  however,  is  subject  to 
seasonable  disturbances.  In  the  concentration  of  a salt  lake  the  de- 
posits vary  with  the  temperature,  the  summer  and  winter  phenomena 
being  often  unlike.  Again,  evaporation  goes  on  during  a dry  season, 
to  be  interrupted  by  a flood;  and  in  the  latter  case  layers  of  silt  are 
deposited  from  time  to  time  over  the  saline  compounds  that  had 
previously  formed.  Alternations  of  gypsum,  salt,  and  clay  are  ex- 
ceedingly common  in  saline  deposits.  In  a lagoon,  cut  off  from  the 
ocean,  a break  of  the  sandy  barrier  or  an  exceptionally  high  tide  may 
admit  a fresh  supply  of  material  for  concentration,  and  so  interrupt 
the  continuity  of  the  process.  Any  change  of  conditions  will  cause 
a corresponding  change  in  the  character  of  the  substances  laid  down. 
Evidently  each  bed  of  salt  should  be  studied  individually,  if  its 
history  is  to  be  understood;  but  the  general  phenomena  in  the  con- 
centration of  sea  water  appear  more  or  less  completely  in  every  case 
and  in  essentially  the  same  order. 

CONCENTRATION  OF  SEA  WATER. 

In  1849  J.  Usiglio 1 published  an  elaborate  study  of  saline  deposits 
from  Mediterranean  water,  the  samples  having  been  taken  at  sea, 
near  Cette,  but  several  miles  from  shore  and  at  a depth  of  1 meter. 
The  water  itself  was  analyzed,  the  order  and  quantity  of  the  salts 
deposited  at  various  concentrations  were  determined,  and  analyses 
were  also  made  of  three  bitterns,  representing  different  densities  and 
different  stages  of  the  process.  The  four  analyses,  reduced  to  ionic 
form  and  to  percentages  of  total  solids,  appear  as  follows : 

1 Annales  chim.  phys.,  3d  ser.,  vol.  27, 1849,  pp.  92,  172. 


SALINE  RESIDUES. 


219 


Analyses  of  Mediterranean  water  and  bitterns. 

A.  The  water  itself,  density  1.0258.  I C.  Bittern  of  density  1.264. 

B.  Bittern  of  density  1.21.  I D.  Bittern  of  density  1.32. 


A 

B 

c 

D 

01  

54.  39 

56. 18 

49.  99 

49. 13 

Br  

1. 15 

1.  22 

2.  68 

3.  03 

S04 

7.  72 

5.  78 

14.  64 

17.  36 

CO,  

. 18 

Na  

31.  08 

32.  06 

20.  39 

12.  89 

K 

. 71 

. 78 

2.  25 

3.  31 

Oa 

1. 18 

.26 

Ms 

3.  59 

3.72 

10.  05 

14.  28 

Salinity,  per  cent 

100.  00 
3.  766 

100.  00 
27.  546 

100.  00 
33.  712 

100.  00 
39.  619 

The  determinations  of  bromine  in  these  analyses  are  obviously 
excessive  and  those  of  potassium  are  low,  but  otherwise  the  data  in  the 
first  column,  considering  the  time  when  they  were  made,  agree  fairly 
well  with  the  more  recent  figures  given  in  Chapter  III  of  this  volume. 
They  show,  first,  the  ehmination  of  calcium  as  carbonate,  and  later 
as  sulphate,  then  the  deposition  of  sodium  chloride,  and  finally  the 
accumulation  of  the  more  soluble  substances  in  the  mother  liquors. 

In  his  study  of  saline  deposition  Usiglio  started  with  5 liters  of 
sea  water,  and  determined  the  character  and  quantity  of  the  salts  laid 
down  at  successive  stages  of  concentration.  In  the  following  table 
the  results  of  his  experiments  appear,  but  are  reduced  to  the  initial 
unit  volume  of  1 liter.  The  quantities  given  are  in  grams. 

Salts  laid  down  in  concentration  of  sea  water. 


Density.® 

Volume. 

Fe203. 

CaC03. 

CaS04 

2H20. 

NaCl. 

MgS04. 

MgCl2. 

NaBr. 

KC1. 

1.  0258 

1.  000 

1.  0500 

.533 

0.  0030 

0.  0642 

1.  0836 

.316 

Trace. 

1. 1037 

.245 

Trace. 

1. 1264 

. 190 

.0530 

0.  5600 

1. 1604 

.1445 

. 5620 

1. 1732 

.131 

. 1840 

1.  2015 

.112 

. 1600 

1.  2138 

.095 

.0508 

3.  2614 

0.  0040 

0.  0078 

1.  2212 

.064 

. 1476 

9.  6500 

.0130 

. 0356 

1.  2363 

.039 

. 0700 

7.  8960 

.0262 

. 0434 

0.  0728 

1.  2570 

.0302 

.0144 

2.  6240 

.0174 

.0150 

.0358 

1.  2778 

.023 

2.  2720 

.0254 

.0240 

.0518 

1.  3069 

.0162 

1.  4040 

.5382 

.0274 

.0620 

Total  deposit. . 

.0030 

.1172 

1.  7488 

27. 1074 

.6242 

.1532 

.2224 

Salts  in  last  bittern . . 

2.  5885 

1.  8545 

3. 1640 

.3300 

0.  5339 

Sum 

.0030 

.1172 

1.  7488 

29.  6959 

2.  4787 

3.  3172 

.5524 

.5339 

° Given  by  Usiglio  in  Baum^  degrees.  Restated  here  in  the  usual  specific  gravities. 


220 


THE  DATA  OF  GEOCHEMISTEY. 


Upon  further  concentration  of  the  mother  liquors  Usiglio  obtained 
variable  results.  Mere  cooling  from  the  temperature  of  day  to  that 
of  night  was  sufficient  to  precipitate  additional  magnesium  sulphate 
which  redissolved  partially  the  day  following.  After  that  more  salt 
was  thrown  down,  then  the  double  sulphate  of  magnesium  and  potas- 
sium, next  the  double  chloride  of  the  same  metals,  and  finally  mag- 
nesium chloride  crystallized  out.  In  the  table  of  results  just  given 
the  order  of  deposition  is  clearly  shown.  First,  ferric  oxide  and 
calcium  carbonate;  then  gypsum;  then  salt,  the  latter  beginning  to 
appear  when  the  water  had  been  concentrated  to  about  one-tenth  of 
its  original  volume. 

In  its  general  outlines,  then,  the  concentration  of  sea  water  is  a 
simple  phenomenon,  but  in  its  details  it  may  be  very  complex.  The 
localities  at  which  it  can  be  completely  traced  are  comparatively  few 
and  the  natural  records  of  it  are,  as  a rule,  defective.  The  mother 
liquors  are  easily  drained  or  washed  away,  leaving  no  trace  of  their 
existence,  and  some  saline  deposits  have  been  partially  redissolved 
and  laid  down  with  modified  composition  elsewhere.  Salt  and  gyp- 
sum may  thus  be  separated,  and  so  the  normal  order  of  their  associa- 
tion becomes  disturbed.  Beds  of  salt,  therefore,  may  be  divided 
into  classes — as  primary  and  secondary,  or  as  complete  and  incom- 
plete, according  to  their  saline  character  or  the  evidence  of  their 
origin.  Of  all  known  localities  the  region  around  Stassfurt,  in  Ger- 
many, gives  us  the  best  record  of  the  complete,  or  nearly  complete, 
process,  and  as  it  has  been  studied  with  unusual  thoroughness  we  may 
properly  consider  it  in  some  detail. 

Ocean  water,  as  we  have  already  seen,  contains  on  the  average 
about  3.5  per  cent  of  solid  matter  in  solution,  so  that  the  mere  evapo- 
ration of  a closed  lagoon  would  give  a layer  of  salt  of  only  moderate 
thickness.  But  salt  deposits  may  be  enormously  thick — a thousand 
meters  or  more,  as  at  Sperenberg,  near  Berlin — and  the  existence  of 
such  masses  requires  some  explanation.  For  this  purpose  we  must 
assume  that  large  quantities  of  brine  have  accumulated  within  a 
limited  space,  such  as  a deep  valley,  like  that  of  the  Dead  Sea,  or 
behind  a bar,  as  suggested  by  G.  Bischof,1  and  more  recently  by 
C.  Ochsenius.2  The  theory  developed  by  Ochsenius  is  briefly  as  fol- 
lows : Let  us  imagine  a deep  bay,  connected  with  the  sea  by  a narrow 
and  shallow  channel,  but  otherwise  cut  off  from  oceanic  circulation  by 
a bar.  If  no  large  streams  enter  the  bay  the  outflow  from  it  will 
be  small,  but  sea  water  can  enter  freely  to  offset  the  losses  due  to 
evaporation.  Evaporation,  of  course,  takes  place  only  at  the  sur- 

1 Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  2,  1864,  p.  48. 

2 Die  Bildung  der  Steinsalzlager  und  ihrer  Mutterlaugensalze,  Halle,  1877.  See  also  a short  paper  in  Proc. 
Acad.  Nat.  Sci.  Philadelphia,  1888,  p.  181.  Ochsenius  was  sharply  criticized  by  J.  Walther  in  Das  Gesetz 
der  Wiistenbildung,  Berlin,  1900.  Ochsenius  replied  in  Centralbl.  Min.,  Geol.  u.  Pal.,  1902,  pp.  551,  557, 
620;  and  a rejoinder  by  Walther  appeared  in  the  same  journal,  1903,  p.  211.  See  also  O.  E.  Branson,  Bull 
Geol.  Soc.  America,  vol.  26.  p.  231, 1915. 


SALINE  RESIDUES. 


221 


face,  and  the  upper  layers,  thus  becoming  denser,  must  sink,  so  pro- 
ducing a saline  concentration  at  the  bottom.  In  this  manner,  being 
continually  supplied  with  new  material  from  without,  the  salinity  of 
the  bay  will  gradually  increase  until  saturation  is  reached  and  the 
deposition  of  salt  begins.  So  long  as  salt  water  can  enter  the  bay 
this  process  will  continue,  and  the  depths  of  the  basin  will,  in  time, 
become  a solid  mass  of  salts,  covered  with  a sheet  of  bittern.  If, 
meanwhile,  an  elevation  of  the  land  takes  place,  separating  the  bay 
completely  from  the  ocean,  evaporation  may  proceed  to  its  limit  and 
the  mother  liquor  will  deposit  its  contents.  In  the  Karaboghaz 
and  other  bays  on  the  eastern  shore  of  the  Caspian  Sea  the  process 
of  saline  concentration  can  now  be  observed  in  actual  operation; 
but  only  a part  of  the  program  has  yet  been  performed. 

This  theory  of  Ochsenius,  however,  is  not  the  only  one  possible 
to  account  for  the  concentration  of  salt.  It  must  be  remembered 
that  salt  is  not  deposited  from  sea  water  until  the  latter  has  been 
concentrated  to  about  one-tenth  of  its  original  volume.  Suppose, 
now,  a large  sheet  of  water  to  be  cut  off  from  the  ocean  by  any  change 
in  the  level  of  the  land,  and  also  that  it  contains  within  its  area  a 
deep  depression.  In  that  depression  the  water  will  gradually  become 
concentrated,  and  its  saline  load  will  tend  to  accumulate  there.  The 
layer  of  salt  in  the  depression  would  be  of  much  greater  thickness 
than  one  formed  by  evaporation  over  a comparatively  level  bottom, 
and  if  the  surface  area  of  the  depression  were  small  in  comparison 
with  that  of  the  original  sheet  of  water,  the  depth  of  the  deposit 
might  be  very  great.  Such  a deposit  might  also  be  reenforced  by 
teachings  from  other  salt  beds,  or  from  diffused  alt  in  adjacent  areas, 
a process  which  is  now  going  on  in  the  valley  of  the  Dead  Sea. 

THE  STASSFURT  SALTS. 

In  the  Stassfurt,  or,  more  properly,  the  Magdeburg-Halberstadt 
region,  the  order  of  deposits  is  as  follows,  going  from  the  surface 
downward : 1 

1.  Drift,  about  8 meters  thick. 

2.  Shales,  sandstones,  and  unconsolidated  clays,  of  varying  thickness. 

3.  Younger  rock  salt,  thickness  very  variable,  sometimes  missing. 

i From  data  given  by  H.  Precht  in  Die  Salz-Industrie  von  Stassfurt  und  Umgegend,  1889;  L.  Loewe, 
Zeitschr.  prakt.  Geologie,  1903,  p.  331;  H.  M.  Cadell,  Trans.  Edinburgh  Geol.  Soc.,  vol.  5,  1884,  p.  92;  and 
G.  Lunge  in  Thorpe’s  Dictionary  of  applied  chemistry,  vol.  3,  p.  265.  See  also  C.  Ochsenius,  on  Loewe’s 
paper,  Zeitschr.  prakt.  Geologie,  1904,  p.  23;  and  on  the  potash  salts,  idem,  1905,  p.  167.  J.  Westphal 
(Zeitschr.  Berg-,  Hiitten-  u.  Salinenwesen  preuss.  St.,  vol.  50, 1902,  p.  1)  has  given  a history  of  the  Stassfurt 
works.  An  important  monograph  is  that  of  E.  Pfeiffer,  Handbuch  der  Kali-Industrie,  Braunschweig, 
1887.  For  a paper  by  J.  Currie,  see  Trans.  Edinburgh  Geol.  Soc.,  vol.  8,  1905,  p.  403.  Other  references  may 
be  found  in  a bibliography  of  saline  minerals,  Zeitschr.  prakt.  Geologie,  1905,  p.  183.  Deutschlands  Kali- 
bergbau,  Berlin,  1907,  contains  papers  on  the  geology  of  the  saline  beds  by  H.  Everding,  and  their  chem- 
istry, by  E.  Erdmann,  with  exhaustive  bibliographies.  See  also  C.  Riemann,  Die  Geologie  der  deutschen 
Salzlagerstatten,  Stassfurt,  1908;  and  H.  E.  Boeke,  Uebersicht  der  Mineralogie,  Petrographic  und  Geologie 
der  Kalisalzlagerstatten,  Berlin,  1909.  Many  papers  relative  to  the  salt  deposits  are  in  the  journal  Kali; 
but  they  can  not  all  be  noticed  here.  A recent  paper  by  O.  Riedel  is  in  Zeitschr.  Kryst.  Min.,  vol.  50,  1912, 
p.  139.  On  the  quantitative  composition  of  the  Stassfurt  beds  see  M.  Rozsa,  Zeitschr.  anorg.  Chemie, 
vol.  90, 1915,  p.  377. 


222 


THE  DATA  OF  GEOCHEMISTRY. 


4.  Anhydrite,  rarely  lacking,  30  to  80  meters  thick. 

5.  Salt  clay,  average  thickness  5 to  10  meters,  very  rarely  absent. 

6.  The  carnallite  zone,  from  15  to  40  meters  thick.  At  Douglashall  a layer  of  rock 

salt  intervenes  between  the  carnallite  and  the  clay.  In  parts  of  the  field 
kainite  overlies  the  carnallite,  is  itself  overlain  by  ‘'sylvinite ” or  “hartsalz,” 
and  that  in  turn  by  schoenite.  These  subzones  are  often  missing. 

7.  The  kieserite  zone. 

8.  The  polyhalite  zone. 

9.  Older  rock  salt  and  anhydrite.  Nos.  7,  8,  and  9 have  a total  thickness  ranging 

from  150  to  perhaps  1,000  meters.  The  anhydrite  forms  layers,  averaging 
7 millimeters  thick,  separating  the  salt  into  sheets  of  8 or  9 centimeters.  These 
layers  have  been  interpreted  as  annual  deposits,  due  possibly  to  seasonal 
variations  in  temperature  or  to  alternating  drought  and  rain.  If  this  suppo- 
sition is  correct,  a Stassfurt  salt  bed  900  meters  thick  would  require  10,000  years 
to  form. 

10.  Anhydrite  and  gypsum. 

We  have  now  a complete  record  of  the  saline  deposition  at  Stass- 
furt, ranging  from  the  calcium  sulphate  at  the  bottom  to  the  mother 
liquor  or  carnallite  salts  at  the  top.  Above  the  carnallite  a protect-, 
ing  layer  of  clay  was  laid  down;  and,  after  that,  probably,  a new 
accession  of  sea  water  began  the  formation  of  a second  series  of  beds.1 
This  younger  salt  and  its  underlying  anhydrite  represent  this  later 
period,  which  has  no  chemical  relation  to  the  first.  So  much  for  the 
broad  outlines.  Now  let  us  pass  on  to  the  details  of  the  record. 

In  the  Stassfurt  deposits  more  than  30  saline  minerals  are 
found,  some  abundantly  and  some  sparingly.  Several  of  them  are 
regarded  as  primary  minerals;  others  are  derived  from  these  by 
secondary  reactions;  a few  of  the  species  are  simple  salts,  but  the 
greater  number  are  double  compounds.  Chlorides,  sulphates,  and 
borates  are  the  characteristic  substances,  but  in  kainite  we  have  a 
mixed  salt  containing  two  acid  radicles,  and  the  rare  sulphoborite  is 
another  example  of  similar  complexity.  Carbonates  are  repre- 
sented but  sparingly,  and  their  normal  occurrence  is  probably  that 
of  the  “ stinkstoiie,  ” or  bituminous  limestone,  which  has  been  found 
beneath  the  anhydrite.  Native  sulphur,  derived  from  anhydrite 
by  the  reducing  action  of  organic  matter,  is  sparingly  present  in  the 
salt  clay,2  and  more  abundantly  in  the  rock  salt  and  carnallite. 
Pyrites  also  is  sometimes  found  in  the  deposits.  Bromine  is  present 
in  the  salts  and  also  iodine,3  and  copper  is  reported  by  W.  Biltz  and 

1 Some  writers  regard  the  younger  salt  as  having  been  formed  by  re-solution  of  older  salt  and  redeposition 
here.  As  the  discussion  is  geological  and  not  chemical,  it  is  unessential  to  our  present  purposes. 

2 Pfeiffer,  Arch.  Pharm.,  3d  ser.,  vol.  27,  1890,  p.  1134.  On  the  salt  clay  see  E.  Marcus  and  W.  Biltz, 
Zeitschr  anorg.  Chemie,  vol.  68,  1910,  p.  91.  Vanadium  was  detected  in  it.  See  also  Marcus,  idem,  vol. 
77,  p.  119, 1912,  for  many  analyses. 

3 On  bromine  see  H.  E.  Boeke,  Zeitschr.  Kryst.  Min.,  vol.  45, 1908,  p.  346.  On  iodine,  A.  Frank,  Zeitsclir. 
angew.  Chemie,  vol.  20, 1907,  p.  1279;  E.  Erdmann,  idem,  vol.  23,  1910,  p.  342;  and  K.  Kraze,  Inaug.  Diss. 
Halle,  1909.  The  presence  of  iodine  in  the  salts  of  the  Stassfurt  region  proper  is  questioned  by  Boeke, 
Erdmann,  and  Kraze.  Kraze,  however,  found  it  in  the  salts  from  Xcu  Stassfurt,  Bleicherode,  and  Kalusz. 
See  also  K.  Koehlichen,  Kali,  vol.  7, 1913,  p.  457.  On  rubidium  in  potash  salts  see  E.  Wilke,  Kali,  vol.  6, 
1912,  p.  245. 


SALINE  RESIDUES. 


223 


E.  Marcus,  as  well  as  ammonium  and  nitrates.1  Helium  occurs  in 
the  salts  in  traces.2 

The  essential  compounds  are  chlorides  and  sulphates,  and  as  the 
latter  are  represented  by  the  oldest  of  the  important  strata  they  may 
be  considered  first.  The  sulphates  found  at  Stassfurt  are  as  follows: 


Anhydrite -CaS04. 

Gypsum 3 CaS04.2H20. 

Glauberite CaS04.Na2S04. 

Polyhalite 2CaS04.MgS04.K2S04.2H20. 

Krugite 4CaS04.MgS04.  K2S04.2H20 . 

Kieserite - MgS04.H20. 

Epsomite MgS04.7H20  (reichardtite) . 

Vanthoffite MgS04.3Na2S04. 

Bloedite MgS04.Na2S04.4H20  (astrakanite). 

Loewite MgS04.Na2S04.2-|H20 . 

Langheinite 2MgS04.  K2S04. 

Leonite MgS04.  K2S04.4H20 . 

Picromerite MgS04 . K2S04 . 6H20  (schoenite) . 

Aphthitalite K3Na(S04)2  (glaserite)  .4 

Kainite MgS04 . KC1 . 3H20 . 


Celestite,  SrS04,  is  also  sometimes  found  in  these  deposits. 

If  we  now  study  these  compounds  with  reference  to  their  origin, 
we  shall  find  that  the  primary  deposition  followed  approximately  in 
the  order  of  their  hydration.  Anhydrous  calcium  sulphate,  anhy- 
drite, forms  the  lowest  member  of  the  series,  and  gradually  merges 
into  the  older  salt.  In  the  latter,  glauberite  and  langbeinite,  both 
anhydrous,  first  appear,  although  they  also  occur,  always  as  second- 
ary minerals,  higher  up.  According  to  H.  Precht,5 6  langbeinite 
replaces  polyhalite  when  the  calcium  sulphate  needed  to  form  the 
latter  mineral  is  present  in  insufficient  quantity.  Polyhalite,  in 
which  the  ratio  of  the  sulphate  molecules  to  water  is  as  four  to  two, 
comes  next,  forming  an  important  part  of  the  upper  layers  in  the 
older  salt,  and  is  followed  by  the  monohydrated  kieserite.  Krugite, 
which  is  still  lower  in  hydration,  occurs  with  polyhalite  in  the  younger 
salt,  so  that  the  two  species  may  be  regarded  as  equivalent  and 
contemporaneous.  The  more  highly  hydrated  species,  bloedite, 
loewite,  picromerite,  and  leonite,  are  principally  found  in  the  kainite 
region  above  the  carnallite,  and  epsomite,  with  its  seven  molecules 
of  water,  is  deposited  in  the  salt  clay.  The  anhydrous  aphthitalite 


1 Zeitschr.  anorg.  Chemie,  vol.  62, 1909,  p.  183;  vol.  64,  1909,  p.  236. 

2 It.  J,  Strutt,  Proc.  Roy.  Soc.,  vol.  81,  ser.  A,  1908,  p.  278.  E.  Erdmann,  Ber.  Deutsch.  chem.  Gesell., 
vol.  43, 1910,  p.  777.  S.  Valentlner,  Kali,  vol.  6,  1912,  p.  1. 

3 Probably,  as  A.  Geuther  (Liebig’s  Annalen,  vol.  218,  1883,  p.  297)  has  shown,  the  formula  here  given 
to  gypsum  should  be  doubled.  It  then  becomes  Ca2S208.4H20,  and  the  hemihydrate,  Ca2S208.H20,  a 
well-known  artificial  compound,  furnishes  evidence  in  favor  of  the  higher  formula. 

4 According  to  B.  Gossner  (Zeitschr.  Kryst.  Min.,  vol.  39,  1904,  p.  155)  glaserite  is  a definite  species  with 
the  formula  given  above.  J.  H.  Van’t  Hoff  and  H.  Barschall  (Zeitschr.  physikaL  Chemie,  vol.  56,  1906, 

p.  212)  question  the  definiteness  of  the  mineral,  and  regard  it  as  a mixture  of  the  two  component  sulphates. 

6 Zeitschr.  angew.  Chemie,  1897,  p.  68. 


224 


.THE  DATA  OF  GEOCHEMISTRY. 


is  a secondary  mineral  in  the  kainite,  and  vanthofiite,  also  anhydrous, 
is  associated  with  aphthitalite  and  loewite  in  the  same  horizon.  The 
loewite  is  probably  formed  by  dehydration  of  bloedite,1  and  the 
yanthofhte  by  a reaction  between  bloedite  and  sodium  sulphate,  the 
process  being  modified  by  the  presence  of  other  substances.  The 
langbeinite  of  the  kainite  region. is  commonly  regarded  as  a secondary 
product,  but  it  may  have  been  one  of  the  parent  species,  for  F.  K. 
Mallet,2  who  has  described  this  mineral  as  found  in  the  Punjab  salt 
range  of  India,  observed  that  on  exposure  to  moist  air  it  gained  57 
per  cent  in  weight  and  altered  into  a mixture  of  epsomite  and  picro- 
merite.  On  the  other  hand,  langbeinite  itself  may  be  derived  by 
various  reactions  from  other  Stassfurt  species,  such  as  leonite, 
kainite,  kieserite,  and  picromerite,  as  Van’t  Hoff  and  Meyerhoffer 
have  shown.  The  fact  that  a given  salt  may  be  produced  by  several 
different  reactions  warns  us  to  be  cautious  in  making  assertions  as 
to  its  origin  at  any  specified  point.  Concentration  and  temperature 
are  two  of  the  determining  factors  in  the  deposition  of  salts,  and  the 
possible  reactions  are  also  profoundly  modified  by  the  presence  of 
other  compounds.  Van’t  Hoff  and  his  colleagues  have  determined 
experimentally  many  of  the  conditions  under  which  the  Stassfurt 
minerals  occur  or  can  be  produced,  and  find  that  their  temperatures 
of  formation  in  a saturated  solution  of  common  salt  are  lower  than 
in  the  absence  of  that  compound.  The  elaborate  researches  of  these 
authors,  however,  are  not  available  for  abstraction  here,  partly 
because  they  are  complicated  by  diagrams,  and  partly  because  the 
investigations  are  still  being  continued.  Only  in  a special  mono- 
graph upon  the  Stassfurt  beds  could  all  the  details  of  their  investi- 
gations be  adequately  discussed.3 

The  chlorides  found  in  the  Stassfurt  region  are  as  follows : 

Halite  or  rock  salt,  NaCl. 

Sylvite,  KC1.  “Sylvinite”  is  a mixture  of  sylvite  and  rock  salt,  while  the  “Hart- 
salz  ” contains  these  substances  together  with  kieserite. 

Douglasite,  K2FeCl4.2H20.(?) 

Carnallite,  KMgCl3.6H20. 

Tachhydrite,  2MgCl2.CaCl2.12H20=3(RCl2.4H20) .4 
Bischofite,  MgCl2.6H20. 


1 See  J.  H.  Van’t  Hoff,  Sitzungsb.  Akad.  Berlin,  1902,  p.  414.  Also  Van’t  Hoff  and  W.  Meyerhoffer, 
idem,  1903,  p.  678;  1904,  p.  659. 

2 Mineralog.  Mag.,  vol.  12,  1899,  p.  159. 

s Van’t  Hoff  and  his  associates  have  already  published  about  fifty  papers  on  the  Stassfurt  salts,  in 
Sitzungsb.  Akad.  Berlin,  from  1897  to  1907.  See  also  Van’t  Hoff,  Physical  chemistry  in  the  service  of 
the  sciences,  Chicago,  1903;  Zur  Bildung  der  ozeanischen  Salzablagerungen,  Braunschweig,  1905;  and  an 
address  in  Ber.  Internat.  Kong,  angew.  Chemie,  Berlin,  1903.  Also  summaries  by  E.  F.  Armstrong,  Proc. 
British  Assoc.  Adv.  Sci.  1901,  p.  262,  and  E.  Janecke,  Zeitschr.  anorg.  Chemie,  1906,  p.  7.  For  a graphic 
representation  of  the  saline  associations  see  also  H.  E.  Boeke,  Zeitschr.  Kryst.  Min.,  vol.  47, 1910,  p.  273. 

* Boeke,  in  a private  communication,  suggests  that  if  the  formula  of  carnallite  is  doubled,  to 
K2Mg2Cl6.12H20,  tachhydrite  becomes  CaMg2Cl<5.12H20.  That  is,  the  salts  are  analogous,  Ca  in  one 
replacing  K2  in  the  other. 


SALINE  RESIDUES. 


225 


With  the  exception  of  the  rock  salt,  which  forms  the  great  mass 
of  the  deposits  overlying  the  anhydrite,  these  chlorides  represent  the 
concentration  of  the  mother  liquors  in  the  carnallite  zone.  They  were 
the  most  soluble  compounds  potentially  existing  in  sea  water,  and, 
with  the  sulphato-chloride,  kainite,  were  among  the  last  substances 
to  crystallize.  Halite  and  douglasite  were  distinctly  primary 
deposits;  carnallite  was  generally,  and  sylvite  occasionally,  primary; 
tachhydrite  and  bischofite  were  secondary  products.  Kainite  was 
sometimes  one  and  sometimes  the  other.  The  “Hartsalz,”  according 
to  Van’t  Hoff  and  Meyerhoffer,1  is  a secondary  product  formed  by  the 
action  of  solutions  upon  a mixture  of  carnallite,  kieserite,  and  sodium 
chloride,  which  was  preceded  by  the  splitting  up  of  kainite  into 
sylvite  and  kieserite.  The  kainite,  in  its  most  conspicuous  develop- 
ment, lies  between  the  carnallite  and  the  “Hartsalz.”  From  the  car- 
nallite itself,  sylvite  and  bischofite  may  be  derived,  or  it  may  be 
formed  by  the  direct  union  of  these  species,  which  are  its  two  com- 
ponents. According  to  C.  Przibylla,2  when  sylvite  and  bischofite 
combine  to  form  carnallite,  there  is  an  increase  of  4.95  per  cent  in 
volume.  Possibly,  therefore,  the  formation  of  carnallite  at  low  levels 
is  prevented  by  pressure. 

In  one  essential  respect,  the  foregoing  paragraph  demands  qualifi- 
cation. According  to  Boeke  3 the  existence  of  douglasite  is  doubtful. 
Another  mineral,  rinneite,  discovered  by  him  in  the  “Hartsalz”  of 
Saxony  and  the  Harz,  has  the  formula  FeCl2.3KCl.NaCl.4  The  sub- 
stance named  douglasite  may  have  been  identical  with  this.  Boeke, 
moreover,  regards  the  “Hartsalz”  as  a direct  deposition  for  the 
reason  that  it  is  distinctly  stratified. 

Two  other  chlorides,  not  found  at  Stassfurt,  have  been  described 
from  similar  deposits  in  adjacent  regions.  Koenenite,  discovered  by 
F.  Rhine  5 in  salts  from  Volpriehausen  in  the  Sollingerwald,  has  the 
complex  formula  Al303.3Mg0.2MgCl2.6  or  8H20.  Baeumlerite,  from 
the  Leine  valley  in  Hannover,  according  to  O.  Renner  6 is  KCl.CaCl2. 

With  the  carnallite  and  its  overlying  potassium  salts,  the  borates 
generally  occur.  They  are  boracite,  sulphoborite,  pinnoite,  aschar- 
ite,  and  heintzite;  one  other,  hydroboracite,  is  found  earlier  in  the 
series,  near  the  lower  limit  of  the  polyhalite  zone.  These  species  are 

1 Sitzungsb.  Akad.  Berlin,  1902,  p.  1106.  See  also  J.  H.  Van’t  Hoff,  F.  B.  Kenrick,  and  H.  M.  Dawson, 
Zeitschr.  physikal.  Chemie,  vol.  39,  1902,  p.  27,  on  the  conditions  of  formation  of  tachhydrite. 

2 Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  p.  254. 

3 Neues  Jahrb.,  1909,  Bd.  2,  p.  19.  For  the  first  description  of  rinneite,  see  Centralbl.  Min.,  Geol.  u.  Pal., 
1909,  p.  72.  On  the  synthesis  of  rinneite  see  Boeke,  Sitzungsb.  Akad.  Berlin,  vol.  24,  1910,  p.  632.  Boeke 
has  described  the  iron  compounds  of  the  Stassfurt  beds  in  Neues  Jahrb.,  1911,  Bd.  1,  p.  48,  and  Centralbl. 
Min.,  Geol.  u.  Pal.,  1911,  p.  48.  See  also  F.  Rinne  and  R.  Kolb,  idem,  p.  357. 

* O.  Schneider  (Centralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  503)  regards  the  NaCl  of  rinneite  as  a mechanical 
admixture. 

5 Centralbl.  Min.,  Geol.  u.  Pal.,  1902,  p.  493. 

6 Idem,  1912,  p.  106. 

97270°— Bull.  616—16 15 


226 


THE  DATA  OF  GEOCHEMISTRY. 


relatively  rare,  except  the  boracite,  and  it  is  not  necessary  to  consider 
them  any  further  at  this  point,  for  their  occurrence  tells  us  little 
about  the  main  phenomena  of  saline  concentration. 

We  must  not  suppose,  for  an  instant,  that  these  zones  of  deposition 
are  regularly  and  completely  separated,  nor  even  that  they  represent 
in  any  close  degree  the  products  observed  in  the  artificial  evaporation 
of  sea  water  or  brine.  In  the  latter  case  a moderate  quantity  of  water 
is  concentrated  by  itself;  at  Stassfurt  more  water  was  continually 
added  from  the  ocean.  On  the  one  hand  calcium  sulphate  is  deposited 
almost  wholly  at  one  time;  on  the  other  new  quantities  were  precipi- 
tated so  long  as  the  evaporating  bay  retained  its  connection  with  the 
sea.  In  the  salt  pan  gypsum  forms  a bottom  layer  before  salt  begins 
to  separate  out;  at  Stassfurt  anhydrite  is  found  in  greater  or  less 
amount  through  all  the  zones,  and  so  also  is  the  sodium  chloride. 
When  a shallow  lake  or  isolated  lagoon  evaporates,  the  artificial 
process  is  closely  paralleled,  but  a concentration  with  continuous 
replenishment  lasting  for  thousands  of  years  is  a very  different  thing. 
The  principles  are  unchanged,  the  broad  outlines  remain  the  same, 
but  the  details  of  the  process  are  greatly  modified. 

E.  Erdmann  1 regards  the  Stassfurt  salts  as  having  been  formed 
from  a shallow  portion  of  the  Permian  ocean,  which  covered  a great 
part  of  North  Germany  and  became  isolated  from  the  main  sea. 
The  evaporation  products  collected  in  depressions  of  the  land  and 
were  reinforced  by  calcium  sulphate  from  fresh-water  affluents. 
Sea  water  alone  contains  too  little  calcium  to  account  for  the  anhy- 
drite present  in  the  beds.  Walther’s  views  are  similar.  Both  reject 
the  “bar”  theory. 

We  are  now  in  a position  to  trace  more  distinctly  the  phenomena 
which  attended  the  formation  of  the  beds  at  Stassfurt.2  For  a long 
time  only  gypsum  was  deposited;  but  later,  as  the  concentration  of 
the  bay  increased,  salt  also  was  laid  down,  and  by  its  action  the  gyp- 
sum was  converted  into  anhydrite.3  From  this  point  onward,  for  a 
considerable  period,  the  calcium  sulphate  derived  from  the  influx  of 
sea  water  above  fell  through  a deep  layer  of  concentrated  brine  and 
was  deposited  directly  as  anhydrite,  in  alternating  layers  with  the 
salt.4  When,  however,  so  much  salt  had  been  precipitated  that  the 
supernatant  solutions  had  become  bitterns  rich  in  magnesium  salts, 
the  calcium  sulphate  united  with  these  salts,  and  polyhalite  was 
formed.  The  polyhalite  region  at  Stassfurt  is  essentially  a bed  of 

1 Zeitschr.  angew.  Chemie,  vol.  21, 1908,  p.  1685.  A short  additional  communication  by  Erdmann  is  in  the 
same  journal,  vol.  22, 1909,  p.  238. 

2 Cf.  G.  Lunge,  Thorpe’s  dictionary  of  applied  chemistry,  vol.  3, 1893,  p.  268. 

3 According  to  J.  H.  Van’t  Hoff  and  F.  Weigert,  Sitzungsb.  K.  Akad.  Wiss.  Berlin,  1901,  p.  1140,  anhy- 
drite forms  from  gypsum  in  sodium  chloride  solutions  at  30°.  In  sea  water  the  transformation  takes  place 
at  25°. 

4 Cf.  J.  H.  Van’t  Hoff  and  P.  Farup,  Sitzungsb.  Akad.  Berlin,  1903,  p.  1000.  H.  Vater  (idem,  1900,  p.  270) 
discusses  marine  anhydrite,  and  gives  many  references  to  literature.  At  ordinary  temperatures,  according 
to  Vater,  calcium  sulphate  crystallizes  from  a saturated  solution  of  salt  in  the  form  of  gypsum. 


SALINE  RESIDUES. 


227 


rock  salt,  containing,  with  other  impurities,  from  6 to  7 per  cent  of 
the  new  mineral.  Possibly  syngenite,  CaK2(S04)2.H20,  a species 
which  occurs  in  a similar  deposit  at  Kalusz  in  Galicia,  but  which  does 
not  seem  to  be  recorded  from  Stassfurt,  was  first  produced.  Syn- 
genite may  be  prepared  artificially  by  the  direct  action  of  potassium 
sulphate  upon  gypsum,  and  it  is  converted  by  strong  solutions  of  mag- 
nesium chloride  and  sulphate  into  polyhalite.1  The  occurrence  of 
syngenite  at  Kalusz  is  below  the  potassium  salts,  in  rock  salt  contain- 
ing anhydrite.  It  is  therefore  the  equivalent  in  position  of  polyhalite.2 

As  the  concentration  of  the  magnesian  mother  liquors  increased, 
kieserite  was  produced,  the  dehydrating  action  of  magnesium  chlo- 
ride preventing  the  formation  of  epsomite.  H.  Precht  and  B.  Witt- 
jen  3 have  shown  that  when  magnesium  chloride  and  sulphate  are 
dissolved  together  and  the  solution  then  evaporated  upon  the  water 
bath,  kieserite  separates  out.  Thus  the  kieserite  zone  was  formed, 
which  contains,  on  an  average,  65  per  cent  of  rock  salt,  17  of  kieserite, 
13  of  carnallite,  3 of  bischofite,  and  2 of  anhydrite.  At  this  point 
polyhalite  disappears.  The  last  step  in  the  concentration  was  the 
formation  of  carnallite,  with  its  associated  minerals,  from  the  chlo- 
rides which  had  hitherto  remained  in  solution.  The  average  com- 
position of  this  zone  is  55  per  cent  of  carnallite,  25  of  rock  salt,  16 
of  kieserite,  and  4 of  various  other  minerals.  The  kainite  layers 
above  the  carnallite  were  probably  formed  by  the  action  of  perco- 
lating waters  upon  the  latter  mineral,  in  presence  of  some  kieserite. 
Finally,  a protecting  layer  of  mud  or  clay  was  laid  down  over  the 
mass  of  salts,  preventing  in  great  measure,  but  perhaps  not  entirely, 
their  subsequent  re-solution.  Into  all  of  the  foregoing  reactions  one 
element  entered  which  counts  for  little  in  their  imitation  on  a small 
scale — namely,  the  element  of  time.  The  prolonged  action  of  the 
mother  liquors,  during  thousands  of  years,  upon  the  earlier  deposits, 
must  have  been  much  more  thorough  than  their  effect  during  an 
experiment  in  the  laboratory.  In  the  latter  case  the  solid  deposits  are 
usually  removed  from  time  to  time,  so  that  the  procedure  does  not 
accurately  repeat  the  operations  of  nature.  These  considerations 
should  especially  be  taken  into  account  in  studying  the  transforma- 
tion of  gypsum  into  anhydrite,  or  the  reverse  reaction  which  has 
often  been  observed.4  Beds  of  anhydrite  may  take  up  water  and  be 

1 E.  E.  Basch,  Sitzungsb.  K.  Akad.  Wiss.  Berlin,  1900,  p.  1084. 

2 A.  Aigner  (Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  1901,  p.  686)  has  described  the  Austrian  polyhalite. 
For  analyses  of  kainite,  carnallite,  etc.,  from  Kalusz  and  Aussee,  see  C.  von  John,  Jahrb.  K.-k.  geol. 
Reichsanstalt,  vol.  42,  1892,  p.  341.  On  mirabilite  from  Kalusz,  see  R.  Zalozieeki,  Monatsh.  Chemie, 
vol.  13,  1892,  p.  504.  Two  papers  on  the  potash  salts  of  Austria  and  the  Tyrol  by  R.  Gorgey  are  in  Min. 
pet.  Mitt.,  vol.  28,  1909,  p.  334,  and  vol.  29,  1910,  p.  148.  Gorgey  (idem,  vol.  31,  1912,  p.  339)  has  also 
described  the  potash  salts  of  Wittelsheim,  Alsace. 

3 Ber.  Deutsch.  chem.  Gesell.,  vol.  14, 1881,  p.  2131. 

* Cf.  F.  Hammerschmidt,  Min.  pet.  Mitt.,  vol.  5,  1882-83,  p.  272;  and  J.  F.  McCaleb,  Am.  Chem.  Jour., 
vol.  11, 1889,  p.  34. 


228 


THE  DATA  OF  GEOCHEMISTRY. 


reconverted  into  gypsum  through  considerable  depths,  as  at  Bex  in 
Switzerland,  where  the  alteration  has  reached  a thickness  of  60  to 
100  feet.  Time  is  an  important  factor  in  all  such  transformations, 
especially  when  one  of  the  reacting  bodies  happens  to  be  a solid  of 
relatively  low  solubility. 

The  temperature  conditions  which  governed  the  deposition  of  the 
Stassfurt  salts  are  briefly  summed  up  by  Van’t  Hoff  1 as  follows: 

1.  Glauberite,  formed  above  10°. 

2.  Langbeinite,  formed  above  37°. 

3.  Loewite,  formed  above  43°. 

4.  Vanthoffite,  formed  above  46°. 

5.  Loewite  with  glaserite,  formed  above  57°. 

6.  Loewite  with  vanthoffite,  formed  above  60°. 

7.  Kieserite  with  sylvite,  formed  above  72°. 

This  scale  of  temperatures  is  designated  as  a “ geological  ther- 
mometer,” and  gives  us  something  like  a definite  idea  of  past  condi- 
tions in  the  Stassfurt  beds.2 

OTHER  SAI/T  BEDS. 

The  Stassfurt  deposits,  as  has  already  been  indicated,  are  alto- 
gether exceptional  in  their  completeness.  Rock  salt  is  generally 
found  in  much  thinner  deposits,  and  as  a rule  it  is  unaccompanied 
by  potassium  or  magnesium  salts  in  any  notable  quantities.  Gypsum 
or  anhydrite,  however,  is  commonly  present,  either  under  the  salt 
or  in  its  near  neighborhood.  Where  gypsum  is  absent  we  may  infer, 
with  a fair  degree  of  probability,  that  the  salt  is  of  secondary  origin 
and  not  derived  directly  from  sea  water,  or  that  it  came  from  the 
evaporation  of  a salt  lake  which  contained  either  no  calcium  or  no 
sulphates.  Gypsum,  of  course,  cannot  form  unless  its  constituents 
are  at  hand.  Furthermore,  gypsum  may  be  produced  otherwise 
than  from  the  concentration  of  sea  water,  and  it  may  exist  as  a 
remainder  where  the  more  soluble  salts  have  been  washed  away.  It 
can  occur  independently  of  or  concomitant  with  the  presence  of  rock 
salt,  and  each  locality  must  be  considered  on  its  individual  merits. 
On  some  small  coral  islands  in  the  Pacific  gypsum  is  found  as  a resi- 
due from  the  evaporation  of  lagoons,  in  beds  which  may  reach  2 feet 
in  thickness.3  Here  the  origin  from  sea  water  is  evident.  On  the 
other  hand,  waters  containing  little  or  no  salt  often  deposit  gypsum. 
I.  C.  Russell,4  for  instance,  has  described  such  a deposit  at  Fillmore, 


1 Zeitschr.  Elektrochemie,  vol.  11,  1905,  p.  709. 

2 The  scientific  investigation  of  the  Stassfurt  salts  is  being  continued  by  a society  formed  for  that  pur- 
pose. For  a list  of  the  publications  of  its  members  see  Van’t  Hoff,  Sitzungsb.  K.  Akad.  Wiss.  Berlin,  No. 
39, 1910,  p.  772. 

3 J.  D.  Dana,  Manual  of  geology,  4th  ed.,  p.  120.  On  the  Cis-Indus  (India)  salt  beds,  which  contain 
potassium  salts,  see  W.  A.  K.  Christie,  Rec.  Geol.  Survey  India,  vol.  44, 1914,  p.  241. 

* Mon.  U.  S.  Geol.  Survey,  vol.  11,  1885,  p.  84.  The  deposition  of  gypsum  by  Lake  Chichen-Kanab, 
Yucatan,  was  mentioned  in  Chapter  V. 


SALINE  EESIDUES. 


229 


Utah,  which  covers  an  area  of  12  square  miles  and  has  been  opened 
to  a depth  of  6 feet  without  reaching  bottom.  Gypsum  is  also  com- 
mon as  an  efflorescence  or  incrustation  in  caves,1  and  it  can  be  pro- 
duced by  the  alteration  of  other  rocks.  The  oxidation  of  pyrites  in 
limestone  may  form  gypsum ; or,  as  was  shown  in  the  preceding  chap- 
ter, it  can  originate  from  double  decomposition  between  other  metallic 
sulphates  and  calcium  carbonate.  L.  W.  Jowa,2  for  example,  pre- 
pared selenite  in  measurable  crystals  by  the  action  of  a solution  of 
ferrous  sulphate  on  chalk. 

In  the  Salina  formation  of  New  York  gypsum  occurs  above  the 
salt,  and  its  presence  is  attributed  by  Dana  3 to  the  alteration  of  the 
overlying  “ Waterlime”  beds.  In  this  region  the  salt  occurs  in  layers 
interstratified  with  shales,  a series  of  shallow-water  deposits  having 
been  successively  covered  by  bodies  of  mud  or  clay.4  At  Goderich, 
Canada,  a similar  but  not  identical  alternation  has  been  observed.5 
Here  a boring  1,517  feet  deep  revealed  dolomite  and  anhydrite,  and 
above  that  were  six  beds  of  salt  alternating  with  similar  materials. 
The  uppermost  salt  was  struck  at  1,028  feet,  and  at  876  feet  dolomite, 
with  seams  of  gypsum,  was  found.  The  anhydrite  at  bottom  was 
probably  normal;  but  what  the  upper  gypsum  signifies  is  not  clearly 
shown.  It  may  be  the  beginning  of  an  unfinished  concentration,  or 
else  quite  independent  of  the  salt  below.  Throughout  the  region  of 
salt  more  or  less  anhydrite  was  found,  but  potassium  compounds 
were  either  absent  or  present  only  in  traces.  Neither  in  New  York 
nor  in  the  Goderich  deposits  were  the  mother  liquors  permitted  to 
crystallize.6 

The  great  salt  deposits  of  Louisiana  and  Texas  are  associated  not 
only  with  gypsum  but  also  with  sulphur,  sulphurous  gases,  and 
petroleum.  At  first,  before  the  petroleum  was  discovered,  the  salt 
beds  were  regarded  as  of  marine  origin.7  Later,  R,.  T.  Hill 8 inter- 
preted them  as  derived  from  hot  saline  waters  rising  from  great 
depths,  and  a similar  view  was  put  forth  by  L.  Hager.9  E.  Coste,10 
a strenuous  advocate  of  the  volcanic  origin  of  petroleum,  has  argued 
that  the  salt  is  its  obvious  companion,  but  his  argument  is  hardly 
conclusive.  Sodium  chloride  is  known  as  a volcanic  sublimate,  and 


* See  G.  P.  Merrill,  Proc.  U.  S.  Nat.  Mas.,  vol.  17,  1905,  p.  77. 

s Annales  Soc.  g6ol.  Belgique,  vol.  23,  1895-96,  p.  cxxviii. 

3 Manual  of  geology,  4th  ed.,  p.  554. 

1 See  sections  given  in  Bull.  New  York  State  Mus.  No.  11,  1893. 

5 T.  S.  Hunt,  Geol.  Survey  Canada,  Rept.  Progress,  1876-77,  p.  221. 

6 The  solubility  of  calcium  sulphate,  gypsum,  anhydrite,  etc.,  in  water  and  various  solutions  has  been 
elaborately  studied.  See  an  excellent  summary  by  F.  K.  Cameron  and  J.  M.  Bell,  in  Bull.  No.  33,  Bur. 
Soils,  U.  S.  Dept.  Agr.,  1906. 

7 See,  for  example,  G.  I.  Adams,  Bull.  U.  S.  Geol.  Survey  No.  184, 1901,  p.  49.  Also  doubts  raised  by 
C.  W.  Hayes  and  W.  Kennedy  in  Bull.  U.  S.  Geol.  Survey  No.  212,  1903,  p.  144. 

8 Jour.  Franklin  Inst.,  vol.  154, 1902,  p.  273. 

9 Eng.  and  Min.  Jour.,  vol.  78,  1904,  pp.  137,  180. 

10  Jour.  Canadian  Min.  Inst.,  vol.  6,  1903,  p.  73. 


230 


THE  DATA  OF  GEOCHEMISTRY. 


some  authors  have  argued  that  the  salt  of  the  ocean  is  volcanic  also ; 
but  extreme  views  of  this  sort  are  rarely  sound.  The  most  that  can 
be  said  is  that  the  origin  of  the  Louisiana-Texas  salt  has  not  yet 
received  its  final  interpretation.1  It  would  be  most  unwise  to  claim 
that  all  salt  deposits  are  formed  in  the  same  way.  Some  are  certainly 
marine,  some  are  residues  from  salt  lakes,  others  may  represent  con- 
centrations from  magmatic  waters.  The  subject,  however,  is  so  large 
that  a more  extended  discussion  of  it  is  impracticable  here. 

ANALYSES  OF  SALT. 

Neither  salt  nor  gypsum  is  found  in  nature  in  a state  of  absolute 
purity,  although  that  condition  is  sometimes  very  nearly  approxi- 
mated. Being  deposited  from  solutions  containing  other  substances, 
some  of  the  latter  are  always  carried  down  and  reveal  their  presence 
on  analysis.  Analyses  of  rock  salt  are  exceedingly  numerous,  and 
only  a moderate  number,  enough  to  show  the  range  of  variation  in 
the  mineral,  need  be  cited  here.2 


1 In  Bull.  Geol.  Survey  Louisiana  No.  7,  1908,  G.  D.  Harris  describes  the  salt  deposits  and  discusses 
their  origin.  He  also  gives  a very  complete  summary  of  information  on  the  salt  deposits  of  the  world. 
The  fullest  treatise  on  salt,  covering  the  globe,  is  by  J.  O.  von  Buschman,  Das  Salz,  2 vols.,  Leipzig,  1906 
and  1909. 

2 See  Thorpe’s  Dictionary  of  applied  chemistry,  vol.  4,  p.  430,  for  additional  data.  Also  Geol.  Survey 
Michigan,  vol.  3,  appendix  B,  and  vol.  5,  pt.  2,  for  Michigan  salt  and  brines;  Bull.  New  York  State  Hus. 
No.  11,  for  New  York  examples;  Prel.  Rept.  Geol.  Louisiana,  1899,  for  material  from  that  State;  and  C.  I. 
Istrati,  Bull.  Soc.  chim.,  3d  ser.,  vol.  2,  1889,  p.  4,  for  analyses  of  Roumanian  salt.  Some  Roumanian 
samples  contain  as  high  as  99.9  per  cent  of  sodium  chloride. 


SALINE  RESIDUES. 


231 


Analyses  of  rock  salt. 

A.  Salt  from  Goderich,  Canada.  Analysis  by  Gould,  for  T.  Sterry  Hunt,  Geol.  Survey  Canada,  Rept. 
Progress,  1876-77,  p.  233. 

B.  Salt  from  Kingman,  Kansas.  Analysis  by  E.  H.  S.  Bailey  and  E.  C.  Case,  Kansas  Univ.  Geol. 
Survey,  vol.  7, 1902,  p.  73.  Ten  other  analyses  of  rock  salt  are  given,  mostly  purer  than  this. 

C.  Saline  incrustation,  Tuthill  Marsh,  Kansas.  Idem,  p.  70.  Analysis  made  in  the  University  of  Kansas 
laboratory,  but  analyst  not  named. 

D.  Salt  from  Petit  Anse,  Louisiana.  Analysis  by  F.  W.  Taylor,  Mineral  Resources  U.  S.  for  1883,  U.  S. 
Geol.  Survey,  p.  564. 

E.  Salt  from  Leoncito,  La  Rioja  Province,  Argentina.  Analysis  by  L.  Harperath,  Bol.  Acad.  nac.  cien. 
Cdrdoba,  Argentina,  vol.  10,  1890,  p.  427.  Remarkable  for  its  high  proportion  of  potassium  salts.  Har- 
perath gives  nineteen  analyses  of  Argentine  salt,  some  of  them  representing  great  purity,  but  several 
approaching  this  one. 

F.  Salt  stalactite  from  a disused  working  at  Redhaugh  colliery,  Gateshead,  England.  Analysis  by 
W.  H.  Dunn,  published  by  P.  P.  Bedson,  Jour.  Soc.  Chem.  Ind.,  vol.  8,  1889,  p.  98.  This  analysis,  in 
the  original,  is  stated  in  the  form  of  radicles.  It  is  recalculated  here  to  salts  for  uniformity  with  the  others. 

G.  Salt  from  bed  deposited  by  the  Katwee  Lake,  north  of  the  Albert  Edward  Nyanza,  central  Africa. 
Analysis  by  H.  S.  Wellcome;  abstract  in  Jour.  Soc.  Chem.  Ind.,  vol.  9, 1890,  p.  734.  An  analysis  of  the 
lake  water  by  A.  Pappe  and  H.  D.  Richmond  is  also  given  in  this  journal.  See  ante,  p.  173. 


A 

B 

C 

D 

E 

F 

G 

NaCl 

99.  687 

97.  51 

71.  82 

98.  731 

81.  491 

99.  00 

82.  71 

KC1 

17. 483 

CaCl2 

.032 

Trace. 

.52 

MrCL 

.095 

. 10 

.013 

.15 

^x2  

Na2S04. 

.57 

21.  98 

5.  32 

k2so4 

.048 

8.43 

CaS04 

.090 

1.  51 

.99 

1. 192 

.978 

MgS04 

1.  29 

Na2C03 

3.  56 

2.  46 

ALOo 

} -13 

Fe203 

.11 

.010 

.15 

Si02 

J 

.024 

Insoluble 

.017 

.20 

.23 

H20 

.079 

.030 

.28 

.82 

100.  000 

100.  00 

100.  00 

100.  000 

100.  000 

99.  95 

99.  89 

In  addition  to  the  impurities  shown  in  the  analyses,  rock  salt  fre- 
quently contains  gaseous  inclusions.  These  have  been  often  exam- 
ined, recently  by  N.  Costachescu,1  who  finds  some  of  them  to  consist 
mainly  of  nitrogen,  and  others  mainly  of  methane.  Other  hydro- 
carbons and  carbon  dioxide  are  also  found.  Rock  salt  is  not  uncom- 
monly colored,  especially  blue.  This  coloration  has  been  attributed 
to  organic  matter,  and  recently,  by  H.  Siedentopf,2  to  the  presence 
of  minute  particles  of  metallic  sodium.  This  very  remarkable  con- 
clusion would  seem  to  require  confirmation. 


1 Ann.  Univ.  Jassy,  vol.  4,  1906,  p.  3.  The  author  gives  a good  summary  of  earlier  investigations. 

2 Physikal.  Zeitschr.,  vol.  6,  1905,  p.  855.  See  also  L.  Wohler  and  H.  Kasamowski,  Zeitschr.  anorg. 
Chemie,  vol.  47,  1905,  p.  853,  and  F.  Cornu,  Centralbl.  Min.,  Geol.  u.  Pal.,  1907,  p.  166,  and  Neues  Jahrb., 
1908,  p.  32.  G.  Spezia  (Centralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  398)  cites  experimental  evidence  adverse  to 
Siedentopf’s  views.  E.  Erdmann  (Ber.  Deutsch.  chem.  Gesell.,  vol.  43,  p.  777)  ascribes  the  blue  of  salt  to 
radioactivity,  which  is  known  to  effect  color  changes  in  minerals. 


232 


THE  DATA  OF  GEOCHEMISTEY, 


ANALYSES  OF  GYPSUM. 

For  gypsum  the  following  analyses,  all  made  in  the  laboratory  of 
the  United  States  Geological  Survey,  are  sufficient  to  show  its  usual 
character: 1 


Analyses  of  gypsum. 

A.  From  Hillsboro,  New  Brunswick.  Analysis  by  George  Steiger. 

B.  From  Alabaster,  Michigan.  Analysis  by  Steiger. 

C.  From  east  of  Cascade,  Black  Hills,  South  Dakota.  Analysis  by  Steiger. 

D.  E.  From  Nephi,  Utah.  Analyses  by  E.  T.  Allen.  This  material  evidently  contains  admixed  anhy- 
drite. 


A 

B 

c 

D 

E 

so3 

46. 18 

46. 18 

45. 45 

48. 14 

39.  53 

co2 

.85 

. 65 

7.  73 

Cl 

Trace. 

.03 

Trace. 

.04 

Si02 

. 10 

AloOq 

1 

\ 

.12 

Fe203 

} . 10 

/ .08 

} . 14 

CaO 

32.  37 

32.  33 

32.  44 

35.  29 

38.  46 

MgO 

Trace. 

1 

.05 

.33 

Trace. 

. 24 

Na-0 

} 14 

.07 

K20 

/ . 10 

. 19 

H20 

20.  94 

20.  96 

20.  80 

15.  88 

12.  69 

Insoluble 

.10 

.05 

.45 

99.  79 

99.  82 

100.  09 

99.  96 

99.54 

BITTERNS. 

In  what  has  been  said  so  far,  we  have  considered  almost  exclusively 
the  concentration  of  sea  water;  but  other  waters  form  other  deposits 
and  yield  different  bitterns.  Analyses  of  bittern  are  not  often 
reported,  and  only  a few  examples  can  be  given  here.2  These  analyses 
are  recalculated  to  ionic  form,  and  give  the  percentage  composition 
of  the  anhydrous  saline  matter. 


1 For  other  data  relative  to  the  composition  and  origin  of  gypsum,  see  G.  P.  Grimsley  and  E.  H.  S.  Bailey, 
Univ.  Geol.  Survey  Kansas,  vol.  5, 1899.  Also  E.  C.  Eckel,  Bull.  U.  S.  Geol.  Survey  No.  213,  1903,  p.  407; 
G.  P.  Grimsley,  Geol.  Survey  Michigan,  vol.  9,  pt.  2,  1903-4,  and  Am.  Geologist,  vol.  34,  1904,  p.  378;  F.  A. 
Wilder,  Jour.  Geology,  vol.  11,  1903,  p.  723;  A.  L.  Parsons,  Twenty-third  Rept.  State  Geologist,  New 
York  State  Mus.,  1903;  and  G.  I.  Adams  and  others,  on  gypsum  deposits  of  the  United  States,  Bull.  U.  S. 
Geol.  Survey  No.  223,  1904.  A recent  report  on  the  gypsum  of  New  York  is  by  D.  H.  Newland  and  H. 
Leighton,  Bull.  New  York  State  Mus.  No.  143,  1910.  On  the  genetic  relations  of  gypsum  and  anhydrite, 
see  R.  C.  Wallace,  Geol.  Mag.,  1914,  p.  276. 

2 In  addition  to  Usiglio’s  analyses  cited  on  p.  219,  ante. 


SALINE  RESIDUES. 


233 


Analyses  of  bitterns. 

A.  Bittern  from  Leslie  Salt  Refining  Works,  San  Mateo,  California.  Analysis  by  R.  F.  Gardner.  From 
sea  water. 

B.  Bittern  of  maximum  concentration,  from  the  brines  of  Syracuse,  New  York.  Analysis  by  C.  A. 
Goessmann,  Am.  Jour.  Sci.,  2d  ser.,  vol.  44,  1867,  p.  80. 

C.  Bittern  from  Pomeroy,  Ohio.  Analysis  by  A.  R.  Merz  and  R.  F.  Gardner. 

D.  Bittern  from  Hartford,  West  Virginia.  Merz  and  Gardner,  analysts. 

E . Bittern  from  Saginaw,  Michigan.  Gardner  analyst.  Analyses  A,  C,  D , E recalculated  to  percentages 
from  the  figures  given  by  J.  W.  Turrentine  in  U.  S.  Dept.  Agric.,  Bur.  Soils  Bull.  No.  94, 1913.  Selected 
from  a number  of  analyses  reported  on  pp.  61-66. 

F.  Bittern  from  the  saline  of  Medellin,  Antioquia,  Colombia.  Analysis  by  J.  B.  Boussingault,  Annales 
chim.  phys.,  5th  ser.,  vol.  2,  1874,  p.  102.  Known  locally  as  “oil  of  salt.” 

G.  Bittern  from  salt  works  of  Allendorf-an-Werra,  Germany.  Analysis  by  Reichardt,  abstract  in  Jour. 

Chem.  Soc.,  vol.  42, 1882,  p.  24.  « 


A 

B 

C 

D 

E 

F 

G 

Cl 

56.  33 

63.  93 

62.  42 

62.  70 

60. 18 

44.  99 

55.  56 

Br 

.94 

1. 16 

2.  07 

2.  21 

1.  33 

1.  02 

.22 

I 

Trace. 

. 03 

S04 

9.  38 

.06 

. 93 

.69 

Trace. 

14.  07 

15.  08 

Na 

22.  83 

10.  24 

.46 

.04 

25.  27 

25.  97 

10.  62 

K 

2.  58 

5.  27 

.57 

.53 

.49 

11. 18 

6.  40 

Li 

Trace. 

.01 

nh4 

.09 

Ca 

. 38 

11.  26 

26.  00 

25.  97 

9.  82 

. 28 

. 07 

Mg 

7.  56 

8.  08 

7.  55 

7.  86 

2.  91 

2.  37 

8.  81 

SiO 

.02 

Organic 

3.  21 

Salinity,  per  cent 

100.  00 
31.  82 

100.  00 
33.  567 

100.  00 
55.  88 

100.  00 
55.  23 

100.  00 
32.  97 

100.  00 
33.  478 

100.  00 
29. 149 

Although  these  bitterns  vary  widely  in  composition,  in  consequence 
of  the  differences  between  the  original  brines,  they  are  nearly  all  note- 
worthy as  showing  the  concentration  in  them  of  bromine.  The  Mich- 
igan brines  are  important  commercial  sources  of  bromine,  and  so,  too, 
are  those  of  the  Kanawha  Valley,  in  West  Virginia.  A.  L.  Baker 1 
reports  that  20  to  30  gallons  of  Kanawha  bittern  wdll  yield  1 pound 
of  bromine,  and  he  has  also  shown  that  they  contain  iodine  in  very 
appreciable  amounts,  from  38.4  to  59.2  milligrams  per  liter.  The 
richness  of  the  Dead  Sea  in  bromine  has  already  been  pointed  out. 
Bitterns  of  this  class  deserve  a more  careful  study  than  they  seem 
to  have  yet  received. 

SODIUM  SULPHATE. 

In  the  evaporation  of  ocean  water  the  sulphates  which  form  are 
first  the  calcium  compound  and  then  the  magnesium  salt,  or  else 
double  sulphates  of  magnesium,  with  either  calcium  or  sodium. 
Anhydrite,  then  polyhalite,  and  then  kieserite,  follow  one  another  in 
regular  succession.  In  many  saline  lakes,  however,  calcium  and  mag- 
nesium are  deficient  in  quantity,  while  sodium  sulphate  is  present  in 
relatively  large  amounts.  In  such  lakes  sodium  sulphate  is  deposited 
in  considerable  quantities,  generally  preceding  the  deposition  of  salt, 


i Chem.  News,  vol.  44,  p.  207,  1881. 


234 


THE  DATA  OF  GEOCHEMISTRY. 


and  its  precipitation  is  determined  or  affected  by  the  season  of  the 
year.  Sodium  sulphate  is  much  more  soluble  in  warm  than  in  cold 
water,  but  the  similar  variation  for  salt  is  comparatively  small;  so 
that  the  mere  change  of  temperature  between  summer  and  winter 
may  cause  mirabilite  to  separate  out,  or  to  redissolve  again.  An 
instance  of  this  kind,  in  the  Karaboghaz,  has  already  been  noticed, 
and  the  Great  Salt  Lake  1 not  only  deposits  sodium  sulphate  during 
winter,  but  even  casts  it  up  in  heaps  upon  the  shore.  The  salt  thus 
formed  is  the  decahydrate,  mirabilite,  Na2SO4.10H2O;  while  from 
warm  solutions,  especially  from  concentrated  brines,  the  anhydrous 
sulphate  thenardite  may  be  deposited.  In  warm  and  dry  air  mira- 
bilite effloresces,  loses  its  water,  and  is  transformed  into  thenardite, 
which  is  a well-known  and  common  mineral.  On  the  surface  of 
Lacu  Sarat,  in  Roumania,2  large  crystals  of  mirabilite  form  during 
winter,  to  redissolve,  at  least  in  part,  when  the  weather  becomes 
warm,  and  many  other  sulphate  or  sulphato-chloride  lakes  exhibit 
similar  phenomena.  The  Siberian  lakes,  studied  by  F.  Ludwig.3 
deposit  mainly  sulphates;  sodium  sulphate  in  Lakes  Altai,  Beisk, 
Domoshakovo,  and  Kisil-Kul,  while  in  the  Schunett  Lake  a quantity 
of  magnesium  sulphate  is  also  formed.  Ludwig  gives  analyses  of 
these  precipitates,  but  the  three  in  the  subjoined  table  are  enough 
to  cite  here.  The  analyses  are  carried  by  Ludwig  to  four  decimal 
places,  but  I have  rounded  them  off  to  two.  He  also  gives  the  Na 
and  Cl  of  the  sodium  chloride  separately,  and  the  insoluble  residue 
he  divides  into  organic  and  inorganic.  The  consolidation  of  the  data 
as  tabulated  below  is  for  the  sake  of  simplicity.  Their  subdivision 
does  not  help  to  illustrate  the  phenomena  now  under  discussion. 

Analyses  of  saline  deposits  in  two  Siberian  lakes. 

A.  Deposit  on  bottom  of  Lake  Altai. 

B.  Deposit  on  shore  of  Lake  Altai. 

C.  Deposit  on  shore  of  Schunett  Lake. 


A 

B 

C 

co2 

0. 12 

0.  03 

0.  63 

so, 

54.  00 

55.  67 

54. 45 

Na20 

41.64 

43.  21 

25.  96 

K20 

1.  93 

NaCl 

. 29 

. 13 

.92 

CaO 

.22 

.01 

.07 

MgO 

.11 

10.  22 

A1203 

} .01 

.07 

Fe,0, 

.11 

.01 

Si02 

.07 

Insoluble  residue 

3.  46 

.91 

5.  70 

99.  95 

99.  97 

100.  03 

1 G.  K.  Gilbert,  Mon.  U.  S.  Geol.  Survey,  vol.  1,  1890,  p.  253. 

2 L.  Mrazec  and  W.  Teisseyre,  Apergu  goologique  sur  les  formations  saliferes  et  les  gisements  de  sel  en 
Itoumanie,  1902.  This  memoir  contains  a bibliography  relative  to  Roumanian  salt. 

3Zeitschr.  prakt.  Geologie,  vol.  11, 1903,  p.  401.  Cf.  ante,  p.  170. 


SALINE  RESIDUES. 


235 


These  lakes,  Altai  and  Schunett,  are  sulphato-chloride  waters,  but 
the  first  effect  of  their  concentration  is  to  bring  about  a partial  separa- 
tion of  their  salts.  The  same  effect  is  perhaps  even  better  exem- 
plified by  Sevier  Lake,  in  Utah,  which  is  at  times  entirely  dry,  form- 
ing a thin  saline  layer  that  in  moister  seasons  partly  redissolves.1 
The  deposits  from  this  lake  have  been  analyzed,  those  from  the 
margin  by  O.  D.  Alien,  those  from  the  center  by  S.  A.  Lattimore,  and 
their  average  composition,  as  cited  by  Gilbert,  is  given  below: 


Average  composition  of  deposits  from  Sevier  Lake , Utah. 


Margin. 

Center. 

Na2S04 

14.3 

84.6 

NaoCO, 

.4 

NaCl 

75.8 

7.0 

CaS04 

Trace. 

MgS04 

5.5 

Trace. 

k2so4 

. 7 

h2o 

3.  6 

8.0 

Insoluble 

. 1 

Trace. 

100.0 

100.0 

Here  the  sodium  sulphate  tends  to  accumulate  at  the  center  of  the 
lake,  whereas  the  later  deposits,  which  are  covered  by  a crust  of 
sodium  chloride,  are  formed  in  larger  relative  proportion  around 
the  margin. 

Fractional  crystallization,  however,  is  only  a part  of  the  process 
by  which  the  saline  constituents  of  a water  may  be  separated.  Salt 
and  alkaline  lakes  are  peculiarly  characteristic  of  desert  regions, 
and  the  smaller  depressions  may  be  alternately  dry  and  filled  with 
water.  Suppose,  now,  following  a suggestion  of  J.  Walther,2  that 
such  a lake,  concentrated  to  a bed  of  salt  covered  by  a thin  sheet  of 
bittern,  is  overwhelmed  by  desert  sands,  so  that  a permanent  saline 
deposit,  protected  from  further  change,  is  formed.  The  bittern  will 
be  absorbed  by  the  sandy  covering,  its  salts  will  rise  by  capillary 
attraction  to  the  surface,  and  the  efflorescence  thus  produced  will  be 
scattered  in  dust  by  the  winds.  On  the  steppes  of  the  lower  Volga, 
according  to  Walther,  there  are  numerous  remainders  of  salt  lakes, 
which  have  been  thus  covered,  and  where,  beneath  the  sand,  solid 
salt  of  great  purity  is  found.  The  mother  liquors  have  vanished, 
and  their  saline  constituents  have  been  scattered  far  and  wide. 


1 G.  K.  Gilbert,  Mon.  U.  S.  Geol.  Survey,  vol.  1,  1890,  pp.  224-227.  See  p.156,  ante,  for  the  composition 
of  the  brine. 

2 Das  Gesetz  der  Wiistenbildung,  Berlin,  1900,  p.  149.  Chapter  13  is  devoted  to  the  subject  of  desertsalts. 
See  also  T.  H.  Holland  (Proc.  Liverpool  Geol.  Soc.,  vol.  11,  p.  227,  1912)  on  the  origin  of  desert  salts. 


236 


THE  DATA  OF  GEOCHEMISTRY. 


MISCELLANEOUS  DESERT  SALTS. 

Wherever  deserts  exist,  there  these  saline  residues  are  common. 
They  are  peculiarly  abundant  in  the  western  part  of  the  United 
States,  especially  in  the  Bonneville  and  Lahontan  basins  and  over 
the  so-called  alkali  plains,  and  they  exhibit  a great  variety  of  com- 
position. Chlorides,  sulphates,  carbonates,  and  borates  occur,  sepa- 
rately or  together,  and  many  analyses  of  these  products  have  been 
recorded.  To  the  sulphato-chloride  class  the  subjoined  analyses  be- 
long, the  other  saline  deposits  being  left  for  separate  consideration 
later.1 

Analyses  of  saline  deposits  from  sulphato-chloride  waters. 

A.  Salt,  Osobb  Valley,  Nevada.  Analysis  by  R.  W.  Woodward,  Rept.  U.  S.  Geol.  Expl.  40th  Par., 
vol.  2,  1877,  p.  707. 

B.  Saline  efflorescence  on  desert,  south  of  Hot  Springs  station,  Nevada.  Analysis  by  O.  D.  Allen,  idem, 
p.  773. 

C.  Incrustation  from  Quinns  River  crossing,  Black  Rock  Desert,  Nevada.  Analysis  by  O.  D.  Allen, 
idem,  p.  791. 

D.  Salt  from  Salt  Lake,  7 miles  east  of  the  Zandia  Mountains,  New  Mexico.  Analysis  by  O.  Loew,  Rept. 
U.  S.  Geol.  Surveys  W.  100th  Mer.,  vol.  3,  1875,  p.  627. 

E.  Efflorescence  from  alkali  flat,  near  Buffalo  Spring,  Nevada.  Analysis  by  O.  D.  Allen,  op.  cit.,  p.  731. 

F.  Efflorescence  from  Santa  Catalina,  Arizona.  Analysis  by  O.  Loew,  op.  cit.,  p.  628. 

G.  Salt  from  shore  of  lake  near  Percy,  Nevada.  Analysis  by  R.  W.  Woodward,  Rept.  U.  S.  Geol.  Expl. 
40th  Par.,  vol.  2,  1877,  p.  148. 

H.  Efflorescence  on  loess,  near  Cordoba,  Argentina.  Analysis  by  Doering,  cited  by  A.  W.  Stelzner, 
Beitrage  zur  Geologie  und  Palaeontologie  der  Argentinischen  Republik,  1885.  A number  of  salts,  etc.,  are 
described  on  pages  295-309.  This  one  is  remarkably  rich  in  potassium. 


A 

B 

c 

D 

E 

F 

G 

H 

NaOl 

96.  49 

95.  67 

85.  27 

82.  57 

70.81 

5.  93 

0.  74 

10.81 

Na2S04 

1.  91 

1.  75 

6.  89 

26.  38 

94.  04 

46.  27 

53. 14 

Na^Oa 

.96 

2.  59 

k2so4 

1.  94 

32.  34 

MgCl2. 

5.  88 

MgS04 

48.  28 

CaS04 

1.  63 

Trace. 

4.  45 

3.  71 

H20 

. 52 

. 73 

8.  57 

4.  66 

Insoluble  residue. . 

.12 

1.  97 

1.  82 

100.  00 

100.  00 

100.  00 

100.  00 

99. 13 

99.  97 

99.  74 

100.  00 

These  analyses,  taken  in  connection  with  those  of  salt  given  on  page 
231,  show  the  same  order  of  variation  as  is  found  in  the  parent  waters 
themselves.  Chlorides  form  one  end  of  the  series,  sulphates  the 
other;  and  every  gradation  may  exist  between  the  two.  Even  dif- 
ferent parts  of  the  same  deposit  may  show  evidence  of  such  a grada- 
tion, as  in  Sevier  Lake,  where  separation  of  the  salts  has  gone  on  to 
a greater  or  less  extent;  but  partial  re-solution  in  time  of  high  water 
can  reverse  the  process  and  bring  about  a new  distribution  of  the 
soluble  substances. 

1 A number  of  analyses  of  similar  products  from  Argentina  are  given  by  F.  Schickendantz,  Revista  del 
Museo  de  la  Plata,  vol.  7,  1895,  p.  1.  See  also  G.  J.  Young,  Bull.  U.  S.  Dept.  Agric.  No.  61,  1914,  on 
the  salines  of  the  Great  Basin,  and  several  papers  by  II.  S.  Gale  in  Bull.  U.  S.  Geol.  Survey  No.  540-N, 
1913. 


SALINE  RESIDUES. 


237 


ALKALINE  CARBONATES. 

From  alkaline  lakes  alkaline  carbonates  are  deposited,  mingled  with 
chlorides  and  sulphates  in  varying  proportions.  In  Hungary,  Egypt, 
Armenia,  and  Venezuela  such  deposits  are  found,  and  they  are  pecu- 
liarly common  in  the  Lahontan  basin  of  Nevada,  and  in  southern 
California.  In  Nevada  they  often  form  “playas,”  or  “playa  lakes ’n — 
beds  which  are  dry  in  summer  and  flooded  to  the  depth  of  a few  inches 
during  the  wet  season.  A number  of  these  alkaline  incrustations 
were  analyzed  by  the  chemists  of  the  Fortieth  Parallel  Survey,  with 
the  results  shown  in  analyses  A to  F of  the  subjoined  table.1 2  With 
these  may  be  included  two  analyses  of  the  soluble  parts  of  incrusta- 
tions, made  by  T.  M.  Chatard  in  the  laboratory  of  the  United  States 
Geological  Survey. 

Analyses  of  incrustations  deposited  by  alkaline  lakes. 

A.  From  western  arm  of  Black  Rock  Desert,  near  the  so-called  “Hardin  City,”  Nevada.  Analysis  by 
O.  D.  Allen,  vol.  2,  1877,  p.  792. 

B.  From  Ruby  Valley,  Nevada.  Analysis  by  R.  W.  Woodward,  vol.  1,  1878,  p.  503. 

C.  From  valley  of  Deep  Creek,  Utah.  Analysis  by  Woodward,  vol.  2,  p.  474. 

D.  From  Antelope  Valley,  Nevada.  Analysis  by  Woodward,  vol.  2,  p.  541. 

E.  From  a point  near  Peko  station,  on  Humboldt  River,  Nevada.  Analysis  by  W oodward,  vol.  2,  p.  594. 

F.  From  Brown’s  station,  Humboldt  Lake,  Nevada.  Analysis  by  Woodward,  vol.  2,  p.  744. 

G.  From  surface  of  playa,  north  arm  of  Old  Walker  Lake,  Nevada.  Soluble  portion,  29.78  per  cent. 

H.  Five  miles  west  of  Black  Rock,  Nevada.  Soluble  portion,  23.10  per  cent. 


A 

B 

C 

D 

E 

F 

G 

H 

Na,COa 

52. 10 

58.  69 

25. 12 

25.  95 

48.  99 

7. 02 

72.  69 

9.  06 

NaHC03 

8.  09 

14.  76 

14.  35 

36.  01 

11. 13 

NajSCh 

27.  55 

28.  32 

17.  43 

33.  31 

4.  42 

49.  67 

17.  49 

27.  05 

NaCl 

18.  47 

2. 11 

38.  01 

24.  51 

7.24 

20.  88 

2.  53 

59.  32 

Na2B407 

3.  34 

11.  30 

4. 15 

1.00 

k2so4 

2.  79 

4.  68 

1.  88 

KC1 

1. 18 

1.  39 

Si02 

1.  96 

2. 18 

98. 12 

100. 00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

The  following  table  contains  analyses,  reported  by  E.  W.  Hilgard,3 
of  the  soluble  part  of  “alkali”  incrustations  from  California.  They 
exhibit  remarkable  peculiarities  of  composition,  especially  in  their 
contents  of  potassium  salts,  nitrates,  and  phosphates. 

1 See  I.  C.  Russell,  Mon.  U.  S.  Geol.  Survey,  vol.  11,  1885,  p.  81. 

2 The  analyses  are  here  cited  as  recalculated  by  T.  M.  Chatard,  Bull.  U.  S.  Geol.  Survey  No.  60, 1890, 
pp.  55, 56.  The  original  statements  do  not  adequately  discriminate  between  carbonates  and  bicarbonates. 

a Appendix,  Rept.  Univ.  California  Exper.  Sta.,  1890.  Other  analyses  are  given  in  this  report. 


238 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  “alkali”  incrustations  from  California . 

A.  From  Visalia,  Tulare  County. 

B.  From  Westminster,  Orange  County. 

C.  From  the  experiment  station,  Tulare  County. 

D.  From  the  Merced  bottoms,  Merced  County. 


A 

B 

c 

D 

Na2C03 

65.  72 

62.  22 

32.  58 
25.  28 
14.  75 
19.  78 
2.25 

75.  95 
4.  67 
1.46 
12.  98 
4.  94 

Na2S04 

NaCl 

3.  98 

10.  57 

NaN03 

NaH2P04 

8.  42 

k2co3 

6.  59 
20.  62 

k2so4 

20.  23 
1.  65 

3.  95 

MgS04 

(NEL),COq 

1.41 

X11  JJ-4/2vyv-,3 

100.  00 

100.  00 

100.  00 

100.00 

Similar  deposits  are  formed  by  the  two  soda  lakes  at  Ragtown, 
Nevada,  and  these  have  been  worked  for  commercial  purposes.  Two 
samples  were  collected  by  Arnold  Hague  in  1868,  before  working 
began;  a third,  representing  the  marketable  product,  was  examined 
by  T.  M.  Chatard.1  The  analyses  are  as  follows,  in  the  form  adopted 
by  Chatard : 

Analyses  of  deposits  from  Soda  Lakes , Ragtown,  Nevada. 


A.  Big  Soda  Lake.  Analysis  by  O.  D.  Allen,  Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2,  1877,  p.  748. 

B.  Little  Soda  Lake.  Analysis  by  Allen,  op.  cit.,  p.  759. 

C.  Little  Soda  Lake,  market  soda.  Analysis  by  Chatard. 


A 

B 

C 

Na2C03 

45.  05 

44. 25 

52.  20 

NaHC03 

34.  66 

34.  90 

25.  05 

Na2S04 

1.29 

. 99 

5. 10 

NaCl 

1.  61 

1.10 

3.  31 

Si02 

.27 

Insoluble 

. 80 

2.  81 

H20 

16. 19 

15.  95 

14. 16 

99.  60 

100.  00 

100.  09 

These  soda  lakes  also  deposit  crystals  of  gaylussite,  of  the  formula 
CaC03.Na2C03.5H20,2  although  the  analysis  of  the  water  3 reveals 
no  calcium.  Probably  the  minute  quantities  of  calcium  that  enter 
the  waters  from  springs  or  otherwise  are  immediately  removed  in 
this  form. 

It  will  be  observed,  on  examining  the  foregoing  analyses,  that  they 
represent  variable  mixtures  of  several  salts.  The  latter,  of  course, 

1 Bull.  U.  S.  Geol.  Survey  No.  60,  1890,  p.  52.  Chatard  cites  a number  of  analyses  of  foreign  urao  or 
trona.  For  analyses  of  Egyptian  urao  see  O.  Popp,  Liebig’s  Annalen,  vol.  155,  1870,  p.  348. 

2 See  analysis  by  O.  D.  Allen,  Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2,  1877,  p.  749. 

3 See  p.  159,  ante,  for  analysis  of  the  water. 


SALINE  RESIDUES. 


239 


have  been  calculated  from  the  analytical  data,  and  the  radicles  might 
have  been  combined  somewhat  differently,  but  without  any  essential 
change  in  the  general  results.  Several  of  the  analyses  are  reckoned 
upon  the  basis  of  anhydrous  material,  and  are  so  far  incorrect,  but 
they  show  with  a fair  degree  of  accuracy  the  relative  proportions  of 
the  several  compounds  which  were  present.  The  carbonates  were 
probably  three  in  number — thermonatrite,  Na2C03.H20;  natron, 
Na2CO3.10H2O;  and  trona,  or  urao,  Na2C03.NaHC03.2H20.  Some- 
times one  and  sometimes  another  of  these  salts  is  in  excess,  but  the 
third  is  the  most  important,  as  the  elaborate  researches  of  Chatard  a 
have  shown.  That  this  is  the  first  salt  to  be  deposited  from  waters 
of  this  class  his  experiments  upon  Owens  Lake  water  clearly  prove. 

At  Owens  Lake,  Inyo  County,  California,  the  manufacture  of 
sodium  carbonate  has  been  carried  out  upon  a commercial  scale.  In 
order  to  determine  the  most  favorable  conditions  for  the  process, 
Chatard  subjected  a quantity  of  the  water  to  fractional  crystalliza- 
tion and  analyzed  the  salts  which  were  successively  deposited.  Two 
concordant  series  of  experiments  were  made,  together  with  a less 
complete  but  corroborative  set,  on  water  from  Mono  Lake.  The 
results  of  the  first  group  were  as  follows: 

Analyses  of  salts  deposited  by  fractional  crystallization  from  water  of  Owens  Lake , 

California. 

A.  The  natural  water  of  Owens  Lake.  Specific  gravity  1.062  at  25°.  Salinity  77.098  grams  per  liter. 
This  analysis,  which  represents  the  composition  of  the  anhydrous  residue,  was  cited  on  page  160  with  all 
carbonates  as  normal;  it  is  here  restated  in  conventional  form. 

B.  First  crop  of  crystals.  Water  concentrated  to  one-fifth  its  original  volume.  Specific  gravity  of 
mother  liquor  1.312  at  27.9°. 

C.  Second  crop  of  crystals.  Specific  gravity  of  mother  liquor  1.312  at  25°. 

D.  Third  crop  of  crystals.  Specific  gravity  of  mother  liquor  1.315  at  26.25°. 

E.  Fourth  crop  of  crystals.  Specific  gravity  of  mother  liquor  1.327  at  35.75°. 

F.  Fifth  crop  of  crystals.  Specific  gravity  of  mother  liquor  1.300  at  13.9°.  This  crop  was  obtained  by 
chilling  the  solution,  in  order  to  determine  the  effect  of  cold. 


A 

B 

c 

D 

E 

F 

h2o 

14.  51 

4.  33 

3.  43 

2.  24 

11.  03 

Na2C03 

34.  95 

43.  75 

22.  84 

18. 19 

12.  51 

55.  04 

NaHC03 

7.  40 

30. 12 

10.  53 

4.  06 

3.88 

4.  09 

Na2S04 

14.  38 

3. 18 

25.  44 

26.  70 

19.  01 

5.  70 

NaCl 

38. 16 

7.  44 

35.  06 

45.  59 

60.  99 

19. 16 

Na2B407 

.63 

NaB02 

& 2.  01 

KC1 

4.  07 

1.07 

1. 12 

1. 14 

1.  21 

2.  93 

(CaMg)CCL 

.08 

. 14 

(AlFeUX 

.05 

.01 

1 .09 

i .06 

.01 

.02 

Si02 

.28 

.055 

.05 

.16 

Organic  matter 

.032 

J 

Insoluble 

.078 

100.  00 

100.  385 

99.  41 

99. 17 

99.  90 

100. 14 

a Chatard  supposes  that  the  biborate  could  not  exist  in  so  strongly  alkaline  a solution  as  the  mother 
liquor  from  which  this  crop  was  obtained. 

b Natural  soda;  its  occurrence  and  utilization:  Bull.  U.  S.  Geol.  Survey  No.  60,  1890,  pp.  27-101.  Cf.  E. 
Le  Neve  Foster,  Proc.  Colorado  Sci.  Soc.,  vol.  3,  1890,  p.  245,  for  data  concerning  Owens  Lake.  See  also 

G.  Lunge,  Zeitschr.  angew.  Chemie,  1893,  p.  3.  On  natural  soda  in  Egypt  see  A.  Lucas,  Survey  Dept. 
Paper  (Egypt)  No.  22,  1912. 


240 


THE  DATA  OF  GEOCHEMISTRY. 


From  these  analyses  we  see  that  the  first  crop  of  crystals  consists 
largely  of  trona,  Na2C03.NaHC03.2H20,  with  a small  excess  of  the 
normal  carbonate,  some  chloride,  and  some  sulphate.  In  C,  D,  and  E 
the  carbonates  diminish,  but  the  normal  salt  is  even  more  largely  in 
excess,  while  the  chlorides  increase  rapidly.  The  final,  chilled  solu- 
tion deposits  chiefly  sodium  carbonate,  with  some  chloride  and  less 
sulphate.  The  order  of  deposition  is  trona,  sodium  sulphate,  sodium 
chloride,  and  finally,  if  we  ignore  the  minor  constituents  of  the  water, 
the  very  soluble  normal  carbonate.  Of  the  trona  itself  Chatard  made 
several  analyses,  and  he  also  prepared  a series  of  artificial  products, 
which  established  the  true  formula  of  the  compound.1  The  best 
specimen  of  trona  from  Owens  Lake  had  the  composition  given  in 
the  first  column  below,  which  is  compared  with  the  composition  as 
calculated  theoretically. 


Composition  of  trona  from  Owens  Lake,  California. 


Found. 

Calculated. 

Na2C03 

45.  86 

46.  90 

NaHCO, 

36.46 

37. 17 

NaCl 

.32 

Na2S04 

1.  25 

h2o 

16. 16 

15.  93 

Insoluble 

.02 

100.  07 

100. 00 

The  prevalent  view  concerning  the  origin  of  the  Lahontan  alkalies 
was  stated  in  Chapter  V (p.  159).  The  waters  of  the  Bonneville  basin, 
or  of  Great  Salt  Lake,  originate  in  an  area  of  sedimentary  rocks  and 
contain  chiefly  substances  which  were  formed  during  earlier  concen- 
trations. In  one  sense,  then,  we  may  call  the  residues  of  that  region 
secondary  depositions.  The  Lahontan  area,  on  the  other  hand,  is 
rich  in  volcanic  materials,  from  which,  by  percolating  waters  charged 
with  atmospheric  or  volcanic  carbon  dioxide,  the  soluble  substances 
were  withdrawn.  These  substances  have  accumulated  in  the  waters 
of  the  basin,  except  for  the  calcium  carbonate,  which  is  now  seen  in 
the  enormous  masses  of  tufa  so  characteristic  of  the  region.  To  Mono 
and  Owens  lakes,  lying  just  outside  of  the  Lahontan  basin,  the  same 
observations  apply.  Alkaline  carbonates,  together  with  sulphates 
and  chlorides,  have  been  formed  by  solution  from  eruptive  rocks,  and 
concentrated  in  these  waters  and  their  residues.  The  seepage  waters 
from  fresh  springs  near  Owens  Lake  percolate  through  beds  of  volcanic 
ash,  and  contain  even  a higher  proportion  of  alkaline  carbonates  than 


Cf.  also  C.  Winkler,  Zeitschr.  angew.  Chemie,  1893,  p.  446;  and  B.  Reinitzer,  idem,  p.  573. 


SALINE  RESIDUES. 


241 


the  lake  itself.1  The  rocks  from  which  the  salts  were  originally 
derived  seem  to  have  been  mainly  rhyolites,  andesites,  and  other 
varieties  rich  in  alkalies  and  relatively  poor  in  lime.  Had  lime  been 
present  in  larger  quantities  more  calcareous  sediments  and  gypsum 
would  have  formed,  with  less  of  the  alkaline  carbonates,  or  even 
none  at  all. 

This  theory,  however,  which  attributes  the  presence  of  alkaline  car- 
bonates to  a direct  derivation  from  volcanic  rocks,  is  not  the  only 
hypothesis  possible.  Even  if  it  holds  with  respect  to  the  Lahontan 
waters  it  is  not  necessarily  valid  elsewhere.  In  order  to  account  for 
the  existence  of  sodium  carbonate  in  natural  waters,  T.  Sterry  Hunt2 
assumed  a double  decomposition  between  sodium  sulphate  and  cal- 
cium bicarbonate,  gypsum  being  thrown  down.  A similar  reaction  is 
accepted  by  E.  von  Kvassay  3 in  his  study  of  the  Hungarian  soda, 
only  in  this  case  sodium  chloride  is  taken  as  the  initial  compound. 
The  latter  salt  is  supposed  to  react  upon  calcium  bicarbonate,  yield- 
ing sodium  bicarbonate,  which  effloresces,  while  the  more  soluble  cal- 
cium chloride,  simultaneously  formed,  diffuses  into  the  ground. 
E.  W.  Hilgard  4 has  shown  experimentally  that  both  reactions  are 
possible,  and  that  either  sodium  sulphate  or  sodium  chloride  can  react 
with  calcium  bicarbonate,  forming  strongly  alkaline  solutions.  From 
such  solutions  crystals  of  gypsum  can  be  deposited,  while  sodium 
bicarbonate  remains  dissolved.  In  Hilgard’s  experiments,  however, 
he  precipitated  and  removed  the  calcium  sulphate  by  means  of  alco- 
hol, a condition  unlike  anything  occuring  in  nature.  S.  Tanatar,5 
therefore,  repeated  the  experiments  without  the  use  of  alcohol  and 
confirmed  Hilgard’s  conclusions.  The  reverse  reaction  is  hindered 
by  the  crystallization  of  the  gypsum  and  the  washing  away  or 
efflorescence  of  the  soluble  carbonate. 

E.  Sickenberger,6  who  examined  the  natron  lakes  of  Egypt,  ob- 
served the  presence  in  them  of  alg96,  and  noticed  the  evolution  of 
hydrogen  sulphide  from  their  waters,  iron  sulphide  being  at  the  same 
time  thrown  down.  He  therefore  ascribes  the  carbonates  to  the 
reduction  of  sulphates  by  organic  matter,  and  subsequent  absorption 

1 See  analyses  by  T.  M.  Chatard,  Bull.  U.  S.  Geol.  Survey  No.  60, 1890,  p.  94.  Chatard  also  discusses  the 
origin  of  the  carbonates  and  cites  the  views  of  earlier  investigators  concerning  other  localities. 

2 Am.  Jour.  Sci.,  2d  ser.,  vol.  28, 1859,  p.  170. 

3 Jahrb.  K.-k.  geol.  Reichsanstalt,  1876,  p.  427.  Cf.  also  H.  Le  Chatelier  on  Algerian  salts,  Compt.  Rend., 
vol.  84,  1877,  p.  396.  Von  Kvassay  gives  a bibliography  of  the  Hungarian  occurrences  and  some  analyses 
of  the  soda. 

* Am.  Jour.  Sci.,4thser.,  vol.  2,  1896,  p.  123.  See  also  paper  in  Rept.  Univ.  California  Agr.  Exper.  Sta., 
1890,  p.  87,  followed  by  an  experimental  research  by  M.  E.  Jaffa. 

5 Ber.  Deutsch.  chem.  Gesell.,  vol.  29,  1896,  p.  1034.  See  also  a memoir  by  H.  Vater,  Zeitschr.  Kryst. 
Min.,  vol.  30,  1899,  p.  373. 

6 Chem.  Zeitung,  1892,  pp.  1645,  1691. 

97270°— Bull.  616—16 16 


242 


THE  DATA  OF  GEOCHEMISTRY. 


of  carbon  dioxide  from  the  air.  G.  Schweinfurth  and  L.  Lewin,1  on 
the  contrary,  while  admitting  that  such  a process  can  go  on  to  some 
extent,  regard  it  as  capable  of  accounting  for  only  a small  part  of  the 
alkaline  carbonates  that  are  formed.  These  lakes  deposit  sodium 
chloride,  sulphide,  and  carbonate;  and  the  authors  attribute  the  last 
salt  to  double  decompositions  with  carbonate  of  lime.  The  percolat- 
ing Nile  waters  contain  calcium  bicarbonate  and  the  soil  through 
which  it  reaches  the  lakes  is  rich  in  salt  and  gypsum.  These  two  sub- 
stances first  react  to  form  sodium  sulphate  and  calcium  chloride  and 
the  former  then  exchanges  with  calcium  bicarbonate,  as  in  Hunt’s  and 
Hilgard’s  investigations.  Sodium  chloride  is  taken  as  the  starting 
point,  and  from  it  the  sulphate  and  carbonate  are  derived. 

We  have,  then,  three  theories  by  which  to  account  for  the  forma- 
tion of  alkaline  carbonates  in  natural  waters  and  soils.2  First,  by 
direct  derivation  from  volcanic  rocks.  Second,  by  reduction  of 
alkaline  sulphates.  Third,  by  double  decomposition  between  cal- 
cium bicarbonate  and  alkaline  sulphates  or  chlorides.  All  three  are 
possible,  and  all  three  are  doubtless  represented  by  actual  occurrences 
in  nature.  The  presence  of  sodium  carbonates  in  the  waters  of  hot 
springs,  which,  it  may  be  observed,  are  common  in  the  Lahontan 
basin,  we  can  ascribe  to  the  operation  of  the  first  process ; the  second 
mode  of  derivation  is  effective  wherever  alkaline  sulphates  and 
organic  matter  are  found  together;  the  third  method  is  perhaps  the 
most  general  of  all.  To  the  action  between  alkaline  salts  and  cal- 
cium bicarbonate,  Hilgard  attributes  the  common  presence  of  sodium 
carbonate  in  the  soils  of  arid  regions,  a mode  of  occurrence  which 
is  very  widespread  and  of  the  utmost  importance  to  agriculture. 
The  reclamation  of  arid  lands  by  irrigation  is  profoundly  affected 
by  the  presence  of  these  salts,  which  sometimes  accumulate  to  such 
an  extent  as  to  destroy  fertility.  Excessive  irrigation  may  defeat 
its  own  purpose  and  destroy  the  value  of  land  which  might  be 
reclaimed  from  the  desert  by  a more  moderate  procedure.3  The 
soluble  salts  which  exist  below  the  surface,  being  dissolved,  rise  by 
capillary  attraction  and  form  the  objectionable  crusts  of  “ alkali.” 

1 Zeitschr.  Gesell.  Erdkunde,  vol.  33,  1898,  p.  1.  Several  references  to  bacteriologic  researches  are  given 
in  this  memoir. 

2 To  these  theories  may  be  added  a fourth,  that  of  C.  Ochsenius  (Zeitschr.  prakt.  Geologie,  1893,  p.  198), 
who  supposes  that  the  alkaline  carbonates  have  been  formed  by  the  action  of  carbon  dioxide,  commonly 
of  volcanic  origin,  on  the  “mother-liquor  salts.”  The  evidence  in  favor  of  this  view  is  so  slender  that  a 
discussion  of  it  would  be  hardly  worth  while. 

s The  reports  of  the  Bureau  of  Soils,  U.  S.  Dept.  Agr.,  and  of  the  agricultural  experiment  stations  of  sev- 
eral Western  States  contain  abundant  literature  on  this  subject.  The  report  of  the  Division  of  Soils  for 
1900  contains  a paper  by  F.  K.  Cameron  on  the  application  of  the  theory  of  solution  to  the  study  of  soils, 
in  which  the  generation  of  alkaline  carbonates  by  double  decomposition  is  discussed  on  the  basis  of  modem 
physical  chemistry.  In  Bull.  42  of  the  New  Mexico  College  of  Agriculture  there  is  a summary  of  the  lit- 
erature on  alkali  soils.  A remarkable  deposit  of  natron  in  San  Luis  Valley,  Colorado,  is  described  by 
W.  P.  Headden,  Am.  Jour.  Sci.,  4th  ser.,  vol.  27, 1909,  p.  305. 


SALINE  RESIDUES. 


243 


BORATES. 

Borates  and  nitrates  are  much  less  frequently  deposited  and  in 
much  smaller  amounts  than  the  salts  which  we  have  so  far  been  con- 
sidering. They  are,  however,  important  saline  residues  and  deserve 
a more  extended  study  than  they  seem  to  have  yet  received.  In 
the  chapter  upon  closed  basins  attention  was  called  to  the  Borax 
Lake  of  northern  California,  and  among  mineral  springs  a number 
containing  borates  were  noted.  The  latter  were  hot  springs,  situated 
in  volcanic  regions,  as  in  the  Yellowstone  Park — a mode  of  occur- 
rence which  must  be  borne  in  mind  if  we  are  to  determine  the  origin 
of  these  substances.  We  must  also  remember  that  borates  exist  in 
sea  water,  from  which  source  the  deposits  at  Stassfurt  are  supposed 
to  be  derived.  Two  sets  of  facts,  therefore,  have  to  be  considered 
in  dealing  with  this  class  of  compounds.  Let  us  first  examine  the 
actual  occurrences  of  borates  as  saline  residues.1 

Borax  Lake,  Lake  County,  California,  has  been  repeatedly  de- 
scribed.2 Its  water  contains  chiefly  sodium  carbonate  and  sodium 
chloride,  with  borax  next  in  importance,  and  it  deposits  the  last- 
named  salt  in  crystals,  some  of  which  are  several  inches  long.  More 
borax,  however,  was  furnished  by  a neighboring  smaller  lake,  Ha- 
chinchama.  The  supply  probably  came,  according  to  Becker,  from 
hot  springs  near  the  lakes,  and  one  spring,  of  which  the  analysis 
has  already  been  given,  contains  not  only  boron,  but  also  a surpris- 
ing quantity  of  ammonium  compounds.  The  same  association  of 
borates  with  ammoniacal  salts  is  also  to  be  observed  in  the  waters 
of  the  Yellowstone  Park,  and  especially  in  that  unique  solution 
known  as  “ the  Devil’s  Inkpot.”  The  hot  springs  of  the  Chaguarama 
Valley,  in  Venezuela,3  furnish  a similar  example;  and  here  again,  as  in 
some  of  the  California  localities  described  by  Becker,  sulphur  and 
cinnabar  are  deposited.  Boric  acid  and  ammonium  chloride  are 
among  the  volcanic  products  of  the  island  of  Vulcano;4  but  the 
famous  “sofhoni”  or  “fumaroles”  of  Tuscany  are  of  much  greater 
importance.  Here  jets  of  steam  carrying  boric  acid  emerge  from  the 
ground  and  supply  great  quantities  of  that  substance  for  industrial 
purposes.  The  following  compounds  of  boron  are  deposited, by  the 
lagoons  in  which  the  boric-acid  vapors  are  concentrated: 


Sassolite H3B03  (orthoboric  acid). 

Larderellite (NH4)2B8013.4H20. 

Bechilite CaB407.4H20  (borocalcite). 

Lagonite Fe///2B6012.3H20. 


1 For  general  information  about  American  localities  see  Mineral  Resources  U.  S.  for  1882,  U.  S.  Geol. 
Survey,  p.  566;  1883-84,  p.  858;  1889-90,  p.  494;  and  1901,  p.  869. 

2 Geol.  Survey  California,  Geology,  vol.  1,  1865,  p.  97.  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13, 
1888,  pp.  264-268.  H.  G.  Hanks,  Third  Ann.  Rept.  State  Mineralogist  (California).  For  analyses  of  the 
water  and  of  an  adjacent  hot  spring,  see  ante,  pp.  160, 197.  This  lake,  situated  about  80  miles  north  of  San 
Francisco,  must  not  be  confused  with  Searles’s  “ Borax  Lake”  in  San  Bernardino  County. 

3 See  E.  Cortese,  Eng.  and  Min.  Jour.,  vol.  78,  November  10,  1904. 

4 See  A.  Bergeat,  Zeitschr.  prakt.  Geologie,  1899,  p.  45. 


244 


THE  DATA  OF  GEOCHEMISTRY. 


One  of  these  salts  is  an  ammonium  borate,  and  another  ammonium 
compound — boussingaultite,  (NH4)2Mg(S04)2.6H20 — is  also  formed 
at  this  locality.  According  to  C.  Schmidt 1 the  condensible  vapors 
from  the  fumaroles  of  Monte  Cerboli  contain  boric  acid  and  am- 
monia in  considerable  amounts,  with  much  less  hydrogen  sulphide. 
Water  issues  with  the  vapors,  and  in  samples  condensed  from  several 
vents  C.  M.  Kurtz  2 found  solid  contents  ranging  from  less  than  1 
to  more  than  7 grams  per  liter.  Four  of  the  lagoon  waters  examined 
by  Kurtz  contained  the  following  quantities  of  foreign  matter: 


Foreign  matter  in  Tuscan  lagoon  waters. 
[Grams  per  liter.] 


Total  solids. . 

Boric  acid 
(H3BO3). 

Ammonium 

sulphate. 

Castelnuovo 

8.  565 

4. 154 

1.  695 

Larderello 

6.  720 

4.  032 

. 760 

Monte  Rotondo,  uppermost  lagoon 

2.  005 

1. 100 

.253 

Monte  Rotondo,  lowest  lagoon 

22.  575 

19.  300 

.587 

The  high  figures  of  the  last  example  represent  a concentration 
from  all  the  upper  waters,  which  are  united  at  the  lowest  level.  In 
the  dark-brown  sediment  of  the  lagoons  Schmidt  found  gypsum,  am- 
monium sulphate,  ammonium  thiosulphate,  ammonium  sulphide, 
ammonium  Carbonate,  magnesia,  and  a little  soda  and  potash  mixed 
with  a clay  derived  from  dolomite  and  colored  by  iron  sulphide.  He 
also  analyzed  the  mother  liquor  left  by  the  lagoon  waters  after  most 
of  their  boric  acid  had  been  deposited.  I have  reduced  his  analysis 
to  percentages  of  total  solids,  and  essentially  to  ionic  form,  except 
that  for  the  excess  of  boric  acid  I prefer  to  use  the  symbol  H3B03. 
Schmidt  gives  the  total  solids  as  16.374  grams  per  liter,  reckoning 
the  free  acid  as  B203;  as  recalculated  the  sum  becomes  18.548.  The 
revised  figures  are  as  follows: 


Analyses  of  mother  liquor  from  Tuscan  lagoon  water. 


• 

Grams, 
per  liter. 

Grams, 
per  liter 

Cl 

. . 0.  39 

Ca 

0. 16 

so4 

..  49.37 

Mg 

1.99 

B03  in  borates 

. . 2.  50 

(Al,  Fe)203 . . . 

06 

H3BO3 

..  26.92 

Mn203 

Na 

..  .89 

Si02 

Trace. 

K 

NH4 

. . 1.  01 
..  16.71 

100.  00 

1 Ann.  Chem.  Pharm.,  vol.  98,  1856,  p. 

273.  In  vol.  102,  1857,  p.  190, 

Schmidt  also  describes  the  rocks 

of  the  region. 

2 Dingler’s  Polyt.  Jour.,  vol.  212,  1874,  p.  493. 


SALINE  RESIDUES. 


245 


In  the  light  of  all  the  foregoing  data,  we  may  reasonably  assume 
that  there  is  a relation  between  boric  acid  and  ammonium,  at  least 
wherever  hot  springs  carry  appreciable  quantities  of  borates.  The 
boron  and  the  nitrogen  appear  together,  a fact  which  has  led  to  the 
hypothesis  that  boron  nitride,  decomposed  by  steam,  has  been  the 
parent  compound.1 

Boron  nitride,  BN,  is  a well-known  artificial  substance;  it  is  very 
stable  and,  with  steam,  gives  the  required  reaction,  but  it  has  not  yet 
been  observed  as  a natural  mineral  species.  Its  invocation,  then,  as 
an  agent  in  the  production  of  borates  is  purely  hypothetical,  however 
probable  it  may  be.  The  same  objection  applies  to  Dumas’s  suppo- 
sition that  boron  sulphide,  B2S3,  also  decomposed  by  steam,  was  the 
source  of  the  boric  acid  contained  in  the  “ soffioni.”  2 That  hypothesis 
was  indicated  by  the  presence  of  hydrogen  sulphide  in  the  boron- 
bearing vapors.  P.  Bolley  3 suggested  that  a reaction  of  ammonium 
chloride  on  borax,  which  he  proved  to  be  experimentally  possible, 
might  give  rise  to  the  observed  phenomena;  and  E.  Bechi,4  in  a later 
memoir  than  the  one  previously  cited,  traced  the  borates  to  the  neigh- 
boring ophiolitic  serpentines,  in  which  he  found  at  least  one  inclu- 
sion of  datolite,  a borosilicate  of  lime.  The  serpentine,  heated  to 
300°  in  a current  of  steam  and  carbonic  acid,  yielded  boric  acid, 
ammonium  compounds,  and  hydrogen  sulphide — the  very  products 
found  in  the  fumaroles.  Serpentine,  however,  is  a secondary  rock,  and 
may  have  derived  its  borates  and  ammonium  salts  from  the  solutions 
which  brought  about  the  transformation  of  the  original  gabbro. 

In  recent  years  E.  Perrone  5 and  R.  Nasini 6 have  suggested  that  the 
Tuscan  boric  acid  may  be  derived  from  the  decomposition,  by  water, 
of  tourmaline  contained  in  deep-seated  granites.  Nasini  supports  this 
opinion  by  showing  that  steam  at  high  temperatures  extracts  boric 
acid  from  tourmaline.  The  suggestion,  however,  does  not  account 
for  the  ammonium  compounds  associated  with  the  boric  acid. 


1 R.  Warington,  Chem.  Gaz.,  1854,  p.  419,  with  special  reference  to  Vulcano,  Lipari  Islands.  H.  Sainte- 
Claire  Deville and  F.  Wohler,  Ann.  Chem.  Pharin.,  vol.  105, 1858, p.  71.  O.  Popp,  idem,  8th supp.  Bd.,  1870, 
p.  5.  E.  Bechi,  Bull.  Soc.  ind.  min.,  vol.  3,  1857-58,  p.  329.  A.  Lacroix  (Compt..  Rend.,  vol.  147,  1908, 
p.  161)  has  found  ammonium  chloride  and  boric  acid  in  recent  fumaroles  of  Vesuvius. 

2 See  paper  by  A.  Payen  on  the  Tuscan  fumaroles,  Annales  chim.  phys.,  3d  ser.,  vol.  1, 1841,  p.  247.  He 
adopts  Dumas’s  theory. 

3 Aim.  Chem.  Pharm.,  vol.  68, 1848,  p.  125. 

4 Atti  R.  accad.  Lincei,3d  ser.,  vol.  2, 1878,  p.  514.  See  also  a summary  by  H.  Schiff  in  Ber.  Deutsch. 

chem.  Gesell.,  vol.  11, 1878,  p.  1690. 

6 Carte  idrographica  d’ltalia,  No.  31,  1904,  p.  355. 

6 Abstract  in  Geol.  Centralbl.,  vol.  8, 1906,  p.413;  and  Atti  R.  accad.  Lincei,  5th  ser.,  vol.  17,  1908,  p.  43. 
For  criticisms  of  Perrone  and  Nasini,  see  G.  d’Achiardi,  Atti  Soc.  toscana  sci.  nat.,  Memorie,  vol.  23, 1907, 
p.  8,  and  Rend.  R.  accad.  Lincei,  5th  ser.,  vol.  17, 1908,  p.  238.  For  a long  paper  on  the  origin  of  boric  acid 
and  the  borates,  see  A.  d’Achiardi,  Atti  Soc.  toscana  sci.  nat.  Pisa,  1878,  vol.  3,  fasc.  2.  Earlier  memoirs 
are  by  H.  Coquand,  Bull.  Soc.  g<§ol.  France,  2d  ser.,  vol.  6,  1848-49,  p.  91;  C.  Sainte-Claire  Deville  and  F. 
Leblanc,  Compt.  Rend.,  vol.  45, 1857,  p.  750;  vol.  47, 1858,  p.  317;  and  F.  Fouqud  and  H.  Gorceix,  idem, 
vol.  69, 1869,  p.  946.  The  gases  from  the  “soffioni”  have  been  studied  by  R.  Nasini,  F.  Anderlini,  and 
R.  Salvadori  (AttiR.  accad.  Lincei,  5th  ser.,  Memorie,  vol.  2,  1895,  p.  388),  as  well  as  by  some  of  the  above- 
named  authorities.  Carbon  dioxide  is  the  principal  gas. 


246 


THE  DATA  OF  GEOCHEMISTRY. 


An  entirely  different  mode  of  occurrence  for  borates  is  shown  on 
an  extensive  scale  in  Nevada  and  southern  California  and  at  a few 
localities  in  Oregon.1  Here  borax,  as  such,  is  found  in  considerable 
quantities;  but  the  calcium  salts  ulexite  and  colemanite  are  by  far  the 
more  important  species. 

In  Esmeralda  County,  Nevada,  at  Teel’s  marsh,  Rhodes’s  marsh, 
Columbus  marsh,  and  Fish  Lake,  ulexite,  NaCaB509.8H20,  is  the 
principal  borate.  It  occurs  in  nodules,  known  locally  as  “cotton 
balls,”  which  have  a fibrous  structure  and  seem  to  be  in  process  of 
formation,  the  smaller  masses  gradually  becoming  larger.2  At 
Rhodes’s  marsh,  according  to  Joseph  Le  Conte,3  the  central  part  of 
the  area  is  occupied  by  a bed  of  common  salt,  around  which  there  are 
deposits  of  sodium  sulphate.  Beyond  the  sulphate  beds  the  borax 
and  ulexite  are  found.  These  “marshes,”  which  are  really  playa 
lakes,  are  of  secondary  origin;  and  M.  R.  Campbell,  speaking  of  the 
similar  formations  in  California,4  attributes  their  borates  to  leachings 
from  beds  of  Tertiary  sediments. 

The  borates  of  southern  California  are  widely  scattered  over  a large 
area,  which  is  practically  a continuation  of  the  Nevada  field.  They 
are  found  especially  in  Inyo  and  San  Bernardino  counties,  in  Death 
Valley,  along  the  basin  of  the  Amargosa  River,  and  elsewhere.  The 
locality  known  as  Searles’s  marsh,  or  Searles’s  borax  lake,  has  been 
worked  since  1873;  and  as  it  has  yielded  a number  of  new  mineral 
species,  it  deserves  special  consideration  here.  In  chemical  interest 
it  rivals  Stassfurt,  although  its  systematic  study  is  hardly  more  than 
begun.  Borings  at  this  point,  according  to  De  Groot,5 6  have  revealed 
the  following  succession  of  deposits: 

Section  at  Searles’s  marsh , San  Bernardino  County , California. 


Feet. 

1.  Salt  and  thenardite 2 

2.  Clay  and  volcanic  sand,  with  some  hanksite 4 

3.  Volcanic  sand  and  black  clay,  with  bunches  of  trona 8 

4.  Volcanic  sand,  containing  glauberite,  thenardite,  and  a few 

crystals  of  hanksite 8 

5.  Solid  trona,  overlain  by  a thin  layer  of  very  hard  material 28 

6.  Mud,  smelling  of  hydrogen  sulphide  and  containing  layers  of 

glauberite,  soda,  and  hanksite 20 

7.  Clay,  mixed  with  volcanic  sand  and  permeated  with  hydrogen 

sulphide 230+ 


1 See  H.  G.  Hanks,  Third  Ann.  Kept.  State  Mineralogist  California,  1883,  and  Am.  Jour.  Sci.,  3d  ser.,  vol. 
37,  1889,  p.  63;  H.  De  Groot,  Tenth  Ann.  Rept.  California  State  Mining  Bureau,  1890;  G.  E.  Bailey,  The 
saline  deposits  of  California:  Bull.  No.  24,  California  State  Mining  Bureau,  1902.  For  the  geology  of  the 
borax  deposits  in  Death  Valley  and  the  Mohave  Desert,  see  M.  R.  Campbell,  Bull.  U.  S.  Geol.  Survey  No. 
200,  1902,  and  an  article  in  Eng.  and  Min.  Jour.,  vol.  74, 1902,  p.  517.  An  important  memoir  on  the  borax 
deposits  of  the  United  States,  by  C.  R.  Keyes,  is  in  the  Bull.  Am.  Inst.  Min.  Eng.,  1909,  p.  867. 

2 Rept.  State  Mineralogist  Nevada,  1871-72,  p.  35. 

3 Third  Ann.  Rept.  State  Mineralogist  California,  1883,  p.  51. 

4 Bull.  U.  S.  Geol.  Survey  No.  213,  1903,  p.  401.  See  also  J.  E.  Spurr,  Bull.  U.  S.  Geol.  Survey  No.  208, 

1903. 

6 Tenth  Ami.  Rept.  California  State  Mining  Bureau,  1890,  p.  535. 


SALINE  RESIDUES. 


247 


The  borax  of  Searles’s  marsh  is  found  chiefly  in  the  top  crust,  or 
crystallized  in  the  water  which  sometimes  accumulates  in  the  depres- 
sions of  the  bed.  This  layer  is  reproduced  by  slow  degrees,  through 
capillary  action,  which  brings  up  the  soluble  salts  from  below,  so  that 
the  same  area  can  be  repeatedly  worked  over.  In  the  workings  the 
following  mineral  species  have  been  found:1 


Anhydrite CaS04. 

Gypsum CaS04 . 2H20 . 

Celestite SrS04. 

Thenardite Na2S04. 

Mirabilite Na2SO4.10H2O. 

Glauberite Na2Ca(S04)2. 

Sulphohalite  2 Na6(S04)2ClF. 

Hanksite Na22K(S04)9(C03)2Cl. 

Borax Na2B407 . 10H2O . 

Colemanite Ca2B60!  x .5H20 . 

Calcite CaC03. 

Dolomite MgCa(C03)2. 

Natron NaCO3.10H2O. 

Trona Na3H(C03)2.2H20 . 

Gaylussite  3 Na2Ca(C03)2.5H20. 

Pirssonite  3 Na2Ca(C03)2.2H20. 

Northupite  3 Na3Mg(C03)2Cl. 

Tychite  4 Na6Mg2(C03)4S04. 

Halite NaCl. 

Soda  niter NaN03. 

Searlesite  5 Na20.B203.4Si02.2H20. 


Sulphur,  from  reduction  of  sulphates.6 

In  the  water  from  15  feet  below  the  crust,  or  “ crystal  layer,” 
ammonium  salts  are  reported  to  occur — a fact  which  becomes  pecul- 
iarly significant  when  it  is  considered  in  connection  with  the  presence 
of  soda  niter  also.  To  this  point  we  shall  recur  later.  It  is  evident 
that  the  paragenesis  of  all  these  mineral  species  presents  a complex 
chemical  problem,  quite  analogous  to  that  investigated  by  Van’t  Hoff 
in  his  studies  of  the  Stassfurt  beds. 


1 De  Groot  also  mentions  cerargyrite,  embolite,  and  gold;  but  these  minerals  have  no  obvious  relationship 
to  the  other  species. 

2 S.  L.  Penfield,  Am.  Jour.  Sci.,  4th  ser.,  vol.  9, 1900,  p.  425. 

s J.  H.  Pratt,  Am.  Jour.  Sci.,  4th  ser.,  vol.  2, 1896,  p.  123  et  seq.;  vol.  3,  1897,  p.  75. 

4 S.  L.  Penfield  and  G.  S.  Jamieson,  idem,  vol.  20,  1905,  p.  217.  The  authors  prepared  tychite  synthet- 
ically. Both  northupite  and  tychite  have  also  been  made  artificially  by  A.  B.  de  Schulten,  Bull.  Soc. 
Min.,  vol.  19,  1896,  p.  164,  and  Compt.  Rend.,  vol.  143,  1906,  p.  403.  The  relations  between  the  two  species 
are  perhaps  more  clearly  expressed  by  formulae  of  the  following  type: 


Tychite 2MgC03.2Na2C03.Na2S0<. 

N orthupite 2MgC  O3. 2N  a2CC>3.2N  aCl . 


On  gaylussite  and  pirssonite,  see  R.  Wegscheider  and  H.  Walter,  Monatsh.  Chemie,  vol.  28, 1907,  p.  633. 

6 E.  S.  Larsen  and  W.  B.  Hicks,  Am.  Jour.  Sci.,  4th  ser.,  vol.  38,  1914,  p.  437.  Searlesite  is  peculiarly 
interesting  as  the  first  known  example  of  an  alkaline  borosilicate. 

e For  a full  description  of  the  minerals  of  Searles’s  marsh,  see  H.  S.  Gale  and  W.  T.  Schaller,  Bull.  U.  S. 
Geol.  Survey  No.  580, 1914,  pp.  296-308.  On  pp.  276  and  277  Gale  cites  analyses  of  the  brine  of  the  marsh 
or  “lake.” 


248 


THE  DATA  OF  GEOCHEMISTRY. 


About  12  miles  north  of  Daggett,  in  the  southern  part  of  San 
Bernardino  County,  a still  different  borate  deposit  is  found.1  Here, 
interstratified  with  lake  sediments,  a solid  bed  of  colemanite  exists, 
which  ranges  from  5 to  30  feet  in  thickness  and  is  highly  crystalline. 
At  one  end  the  colemanite  is  much  mixed  with  sand,  gypsum,  and 
clay,  suggesting  that  it  had  been  laid  down  at  the  edge  of  an  evapo- 
rating sheet  of  water.  Campbell  regards  the  borax  of  the  Amargosa 
marshes  as  probably  derived  from  the  leaching  of  deposits  simi- 
lar to  this.  H.  S.  Gale,2  however,  who  has  more  recently  studied 
the  colemanite,  regards  it  as  a vein  mineral. 

From  another  point  in  the  Mohave  Desert  a mineral  has  been  re- 
ported3 (bakerite),  having  the  empirical  formula  8Ca0.5B203.6Si02. 
6H20;  but  its  definite  character  is  yet  to  be  ascertained.  Priceite, 
which  is  probably  a massive  form  of  colemanite,  is  found  in  Curry 
County,  Oregon,  on  the  shore  of  the  Pacific.  It  occurs  in  com- 
pact nodules,  from  the  size  of  an  egg  up  to  several  tons  in  weight, 
associated  with  serpentine.4  Pandermite,  another  variety  of  the 
same  species,  from  near  Panderma,  on  the  Sea  of  Marmora,  also 
forms  nodules,  but  in  a bed  underlying  a thick  stratum  of  gypsum. 
Colemanite  and  its  modifications,  then,  exist  under  a variety  of  dif- 
ferent conditions,  and  we  can  not  say  that  it  has  always  been  pro- 
duced in  the  same  way.  It  is  stated  by  Campbell,5  however,  that 
the  lake-bed  deposits  of  California  were  probably  laid  down  during 
a period  of  volcanic  activity. 

Both  colemanite  and  pandermite  have  been  prepared  artificially 
by  J.  H.  Van’t  Hoff,6  who  acted  on  ulexite  (boronatrocalcite)  with 
saturated  solutions  of  alkaline  chlorides.  With  a solution  of  sodium 
and  potassium  chlorides  at  110°  pandermite  was  formed  to  which  Van’t 
Hoff  assigns  the  formula  Ca8B20O38.15H2O.  Colemanite,  Ca2B6On. 
5H20,  forms  from  ulexite  in  a sodium  chloride  solution  most  readily 
at  70°.  Van’t  Hoff,  it  will  be  noticed,  does  not  regard  pandermite 
and  colemanite  as  identical. 

Immediately  south  of  Lake  Alvord,  in  Harney  County,  Oregon,  an 
extensive  marsh  is  covered  by  an  incrustation  containing  borax,  salt, 
sodium  sulphate,  and  sodium  carbonate  in  varying  proportions.7 
This  locality  has  been  worked  for  borax,  and  the  deposit  is  said  to  be 
continually  reproduced.  The  region  calls  for  more  complete  exami- 
nation, especially  on  the  chemical  side. 

1 See  M.  R.  Campbell,  Bull.  U.  S.  Geol.  Survey  No.  200,  and  W.  H.  Storms,  Eleventh  Ann.  Rept.  Cal- 
ifornia State  Mining  Bureau,  1893,  p.  345. 

2 Prof.  Paper  U.  S.  Geol.  Survey  No.  85, 1913,  p.  3. 

3 W.  B.  Giles,  Mineralog.  Mag.,  vol.  13, 1903,  p.  353. 

* Information  received  from  J.  S.  Diller,  who  has  examined  the  locality. 

b Eng.  and  Min.  Jour.,  vol.  74, 1902,  p.  517. 

e Sitzungsb.  Akad.  Berlin,  vol.  39, 190G,  pp.  566,  689. 

i W.  D.  Dennis,  Eng.  and  Min.  Jour.,  vol.  73, 1902,  p.  581. 


SALINE  RESIDUES. 


249 


In  the  arid  region  of  southern  California  beds  containing  sodium 
nitrate  are  found  near  the  borate  deposits.  The  same  association,  if 
we  can  justly  call  it  so,  also  exists  in  South  America,  where  the  soda 
niter  of  the  Tarapaca  and  Atacama  deserts  is  accompanied,  more  or 
less  closely,  by  ulexite.  As  early  as  1844  A.  A.  Hayes  1 described  the 
calcium  borate  from  near  Iquique,  and  noted  its  association  with 
glauberite,  gypsum,  pickeringite,  and  a native  iodate  of  sodium. 
D.  Forbes,2  describing  more  fully  the  salines  of  this  region,  which  he 
regarded  as  post-Tertiary,  added  salt,  epsomite,  mirabilite,  thenardite, 
glauberite,  soda  alum,  anhydrite,  soda  niter,  and  borax  to  the  list  of 
species.  The  salines  themselves  Forbes  attributed  to  the  concentra- 
tion of  sea  water,  but  the  borates  were,  he  believed,  of  volcanic  origin. 
They  occur  in  the  more  elevated  parts  of  the  saline  region,  in  which 
he  found -active  fumaroles;  but  the  latter  were  not  examined  for 
boron.  Later  3 he  was  able  to  confirm  this  view  by  finding  a calcium 
borate,  either  ulexite  or  bechilite,  actually  in  process  of  deposition 
at  the  hot  springs  of  Banos  del  Toro,  in  the  Cordilleras  of  Coquimbo. 
L.  Darapsky,  in  his  work  on  the  Taltal  district,4  speaks  of  ulexite  as 
a regular  companion  of  the  nitrates,  and  especially  notes  the  presence 
of  borates  in  the  waters  of  a lagoon  at  Maricunga.  The  borax  “lake ” 
of  Ascotan,  according  to  R.  T.  Chamberlin,5  derives  its  borates, 
mainly  ulexite,  from  leachings  from  adjacent  volcanoes. 

Farther  east,  in  Argentina,  several  borate  localities  are  known. 
J.  J.  Kyle  6 describes  ulexite,  associated  with  glauberite,  from  the 
Province  of  Salta,  and  refers  to  its  existence  in  Catamarca.  It  is  also 
found  at  Safinas  Grandes,  Province  of  Jujuy,  according  to  H.  Butt- 
genbach,7  who  describes  the  occurrence  in  some  detail.  The  center 
of  the  deposit  is  covered  with  rock  salt  20  to  30  centimeters  in  thick- 
ness, and  around  its  borders  the  ulexite  nodules  are  unevenly  dis- 
tributed. Gypsum,  soda  niter,  glauberite,  and  pickeringite  are  also 
found  with  it,  the  gypsum  predominating.  Boracite  and  carnallite 
are  absent.  The  locality  is  overflowed  in  spring  by  water  from  the 
mountains,  but  is  dry  in  summer,  and  Buttgenbach  expresses  the 
opinion  that  ulexite  is  produced  every  year  at  flood  time.  It  will 
be  remembered  that  this  same  phenomenon  of  growth  was  noted  in 
connection  with  the  Nevada  mineral.  The  boric  acid  of  the  ulexite 

1 Am.  Jour.  Sci.,  1st  ser.,  vol.  47, 1844,  p.  215. 

2 Quart.  Jour.  Geol.  Soc.  London,  vol.  17, 1861,  p.  7. 

3 Philos.  Mag.,  4th  ser.,  vol.  25, 1863,  p.  113. 

4 Das  Departement  Taltal  (Chile),  Berlin,  1900.  See  especially  pp.  149, 150, 163.  An  abstract  is  printed 
in  Zeitschr.  prakt.  Geologic,  1902,  p.  153. 

5 Jour.  Geology,  vol.  20,  p.  763, 1912. 

6 Anales  Soc.  cient.  Argentina,  vol.  10, 1880,  p.  169. 

7 Annales  Soc.  gdol.  Belgique,  vol.  28,  M,  1900-1901,  p.  99.  Analyses  of  the  ulexite  are  given. 


250 


THE  DATA  OF  GEOCHEMISTRY. 


is  regarded  by  Buttgenbach  as  being  of  volcanic  origin.1  The  same 
view  is  held  by  A.  Jockamowitz  2 with  regard  to  the  ulexite  of  the 
Salinas  Lagoon,  Province  of  Arequipa,  Peru. 

The  old  localities  for  borax  in  Tibet  and  the  adjacent  regions  have 
been  little  visited  by  Europeans,  and  detailed  information  concerning 
them  is  very  scanty.  H.  von  Schlagintweit,3  however,  has  described 
the  great  borax  deposits  of  the  Puga  Valley,  in  Ladak,  where  the  min- 
eral covers  the  ground  over  a large  area  to  an  average  depth  of  3 
feet.  The  borax  is  a deposit  from  hot  springs,  which  issue  more  than 
15,000  feet  above  sea  level,  at  a temperature  ranging  from  54°  to  58° 
C.  The  saline  mass  also  contains  free  boric  acid  and  sulphur,  with 
less  salt,  ammonium  chloride,  magnesium  sulphate,  and  alum,  and 
there  is  much  gypsum  in  its  vicinity.  No  ulexite  was  found. 

On  the  peninsula  of  Kertch,  near  the  Sea  of  Azov,  borax  occurs 
among  the  erupted  substances  of  the  so-called  “mud  volcanoes.”  4 
It  effloresces  upon  the  surface  of  the  dried  mud,  and  is  more  or  less 
mixed  with  salt  and  soda. 

Since  borates  are  present  in  sea  water,  it  follows  that  they  must 
also  occur  among  the  products  of  its  evaporation.  This  conclusion  is 
best  verified  at  Stassfurt,  where  the  following  species  are  found: 5 

Boracite Mg7Cl2B16O30. 

. Pinnoite MgB204.3H20. 

Ascharite 3Mg2B205 . 2H20 . 

Heintzite K2Mg4B22038 . 14H20 . 

Hydroboracite  (?) CaMgB60n.6H20. 

Sulphoborite 2MgS04 .4MgHB03 . 7 H20 . 

Of  these  species,  hydroboracite  is  found  in  the  lower  deposits  at 
Stassfurt,6  associated  with  anhydrite;  the  others  are  characteristic 
of  the  carnallite  zone.  That  is,  they  are  mother  liquor  salts,  and 
among  the  latest  substances  to  crystallize.  It  is  also  to  be  noted 
that  they  are  essentially  magnesian  borates,  and  that  calcium,  which 
is  the  dominant  metal  in  the  Chilean  and  Californian  localities, 
occurs  in  only  one  of  the  StassfuFt  species.  This  is  what  we  should 
expect  from  sea  water,  in  which  magnesium  is  abundant  and  calcium 
relatively  subordinate.  In  any  general  discussion  of  the  genesis  of 
borates  this  distinction  must  be  borne  in  mind.7 


1 In  Chem.  Zeitung,  vol.  30,  1906,  p.  150,  F.  Reichert  describes  eight  of  the  Argentine  “borateras”  and 
gives  analyses  of  their  products.  His  complete  report,  Los  yacimientos  de  boratos,  etc.,  is  in  Anales  del 
Ministerio  de  agricultura,  Buenos  Aires,  1907.  For  an  abstract,  see  Zeitschr.  Kryst.  Min.,  vol.  47,  1909,  p. 
205. 

2 Bol.  Cuerpo  ing.  minas,  Peru,  No.  49, 1907. 

3 Sitzungsb.  Acad.  Munchen,  vol.  8, 1878,  p.  518. 

4 W.  S.  Vernadsky  and  S.  P.  Popoflf,  Zeitschr.  prakt.  Geologie,  1902,  p.  79. 

5 Liineburgite,  a magnesium  borophosphate  found  with  the  potash  salts  of  Liineburg,  Hannover,  may 
fairly  be  included  with  this  list. 

6 In  his  paper  on  the  borates  of  the  German  potash  salts,  H.  E.  Boeke  (Centralbl.  Min.,  Geol.  u.  Pal., 
1910,  p.  531)  does  not  mention  hydroboracite.  Its  identification  is,  perhaps,  not  quite  certain. 

' See  also  W.  Biltz  and  E.  Marcus  (Zeitschr.  anorg.  Ohemie,'vol.  72,  1911,  p.  302)  on  the  borates  of 
Stassfurt. 


SALINE  RESIDUES. 


251 


In  the  gypsum  beds  of  Nova  Scotia  ulexite,  howlite,  and  crypto- 
morphite  are  found,  associated  with  anhydrite,  selenite,  mirabilite, 
salt,  aragonite,  and  calcite.1  Howlite  is  represented  by  the  formula 
H5CaB2Si014;  cryptomorphite  2 is  probably  H2Na4Ca6(B407)9.22H20. 
If  this  gypsum  is,  as  most  authorities  assume,  a marine  deposit,  these 
salts  occupy  a position  similar  to  that  filled  by  hydroboracite  at 
Stassfurt,  but  the  total  absence  of  magnesium  is  rather  striking.3 

In  order  to  account  for  the  origin  of  boric  acid  and  saline  borates, 
three  hypotheses  have  been  proposed  and  strenuously  advocated. 
First,  they  may  be  derived  from  the  leaching  of  rocks  containing 
borosilicates,  such  as  tourmaline,  axinite,  dumortierite,  danburite, 
and  datolite.  Second,  they  are  supposed  to  be  of  volcanic  origin. 
Third,  they  are  regarded  as  marine  deposits.  Probably  each  mode 
of  derivation  is  represented  by  actual  occurrences  in  nature,  as  may 
be  judged  from  the  evidence  brought  forward  in  the  preceding  pages, 
but  the  first  supposition  has  not  been  directly  tested  at  any  known 
locality.  Many  rocks,  especially  granites  and  mica  schists,  contain 
tourmaline;  they  undergo  decomposition,  and  boric  acid  is  washed 
away;  but  borates  from  that  source  have  not  been  found  to  accumu- 
late in  any  known  saline  residue.  They  may  do  so,  but  they  have  not 
been  directly  traced.  If,  however,  it  could  be  shown  that  volcanic 
borates  came  from  the  thermal  metamorphism  of  tourmaline-bearing 
rocks,  the  first  and  second  hypotheses  might  be  partly  unified.  Even 
then  the  question  of  the  formation  of  soluble  borates  by  weathering 
would  be  untouched. 

The  volcanic  theory  seems  to  fit  a considerable  number  of  borate 
localities,  although  its  application  to  some  cases  may  have  been  forced, 
and  for  others  its  validity  has  been  doubted.  Several  writers  have 
denied  the  volcanic  character  of  the  Tuscan  fumaroles,  despite  the 
thermal  activity  of  the  region  and  the  presence  in  it  of  eruptive 
rocks.4  That  boric  acid  is  emitted  from  volcanic  vents  is,  however, 
unquestionable.  It  is  there  associated  with  ammonium  salts  precisely 
as  it  is  at  Monte  Cerboli — an  association  which  can  not  be  overlooked 
or  disregarded. 

The  marine  origm  of  borates  is  most  evident  at  Stassfurt,  although 
even  here  their  presence  has  been  attributed  to  the  injection  of  vol- 
canic gases.  Here,  however,  and  also  in  the  gypsum  beds  of  Nova 
Scotia  the  nitrogen  compounds  are  lacking,  a clear  distinction  from 
the  presumably  volcanic  occurrences.  At  Stassfurt  the  volcanic 

1 See  H.  How,  Am.  Jour.  Sci.,  2d  ser.,  vol.  32, 1861,  p.  9;  Philos.  Mag.,  4th  ser.,  vol.  35,  1868,  p.  31;  vol.41, 
1871,  p.  270. 

2 Calculated  by  F.  W.  Clarke  from  How’s  analysis. 

3 The  suggestion  of  J.  W.  Dawson  (Acadian  geology,  1891,  p.  262)  that  these  enormous  masses  of  gypsum 
were  produced  by  the  action  of  acid  volcanic  waters  on  limestone  is  of  doubtful  significance.  The  region, 
however,  contains  eruptive  rocks  in  great  abundance,  a fact  which  may  partly  justify  the  speculation. 

* See,  for  example,  a letter  from  W.  P.  Jervis,  published  by  H.  G.  Hanks  in  Third  Ann.  Rept.  State  Min- 
eralogist California,  1883,  p.  68;  also  L.  Dieulafait,  Compt.  Rend.,  vol.  100, 1885,  p.  1240. 


252 


THE  DATA  OF  GEOCHEMISTRY. 


hypothesis  seems  to  be  quite  superfluous,  and  the  derivation  of  all 
the  saline  substances  which  there  coexist  can  be  most  easily  ex- 
plained as  due  to  the  concentration  of  sea  water.  The  existence  of 
borates  in  the  latter  is  clearly  established;  but  whence  were  they 
derived  ? Any  answer  to  that  question  must  be  purely  speculative. 
Whether  we  invoke  the  aid  of  submarine  volcanoes  or  attribute  our 
borates  to  leachings  from  the  land,  we  go  beyond  the  limits  of  our 
knowledge  and  remain  unsatisfied. 

Confining  ourselves,  then,  to  considerations  of  a proximate  char- 
acter, we  may  fairly  assert  that  certain  borate  localities  are  of  volcanic 
and  others  of  oceanic  origin.  Nevertheless,  attempts  have  been  made 
to  explain  all  these  deposits  by  the  marine  hypothesis,  as  in  the 
memoirs  of  C.  Ochsenius  1 and  L.  Dieulafait.2  Dieulafait  tries  to 
prove  that  all  saline  deposits  are  primarily  derived  from  sea  water, 
in  either  ancient  or  modern  times,  and  even  the  Tuscan  “soffioni” 
are  supposed  by  him  to  draw  their  boric  acid  from  subterranean  salif- 
erous sediments.  Mother  liquors,  rich  in  magnesium  chloride  and 
heated  by  steam,  are  thought  to  liberate  hydrochloric  acid,  which, 
acting  upon  the  magnesium  borates,  sets  boric  acid  free,  to  be  carried 
upward  by  the  escaping  vapors.  These  reactions  are  possible,  but  it  is 
not  proved  that  they  have  actually  occurred.  Ochsenius  also  argues 
in  much  the  same  way,  and  points  out  that  beds  of  rock  salt  exist  at 
no  very  great  distance  from  the  region  of  fumaroles.  Their  mother 
liquors  are  to  his  mind  the  source  of  the  boric  acid. 

If  we  turn  to  the  ulexite  and  colemanite  beds  of  California  and 
Chile,  we  find  a distinct  set  of  phenomena  to  be  interpreted.  Here  we 
deal  undoubtedly  with  ancient  lake  beds,  but  the  residues  contain 
calcium,  not  magnesium  borate.  Some  of  the  deposits  are  below  sea 
level,  as  at  Death  Valley;  others  are  thousands  of  feet  above,  as  at 
Maricunga;  and  in  or  near  all  of  them  nitrates  are  also  found.  Hot 
springs  are  common  in  both  regions,  in  California  as  well  as  in  Chile; 
but  they  have  not  been  exhaustively  studied.  Do  they  contain  boric 
acid  and  ammonia  ? If  so,  did  the  lake  beds  derive  their  nitrates  from 
such  sources  ? These  questions  are  legitimate  ones  for  future  investi- 
gators to  answer,  and  the  replies  may  help  to  solve  the  problem  now 
before  us.  Ammonia,  by  oxidation,  yields  nitric  acid — a reaction 
which  has  been  studied  exhaustively  in  the  interests  of  agriculture. 
Forbes  found  a calcium  borate  forming  in  a Chilean  hot  spring.3 
Magnesium  borates  do  not  occur  in  either  group  of  localities.  From 
these  facts  we  see  that  a volcanic  origin  is  conceivable  for  the  deposits 
in  question,  whereas  a marine  source  is  not  at  all  clearly  indicated. 

1 Zeitschr.  prakt.  Geologie,  1893,  pp.  189, 217.  Borates  especially  on  pp.  222, 223. 

2 Annales  chim.  phys.,  5th  ser.,  vol.  12,  1877,  p.  318;  vol.  25,  1882,  p.  145.  Also  Compt.  Rend.,  vol.  85, 
1877,  p.  605;  vol.  94,  1882,  p.  1352;  vol.  100,  1885,  pp.  1017,  1240. 

3 Some  of  the  Chilean  thermal  waters,  analyzed  by  P.  Martens  (Actes  Soc.  sci.  Chili,  vol.  7, 1897,  p.  311), 
contain  both  borates  and  ammonium  salts,  but  not  in  remarkable  proportions. 


SALINE  RESIDUES. 


253 


Neither  hypothesis  can  be  adopted  with  any  degree  of  assurance;  but 
the  volcanic  theory  is  the  more  plausible  of  the  two.  As  we  pass  on 
to  the  study  of  the  nitrate  beds,  these  suggestions  may  become  a little 
clearer.  For  the  moment  the  following  summary  may  serve  to  assist 
future  discussion: 

(1)  Marine  deposits  contain  magnesium  borates. 

(2)  Lake-bed  deposits  contain  calcium  borates,  with  nitrates 
near  by. 

(3)  Volcanic  waters  and  fumaroles,  when  they  yield  borates,  yield 
ammonium  compounds  also. 

NITRATES. 

Nitrates  are  commonly  formed  in  soils  by  the  oxidation  of  organic 
matter,  a process  in  which  the  nitrifying  micro-organisms  play  an 
important  part.1  In  moist  climates  these  salts  remain  in  the  ground 
water,  are  consumed  by  growing  plants,  or  are  washed  away;  in  arid 
or  protected  regions  they  may  accumulate  to  a considerable  extent. 
Some  nitrates  are  also  derived  from  atmospheric  sources,  the  acid 
being  formed  by  electrical  discharges  and  brought  down  by  rain,  but 
their  amount  is  probably  only  a small  portion  of  the  entire  product. 
Wherever  organic  matter  putrefies  in  contact  with  alkaline  materials, 
such  as  lime  or  wood  ashes,  nitrates- are  produced — a process  which 
has  been  carried  on  artificially  in  various  countries  in  order  to  supply 
the  industrial  demand  for  saltpeter.  In  sheltered  places,  such  as 
caverns,  calcium  nitrate  is  often  produced  in  large  quantities,  and  its 
formation  has  commonly  been  attributed  to  the  nitrification  of  bat 
guano.2  This  supposition,  however,  may  not  cover  all  cases,  for 
W.  H.  Hess  3 claims  that  nitrates  are  uniformly  distributed  over  cave 
floors  in  Kentucky  and  Indiana,  even  in  the  remote  interiors  of  cav- 
erns where  no  guano  exists.  In  drippings  from  the  roof  of  the  Mam- 
moth Cave  he  found  5.71  milligrams  per  liter  of  N205,  whose  source 
he  ascribes  to  percolating  waters  from  outside.  The  cave,  in  his 
opinion,  acts  as  a receptacle  for  stopping  a part  of  the  surface  drain- 
age, in  which  nitrates  are  produced  in  the  usual  way.  Earth  gathered 
far  within  the  cavern  contains  nitrates,  but  almost  no  organic  matter. 
The  deposits  of  potassium  nitrate  found  in  Hungary  are  traced  by 

1 See  for  example  W.  P.  Headden  (Proc.  Colorado  Sci.  Soc.,  vol.  10, 1911,  p.  99),  on  unusual  accumula- 
tions of  nitrates  in  certain  Colorado  soils.  He  cites  other  literature. 

2 See  A.  Muntz  and  V.  Marcano,  Ann.  chim.  phys.,  6th  ser.,  vol.  10, 1887,  p.  550,  on  cave  earth  from  Vene- 
zuela. For  an  account  of  saltpeter  earth  in  Turkestan  see  N.  Ljubavin,  Jour.  Chem.  Soc.,  vol.  48,  1885,  p. 
128.  On  nitrate  earth  at  Tacunga,  Ecuador,  see  J.  B.  Boussingault,  Annales  chim.  phys.,  4th  ser.,  vol.  7, 
1866,  p.  358,  followed  by  a letter  from  Chabrid  on  Algerian  saltpeter.  M.  Glasenapp  (Ann.  Geol.  Min. 
Russie,  vol.  12, 1910,  p.  42,  abstract)  describes  an  impregnation  of  potassium  nitrate  in  the  Senonian  sand- 
stones of  the  Caucasus. 

3 Join-.  Geology,  vol.  8,  1900,  p.  129.  The  views  advanced  by  Hess  have  been  disputed  by  H.  W. 
Nichols  (Jour.  Geology,  vol.  9, 1901,  p.  236),  who  regards  guano  as  the  chief  source  of  cave  nitrates. 


254 


THE  DATA  OF  GEOCHEMISTRY. 


C.  Ochsenius  1 to  the  mother  liquors  of  sea  water,  their  potassium 
chloride  being  first  transformed  to  carbonate,  which  latter  is  then 
nitrified  in  presence  of  organic  substances.  In  this  suggestion  the 
hypothetical  element  is  rather  large,  although  it  is  plausibly  defended. 

We  have  already  noticed  the  existence  of  soda  niter  among  the  min- 
erals of  Searles’s  marsh,  and  its  probable  association  with  ammonium 
compounds.  The  same  substance  is  also  reported  to  occur  in  large 
quantities  at  various  other  points  in  southern  California,  especially 
around  Death  Valley  and  along  the  boundary  between  Inyo  and 
San  Bernardino  counties.2  It  is  said  to  form  beds  associated  with 
the  later  Eocene  clays,  and  in  some  cases  to  impregnate  the  latter; 
but  its  direct  conjunction  with  borates  is  not  positively  asserted, 
except  in  the  locality  at  Searles’s  marsh.  The  fact  that  soda  niter 
exists  in  the  same  region  with  the  borates  is  important,  however,  for 
it  correlates  the  California  deposits  with  the  Chilean  beds,  where  a 
similar  relationship  is  recognized.  According  to  Bailey,3  the  rare 
species  darapskite  and  nitroglauberite,  previously  known  only  from 
Chile,  are  also  found  in  the  nitrate  beds  of  California. 

In  the  deserts  of  Atacama  and  Tarapaca,  in  the  northern  part  of 
Chile,4  are  found  the  largest  known  deposits  of  nitrates  in  the  world. 
The  crude  sodium  nitrate  is  termed  locally  “caliche,”  and  the  “cali- 
cheras”  are  scattered  over  a large  area  which  also  contains  beds  of 
salt,  “salares,”  and  the  deposits  of  ulexite  which  we  have  already 
considered.  According  to  V.  L’Olivier,5  the  nitrates  were  first  de- 
posited, then  the  salt,  generally  to  the  westward  of  the  calicheras, 
and  finally  the  borates,  which  lie  more  to  the  east  and  in  the  higher 
levels  of  the  evaporation  basins.  Some  ulexite,  however,  is  found  in 
the  nitrate  beds.  A characteristic  calichera,  in  the  Atacama  Desert, 
50  miles  west  of  Taltal,  is  described  by  J.  Buchanan  6 as  being  made 
up  of  the  following  layers : 


1 Zeitschr.  prakt.  Geologie,  1893,  p.  60. 

2 G.  E.  Bailey,  Bull.  No.  24,  California  State  Mining  Bureau,  1902,  pp.  139-188. 

3 Op.  cit.,  p.  170. 

* The  region  was  formerly  a part  of  Peru  and  Bolivia. 

s Annales  chim.  phys.,  5th  ser.,  vol.  7,  1876,  p.  289.  For  other  details  see  D.  Forbes,  Quart.  Jour.  GeoL 
Soc.,  vol.  17, 1861,  p.  7;  C.  Ochsenius,  Zeitschr.  Deutsch.  geol.  Gesell.,  1888,  p.  153;  and  L.  Darapsky,  Das 
Departement  Taltal  (Chile),  Berlin,  1900.  See  also  A.  Pissis,  Nitrate  and  guano  deposits  in  the  Desert 
of  Atacama,  London,  1878,  published  by  authority  of  the  Chilean  Government.  An  earlier  description 
of  the  nitrate  field  by  J.  W.  Flagg  is  given  in  Am.  Chemist,  vol.  4, 1874,  p.  403;  and  there  is  a recent  important 
memoir  by  Semper  and  Michels,  Zeitschr.  Berg-,  Hiitten-  u.  Salinenwesen  preuss.  St.,  1904,  pp.  359-482, 
See  also  W.  S.  Tower,  Min.  and  Sci.  Press,  vol.  107, 1913,  p.  496,  and  W.  H.  Ross,  Pop.  Sci.  Monthly,  vol. 
85, 1914,  p.  134. 

6 Jour.  Soc.  Chem.  Ind.,  vol.  12,  1893,  p.  128.  See  also  B.  Simmersbach  and  F.  Mayr,  Zeitschr.  prakt. 
Geologie,  1904,  p.  273. 


SALINE  RESIDUES. 


255 


Section  of  typical  calichera  in  Atacama  Desert , Chile. 

Ft.  in. 

1.  Sand  and  gravel 1-2 

2.  “Chusca,”  a porous,  earthy  gypsum 6 

3.  A compact  mass  of  earth  and  stones 2-10 

4.  “Costra,”  a low-grade  caliche,  containing  much  sodium 

chloride,  feldspar,  and  earthy  matter 1-3 

5.  “ Caliche.’’  (In  the  Tarapaca  Desert  it  is  from  4 to  12  feet 

thick) 14-2 

6.  “Coba,”  a clay ±3 

The  costra  contains  a considerable  amount  of  bloedite;  the  rarer 
minerals,  to  be  mentioned  presently,  are  found  in  the  caliche. 

The  composition  of  the  caliche  is  very  variable,  as  the  following 
analyses,  cited  by  R.  A.  F.  Penrose,  jr.,  show.1 

Analyses  of  caliche. 


A 

B 

c 

D 

E 

F 

G 

NaN03 

28.  54 

53.  50 

41. 12 

61.  97 

22.  73 

24.  90 

27.  08 

kno3 

Trace. 

17.  25 

3.  43 

5.15 

1.  65 

2.  50 

1.  34 

NaCl 

17.  20 

21.  28 

3.  58 

27.  55 

41.  90 

24.  50 

8.  95 

CaCl2 

5.  25 

MrCI,.* 

. 18 

KC104 

Trace. 

.78 

.75 

.21 

Trace. 

Trace. 

Trace. 

Na23  04 

5.  40 

1.  93 

Trace. 

2. 13 

.94 

6.  50 

None. 

MgS04 

3.  43 

1.  35 

10.  05 

.15 

3. 13 

6.  50 

None. 

CaS04 

2.  67 

.48 

3.  86 

.41 

4.  80 

4.  50 

2.  89 

Na2B407 

.49 

.56 

.20 

.43 

.53 

.15 

.52 

Nal 

. 047 

NaI03 

.043 

.01 

.05 

.94 

.07 

.054 

.08 

NH4  salts 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Na2Cr04 

Trace. 

Trace. 

Trace. 

Insoluble 

40.  30 

2.  07 

31.86 

.39 

22.  50 

28.  40 

47.  34 

H20,  combined,  etc.. 

1.  88 

.79 

5. 00 

.67 

1.  75 

2.  00 

6.  37 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Anhydrite,  gypsum,  thenardite,  mirabilite,  bloedite,  epsomite, 
glauberite,  and  salt  are  associated  with  the  nitrates,  and  also  the  four 
following  more  unusual  species : 


Darapskite NaNOs . N a2S04.H20 . 

N itroglauberite 6NaN03 . 2N  a2S04 .3H20 . 

Lautarite Cal206. 

Dietzeite 7CaI206.8CaCr04. 


The  lautarite  and  dietzeite  are  remarkable  as  the  first  definitely 
known  iodates  to  be  found  in  the  mineral  kingdom,  although  A.  A. 
Hayes  2 reported  sodium  iodate  as  long  ago  as  1844.  In  dietzeite 
we  have  a compound  of  iodate  and  chromate  which  is  analogous  to 


1 Jour.  Geology,  vol.  18, 1910,  p.  14;  D.  G.  Buchanan, analyst.  F.or  other  analyses  see  L.  Darapslcy,  Das 
Departement  Taltal,  Berlin,  1900;  A.  Zillaruello,  Anales.  Soc.  cient.  Argentina,  vol.  68,  p.  20;  and  F,  W. 
Dafcrt.  Monatsh.  Chem.,  vol.  29,  1908,  p.  235. 

2 See  ante,  p.  249. 


256 


THE  DATA  OF  GEOCHEMISTRY. 


some  artificial  salts  but  whose  origin  it  is  difficult  to  understand. 
Bromine  is  generally  believed  to  be  absent  from  nitrate  beds,  but 
A.  Muntz  1 claims  to  have  found  it,  in  the  form  of  bromates,  in  the 
mother  liquors  from  which  the  saltpeter  had  crystallized  out.  Fur- 
thermore, in  recent  years  considerable  quantities  of  perchlorates, 
running  in  exceptional  cases  as  high  as  6.79  per  cent  of  KC104,  have 
been  discovered  in  Chilean  nitrates.2  Finally,  these  nitrates  always 
•contain  some  borates,  perceptible  traces  of  rubidium  and  lithium, 
but  probably  no  caesium.3  The  borates  may  be  small  in  amount,  but 
it  is  doubtful  whether  they  are  ever  quite  absent. 

The  nitrate  beds  of  South  America  are  not  entirely  confined  to 
Chile,  although  the  Chilean  deposits  outrank  all  others  in  impor- 
tance. The  locality  at  Salinas  Grandes,  Argentina,  has  already  been 
noticed  in  connection  with  its  borates,  and  the  niter  there  seems  to 
be  in  entirely  subordinate  quantities.  In  the  Argentine  Territory 
of  Santiago  del  Estero,  according  to  W.  F.  Reid,4  there  are  salines 
which  form  crusts  of  salt  during  summer;  and  in  the  centers  of  the 
lagoons  mother  liquors  exist  from  which  sodium  nitrate  is  obtained. 
Zaracristi 5 has  described  another  occurrence  in  the  valley  of  the 
river  San  Sebastiano,  in  Colombia,  where  beds  of  sodium  nitrate 
overlie  a mixture  of  gypsum  and  calcareous  clay,  containing  some 
oxide  of  iron  and  common  salt.  This  deposit  is  very  impure.  An 
immense  deposit  of  potassium  nitrate,  according  to  F.  Sacc,6  exists 
near  Cochabamba,  Bolivia,  in  direct  association  with  borax.  Sacc’s 
analysis  of  a sample  from  this  locality  gives  the  following  percentage 
composition  of  the  salts: 

Analysis  of  nitrate  deposits  near  Cochabamba , Bolivia. 


KNOs 60.70 

N^B.Oy 30.70 

NaCl Trace. 

H20 Trace. 

Organic  matter 8.  60 


100. 00 

The  soil  below  the  layer  also  contains  borax.  Sacc  attributes  the 
nitrates  to  the  oxidation  of  ammonium  salts  in  the  soil.  The  associa- 
tion of  borates  with  potassium  nitrate  is  especially  noteworthy,  and 
the  locality  ought  to  receive  a more  detailed  examination. 


1 Annales  chim.  phys.,  6th  ser.,  vol.  11, 1887,  p.  121. 

2 B.  Sjollema,  Chem.  Zeitung,  vol.  20, 1896,  p.  1002.  As  the  perchlorates  are  believed  to  injure  the  nitrate 
as  a fertilizer,  a voluminous  discussion  over  their  detection  and  effects  has  appeared  in  the  agricultural 
journals. 

3 L.  Dieulafait,  Compt.  Rend.,  vol.  98, 1884,  p.  1545. 

« Jour.  Soc.  Chem.  Ind.,  vol.  19,  1900,  p.  414. 

5 Berg.  u.  Hvittenm.  Zeitung,  vol.  55, 1896,  p.  391.  Two  analyses  are  given. 

6 Compt.  Rend.,  vol.  99, 1884,  p.  84. 


SALINE  RESIDUES. 


257 


No  satisfactory  explanation  of  the  nitrate  beds  has  yet  been  found, 
although  many  theories  have  been  proposed  to  account  for  them. 
In  addition  to  that  of  Forbes,  already  cited  in  relation  to  the  borates, 
the  following  discussions  of  the  subject  are  worth  considering.  C. 
Noellner,1  who  assumed  a marine  origin  for  the  deposits,  suggested 
that  their  nitrogen  might  be  derived  from  decomposition  of  great 
masses  of  seaweeds ; but  this  view  has  not  been  generally  accepted. 
For  example,  the  beds  at  Maricunga  2 are  3,800  meters  above  sea  level 
and  180  miles  from  the  coast,  and  other  localities  present  similar 
difficulties  of  distance  and  elevation.  The  plain  of  Tamarugal, 
studied  by  W.  Newton,3  lies  between  the  coast  range  and  the  Andes, 
3,000  feet  above  the  sea,  and  the  nitrate  beds  have  peculiarities  which 
seem  to  preclude  either  an  oceanic  origin  or  a derivation  from  guano. 
Here,  at  least,  bromides  are  absent,  and  only  traces  of  phosphates  can 
be  found.  Sea  water  would  yield  the  former;  from  guano  the  latter 
would  remain.  Newton  regards  the  nitrates  as  originally  formed  by 
the  oxidation  of  organic  matter  in  alluvial  soil.  Tropical  floods, 
which  cover  the  plain  once  in  every  seven  or  eight  years,  bring  upon 
it  the  concentrated  fertility  of  thousands  of  square  miles  and  sweep 
the  deposits  to  the  landward  side  of  the  coast  chain,  where  they  are 
mainly  found.  This  is  Newton’s  view,  although  he  admits  the  possi- 
bility that  electrically  generated  atmospheric  nitrates  may  also  be 
present.  The  same  possibility  is  recognized  by  Semper  and  Blancken- 
horn,  but  rejected  by  A.  Muntz,4  who  regards  the  electrical  source  as 
quite  inadequate.  Muntz  accepts  an  organic  origin  for  the  nitrates, 
and  argues  that  the  calcium  salt  was  first  formed,  as  in  the  ordinary 
artificial  process  of  nitrification.  That  compound  then  reacts  with 
sodium  chloride,  forming  calcium  chloride  and  sodium  nitrate,  a 
transformation  which  he  effected  experimentally.  The  same  result 
was  also  obtained  later  by  A.  Gautier,5  who  finds  in  guano  the  source 
of  the  nitrogen.  The  reaction  is  further  suggested  by  the  facts  that 
the  Chilean  niter  is  always  associated  with  salt,  and  that  calcium 
chloride  is  found  in  the  underground  waters  of  the  Pampas.  Muntz 
also  proved,  by  direct  experiment,  that  iodides  in  a nitrifying  mix- 
ture were  oxidized  to  iodates;  and  from  the  absence  of  phosphates 
in  the  nitrate  beds  he  infers  that  the  nitrates  have  been  transported 
in  solution  and  redeposited  at  a distance  from  the  original  seat  of 
their  formation. 

1 Jour,  prakt.  Chemie,  vol.  102,  1867,  p.  459. 

2 See  E.  Semper  and  M.  Blanckenhorn,  Zeitschr.  prakt.  Geologie,  1903,  p.  309. 

s Jour.  Soc.  Chem.  Ind.,  vol.  19, 1900,  p.  408.  See  also  an  earlier  paper  in  Geol.  Mag.,  1896,  p.  339. 

4 Annales  chim.  phys.,  6th  ser.,  vol.  11,  1887,  p.  111. 

6 Annales  des  mines,  9th  ser.,  vol.  5, 1894,  p.  50. 

97270°— Bull.  616—16 17 


258 


THE  DATA  OF  GEOCHEMISTRY. 


C.  Ochsenius,1  who  has  written  voluminously  on  the  Chilean 
nitrates,  regards  them  as  derived  from  the  mother  liquors  of  salt 
deposits  in  the  Andes.  These  are  supposed  to  flow  downward  to  the 
plains,  their  chlorides  being  partly  converted  to  carbonates  by  car- 
bonic acid  of  volcanic  origin.  The  nitrogen  is  brought  as  ammoniacal 
dust  from  guano  beds  upon  or  near  the  seacoast,  the  heavier  phos- 
phatic  particles  being  left  behind.  That  such  dust  is  carried  by  the 
winds  is  certain;  but  is  it  carried  in  sufficient  amounts  to  account  for 
large  nitrate  deposits  far  inland  ? Another  difficulty  is  suggested  by 
Darapsky,  who  points  out  in  his  work  on  Taltal  the  comparative 
scarcity  of  carbonates  in  the  nitrate  regions.  Even  the  waters  of  the 
Pampas  contain  little  carbonic  acid,  and  among  the  mineral  springs 
of  Chile  and  Argentina  carbonated  waters  are  the  exception  rather 
than  the  rule. 

Penrose,2  in  his  recent  study  of  the  nitrates,  favors  a marine  origin 
for  them,  on  the  ground  that  the  pampa,  where  the  nitrate  deposits 
occur,  was  once  a part  of  the  ocean  bottom.  Their  nitrogen  he 
derives  from  guano,  and  their  iodine  either  from  decomposing  sea- 
weeds or  from  mineral  springs.  The  borates  he  ascribes  to  the 
decomposition  of  rocks  containing  boron-bearing  minerals.  The 
absence  of  bromides  and  the  occurrence  of  nitrates  at  great  eleva- 
tions he  does  not  try  to  explain. 

That  the  nitrate  beds  are  proximately  derived  from  the  evapora- 
tion of  saline  waters  is  beyond  doubt,  but  their  marine  origin,  in 
light  of  what  has  been  said,  seems  to  be  questionable.  The  ultimate 
source  of  their  nitrogen  is  a more  troublesome  question  and  remains, 
so  far,  unsolved.  The  weight  of  opinion  favors  a derivation  from 
organic  matter,  and  from  this  point  of  view,  Newton’s  explanation 
of  the  deposits  is  as  satisfactory  as  any.  Explanations  of  this  order, 
however,  are  incomplete,  for  they  take  no  account  of  the  remarkable 
association  of  boron  and  nitrogen.  Why  do  borates  and  ammonia 
occur  together  in  volcanic  waters,  or  borates  and  nitrates  in  the 
deposits  of  both  Chile  and  California  ? This  fact,  which  has  already 
been  emphasized,  is  surely  not  without  significance,  and  it  legitimizes 
the  suspicion  that  the  nitrates  may  be  partly  derived  from  volcanic 
sources.  To  be  sure,  this  is  only  a suspicion,  but  it  is  one  which 
ought  not  to  be  left  out  of  account.  Hot  springs  are  common  in 
the  deserts  of  California  and  Nevada;  they  are  also  found  along  the 
volcanic  Andean  chain;  do  they  contain  boron  and  ammonia  as  a 
general  rule,  or  only  in  sporadic  instances  ? Such  waters,  collecting 
in  lagoons  in  the  presence  of  some  organic  matter  and  the  nitrifying 

1 Zeitschr.  prakt.  Geologie,  1893,  p.  217;  1901,  p.  237;  1904,  p.  242.  Zeitsehr.  Deutsch.geol.  Gesell.,1888, 
p.  153.  Ochsenius’s  work,  Die  Bildung  des  Natronsalpeters  aus  Mutterlaugensalzen,  Stuttgart,  1887,1 
have  not  been  able  to  see.  His  controversial  papers,  cited  above,  give  a complete  exposition  of  his  views. 

2 Jour.  Geology,  vol.  18, 1910,  p.  16. 


SALINE  RESIDUES. 


259 


organisms,  would  yield  nitrates,  and  the  latter  would  be  found  in 
the  dried  residues.  A careful  examination  of  all  hot  springs  existing 
in  the  vicinity  of  nitrate  beds  is  needed  before  we  can  decide  how 
much  weight  can  be  given  to  this  volcanic  hypothesis.1  It  may  be 
discarded,  but  it  should  at  least  be  thoroughly  investigated. 

THE  ALUMS. 

One  more  class  of  saline  residues  remains  to  be  mentioned.  Waters 
containing  sulphates  of  iron  or  aluminum  form  deposits  of  these 
salts,  which  may  be  neutral  or  basic,  simple  or  complex.  Their  for- 
mation, however,  is  very  local,  and  compounds  of  this  character  are 
rarely  found  far  from  their  points  of  origin. 

They  are  commonly  derived,  directly  or  indirectly,  from  the  oxida- 
tion of  sulphides,  and  occur  as  incrustations  or  even  as  stalactites, 
around  mineral  springs,  or  in  the  shafts  or  tunnels  of  mines.  Acid 
solutions,  produced  by  the  oxidation  of  pyrite,  act  upon  aluminous 
rocks  and  form  sulphates  of  alumina.  Alunite  and  alunogen  are 
among  the  commoner  species  so  generated.  Alunogen  and  halotri- 
chite,  the  latter  a sulphate  of  aluminum  and  iron,  are  found  in  large 
quantities  in  Grant  County,  N.  Mex.2  Sulphates  of  iron  of  numer- 
ous species  are  especially  abundant  in  the  arid  region  of  Chile. 
Sulphates  of  zinc,  copper,  cobalt,  and  nickel  are  deposited  by  mine 
waters.  Some  of  the  species  thus  developed  will  be  considered  in 
subsequent  chapters,  either  in  relation  to  the  decomposition  of  rocks 
or  in  connection  with  the  study  of  metallic  ores. 


1 According  to  T.  Van  Wagenen  (Min.  and  Sci.  Press,  vol.  84,  1902,  p.  63),  sodium  nitrate  is  found  in  and 
around  an  extinct  hot  spring  at  the  foot  of  the  Humboldt  Sink,  Humboldt  County,  Nev. 

2 See  C.  W.  Hayes,  Bull.  U.  S.  Geol.  Survey  No.  315,  1907,  p.  215.  On  alunogen  in  Colorado  see  W.  P. 
Headden,  Proc.  Colorado  Sci.  Soc.,  vol.  8,  1905,  p.  62;  also  P.  Termier  on  the  derivation  of  alunite  from 
feldspar,  Bull.  Soc.  min., vol.  31, 1908,  p.  215.  W.  Cross,  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey, pt.  2, 
1896,  p.  314,  and  H.  W.Turner,  Am.  Jour.  Sci.,  4th  ser.,  vol.  5, 1898,  p.  424, have  described  quartz-alunite 
rocks.  On  alunite  in  ore  bodies  see  F.  L.  Ransome , Econ.  Geology,  vol.  2, 1907,  p.  667.  These  occurrences 
are  products  of  rock  decomposition  rather  than  residues  from  saline  waters.  On  the  remarkable  vein  of 
alunite  at  Marysvale,  Utah,  see  B.  S.  Butler  and  H.  S.  Gale,  Bull.  U.  S.  Geol.  Survey  No.  511, 1912. 


CHAPTER  VIII. 

VOLCANIC  GASES  AND  SUBLIMATES. 

GASEOUS  EMANATIONS. 

Regardless  of  all  speculations  as  to  the  origin  of  the  lithosphere 
or  as  to  the  nature  of  the  earth’s  interior,  we  must  recognize  the  fact 
that  some  rocks  were  formed  by  the  cooling  of  molten  materials,  and 
we  can  study  the  phenomena  of  their  development  quite  independ- 
ently of  cosmogonic  hypotheses.  Fluid  magmas  are  seen  to  issue 
from  the  earth  and  to  solidify  as  lavas;  they  may  be  emitted  quietly 
or  with  explosive  violence,  and  they  are  accompanied  by  gaseous  or 
vaporous  emanations,  which  either  escape  into  the  air,  are  partially 
occluded  by  the  cooling  mass,  or  condense  in  the  form  of  water. 
Gases,  water,  mud,  and  fused  or  incandescent  rocks  are  thrown  out 
by  volcanoes,  and  many  of  the  attendant  phenomena  can  be  directly 
observed,  or  even  reproduced  in  the  laboratory.  To  the  geophysicist 
the  nature  of  the  volcanic  forces  is  a prime  subject  of  interest;  chem- 
istry concerns  itself  more  with  the  nature  of  the  products,  and  the 
latter  theme  is  the  one  which  demands  attention  now. 

During  a volcanic  eruption  the  gaseous  emanations  are  the  first 
to  appear,  and  their  evolution  continues  more  or  less  conspicuously 
until  the  discharge  ends.  Their  emission  does  not  cease  even  then, 
for  gases  are  given  off  from  the  cooling  lavas,  and  also  from  the  hot 
springs  and  solfataras  which  are  formed  in  the  course  of  the  out- 
break. These  gases  vary  much  in  character,  and  in  a single  eruption 
they  may  present  great  differences  in  composition,  changing  from 
place  to  place  and  from  time  to  time.  For  analysis  they  are  com- 
monly drawn  from  vents,  crevices,  or  fumaroles  at  different  dis- 
tances from  the  center  of  activity,  for  the  main  crater  itself  is  rarely 
accessible  until  after  the  eruptions  have  ceased.  Furthermore,  it  is 
difficult  to  collect  the  gases  quite  free  from  admixtures  of  atmos- 
pheric air,  and  the  samples  analyzed  are  therefore,  as  a rule,  impure. 
Still  much  is  known  concerning  them,  and  many  analyses  of  these 
exhalations  have  been  recorded. 

It  has  long  been  held  by  nearly  all  authorities  that  water  vapor  or 
steam  is  the  most  abundant  of  the  volcanic  gases.  The  statement  is 
generally  accepted  that  it  forms  as  much  as  99  per  cent  of  the  entire 
gaseous  output,  but  it  soon  condenses  to  liquid  and  is  added  or 
restored  to  the  hydrosphere.  For  instance,  F.  Fouque,1  observing 

i See  A.  Geikie,  Textbook  of  geology,  4th  ed.,  p.  266.  I have  not  been  able  to  find  the  original  source  of 
this  citation. 

260 


VOLCANIC  GASES  AND  SUBLIMATES. 


261 


one  of  the  many  parasitic  cones  on  Etna,  estimated  that  in  one  hun- 
dred days  it  discharged  vapor  equivalent  to  2,100,000  cubic  meters 
of  water,  or  462,000,000  imperial  gallons.  This  great  quantity  is 
only  a small  fraction  of  what  the  entire  volcano  must  have  annually 
emitted  and  its  proximate  origin  may  well  be  a subject  for  specula- 
tion. Is  the  water  originally  magmatic  or  only  of  surface  origin; 
truly  essential  or  merely  extraneous  ? On  this  scheme  there  is  active 
controversy,  which  will  be  considered  in  due  order  later. 

The  other  volcanic  gases,  the  term  “gas”  being  used  in  its  ordi- 
nary significance,  are  hydrogen,  oxygen,  nitrogen,  argon,  helium, 
hydrogen  sulphide,  sulphur  dioxide,  carbon  dioxide,  carbon  monoxide, 
hydrochloric  acid,  chlorine,  methane,  hydrofluoric  acid,  and  silicon 
fluoride.1  Many  other  substances  are  found  among  volcanic  exhala- 
tions and  are  deposited  as  sublimates  around  vents  and  fumaroles. 
Let  us  first  consider  the  composition  of  the  true  gases,  noting  in 
advance  that  they  were  dried  before  analysis  in  order  to  eliminate 
the  excess  of  water. 

It  is  not  necessary  for  our  purposes  to  go  any  farther  back  in  time 
than  to  the  middle  of  the  last  century,  when  R.  W.  Bunsen  published 
the  results  of  his  Icelandic  researches.2  From  among  his  analyses  of 
volcanic  gases  the  following  examples  are  selected: 

Analyses  of  volcanic  gases  from  Iceland. 

A.  From  a fumarole  in  the  great  crater  of  Hekla. 

B.  From  a fumarole  in  the  lava  of  1845,  Hekla. 

C.  From  the  solfatara  of  Krisuvik. 

D.  From  a fumarole  a quarter  of  a league  distant  from  Krisuvik. 

E.  From  a group  of  fumaroles  at  Reykjalidh,  in  the  extreme  north  of  Iceland. 


A 

B 

C 

D 

E 

n2 

81.81 

78.90 

1.67 

0.50 

0.72 

Oo 

14.21 

20.09 

Ho 

4.30 

4.72 

25. 14 

C02 

2.44 

1.01 

87.43 

79.07 

50.00 

H2S 

None. 

6.60 

15.71 

24. 12 

S02 

1.54 

100. 00 

100. 00 

100. 00 

100.00 

99.  98 

1 The  two  fluorine  compounds  are  reported  by  A.  Scacchi  from  Vesuvius,  Catalogo  dei  minerali  Vesu- 
viani,  Naples,  1887.  See  also  E.  S.  Dana,  System  of  mineralogy,  6th  ed.,  p.  169.  According  to  A.  Gautier, 
(Compt.  Rend.,  vol.  157, 1913,  p.  820)  volcanic  gases  generally  contain  fluorine  compounds.  In  a gas  from 
Vesuvius  he  found  0.110  milligram  of  F per  l'ter.  In  a sublimate  from  the  volcano  Chinyero,  Canary 
Islands,  A.  del  Campo  (Jour.  Chem.  Soc.,  vol.  104,  ii,  1913,  p.  145)  found  ammonium  fluoride. 

* Annales  chim.  phys.,  3d  ser.,  vol.  38,  1853,  p.  215.  For  these  analyses  and  others,  see  pp.  260-266.  An 
earlier,  classical  memoir  by  Eliede  Beaumont,  entitled  “Emanations  volcaniques  et  metalliferes,”  appeared 
in  Bull.  Soc.  geol.  France,  2d  ser.,  vol.  4,  1847,  p.  1249.  An  important  article  on  the  gases  of  the  hot  springs 
of  Iceland  and  their  radioactivity,  by  T.  Thorkelsson,  is  in  the  Memoirs  of  the  Danish  Acad.,  7th  ser., 
vol.  8, 1910,  p.  181. 


262 


The  data  of  geochemistry. 

The  water  condensed  from  the  fumaroles  of  Hekla  carried  a little 
hydrochloric  acid,  but  in  amounts  too  small  for  determination. 

Among  the  sublimates  formed  by  these  fumaroles,  Bunsen  noted 
sulphur  and  various  metallic  chlorides,  especially  common  salt.  One 
sublimate,  however,  contained  81.68  per  cent  of  ammonium  chloride. 

Because  of  their  accessibility  the  Italian  volcanoes  have  been 
studied  with  peculiar  thoroughness,  and  with  regard  to  their  gaseous 
exhalations  the  data  are  most  abundant.  In  1856  C.  Sainte-Claire 
Deville  1 published  a description  of  the  fumaroles  found  on  Vesuvius 
during  the  eruption  of  1855,  which  he  classified  in  the  order  of  dimin- 
ishing volcanic  intensity.  The  classes  proposed  are  as  follows: 

1.  Dry  fumaroles.  Sublimates  of  metallic  chlorides,  with  traces  of  sulphates. 
Sometimes  fluorides  are  formed,  as  observed  by  Scacchi  on  the  lava  of  1850.  These 
fumaroles  are  emitted  directly  from  incandescent  lava,  and  the  subliming  vapors  are 
mixed  with  a gas  which  is  essentially  atmospheric  air.  A special  group  of  dry  fuma- 
roles emit  ammonium  chloride. 

2.  Acid  fumaroles.  Water  vapor,  mixed  with  hydrochloric  and  sulphurous  acids. 
Commonly  accompanied  by  chlorides  of  iron  and  copper,  which  are  deposited  around 
the  vents.  The  vents  occur  on  lava,  either  in  the  main  crater  or  along  the  fissure  of 
eruption.  The  hydrochloric  acid  is  very  largely  in  excess  of  the  sulphurous. 

3.  Fumaroles  emitting  water  vapor  containing  hydrogen  sulphide  or  free  sulphur. 
Their  temperature  rarely  exceeds  80° . 

4.  Mofettes.  Emissions  of  water  vapor  with  carbon  dioxide.  These  appear  where 
the  volcanic  intensity  has  become  very  slight. 

5.  Fumaroles  emitting  water  vapor  alone. 

Although,  as  we  shall  see  later,  this  classification  is  incomplete,  it 
serves  a useful  purpose  in  giving  a rough  outline  of  the  phenomena. 
At  the  point  of  greatest  activity  dry  vapors  appear;  farther  away, 
or  as  cooling  progresses,  acids  are  formed,  and  emanations  of  carbon 
dioxide  mark  the  dying  out  of  the  volcanic  energy.  But  there  are 
fumaroles,  like  some  of  those  in  Iceland,  which  do  not  fall  in  any 
one  of  these  classes. 

In  1858  C.  Sainte-Claire  Deville  and  F.  Leblanc  2 published  their 
analyses  of  volcanic  gases,  not  only  from  Vesuvius,  but  also  from 
Vulcano,  Etna,  and  other  localities.  A fumarole  in  the  crater  of 
Vesuvius,  emitting  a gas  of  extremely  suffocating  odor,  yielded  hydro- 
chloric acid  and  sulphur  dioxide  in  the  ratio  of  86.2  : 13.8.  The 
bulk  of  the  gas,  after  removal  of  these  substances  and  water,  was 
essentially  atmospheric  air  slightly  impoverished  in  oxygen.  Other 
Vesuvian  fumaroles  also  emitted  similar  air,  with  small  but  vari- 
able admixtures  of  sulphur  dioxide,  hydrogen  sulphide,  and  carbon 
dioxide.  Sulphur  dioxide  and  carbon  dioxide,  however,  were  mutu- 
ally exclusive  and  never  occuned  together.  The  emanations  from 
Etna  resembled  those  from  Vesuvius. 


1 Bull.  Soc.  geol.  France,  2d  ser.,  vol.  13,  1855-56,  p.  606;  vol.  14,  1856-57,  p.  254. 

2 Annales  chim.  phys.,  3d  ser.,  vol.  52,  1858,  p.  5. 


VOLCANIC  GASES  AND  SUBLIMATES. 


263 


At  Vulcano  Deville  and  Leblanc  made  a number  of  striking  obser- 
vations, which  are  well  illustrated  by  the  following  selected  analyses : 

Analyses  of  gases  from  Vulcano. 

A.  Gas  from  the  crater  issuing  at  a temperature  above  the  melting  point  of  lead.  This  fumarole  deposits 
boric  acid.  The  gas  was  collected  from  a vent  which  emitted  flames. 

B.  A gas  similar  to  the  foregoing,  but  not  accompanied  by  boric  acid. 

C.  Sulphurous  fumarole  from  the  north  flank  of  Vulcano. 

D.  Gas  from  a cavity,  filled  with  hot  water,  known  as  “ Acqua-Bollente,”  and  situated  near  the  seashore. 

E.  Gas  from  depressions  still  farther  from  the  crater,  collected  over  water  having  a temperature  of  25°  C. 


A 

B 

c 

D 

E 

co2 

None. 

None. 

None. 

6.4 

86.0 

so2 

39. 13 

27.  50 

69.  6 

h2s.. 

83. 1 

o2 

10.  10 

14.  02 

5.5 

. 7 

None. 

N2 

50.  77 

58.  48 

24.  9 

9.8 

14.0 

100.  00 

100.  00 

100.0 

100.0 

100.0 

These  analyses  show  very  well  the  progressive  change  in  the  fuma- 
roles  as  they  recede  from  the  eruptive  center.  At  the  end  of  their 
memoir  Deville  and  Leblanc  give  analyses  of  gases  emitted  from 
various  springs  in  Sicily  which  have  some  relations  to  the  volcanic 
activity  of  Etna.  Some  of  them  give  off  mainly  carbon  dioxide; 
others  yield  methane,  CH4,  in  considerable  quantities.  A few  analyses 
will  illustrate  the  character  of  these  exhalations. 

Analyses  of  gases  from  Sicilian  springs. 

A.  From  the  Lake  of  Palici.  B.  From  the  Salinelle  of  Paterno.  C.  From  the  Macaluba  de  Xirbi. 
D.  From  the  Macaluba  de  Girgenti. 


A 

B 

c 

D 

C02 

94.  70 

90.  7 

0.  70 

1. 15 

02 

1.  10 

1.  0 

5.  17 

1.  70 

No 

3.  52 

3.  3 

20.  40 

6.  75 

ch4 

.68 

5.0 

73.  73 

90.  40 

100.  00 

100.0 

100.  00 

100.  00 

The  conclusion  finally  stated  by  Deville  and  Leblanc  is  as  follows: 
The  nature  of  the  emanations  from  a given  point  varies  with  the  time 
which  has  elapsed  since  the  beginning  of  the  eruption ; the  fumaroles 
at  different  points  vary  with  their  distance  from  the  volcanic  center. 
In  both  cases  the  order  of  variation  is  the  same. 


264 


THE  DATA  OF  GEOCHEMISTRY. 


In  1865  F.  Fouque  1 studied  the  Italian  field  with  special  reference 
to  the  exhaled  gases.  In  the  crater  of  Vulcano  he  examined  three 
fumaroles,  at  different  temperatures,  with  results  as  follows: 

Analyses  of  gases  from  fumaroles,  Vulcano. 


A.  Temperature  above  350°.  B.  Temperature  250°.  C.  Temperature  150®. 


A 

B 

c 

HC1+S02 

73.  80 

66.00 

27. 19 

co2 

23.  40 

22.  00 

59.  62 

Oo 

. 52 

2.  40 

2.  20 

No 

2.28 

9.  60 

10.  99 

100.  00 

100.  00 

100.  00 

In  these  gases  the  hydrochloric  acid  was  most  abundant,  the  sul- 
phur dioxide  being  almost  negligible.  Around  the  vents  realgar, 
ferric  chloride,  and  ammonium  chloride  were  deposited.  Another 
group  of  fumaroles,  at  a temperature  of  100°,  gave  deposits  of  sul- 
phur, sometimes  with  and  sometimes  without  boric  acid.  Their 
composition  is  given  below,  under  D and  E. 


Analyses  of  gases  from  fumaroles,  Vulcano. 


D 

E 

F 

HC1 

7.  3 

None. 

h2s „ 

10.  7 

Trace. 

17.  55 

co2 

68.  8 

63.  59 

77.  02 

Oo 

2.  7 

7.  28 

. 70 

No 

11.  2 

29. 13 

4.  73 

a 100.  7 

100.  00 

100.  00 

a This  summation  suggests  a misprint  somewhere  in  the  original  column  of  figures. 


Analysis  F represents  gas  from  the  fumarole  known  as  “Acqua- 
Bollente,”  which  was  examined  by  Deville  and  Leblanc  nine  years 
earlier.  The  loss  of  hydrogen  sulphide  and  the  gain  of  carbon 
dioxide  during  that  period  are  most  striking  and  show  a decrease 
of  volcanic  activity.2  The  temperature  of  the  fumarole  is  given  as 
86°  C.  Fouque’s  analyses  of  gases  from  two  small  solfataras  at 
Pozzuoli,  near  Vesuvius,  also  indicate  a relationship  between  compo- 
sition and  temperature. 

1 Compt.  Rend.,  vol.  61, 1865,  pp.  210,  421,  564,  754. 

2 See  note  by  Deville,  Compt.  Rend.,  vol.  61,  1865,  p.  567.  For  recent  analyses  of  gases  from  Italian  vol- 
canic sources,  see  R.  Nasini,  F.  Anderlini,  and  R.  Salvadori,  Gazz.  chim.  ital.,  vol.  36,  fasc.  1,  1906,  p.  429. 


VOLCANIC  GASES  AND  SUBLIMATES. 


265 


Analyses  of  gases  from  Pozzuoli. 


G (tempera- 
ture 96°). 

H (tempera- 
ture 77.5°). 

h2s 

11.  43 

None. 

CO, 

56.  67 

15.  09 

02 

5.  72 

15.  51 

No 

26. 18 

69.  40 

100.  00 

100.  00 

An  elaborate  examination  of  the  gases  emitted  by  Etna  during  sev- 
eral eruptions  led  O.  Silvestri *  1 to  conclusions  much  like  those  reached 
by  Deville  and  Leblanc,  and  he  describes  fumaroles  of  several  classes, 
representing  a progressive  diminution  of  volcanic  intensity.  The 
data  may  be  briefly  summarized  as  follows: 

1.  The  fresh,  still  flowing  lava  acts  like  one  great  fumarole,  and  emits  from  its  sur- 
face white  fumes.  These  are  partly  condensible,  yielding  a solid  saline  residue  and 
a small  amount  of  liquid  containing  free  hydrochloric  and  sulphurous  acids.  The 
incondensible  gas,  as  in  the  cases  previously  noted,  is  essentially  atmospheric  air 
slightly  deficient  in  oxygen.  One  sample,  upon  analysis,  gave  02,  18.79  per  cent; 
N2,  81.21  per  cent.  The  white  residue  contained  chiefly  sodium  chloride  and  car- 
bonate, and  three  deposits  collected  from  the  surface  of  the  lava  had  the  composition 
shown  in  the  subjoined  table.  As  the  lava  cools,  the  exhalations  become  localized 
and  change  their  character  with  decreasing  temperature. 


Analyses  of  deposits  from  surface  of  lava. 


NaCl 

50. 19 

63.  02 

76.  01 

KC1 

. 50 

. 27 

. 03 

Na2C03 

11. 12 

6.  49 

2. 11 

Na2S04 

1. 13 

Trace. 

. 75 

HoO 

30.  76 

30.  22 

21. 10 

100.  00 

100.  00 

100.  00 

In  some  cases  the  fumes  also  contain  copper  chloride,  which  forms,  on  the  lava, 
deposits  of  atacamite  and  tenorite,  the  latter,  obviously,  by  oxidation. 

2.  Ammonium-chloride  fumaroles,  which  are  divided  into  two  subclasses.  First, 
acid  fumaroles,  which  form  mostly  upon  the  terminal  walls  of  the  lava  stream  and 
emit  much  hydrochloric  acid.  They  also  contain  ferric  chloride,  which  is  partly  con- 
densed as  such  and  partly  oxidized  to  hematite.  As  the  temperature  falls  they 
develop  hydrogen  sulphide  and  deposit  crystals  of  sulphur.  Second,  alkaline  fuma- 
roles, which  are  free  from  hydrochloric  acid  and  ferric  chloride  and  deposit  only 
ammonium  chloride.  They  represent  a lower  temperature  than  the  acid  type.  The 
gaseous  portion  of  these  exhalations,  acid  or  alkaline,  is  still  essentially  air,  contain- 
ing from  81.19  to  84.17  per  cent  of  nitrogen. 

1 1 fenomeni  vulcanici  presentati  dell’  Etna,  etc. , Catania,  1867.  The  data  here  given  are  from  an  abstract 
by  G.  vom  Rath,  Neues  Jahrb.,  1870,  pp.  51,  257.  See  also  the  great  monograph,  “Der  Aetna,”  by  Sarto- 
rius  von  Waltershausen  and  A.  von  Lasaulx,  2 vols.,  Leipzig,  1880.  On  the  exhalations  of  Etna  see  also 

I.  G.  Ponte,  Atti  R.  accad.  Lincei,  vol.  23,  pt.  2,  1914,  p.  341. 


266 


THE  DATA  OF  GEOCHEMISTRY. 


3.  Water  fumaroles,  which  give  off  only  water  vapor,  mixed  with  impoverished  air. 
Temperature  relatively  low. 

4.  Fumaroles  emitting  water  vapor  and  carbon  dioxide,  the  last  phase  of  activity. 
The  gases  from  two  of  three  fumaroles  in  the  crater  of  Etna,  analyzed  by  Silvestri, 
had  the  following  composition: 


Analyses  of fumarole  gases  from  Mount  Etna. 


n2 

77.  28 

79.  07 

o2 

17.  27 

18.  97 

co2 

5.  00 

1.  61 

h2s 

.45 

.35 

100.  00 

100.  00 

Although  the  observations  made  by  T.  Wolf  1 at  Cotopaxi  were 
only  qualitative,  they  confirm  the  belief  that  a regular  order  exists 
in  the  composition  of  volcanic  exhalations.  Near  the  crater  the  fumes 
of  hydrochloric  acid  were  overwhelming  and  there  was  a suspicion 
of  free  chlorine.  At  lower  levels  on  the  mountain  hydrogen  sulphide 
was  recognized,  and  occasionally  sulphur  dioxide.  The  order,  so  far 
as  it  was  studied,  is  the  same  as  that  noted  in  the  volcanoes  of  the 
Mediterranean. 

In  his  great  monograph  on  the  volcanic  eruptions  of  Santorin,2 
F.  Fouque  discusses  at  some  length  the  gaseous  emanations,  in  which, 
as  in  the  Icelandic  craters,  free  hydrogen  appeared,  and  also  small 
quantities  of  hydrocarbons.  The  great  eruption  of  Nea  Kameni,  one 
of  the  islands  of  the  archipelago,  began  in  January,  1866,  and  some 
of  the  gases  analyzed  were  collected  in  March.  For  the  first  time 
hydrogen  and  marsh  gas  were  taken  from  an  active  volcano  in  the 
presence  of  true  volcanic  flames,  and  it  was  shown  beyond  reasonable 
doubt  that  in  the  central  fires  water  had  been  dissociated  into  its 
elements.  Ordinarily  the  combustible  gases  are  burned  as  soon  as 
they  reach  the  air,  hut  the  peculiar  conditions  prevailing  at  Santorin 
permitted  their  accumulation  unchanged  and  rendered  their  complete 
identification  possible.  The  subjoined  analyses  represent  mixtures 
containing  gases  of  this  class: 


1 Neues  Jahrb.,  1878,  p.  163. 


2 Santorin  el  ses  eruptions,  Paris,  1879. 


VOLCANIC  GASES  AND  SUBLIMATES. 


267 


Analyses  of  volcanic  gases  from  Santorin. 

A.  Gas  collected  on  Nea  Kameni,  March  17,  1866,  from  the  surface  of  sulphurous  water  in  a fissure  be- 
tween Giorgios  and  Aphroessa,  temperature  78°.  Three  other  similar  analyses  are  tabulated  with  this. 

B.  From  the  same  fissure  on  Nea  Kameni,  temperature  69°.  Collected  March  25, 1866. 

C.  Gas  collected  March  7, 1867,  over  sea  water,  near  the  end  of  a still  incandescent  lava  stream. 

D.  Occurrence  similar  to  C,  but  from  a different  stream.  • Taken  March  5, 1867. 


A 

B 

C 

D 

h2s 

Trace. 

Trace. 

co2 

36.42 

50.  41 

0.  22 

None. 

Ho 

29.43 

16. 12 

56.  70 

1.  94 

ch4 

.86 

2.  95 

.07 

1.00 

o2 

.32 

.20 

21. 11 

a 24.  94 

No 

32.  97 

30.  32 

21.90 

72. 12 

100.  00 

100.  00 

100.  00 

100.  00 

a 25.94  in  table,  but  corrected  in  list  of  errata  at  the  end  of  the  volume. 


Gas  C was  a true  explosive  mixture,  which  detonated  violently  upon 
contact  with  a flame.  In  collecting  it  special  care  was  taken  to  avoid 
an  admixture  of  air:  its  oxygen,  therefore,  is  not  from  extraneous 
sources.  It  is  possible,  however,  that  both  the  oxygen  and  the  hydro- 
gen in  this  instance  came  from  the  decomposition  of  sea  water  in 
contact  with  hot  lava,  although  Fouque  believed  that  they  were  pres- 
ent in  the  molten  stream.  In  1866  the  largest  proportions  of  hydrogen 
were  found  in  gases  taken  from  the  principal  fissures  of  the  eruption, 
and  they  diminished  in  quantity  with  the  distance  of  their  points  of 
issue  from  the  focus  of  activity.  A precisely  similar  diminution 
follows  the  lapse  of  time,  as  shown  by  analyses  A and  B of  gases  from 
the  same  locality,  but  collected  eight  days  apart. 

Gases  collected  in  May,  1866,  and  some  taken  at  greater  distances 
from  the  center  of  eruption  consisted  either  of  carbon  dioxide  or  of 
atmospheric  air  which  had  been  entangled  in  the  lavas.  Some  were 
heavily  loaded  with  water  vapor,  which,  when  condensed  and  oxi- 
dized by  nitric  acid,  gave  a solution  containing  hydrochloric  and 
sulphuric  acids,  the  former,  as  in  the  instances  previously  cited,  being 
largely  in  excess  of  the  latter.  Several  of  the  dried  gases  had  the 
composition  shown  in  the  subjoined  table. 


268 


THE  DATA  OF  GEOCHEMISTRY, 


Analyses  of  volcanic  gases  from  Santorin. 

A.  Gas  taken  May  4, 1866,  from  the  bottom  of  a fissure  on  Nea  Kameni.  Collected  over  sulphurous  water, 
at  temperature  56°. 

B.  Collected  May  12, 1866,  at  the  foot  of  the  cone  Giorgios,  from  a small  fumarole  surrounded  by  crystals 
of  sulphur.  Temperature  87°. 

C.  Like  B and  near  it,  the  sulphur  partly  crystallized  and  partly  fused.  Temperature  122°. 

D.  Gas  from  periphery  of  eruptive  field,  March,  1867. 

E.  Gas  collected  near  the  port  of  St.  George  of  Nea  Kameni,  March  9,  1867. 


A 

B 

C 

D 

E 

h2s 

Trace. 

0.  42 

0.  90 

co2 

95.  37 

5.  88 

12.  24 

None. 

56.  63 

02 

.49 

18.  99 

16.  41 

20.  62 

1.  84 

n2 

4. 14 

74.  71 

70.  45 

79.  38 

41.  41 

ch4 

. 12 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

These  analyses  all  tell  the  same  story  as  that  given  by  the  Italian 
investigations;  carbon  dioxide  appears  as  the  volcanic  intensity  dies 
away;  only  at  Santorin  the  maximum  of  activity  is  represented  by 
hydrogen,  and  the  acid  products  were  less  completely  examined. 

For  other  volcanic  regions  the  data  relative  to  gaseous  exhalations 
are  not  so  complete.  Three  analyses  by  H.  Moissan1  of  gases  from 
West  Indian  fumaroles  are,  however,  especially  interesting  on  account 
of  the  determinations  of  argon.2  The  analyses  are  as  follows: 

Analyses  of  gases  from  West  Indian  fumaroles. 

A.  From  a fumarole  on  Mont  Pelee,  Martinique.  Gas  collected  by  Lacroix  after  the  great  eruption  of 
May,  1902.  Temperature  about  400°.  Gas  at  first  saturated  with  steam.  Around  this  vent  ammonium 
chloride  and  sulphur  were  deposited. 

B.  From  the  Fumarole  du  Nord,  Guadeloupe. 

C.  From  the  Fumarole  Napoleon,  Guadeloupe. 

Gases  A and  B,  previous  to  analysis,  were  both  saturated  with  water. 


• 

A 

B 

c 

co2 

15.38 

52.8 

69.5 

CO •. 

1.60 

None. 

None. 

CH, 

5.46 

None. 

None. 

Ho 

8.12 

None. 

None. 

Oo 

13.67 

7.5 

2.7 

No 

54.94 

36.07 

22.32 

A 

.71 

.73 

.68 

HC1 | 

Trace. 

Trace. 

None. 

H2S 

2.7 

4.5 

S,  vapor 

Trace. 

Trace. 

Trace. 

99.88 

99.80 

99.70 

1 Compt.  Rend.,  vol.  135, 1902,  p.  1085;  vol.  138, 1904,  p.  936.  For  details  relative  to  these  fumaroles  and 
other  volcanic  emanations,  see  the  monograph  by  A.  Lacroix,  La  Montagne  Pel6e  et  ses  Eruptions,  Paris, 
1904.  F.  Fouqu6,  Compt.  Rend.,  vol.  66, 1868,  p.  915,  analyzed  gases  from  a submarine  eruption  near  the 
Azores.  H.  Gorceix  (idem,  vol.  75, 1872,  pp.  154, 270;  vol.  78, 1874,  p.  1309)  examined  gases  from  Vesuvius, 
Santorin,  and  Nisyros;  gases  from  St.  Paul  Island  were  studied  by  C.  Velain,  idem,  vol.  81, 1872,  p.  332. 
A paper  by  W.  Hempel  on  volcanic  gases  is  in  Zeitschr.  Vulkanologie,  vol.  1, 1914,  p.  153. 

2 Argon  and  helium  have  been  detected  in  the  gases  from  the  boric  fumaroles  of  Tuscany  by  C.  Porlezza 
and  G.  Norzi,  Atti  R.  accad.  Lincei,  vol.  20, 1911,  p.  338. 


VOLCANIC  GASES  AND  SUBLIMATES. 


269 


Here  the  recent  gas  is  noticeably  charged  with  combustible  sub- 
stances, the  lower  activity  of  Guadeloupe  being  shown  by  their 
absence  and  by  the  larger  quantities  of  carbon  dioxide.  Carbon  mon- 
oxide appears  in  the  Mont  Pelee  emanation,  which  emphasizes  the 
observations  made  by  W.  Libbey  1 on  Kilauea.  He,  by  spectroscopic 
study  of  the  volcanic  flames,  found  that  hydrogen,  carbon  monoxide, 
and  hydrocarbons  were  probably  present.  Hydrogen  had  been  simi- 
larly observed  by  J.  Janssen 2 much  earlier — namely,  in  volcanic 
flames  at  Santorin  in  1867,  and  at  Kilauea  in  1883.  The  spectral  lines 
of  sodium,  copper,  chlorine,  and  carbon  compounds  were  also  seen. 

Much  more  fundamental  work  on  Kilauea  was  done  by  A.  L.  Day 
and  E.  S.  Shepherd,3  who  spent  several  months  on  the  volcano  during 
1912.  They  not  only  determined  the  temperature  of  the  molten  lava 
hi  situ,  but  also  collected  the  volcanic  gases  directly  from  an  active 
cone.  An  iron  tube  was  passed  through  the  thin  wall  of  the  cone  into 
the  liquid  lava,  and  connected  externally  with  a train  of  glass  tubes 
through  which  the  gases  were  drawn  by  pumping.  In  the  tubes  at  the 
beginning  of  the  train  300  cubic  centimeters  of  water  were  condensed 
in  about  15  minutes;  this  water  and  the  attendant  gases  were  after- 
ward analyzed.  The  water  contained  various  saline  substances, 
partly  perhaps  derived  from  the  glass,  but  notable  quantities  of 
fluorine,  chlorine,  and  sulphur  dioxide  were  also  determined.  The 
dried  gases  from  five  of  the  tubes  had  the  following  composition  by 
volume : 

Analyses  of  gases  from  Kilauea. 


co2 

23.8 

58.0 

62.3 

59.2 

73.9 

CO 

5.6 

3.9 

3.5 

4.6 

4.0 

Ho 

7.2 

6.  7 

7.5 

7.0 

10.2 

No 

63.3 

29.8 

13.8 

29.2 

11.8 

so2 

None. 

1.5 

12.8 

None. 

None. 

99.9 

99.9 

99.9 

100.0 

99.9 

No  chlorine  was  found  in  these  gases  and  no  argon,  the  latter  fact 
proving  that  there  was  no  admixture  of  atmospheric  air.  The  gases 
were  truly  magmatic.  The  significance  of  these  observations  will 
appear  later  in  relation  to  the  researches  of  Brun.  The  abundance  of 
water  in  the  molten  lava  was  definitely  established. 

SUBLIMATES. 

It  has  already  been  remarked  that  the  gases  issuing  from  a volcano 
are  often  if  not  always  accompanied  by  substances  which  are  gaseous 
only  at  high  temperatures  and  are  deposited,  upon  cooling,  in  solid 


1 Am.  Jour.  Sci.,  3d  ser.,  vol.  47,  1894,  p.  372. 

2 Compt.  Rend.,  vol.  64, 1867,  p.  1303;  vol.  97,  1883,  p.  601. 

* Bull.  Geol.  Soc.  America,  vol.  24, 1913,  p.  573. 


270 


THE  DATA  OF  GEOCHEMISTRY. 


form.  These  sublimates,  as  they  are  called,  are  of  many  different 
kinds,  and  it  is  sometimes  difficult  to  determine  whether  a given 
example  is  a true  sublimation  or  is  produced  by  secondary  changes. 
To  discriminate  between  the  products  of  direct  condensation  from 
vapor  and  substances  due  to  the  action  of  the  gases  upon  lava  is  not 
always  easy.  Some  of  the  so-called  sublimates  are  nonexistent  at 
high  temperatures,  and  are  formed  only  upon  cooling;1  others  result 
from  decompositions  of  volatile  matter;  and  still  others  are  generated 
by  reactions  between  different  gases.  For  example,  sulphur  may  be 
directly  sublimed;  it  may  be  formed  by  the  decomposition  of  hydro- 
gen sulphide  or  by  the  partial  oxidation  of  that  compound;  and  it  is 
precipitated  from  mixtures  of  hydrogen  sulphide  and  sulphur  dioxide, 
two  compounds  which  can  not  exist  together.  When  they  are  com- 
mingled, sulphur  is  set  free.  By  either  of  these  processes  volcanic 
sulphur  can  be  deposited;  but  only  the  first  is  strictly  a sublimation; 
that  is,  the  volatilization  and  recondensation  of  a substance  without 
chemical  change.  It  is  perhaps  permissible,  however,  to  use  the  term 
sublimate  a little  more  loosely,  for  rigidly  accurate  discrimination  is 
not  practicable  in  the  present  instance.  Any  solid,  then,  depos- 
ited by  or  from  volcanic  gases,  may  be  regarded  conventionally  as  a 
sublimate.2 

The  most  conspicuous  of  all  the  volcanic  sublimation  products  is 
undoubtedly  native  sulphur.  It  is  found  in  or  near  all  active  volcanic 
craters,  and  it  often  contains  appreciable  quantities  of  selenium,  as 
in  the  well-known  selensulphur  of  the  Lipari  Islands.  Tellurium  has 
been  found  in  Japanese  sulphur,3  to  the  extent  of  0.17  per  cent;  and 
A.  Cossa  4 reports  it  as  present  in  some  of  the  soluble  salts  which  are 
formed  stalactitically  in  the  crater  of  Vulcano.  The  last-named 
locality  has  been  studied  with  more  than  ordinary  thoroughness,  and 
among  its  fumarole  deposits,  which  are  partly  sublimates  and  partly 
secondary  products,  A.  Bergeat 5 names  realgar,  boric  acid,  sodium 
chloride,  ammonium  chloride,6  ferric  chloride,  glauberite,  lithium 
sulphate,  sodium  sulphate,  alum,7  hieratite,8  and  compounds  of  cobalt, 
zinc,  tin,  bismuth,  lead,  copper,  and  phosphorus.  The  chlorides 
named  in  this  list  are  commonly  found  in  volcanic  craters,  and  the 
chlorides  of  potassium,  calcium,  magnesium,  ferrous  iron,  manganese, 
lead,  and  aluminum  have  also  been  observed. 

1 For  example,  ammonium  chloride,  which  when  vaporized  is  dissociated  into  NH3+HCI. 

2 On  the  conditions  under  whichx  different  modifications  of  sulphur  are  deposited  around  volcanoes 
see  A.  Brim,  Chem.  Zeitung,  No.  15, 1909.  Bran  holds  that  the  H2S,  SO2  reaction  does  not  take  place  in 
solfataras. 

3 E.  Divers  and  T.  Shimidzu,  Chem.  News,  vol.  48, 1883,  p.  284. 

4 Zeitschr.  anorg.  Chemie,  vol.  17, 1898,  p.  205. 

6  Die  Aeolischen  Inseln:  Abhandl.  Math.-phys.  Classe,  K.  bayer.  Akad.,  vol.  20,  Abth.  1, 1899,  p.  193. 

6 Containing,  according  to  Deville  and  Leblanc  (Annales  chim.  phys.,  3d  ser.,  vol.  52,  1858,  p.  5),  also 
iodide. 

7 Potash  alum,  containing  caesium,  rubidium,  and  thallium.  A.  Cossa,  Atti  R.  accad.  Lincei,  1878,  pt. 
2,  p.  34. 

8 Potassium  silicofluoride,  K2SiF6.  A.  Cossa,  Compt.  Rend.,  vol.  94,  1882,  p.  457. 


VOLCANIC  GASES  AND  SUBLIMATES. 


271 


At  Vesuvius  A.  Lacroix  1 found  large  crystals  of  potassium  chloride 
and  other  crystals  consisting  of  a double  chloride  of  potassium  and 
manganese.  Mixed  chlorides  of  sodium  and  potassium  are  reported 
by  E.  Casoria  2 and  G.  Freda.3  These  salts,  however,  are  interpreted 
by  F.  Henrich4  as  secondary,  formed  by  the  action  of  moisture  and 
hydrochloric  acid  on  the  alkaline  silicates  of  the  heated  lavas.  From 
ferric  chloride  the  rare  minerals  kremersite,  KNH4FeCl5.H20,  and 
erythrosiderite,  K2FeCl5,  are  derived,  and  also  hematite;  while  copper 
chloride  yields  the  oxide,  tenorite;  chlorothionite,  K2S04.CuC12;  dole- 
rophanite,  Cu2S05;  and  cyanochroite,  K2Cu(S04)2.6H20;  with  some 
hydrous  chlorides  and  oxychlorides.  Even  manganese  is  found  in 
the  mineral  chlormanganokalite,  K4MnCl6,  discovered  by  H.  J. 
Johnston-Lavis.5  The  simple  anhydrous  chlorides  are  the  true  sub- 
limates; the  other  compounds  are  generated  from  them  by  secondary 
reactions.  From  the  fluorine  gases  we  get  hieratite,  ammonium 
silicofluoride,  rarely  fluorspar,  and  the  oxyfluoride  of  calcium  and 
magnesium,  nocerite.  Most  of  these  substances  were  first  described 
from  Vesuvius,  and  we  owe  our  knowledge  of  them  to  the  indefatigable 
labors  of  A.  Scacchi,  who  has  also  described  many  sulphates,  simple, 
double,  or  basic,  which  are  formed  by  the  action  of  solfataric  vapors 
upon  the  surrounding  rocks.  Similar  sulphates,  of  sodium,  potassium, 
calcium,  magnesium,  and  aluminum,  were  found  by  A.  Lacroix 6 
among  the  fumarole  products  of  Mont  Peiee.  Sodium  carbonate  is 
also  produced  in  a secondary  way.  Silver  was  discovered  by  J.  W. 
Mallet 7 in  volcanic  ash  from  Cotopaxi  and  Tunguragua ; and  it  is 
quite  probable  that  this  metal,  which  volatilizes  readily,  was  ejected 
as  vapor.  Silver  begins  to  vaporize  not  much  above  its  melting  point, 
and  at  the  temperature  of  the  oxyhydrogen  flame  it  can  be  distilled 
easily.  Sulphides  have  been  found  as  sublimation  products  at 
Vesuvius,  formed  perhaps  by  the  action  of  hydrogen  sulphide  upon 
volatilized  metallic  chlorides.  A.  Lacroix  8 and  F.  Zambonini 9 both 
report  galena  among  the  substances  produced  during  the  eruption  of 
April,  1906,  and  Lacroix  mentions  pyrite  and  pyrrho tite  also. 

1 Compt.  Rend.,  vol.  142,  1906,  p.  1249.  See  also  H.  J.  Johnston-Lavis,  Nature,  May  31,  1906.  In  Bull. 
Soc.  min.,  vol.  30,  1907,  p.  219,  Lacroix  has  described  the  minerals  of  the  Vesuvian  fumaroles  in  consid- 
erable detail. 

2 Abstract  in  Zeitschr.  Kryst.  Min.,  vol.  41, 1906,  p.  276.  Casoria  found  molybdenum,  bismuth,  copper, 
and  zinc  in  Vesuvian  salts. 

3 Gazz.  chim.  ital.,  vol.  19, 1888,  p.  16. 

4 Zeitschr.  angew.  Chemie,  vol.  19,  1906,  p.  326;  vol.  20,  1907,  p.  179. 

5 Mineralog.  Mag.,  vol.  15, 1908,  p.  54. 

s Bull.  Soc.  min.,  vol.  28,  1905,  p.  60.  Lacroix  (Compt.  Rend.,  vol.  144,  1907,  p.  1397)  has  recently  dis- 
covered a double  sulphate  of  potassium  and  lead  among  the  fumarole  products  of  Vesuvius.  This  new 
mineral  is  named  palmierite. 

7 Proc.  Roy.  Soc.,  vol.  42, 1887,  p.  1;  vol.  47, 1889-90,  p.  277. 

8 Compt.  Rend.,  vol.  143, 1906,  p.  727. 

9 Idem,  p.  921.  In  Zambonini’s  great  monograph,  Mineralogia  Vesuviana,  published  by  the  Naples 
Academy  in  1910,  full  details  are  given  of  each  species  found  at  Vesuvius,  together  with  thorough  biblio- 
graphic references. 


272 


THE  DATA  OF  GEOCHEMISTRY. 


The  ammonium  salts  found  in  volcanic  emanations  were  partially- 
considered  in  the  preceding  pages.  They  are  very  common,  hut  their 
significance  has  been  variously  interpreted.  Some  writers  have 
argued  that  their  nitrogen  is  derived  from  organic  matter,  such  as 
vegetation,  with  which  the  flowing  lava  has  come  into  contact — an 
opinion  which  is  not  well  sustained.  O.  Silvestri,1  in  1875,  found 
silvery  incrustations  of  an  iron  nitride,  Fe5N3,  on  an  Etna  lava,  and 
conducted  a series  of  experiments  to  determine  its  origin.  Fragments 
of  lava  were  first  heated  in  gaseous  hydrochloric  acid,  when  water 
was  expelled,  silica  was  liberated,  and  chlorides  of  iron  were  formed. 
Subsequent  heating  of  the  mass  in  a stream  of  ammonia  formed 
hydrochloric  acid  again,  together  with  ammonium  chloride,  hydrogen, 
and  a nitride  of  iron.  Ammonium  chloride,  acting  on  lava  at  a red 
heat,  gave  similar  products.  Ammonia  alone,  passed  over  heated 
lava,  was  decomposed,  yielding  a gas  containing  90  per  cent  of  hydro- 
gen, while  a large  part  of  its  nitrogen  was  absorbed. 

On  the  other  hand,  it  is  well  known  that  when  metallic  nitrides  are 
heated  in  steam,  ammonia  is  formed.  We  have,  therefore,  something 
like  a group  of  reversible  reactions  to  deal  with,  not  strictly  reversible 
perhaps,  but  of  such  a character  as  to  render  it  uncertain  which  com- 
pound, nitride  or  ammonia,  existed  first.  Either  substance  can  be 
generated  from  the  other.  J.  Stoklasa,2  however,  regards  it  as  pos- 
sible that  nitrides,  formed  deep  within  the  earth,  are  the  initial  com- 
pounds. At  all  events,  he  has  clearly  shown  that  the  nitrogen  of  lava 
is  an  original  constituent,  and  not  of  organic  origin.  In  all  of  the 
lavas  ejected  by  Vesuvius  during  the  eruption  of  1906  ammonium 
compounds  were  found,  the  largest  amount,  300  milligrams  of  NH3 
per  kilogram,  being  extracted  from  an  olivine  bomb.  The  water- 
soluble  portion  of  the  lapilii  contained  33  per  cent  of  ammonium 
chloride.  Organic  contamination,  in  the  samples  of  lava  examined, 
was  impossible.  An  alternative  hypothesis,  framed  to  account  for 
the  volcanic  ammonia,  is  that  of  O.  Kosenbach,3  who  argues  that  it 
may  be  generated  by  reactions  between  atmospheric  nitrogen  and 
hot  lava,  in  presence  of  moisture  and  hydrochloric  acid.  This  sug- 
gestion is  supported  by  very  little  evidence  and  needs  experimental 
verification. 

It  is  difficult  to  assign  any  limit  to  the  possibilities  of  sublima- 
tion within  the  vent  of  an  active  volcano.  Given  a temperature 
sufficiently  high,  and  almost  any  mineral  matter  may  be  volatilized 
or  decomposed  into  volatile  constituents.  In  the  electric  furnace, 

1 Gazz.  chim.  ital.,  vol.  5, 1875,  p.  301;  Pogg.  Annalen,  vol.  157,  1876,  p.  165.  Silvestri’s  results  have  been 
questioned  and  need  confirmation. 

2 Ber.  Deutsch.  chem.  Gesell.,  vol.  39,  1906,  p.  3530;  Chem.  Zeitung,  vol.  30, 1906,  p.  740;  Centralbl.  Min., 
Geol.  u.  Pal.,  1907,  p.  161.  See  also  R.  V.  Matteucci,  Centralbl.  Min.,  Geol.  u.  Pal.,  1901,  p.  45,  on  am- 
monium chloride  in  the  crater  of  Vesuvius. 

3Natur.  Wochenschr.,  vol.  21,  1906,  p.  740. 


VOLCANIC  GASES  AND  SUBLIMATES. 


273 


H.  Moissan1  has  vaporized  alumina,  lime,  magnesia,  silica,  zirconia, 
and  titanic  oxide,  and  these  substances  are  all  found  in  volcanic  rocks. 
The  oxides  of  the  iron  group  are  more  stable,  and  fuse  but  do  not  seem 
to  distill.  According  to  these  observations,  alumina  volatilizes  most 
easily,  lime  quite  easily,  and  magnesia  with  less  facility.  P.  Schutzen- 
berger  2 has  observed  that  silica  gradually  loses  weight  in  a good  wind 
furnace,  whose  temperature  is  far  below  that  of  the  electric  arc;  and 
E.  Cramer 3 has  completely  vaporized  rock  crystal  under  similar  con- 
ditions. Cramer  used  a Deville  furnace,  with  gas  carbon  or  retort 
graphite  for  fuel,  with  a blast  of  air;  and  in  one  experiment  4.517 
grams  of  quartz  were  evaporated.  At  the  temperature  of  melting 
cast  iron,  quartz  was  stable  and  lost  no  weight;  although  Moissan4 
has  observed  that  at  1,200°  silica  appears  to  have  an  appreciable 
tension.  According  to  A.  L.  Day  and  E.  S.  Shepherd,5  quartz  vapor- 
izes rapidly  in  air  at  about  the  temperature  of  melting  platinum. 
Silica,  then,  is  volatile  at  temperatures  which  are  probably  reached 
or  exceeded  within  the  volcanic  reservoirs ; and  it  may  appear  among 
the  products  of  sublimation.  In  fact,  quartz,  tridymite,  and  various 
silicates  have  been  repeatedly  observed  in  lavas  under  conditions 
which  indicated  an  origin  of  this  kind.  A.  Scacchi,6  for  example, 
reports  leucite,  augite,  hornblende,  mica,  sodalite,  microsommite, 
cavolinite,  garnet,  and  possibly  sanidine  and  vesuvianite  as  formed 
by  sublimation  at  Vesuvius.  Furthermore,  experiments  recently 
conducted  by  A.  L.  Day  and  E.  T.  Allen  in  the  laboratory  of  the 
United  States  Geological  Survey  have  shown  that  feldspars  can  be 
easily  sublimed  at  the  temperature  of  the  electric  arc,  a temperature 
which  is  in  the  neighborhood  of  3,700°  C.7  The  actual  temperature 
at  which  the  volatility  of  silicates  begins  is  yet  to  be  ascertained; 
but  it  is  certainly  lower  than  that  employed  in  Day  and  Allen’s 
experiments.  It  may  fall  within  the  range  of  volcanic  tempera- 
tures; and  in  that  case  sublimation  can  be  supposed  to  play  an  appre- 
ciable part  among  the  phenomena  of  eruptions.8  If  the  more  vola- 
tile substances  accumulate  in  the  upper  portions  of  a reservoir,  they 


1 Le  four  electrique,  pp.  32-49,  Paris,  1897.  See  also  Compt.  Rend.,  vol.  116,  1893,  p.  1222. 

2 Compt.  Rend.,  vol.  116, 1893,  p.  1230. 

s Zeitschr.  angew.  Chemie,  1892,  p.  484. 

* Compt.  Rend.,  vol.  138,  1904,  p.  243. 

s Science,  new  ser.,  vol.  23,  1906,  p.  670. 

6 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  24,  1872,  p.  493.  Condensed  from  the  Italian  original  by  J.  Roth. 
See  also  G.  vom  Rath,  Neues  Jahrb.,  1866,  p.  824,  on  augite  as  a fumarole  product.  H.  Traube  (Centralbl. 
Min.,  Geol.  u.  Pal.,  1901,  p.  679)  has  described  the  artificial  production  of  minerals  by  sublimation. 

7 3,900°  to  4,000°  absolute.  See  C.  W.  Waidner  and  G.  K.  Burgess,  Bull.  Bureau  of  Standards,  vol.  1, 
1904, p.  109. 

8 J.  Joly  (Proc.  Roy.  Irish  Acad.,  3d  ser.,  vol.  2, 1891,  p.  38)  mentions  the  sublimation  of  enstatite  at  the 
highest  temperatures  observed  on  the  platinum  ribbon  of  his  meldometer.  In  this  case  the  temperature 
could  not  have  exceeded  1,700°.  Some  of  the  so-called  sublimed  silicates  of  volcanoes,  however,  may  not 
be  true  sublimates  at  all,  but  products  of  reactions  between  silica  and  volatile  chlorides  or  fluorides.  Such 
reactions  are  more  than  probable. 


97270°— Bull.  616—16 18 


274 


THE  DATA  OF  GEOCHEMISTRY. 


would  appear  among  the  first  ejectamenta;  and  the  difference 
between  the  earlier  and  later  outflows  of  an  eruption  would  be  partly 
accounted  for.  Whether  this  factor  in  the  eruptive  process  is  rela- 
tively small  or  large  can  not  be  determined  at  present.  It  probably 
exists,  and  it  may  be  important ; but  no  more  definite  conclusion  can 
be  drawn  from  the  established  evidence. 

OCCLUDED  GASES. 

Although  we  can  not  determine  with  absolute  certainty  the  origin 
of  volcanic  gases,  the  subject  is  not  entirely  unsuited  to  scientific  dis- 
cussion. Some  evidence  exists,  and  from  it  some  conclusions  may  be 
legitimately  drawn.  It  has  long  been  known  that  nearly  if  not  quite 
all  rocks,  upon  heating  to  redness,  give  off  large  quantities  of  gas — a 
fact  which  was  noted  by  Priestley  as  early  as  1781.1  In  recent  years 
these  gases  have  been  elaborately  studied,  and  from  two  points  of 
view.  At  first  they  were  thought  to  be  occluded  in  the  rocks;  and, 
indeed,  inclosures  of  carbon  dioxide  are  not  rare;  but  latterly  it  has 
been  shown  that  igneous  action  may  generate  them  from  the  solid 
minerals  themselves.  Let  us  first  assemble  the  data,  and  then  con- 
sider their  significance. 

That  quartz  and  other  crystalline  minerals  often  contain  cavities 
filled  with  carbon  dioxide  is  well  known,  and  inclusions  of  this  order 
have  been  studied  by  several  competent  authorities.2  Hawes  and 
Wright  examined  the  remarkable  smoky  quartz  from  Branchville, 
Connecticut,  which  contains  so  many  inclusions  of  gas  that  it  explodes 
almost  like  a percussion  cap  when  struck  with  a hammer.  In  this 
case  the  gas,  as  analyzed  by  Wright,  gave  98.33  per  cent  of  C02, 
with  1.67  per  cent  of  nitrogen,  and  traces  of  hydrogen  sulphide,  sul- 
phur dioxide,  ammonia,  a fluorine  compound,  and  possibly  chlorine. 
Much  water  was  also  present  with  the  gaseous  inclusions.  In  other 
minerals  other  gases  are  sometimes  found  in  notable  quantities,  as, 
for  example,  hydrogen  sulphide  in  a Canadian  calcite,3  and  marsh 
gas,  which  Bunsen 4 extracted  from  the  rock  salt  of  Wielieczka.  In 
the  latter  instance  the  inclosed  gases  contained  84.60  per  cent  of 
methane,  10.35  per  cent  of  nitrogen,  and  small  quantities  of  oxygen 
and  carbon  dioxide.  These  minerals,  however,  are  not  volcanic,  and 
they  are  cited  here  merely  to  show  that  gaseous  inclusions  are  not 
unusual.  The  observations  of  W.  Bamsay  and  M.  W.  Travers5  are 

1 See  his  letters  to  Josiah  Wedgwood,  in  Scientific  correspondence  of  Joseph  Priestley,  edited  by 
H.  Carrington  Bolton,  New  York,  1892,  privately  published. 

2 See  especially  W.  N.  Hartley,  Jour.  Chem.  Soc.,  vol.  29, 1876,  p.  137;  vol.  30, 1876,  p.  237.  G.  W.  Hawes, 
Am.  Jour.  Sci.,  3d  ser.,  vol.  21, 1881,  p.  203.  A.  W.  Wright,  idem,  p.  209. 

3 See  B.  J.  Harrington,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19,  1905,  p.  345. 

4 Annalcs  chim.  phys. , 3d  ser.,  vol.  38,  1853,  p.  269. 

5 Proc.  Roy.  Soc.,  vol.  60, 1896-97,  p.  442.  Argon  and  helium  have  also  been  found  in  malacone,  a variety 
of  zircon,  by  E.  S.  Kitchin  and  W.  G.  Winterson  (Jour.  Chem.  Soc.,  vol.  89,  1906,  p.  1568).  Many  of  the 
rare-earth  minerals,  according  to  H.  Erdmann  (Ber.  Deutsch.  chem.  Gesell.,vol. 29, 1896,  p.  1710),  contain 
small  quantities  of  nitrogen. 


VOLCANIC  GASES  AND  SUBLIMATES. 


275 


also  interesting,  for  in  zircon  they  found  both  argon  and  helium,  and 
the  latter  gas  was  yielded  by  a number  of  other  rare-earth  minerals 
and  also  uraninite,  all  obtained  from  pegmatite  veins. 

In  1876,  in  the  course  of  his  investigations  upon  the  gases  evolved 
from  meteorites,  A.  W.  Wright 1 found  that  a specimen  of  trap,  heated 
to  redness,  gave  off  three-fourths  of  its  volume  of  gas,  which  con- 
tained 13  per  cent  of  carbon  dioxide,  the  remainder  being  chiefly 
hydrogen.  In  1896,  W.  A.  Tilden  2 made  a similar  observation  upon 
the  red  Peterhead  granite.  This  rock  gave  off  2.61  times  its  volume 
of  gases,  containing  24.8  per  cent  of  C02  and  75.2  per  cent  of  hydro- 
gen. A year  later 3 Tilden  published  the  results  of  his  experiments 
upon  a considerable  number  of  rocks  and  minerals,  24  examples  in  all. 
For  most  of  these  only  partial  analyses  were  made,  but  in  five  cases 
the  gases  evolved  were  more  completely  examined.  The  data  are  as 
follows  for  the  percentage  composition  of  the  gases  and  for  the  vol- 
ume obtained  from  a unit  volume  of  rock: 


Volume  and  composition  of  gases  evolved  from  rocks . 


Rock. 

Volume 
of  gas. 

Composition  of  gas. 

C02 

CO 

ch4 

n2 

h2 

Granite 

2.8 

23.  60 

6.  45 

3.  02 

5. 13 

61.  68 

Gabbro 

6.4 

5.  50 

2. 16 

2.  03 

1.  90 

88.  42 

Pyroxene  gneiss 

7.  3 

77.  72 

8.  06 

.56 

1. 16 

12.  49 

Corundum  gneiss 

17.8 

31.  62 

5.  36 

. 51 

.56 

61.  93 

Basalt 

8.0 

32.  08 

20.  08 

10.  00 

1.  61 

36. 15 

Even  such  a mineral  as  beryl  gave  off  6.7  volumes  of  gas,  in  which 
hydrogen  largely  predominated.  The  gases  appeared  to  Tilden  to  be 
wholly  inclosed  in  very  minute  cavities,  so  small  that  little  was  lost 
when  the  rocks  were  reduced  to  powder.  Their  extraction  was 
effected  by  the  usual  process  of  heating  the  pulverized  material  in 
vacuo. 

In  1898  M.  W.  Travers4  described  a series  of  experiments  upon  the 
extraction  of  gases  from  various  minerals  and  rocks,  which  led 
to  results  resembling  those  obtained  by  Tilden.  The  conclusions 
reached,  however,  were  quite  different;  for  Travers  was  able  to  show 
that  in  some  cases  at  least  the  gases  were  not  occluded  but  were 
derived  from  the  interaction  of  nongaseous  substances.  Chlorite, 
serpentine,  gabbro,  mica,  talc,  feldspar,  and  glauconite  were  studied, 
and  in  each  instance  the  hydrogen  and  carbon  monoxide  that  were 
evolved  by  heating  the  mineral  in  vacuo  were  quantitatively  related 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  12,  1876,  p.  171. 

2 Proc.  Roy.  Soc.,  vol.  59, 1895-96,  p.  223. 

3 Chem.  News,  vol.  75, 1897,  p.  169.  Proc.  Roy.  Soc.,  vol.  60,  1896-97,  p.  453. 

4 Proc.  Roy.  Soc.,  vol.  64,  1898-99,  p.  130. 


276 


THE  DATA  OF  GEOCHEMISTRY. 


to  the  ferrous  oxide  and  water  which  the  specimen  contained.  The 
inference  is  that  these  gases  were  generated  by  a reaction  between  the 
ferrous  salts,  the  carbon  dioxide,  and  the  water  of  the  original  sili- 
cates. Unfortunately,  Travers’s  conclusions  can  not  be  directly 
applied  to  Tilden’s  work,  for  the  latter  gave  no  analyses  of  the  rocks 
themselves.  It  is  noticeable,  however,  that  the  largest  evolution  of 
gas  cited  in  Tilden’s  series  was  that  from  the  corundum  gneiss  of 
Seringapatam,  and  not  from  the  presumably  more  highly  ferruginous 
pyroxene  gneiss  and  basalt.  The  yield  of  gas  from  beryl  was  also 
very  considerable,  a fact  which  Travers’s  observations  do  not  explain. 
That  molten  glass  absorbs  combustible  gases,  probably  hydrogen,  was 
observed  by  H.  Sainte-Claire  Deville  and  L.  Troost.1  The  glass  on 
cooling  gives  out  much  of  the  gas  in  the  form  of  bubbles.  Even 
solid  glass,  at  200°  and  under  a pressure  of  200  atmospheres,  has  been 
found  by  J.  B.  Hannay2  to  absorb  oxygen  and  carbon  dioxide. 
When  the  charged  glass  is  cooled  under  pressure  the  gases  are 
retained,  but  on  quick  heating  to  the  softening  point  they  are  expelled 
with  almost  explosive  violence,  driving  the  glass  into  foam.  By  slow 
heating  to  300°  most  of  the  dissolved  gas  can  be  quietly  discharged. 

The  investigations  of  A.  Gautier3  led  to  the  same  conclusion  as 
that  reached  by  Travers,  but  the  work  was  more  extended  and  various 
methods  of  attack  were  employed.  Two  samples  of  the  same  granite, 
collected  at  different  times  and  heated  to  100°  in  vacuo  with  sirupy 
phosphoric  acid,  gave  off  the  following  gases,  measured  in  cubic  cen- 
timeters per  kilogram  of  rock: 


Gases  evolved  by  granite  in  vacuo  at  100°. 


A 

B 

HC1  and  SiF4 

Trace. 

Trace. 

H2S 

1.  33 

22.  7 

CO,... 

272.  6 

237.  5 

Hydrocarbons 

12.  3 

5.  3 

H2 

53.  05 

191.  48 

N2  (rich  in  argon) 

232.  50 

102,  48 

571.  78 

559.  46 

On  heating  the  same  rock  to  300°  with  water  alone  gases  were 
evolved  as  follows,  in  cubic  centimeters  per  kilogram: 

1 Compt.  Rend.,  vol.  57, 1863,  p.  965. 

2 Chem.  News,  vol.  44,  1881,  p.  3.  A.  A.  Campbell  Swinton  (Chem.  News,  vol.  95,  1907,  p.  134)  has  also 
shown  that  gases  are  occluded  by  the  glass  walls  of  vacuum  tubes.  Barus’s  work  on  the  absorption  of  water 
by  glass  is  considered  in  Chapter  IX. 

3 Compt.  Rend.,  vol.  131,  1900,  p.  647;  vol.  132,  1901,  pp.  58,  189;  vol.  136,  1903,  p.  16.  Annales  chim. 
phys.,  7th  ser.,  vol.  22,  p.  97,  1901. 


VOLCANIC  GASES  AND  SUBLIMATES. 


277 


Gases  evolved  by  granite  heated  to  300°  with  water. 


A 

B 

h2s  

1.  3 

1.  0 

COo 

7.  2 

5.  3 

h9 

46.  0 

14.  6 

No 

. 3 

5.9 

Hence,  it  is  clear  that  the  action  of  water  alone  on  an  igneous  rock 
moderately  heated  tends  to  develop  gases  closely  similar  in  character 
to  those  which  are  emitted  by  active  volcanoes.  Heated  to  redness 
in  vacuo,  powdered  rocks  emit  much  more  gas  and  the  volcanic 
phenomena  are  imitated  even  more  closely.  In  the  subjoined' table 
A,  B,  and  C are  analyses  of  gases  thus  extracted  from  the  granite 
of  Vire;  D represents  a granitoid  porphyry,  E an  ophite,  and  F lher- 
zolite.  The  percentages  by  volume  are  given,  and  the  volume  of 
gas,  reduced  to  0°  and  760  millimeters,  yielded  by  1 kilogram  of 
rock. 

Analyses  of  gas  evolved  from  powdered  rocks  heated  to  redness. 


A 

B 

C 

D 

E 

F 

C02 

14.  80 

8.  98 

14.  42 

59.25 

35.  71 

78.35 

H2S 

Trace.  . 

1.  71 

.69 

None. 

.45 

11.  85 

CO 

4.  93 

5. 12 

5.  50 

4.20 

4.  85 

1.  99 

CH4 

2.  24 

1.09 

1.  99 

2.  53 

1.  99 

.01 

h2 

77.  30 

82.  80 

76.  80 

31.09 

56.29 

7.  34 

N2  (with  argon) 

.83 

.42 

.40 

2. 10 

.68 

Trace. 

Volume  of  gas,  cubic  centi- 

100.10 

100. 12 

99.  80 

99. 17 

99.  97 

99.  54 

meters 

2,  709 

4,  209 

2,  570 

2,  846 

2,  517 

5,  450 

Before  heating,  these  rocks  were  dried  at  250°  to  300°  to  remove 
hygroscopic  moisture.  The  volume  of  gas  extracted  from  one  volume 
of  rock  amounted  to  6.7  from  the  granite,  7.6  from  the  porphyry,  7.6 
from  the  ophite,  and  15.7  from  the  lherzolite.  The  granite,  it  will  be 
seen,  gives  the  smallest  evolution  of  gas  per  volume  of  material,  but 
it  is  by  far  the  richest  in  hydrogen.  Even  in  this  case,  according  to 
Gautier,  a cubic  decimeter  of  granite  at  1,000°  would  give,  calculated 
for  that  temperature,  about  20  liters  of  mixed  gases  and  89  liters  of 
steam — more  than  one  hundred  times  its  initial  volume. 

In  order  to  prove  that  the  gases  are  not  simply  inclosed  in  the 
rocks,  Gautier  extended  his-  experiments  along  several  lines.  First, 
he  argued,  inclosed  gases  should  not  vary  in  composition  during  the 
process  of  extraction,  whereas  gases  generated  by  heat  might  do  so. 


278 


THE  DATA  OF  GEOCHEMISTRY. 


The  latter  condition  held  in  the  case  of  granite  when  two  fractions  of 
the  gas  were  examined  separately.  The  analyses  are  as  follows: 


Analyses  of  gas  evolved  from  granite. 


First 

third. 

Last  two- 
thirds. 

co2 

20. 19 

6. 13 

H,S 

1.28 

.41 

CO 

. 57 

1.  02 

ch4 

2.  04 

. 80 

h2 

75.  54 

91.  64 

No 

.30 

. 30 

99.  92 

100. 30 

A similar  variation  was  exhibited  during  the  evolution  of  gas  from 
ophite. 

In  his  third  memoir  Gautier  showed  that  ferrous  silicates  heated 
to  redness  in  a current  of  steam  yield  a gas  containing  65  per  cent 
of  hydrogen.  Therefore  the  water  of  constitution  in  a rock,  acting 
on  the  compounds  of  iron  therein  contained,  can  give  the  same 
reaction.  To  test  this  conclusion  still  further,  Gautier  heated  150 
grams  of  dried  and  powdered  ophite  to  redness  in  vacuo  and  obtained 
2.25  grams  of  water  and  371  cubic  centimeters  of  gas,  contain- 
ing 202  cubic  centimeters  of  hydrogen  and  122  cubic  centimeters 
of  carbon  dioxide.  After  the  evolution  of  gas  had  ceased,  the  mate- 
rial was  allowed  to  cool,  and  then  reheated  in  a current  of  steam 
carrying  a little  carbonic  acid.  By  this  means  70  cubic  centimeters 
of  gas  were  developed,  having,  after  the  removal  of  carbon  dioxide, 
the  subjoined  composition: 


CO.... 
CH4. . . 
H2.... 

N2,  etc 


3.32 
6.  08 
36.20 
54.  20 


99.  80 

This  gas  was  certainly  not  preexistent  in  the  rock,  for  that  had  been 
previously  exhausted,  and  yet  it  was  moderately  rich  in  hydrogen. 

Gautier’s  conclusions  were,  in  the  main,  confirmed  by  K.  Huttner.1 
He,  too,  found  that  the  gases  in  question  are  generated  by  reactions 
brought  about  by  heat  within  the  rock;  only,  instead  of  regarding 
the  CO  as  derived  from  the  action  of  C02  on  ferrous  silicates,  he 
showed  that  it  can  be  produced  by  the  reducing  action  of  the  liberated 
hydrogen  upon  C02.  Bocks  containing  more  or  less  water  were 
heated  in  a stream  of  carbon  dioxide,  when  both  hydrogen  and  car- 
bon monoxide  were  given  off. 


Zeitschr.  anorg.  Chemie,  vol.  43,  1905,  p.  8. 


VOLCANIC  GASES  AND  SUBLIMATES. 


279 


That  such  a reduction  was  possible  had  long  been  known;  but 
Gautier,1  in  a later  investigation,  studied  the  reaction  much  more 
thoroughly  and  found  that  it  was  reversible.  At  a white  heat  the 
reaction  is  as  follows: 

C02  + 3H2  = CO  + H20  + 2H2. 

At  temperatures  between  1,200°  and  1,250°,  on  the  other  hand,  the 
equation  becomes — 

3CO  + 2H20  = 2C02  + 2H2  + CO. 

In  another  series  of  experiments,  Gautier  2 found  that  hydrogen 
at  high  temperatures,  reduced  carbon  monoxide,  forming  carbon 
dioxide,  water,  and  either  free  carbon  or  methane.3  At  900°  to 
1,000°  the  reaction  appeared  to  be — 

4CO  + 2H2  = 2H20  + C02  + 3C. 

Between  1,200°  and  1,220°  it  was — 

4CO  + 8H2  = 2H20  + C02  4-  3CH4. 

From  these  reactions,  which  seem  to  be  contradictory  but  which 
depend  upon  varying  conditions  of  temperature  and  concentration, 
the  coexistence  of  water  vapor,  hydrogen,  and  both  oxides  of  car- 
bon in  volcanic  emanations  becomes  intelligible.  When  water  emit- 
ted by  heated  rocks  mingles  with  carbon  dioxide  from  any  source 
whatever,  within  the  vent  of  a volcano,  any  of  these  reactions  may 
take  place,  and  mixed  gases,  which  sometimes  contain  traces  of 
formic  acid,  are  generated.  This  mixture  is  a powerful  reducing 
agent,  which  acts  upon  the  iron  silicates  in  an  opposite  direction  to 
that  of  the  oxidizing  vapor  of  water.  Either  oxidation  or  reduction 
is  therefore  possible,  according  to  the  preponderance  of  one  constitu- 
ent or  another  among  the  volcanic  gases. 

Going  further,  Gautier 4 investigated  the  reactions  between  steam 
and  the  metallic  sulphides.  At  incipient  redness  steam  changes 
the  iron  sulphide,  FeS,  into  magnetite,  Fe304,  with  formation  of  free 
hydrogen  and  hydrogen  s’ulphide.  Galena,  in  a current  of  super- 
heated steam,  was  partly  sublimed  and  recrystallized  as  such  5 6 and 
partly  decomposed  into  metallic  lead  and  free  sulphur.  A little  sul- 
phate of  lead  was  formed  at  the  same  time.  With  cuprous  sulphide, 
under  like  conditions,  copper  was  liberated  and  a mixture  of  hydro- 
gen with  sulphur  dioxide  was  formed.  The  same  gaseous  mixture 
was  also  generated  by  the  action  of  steam  upon  hydrogen  sulphide. 

1 Compt.  Rend.,  vol.  142,  1906,  p.  1382;  Bull.  Soc.  chim.,  3d  ser.,  vol.  35,  1906,  p.  929.  Gautier  gives 
references  to  earlier  literature.  See  also  O.  Boudouard,  Bull.  Soc.  chim.,  3d  ser.,  vol.  25,  1901. 

2 Compt.  Rend.,  vol.  150, 1910,  p.  1564. 

3 Sir  B.  C.  Brodie  (Proc.  Roy.  Soc.,  vol.  21, 1873,  p.  245)  also  obtained  methane  by  the  action  of  electric 

discharges  upon  a mixture  of  CO  and  H2.  The  reaction  suggested  is  C0+3H2=CH4+H20. 

* Compt.  Rend.,  vol.  142, 1906,  p.  1465;  Bull.  Soc.  chim.,  3d  ser.,  vol.  35,  1906,  p.  934. 

6 This  recalls  the  existence,  already  mentioned,  of  galena  as  one  of  the  Vesuvian  sublimates. 


280 


THE  DATA  OF  GEOCHEMISTRY. 


From  these  facts  Gautier  infers  that  the  sulphur  dioxide  of  volcanoes 
is  produced  by  the  reduction  of  sulphides,  followed  by  the  oxidation 
of  the  hydrogen  sulphide  so  liberated.  This  oxidation  can  be  brought 
about,  as  Gautier 1 has  shown,  by  reactions  between  metallic  oxides 
and  hydrogen  sulphide,  a reversion  of  some  of  the  other  reactions 
studied.  At  a red  heat  steam  reduces  ferrous  sulphide,  forming  mag- 
netite. At  a white  heat  hydrogen  sulphide  reconverts  magnetite  into 
FeS,  and  a mixture  of  sulphur  dioxide  with  hydrogen  is  generated. 
Hydrogen  sulphide  may  also  react  with  carbon  dioxide  to  form  car- 
bonyl sulphide,  COS,  and  water.  In  short,  Gautier  has  shown  that  a 
large  number  of  reactions  are  possible,  starting  only  with  water,  car- 
bon dioxide,  and  the  solid  constituents  of  lavas.  Many  of  these  reac- 
tions are  reversible,  and  they  give  rise  to  nearly  all  the  gaseous  mix- 
tures which  appear  hi  volcanic  emanations.  The  nitrogen  of  the  vol- 
canic gases  Gautier,  like  several  other  authorities,  attributes  to  the 
presence  of  nitrides  in  the  lava. 

In  a more  general  memoir  Gautier2  has  summed  up  his  views 
upon  the  chemistry  of  volcanism.  The  phenomena,  he  thinks,  are 
due  to  Assuring  and  subsidence  in  the  crust  of  the  earth,  whereby 
masses  of  crystalline  rocks  are  lowered  into  the  heated  region.  Gases 
are  then  developed,  in  accordance  with  the  reactions  that  he  has 
established,  under  enormous  pressures  and  in  immense  quantities. 
To  illustrate  the  magnitude  of  the  phenomena  to  which  the  reactions 
may  give  rise,  Gautier  in  one  of  his  earlier  papers  shows  that  a cubic 
kilometer  of  granite  would  yield  28,400,000  metric  tons  of  water  and 
5,293,000,000  cubic  meters  of  hydrogen,  measured  at  ordinary  temper- 
atures. That  amount  of  hydrogen,  burning,  would  give  4,266,000 
tons  of  water,  making  nearly  31,000,000  tons  in  all,  or  as  much  as 
passes  Paris  in  the  Seine  during  an  average  flow  of  12  hours. 
We  can  therefore  account  for  the  evolution  of  volcanic  steam  and 
gases  by  the  action  of  heat  alone  without  involving  either  the  infiltra- 
tion of  sea  water  or  unknown  and  imaginary  sources  of  supply  deep 
within  the  bowels  of  the  earth.  Given  a.  mechanical  source  of  heat 
and  rocks  of  ordinary  composition,  and  the  observed  chemical 
phenomena  will  follow.  Gautier,  however,  goes  further  than  the 
experimental  data  warrant.  He  supposes  that  the  nucleus  of  the 
earth  consists  largely  of  iron,  containing  hydrogen  and  carbon 
monoxide  in  solution.  He  also  assumes  the  existence  of  metallic 
carbides,  from  which  CO  and  hydrocarbons  may  be  generated. 
Sodium  chloride,  moreover,  he  regards  as  nuclear;  and  upon  supposi- 
tions of  this  sort  he  builds  up  an  elaborate  argument,  of  which  the 
soundness  is  yet  to  be  established.  It  is  rich  in  suggestions  which 

i Compt.  Rend.,  vol.  143, 1906,  p.  7;  Bull.  Soc.  chim.,  3d  ser.,  vol.  35, 1906,  p.  939. 

3 Annales  des  mines,  10th  sor.,  vol.  9, 1906,  p.  316.  Compare  F.  Loewinson-Lessing  (Compt.  rend.  VII 
Cong.  g6ol.  internat.,  1897,  p.  369),  who  attributes  volcanic  gases  to  the  absorption  of  sedimentary  rocks 
by  magmas.  Clays  yield  water,  limestones  furnish  C02,  etc. 


VOLCANIC  GASES  AND  SUBLIMATES. 


281 


may  or  may  not  bear  fruit  in  future  discoveries.  The  carbide  theory, 
I may  say,  is  not  due  to  Gautier  alone.  It  was  also  advanced  by 
H.  Moissan,1  who  attributes  volcanic  activity  to  the  action  of  water 
upon  metallic  carbides,  although  these  compounds  are  not  seen  as 
natural  products  on  the  surface  of  the  earth.  Water,  acting  upon 
the  artificial  carbides,  develops  hydrogen  and  hydrocarbon  gases; 
the  latter,  through  the  influence  of  heat,  partly  polymerize  to  liquid 
or  solid  compounds  and  partly  burn,  yielding  carbonic  acid  and  water; 
and  so  the  observed  order  of  evolution  seen  in  volcanic  eruptions  is 
paralleled.  This  view  also  finds  some  support  in  the  observations 
of  O.  Silvestri 2 who  obtained  both  solid  paraffin  and  liquid  hydro- 
carbons from  the  lavas  of  Etna.  The  theory  accounts  conveniently 
for  some  products  of  volcanism  and  may  be  true  in  part,  for  the 
carbides  are  readily  formed  and  are  likely  to  be  present  below  the 
region  to  which  the  surface  waters  penetrate!  If  deep-seated  waters 
really  exist,  then  the  carbide  hypothesis  must  be  abandoned,  or  else 
so  qualified  as  to  deprive  it  of  any  real  significance.3 

Probably  the  most  elaborate  research  upon  the  gases  extractable 
from  rocks  is  that  of  R.  T.  Chamberlin.4  He  gives  more  than  a 
hundred  analyses  of  gases  obtained  from  rocks,  minerals,  and  meteor- 
ites, finding  H2S,  CO,  C02,  CH4,  H2  and  N2.  Chlorine  and  its  com- 
pounds are  not  reported.  The  largest  quantities  of  gas  were  with- 
drawn from  ferromagnesian  rocks,  and  in  general,  hydrogen  and  the 
carbon  oxides  predominated.  In  deep-seated  rocks  H2  and  C02 
were  about  equally  important;  in  surface  flows  the  latter  gas  was 
more  conspicuous.  Among  igneous  rocks  the  oldest  yielded  the  most 
gas,  recent  lavas  gave  very  much  less  than  the  Archean  plutonics. 

Chamberlin  discusses  his  analyses  with  much  thoroughness,  espe- 
cially with  reference  to  the  origin  of  the  gases.  Like  Gautier  he 
ascribes  the  major  portion  of  them  to  reactions  within  the  rocks, 
brought  about  by  heating.  There  must  be,  however,  some  gaseous 
occlusions,  as  in  the  case  of  beryl,  which  yielded  him  much  more 
hydrogen  than  could  possibly  be  generated  by  the  small  amounts  of 
water  and  iron  that  the  mineral  contained.  Inclusions,  such  as  gas 
bubbles  in  quartz  and  the  like,  he  regards  as  of  minor  importance. 
The  water  required  to  yield  the  hydrogen  Chamberlin  attributes  in 
great  part  to  the  micas  of  the  deep-seated  rocks — that  is,  it  was 

1 Proc.  Roy.  Soc.,  vol.  60, 1896-97,  p.  156.  See  also  E.  Stecher,  14.  Ber.  Naturw.  Gesell.  Chemnitz,  1900; 
A.  Rossel,  Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  14,  1902,  p.  481;  and  H.  Lenicque,  Mem.  Soc.  ingen.  civils 
France,  October,  1903,  p.  346. 

2 Gazz.  chim.  ital.,  vol.  7,  1877,  p.  1. 

3 See  the  discussion  over  juvenile  and  vadose  waters  in  Chapter  VI,  and  also  Gautier’s  memoir,  there 
cited,  on  the  relations  between  volcanism  and  thermal  springs.  The  occurrence  of  hydrocarbons  has 
been  noted  at  many  volcanic  centers. 

4 Pub.  No.  106,  Carnegie  Inst.  Washington,  1908.  Several  analyses  of  gases  from  lavas  of  Mont  Pelee 
and  Vesuvius  are  given  by  M.  Grossmann,  Compt.  Rend.,  vol.  148,  1909,  p.  991.  Another  paper  on  gases 
from  rocks  is  by  R.  J.  Strutt,  Proc.  Roy.  Soc.,  vol.  70A,  1907,  p.  436. 


282 


THE  DATA  OF  GEOCHEMISTRY. 


originally  magmatic,  and  locked  up  in  the  minerals  when  the  magma 
consolidated. 

In  an  interesting  series  of  papers  A.  Brun  1 has  advanced  views  in 
strong  contrast  with  those  of  previous  writers,  for  he  regards  water  as 
of  minor  importance  in  the  production  of  volcanic  phenomena.  He 
agrees,  however,  with  Gautier  in  believing  that  the  gases  emitted  by 
lava  at  the  instant  of  its  fusion  are  generated  within  it  by  chemical 
reactions.  Their  sources,  he  thinks,  are  nitrides  of  iron  and  silicon, 
hydrocarbons,  and  certain  chloro-silicates,  such  as  the  compound 
Ca2Cl2Si03,  which  he  artificially  prepared.2  Hydrocarbons,  in  small 
amount,  he  extracted  from  lava,  as  Silvestri  had  done  before  him. 
From  a Lipari  lava,  by  heating  to  temperatures  between  800°  and 
900°,  Brun  obtained  abundant  ammonium  chloride.  Quickly  ignited 
at  900°  it  gave  off  free  nitrogen.  At  volcanic  temperatures  the  rock 
emitted  chlorine  and  hydrochloric  acid.  The  observed  volcanic  gases, 
according  to  Brun,  are  evolved  by  the  action  of  the  molten  magma 
upon  the  compounds  named  above,  and  the  temperatures  of  several 
stages  in  the  process  are  as  follows: 

0°  to  825°.  Volatilization  of  water. 

825°.  First  evolution  of  chloride  vapors. 

874°  to  1,100°.  Temperature  of  explosions. 

1,100°.  Mean  temperature  of  flowing  lava.3 

The  vast  clouds  of  vapor  arising  from  volcanoes  are  thought  by 
Brun  to  consist  mainly  of  volatilized  chlorides,  with  little  or  no 
steam.  This  conclusion  is  in  direct  opposition  to  the  prevailing 
belief. 

In  support  of  his  views,  Brun  has  personally  studied  Stromboli, 
Vesuvius,  the  volcanoes  of  Java  and  the  Canary  Islands,  and  Kilauea. 
In  all  cases  he  claims  to  have  found  the  fresh  volcanic  glass  or  cinder 
to  he  practically  anhydrous,  and  to  yield  a sublimate  of  ammonium 
chloride  on  heating  to  moderate  temperatures.  At  higher  tempera- 
tures, at  or  near  the  fusing  point,  gases  were  given  off  with  explosive 
violence,  and  of  a character  quite  unlike  anything  reported  by  pre- 
vious observers.  For  example,  four  obsidians  from  Krakatoa  gave 
498,  543,  380,  and  435  cubic  centimeters  of  gas  per  kilogram,  of  the 
following  composition: 


1 Arch.  sc-i.  phys.  nat.,  4th  ser.,  vol.  19, 1905,  pp.  439,  589;  vol.  22, 1906,  p.  425;  vol.  25, 1908,  p.  146;  vol.  27, 

1909,  p.  113;  vol.  28, 1909,  p.  45;  vol.  29, 1910,  pp.  99,  618  (the  last  paper  jointly  with  L.  W.  Collet);  vol.  30, 

1910,  p.  576.  A general  summary  of  his  conclusions  is  given  by  Brim  in  Rev.  gen.  sci.,  1910,  p.  51.  His  com- 
plete researches  have  been  brought  together  in  a superb  quarto,  Recherches  sur  l’exhalaison  volcanique, 
Geneva,  1911. 

2 Chlorosilicates  known  to  exist  in  nature,  like  sodalite  and  several  other  species,  are  more  probable 
sources  of  chlorine.  Sodalite  is  among  the  minerals  reported  as  sublimates  at  Vesuvius. 

2 The  temperature  of  the  lava  at  Kilauea  is  given  by  Brun  as  1,290°±40°.  Arch.  sci.  phys.  nat.,  4th  ser., 
vol.  30, 1910,  p.  576.  Day  and  Shepherd,  by  means  of  a thermocouple  lowered  into  the  center  of  the  lava 
pool,  determined  its  temperature  as  1,000°.  Carnegie  Inst.  Washington,  Year  Book  No.  10, 1911,  p.  91. 


VOLCANIC  CASES  AND  SUBLIMATES. 


283 


Gases  from  Krakatoa. 


A 

B 

C 

D 

Cl2 

59.  64 
11.  63 

7.  99 
6.  73 

.50 
4.  78 

8.  73 

49.  94 
15.  54 
11.  61 
6.  87 
Trace. 
5.  68 
10.  36 

82.  04 
None. 
2.  46 
8.89 
None. 

63.2 

None. 

} 29.8 
Trace. 

HC1 

so2 

co2 

02 

CO 

N2  and  other  inert  gases 

6.  61 

7.0 

100.  00 

100.  00 

100.  00 

100.  00 

The  chlorine  contained  a little  sulphur  chloride,  and  ammonium 
chloride  was  also  collected  and  determined.  Other  obsidians  from 
other  volcanoes  gave  similar  results,  but  with  larger  proportions  of 
HC1  and  S02  and  much  less  free  chlorine.  In  order  to  account  for 
the  extraordinary  difference  between  these  gases  and  those  obtained 
by  former  investigators,  Brun  claims  that  he  studied  relatively  fresh 
or  “live”  material,  while  his  predecessors  examined  old  or  “dead” 
rocks,  such  as  granites,  etc.  The  distinction  is  of  doubtful  signifi- 
cance.1 The  surprising  amounts  of  free  chlorine  found  in  Bran’s 
analyses  are  also  questionable. 

The  publication  of  Bran’s  researches  naturally  led  to  controversy, 
especially  between  himself  and  Gautier.2  Brun  urges  that  the  well- 
known  volcanic  sublimates  of  metallic  chlorides,  such  as  the  chlorides 
of  magnesium  and  iron,  are  incompatible  with  the  presence  of  water 
in  the  magma,  for  they  are  easily  hydrolyzed.  To  this  Gautier 
replies  that  a large  amount  of  hydrochloric  acid  in  the  volcanic  emana- 
tions would  inhibit,  partially  or  altogether,  the  usual  hydrolysis. 
Brun  of  course  recognizes  the  obvious  fact  that  superficial  or  meteoric 
waters  play  some  part  in  eruptions,  especially  in  the  formation  of 
fumaroles,  but  he  regards  that  part  as  insignificant  and  is  most 
emphatic  in  declaring  that  the  magma  itself,  in  the  volcanic  chimney, 
is  anhydrous.  The  last  point  is  the  one  on  which  he  and  Gautier 
principally  differ.  The  fumarole  gases,  so  far  as  they  have  been 
studied,  seem  to  be  generally  hydrous,  as  is  shown  by  a group  of 
analyses  by  Gautier.3  These  gases  were  collected  at  Vesuvius,  A 
and  B three  months  after  the  eruption  of  1906,  C and  D about  fifteen 
months  later.  Gases  A and  B were  emitted  at  a temperature  near 
300°,  C and  D at  250°  to  280°.  The  undried  gases  had  the  subjoined 
composition. 


1 Two  of  Chamberlin’s  analyses  relate  to  gases  from  fresh  Vesuvian  lava  of  the  eruption  of  1906.  They 
contained  principally  CO2  with  much  S02,  some  CO  and  CH4,  and  minor  amounts  of  H2  and  N2.  These 
gases  bear  no  resemblance  to  those  reported  by  Brun.  On  the  other  hand,  R.  Beck  (Monatsb.  Deutsch. 
geol.  Gesell.,  1910,  p.  240)  found  in  gas  extracted  from  obsidian  14.47  per  cent  Cl2  and  50.75  HC1. 

2 For  Gautier’s  share  in  the  controversy  see  Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  24,  1907,  p.  463,  and  Revue 
sci.,  5th  ser.,  vol.  8,  1907,  p.  545,  and  Nov.  27,  1909.  See  also  K.  Sapper,  Centralbl.  Min.,  Geol.  u.  Pal., 
1909,  p.  609;  A.  C.  Lane,  Tufts  Coll.  Studies,  vol.  3, 1908,  p.  39;  and  J.  Schwertschlager,  Centralbl.  Min., 
Geol.  u.  Pal.,  1911, .p.  777.  Bran’s  papers  have  already  been  cited. 

3 Bull.  Soc.  chim.,  4th  ser.,  vol.  5,  1909,  p.  977.  See  also  Compt.  Rend.,  vol.  148,  1909,  p.  1708;  vol.  149, 
1909,  p.  84. 


284 


THE  DATA  OE  GEOCHEMISTRY. 


Gases  from  Vesuvius. 


A 

B 

c 

D 

HC1 

0.  78 

Trace. 

None. 

None. 

co2 

11.  03 

6.  68 

0.  80 

0.  66 

CO 

None. 

None. 

. 15 

.02 

h2 

1.24 

Trace. 

. 54 

. 02 

Oo 

3.  72 

6.  00 

4.  59 

3.  68 

N2,  A,  etc 

15.  49 

24.  88 

21.23 

17.  86 

H20  vapor 

67.  74 

62.44 

72.  69 

77.  76 

100.  00 

100.  00 

100.  00 

100.  00 

The  water  in  these  gases  may  of  course  have  been  of  superficial 
origin.  J.  Prestwich1  has  noted  that  wells  and  springs  near  vol- 
canoes generally  show  a remarkable  shrinkage  just  before  eruptions, 
an  observation  which  has  some  bearing  upon  the  character  of  the 
more  persistent  volcanic  emanations.  The  water  that  so  vanishes 
may  well  reappear  in  the  fumaroles  which  form  later.  A very  serious 
objection  to  Brun’s  opinions  is  the  fact  that  deep-seated  plutonic 
rocks,  which  presumably  solidified  out  of  reach  of  percolating  waters 
from  above,  contain  micas,  of  which  water  is  one  of  the  essential  con- 
stituents. The  analcite  basalts  and  the  highly  hydrated  pitchstones2 
are  also  difficult  to  understand  if  the  magma  is  really  anhydrous. 

Still  more  conclusive  against  Brun’s  views  are  the  observations 
of  Day  and  Shepherd,  already  cited,  who  actually  collected  consider- 
able quantities  of  water  directly  from  the  molten  lava  of  Kilauea. 
There,  at  least,  the  magma  is  not  anhydrous.  Brun’s  arguments  by 
which  he  seeks  to  prove  its  anhydrous  nature  are  all  discussed  by 
Day  and  Shepherd,  and  effectively  answered. 

On  the  whole,  the  work  of  Gautier  on  the  chemistry  of  the  volcanic 
gases  seems  to  be  the  most  general  and  satisfactory.  Deductions  from 
it,  however,  must  not  be  pushed  too  far,  for  the  evidence  does  not 
cover  all  the  ground.  That  rocks  contain  some  gaseous  inclusions  is 
established,  although  hydrogen  may  not  be  among  them;  and  these 
were  probably  entangled  when  the  magma  first  solidified.  Percolating 
waters  certainly  reach  volcanic  matter  from  above,  and  it  is  highly 
probable  that  some  water  filters  in  from  the  sea.  A volcano  on  the 
seaboard  could  hardly  escape  from  receiving  some  accessions  of  that 

1 Proc.  Roy.  Soc.,  vol.  41, 1886,  p.  117. 

2 In  a recent  publication  (Zeitschr.  f.  Vulkanologie,  vol.  1,  p.  3,  1914),  Bran  attempts  to  show  that  the 
water  of  mica  is  not  an  essential  part  of  the  molecule.  Upon  that  assumption  the  formula  of  muscovite 
becomes  irrational.  According  to  O.  Stutzer  (Monatsb.  Deutsch.  geol.  Gesell.,  1910,  p.  102)  the  water  of 
pitchstone  is  not  magmatic. 


VOLCANIC  GASES  AND  SUBLIMATES. 


285 


kind.1  What  the  relative  magnitude  of  these  several  factors  may  be 
we  have  no  means  of  determining.  Furthermore,  experiments  like 
those  of  Gautier  do  not  reproduce  the  conditions  existing  within  a 
volcano.  His  rocks  were  heated  under  conditions  which  removed  the 
gaseous  products  as  fast  as  they  were  formed;  in  a volcanic  reservoir 
they  must  accumulate  in  contact  with  or  permeating  the  lava  until  the 
pressure  has  been  relieved  by  an  explosion.  Steam  may  oxidize  a 
ferrous  compound,  but  the  hydrogen  in  its  turn  is  a powerful  re- 
ducing agent.  There  are  here,  then,  two  opposing  tendencies,  and 
we  can  not  readily  decide  what  sort  of  an  equilibrium  would  be 
established  between  them.  It  is  probable  that  in  the  depths  of  a 
volcano  temperatures  prevail  which  dissociate  water  into  its  elements, 
unless  the  enormous  pressures  there  existing  should  compel  some  sort 
of  union  that  would  otherwise  be  impossible.  The  chemistry  of  great 
pressures  and  concurrently  high  temperatures  is  entirely  unknown, 
and  its  problems  are  not  likely  to  be  unraveled  by  any  experiments 
within  the  range  of  our  resources.  The  temperatures  we  can  com- 
mand, but  the  pressures  are  as  yet  beyond  our  reach.  We  may  devise 
mathematical  formulae  to  fit  determinable  conditions;  but  the  mo- 
ment we  seek  to  apply  them  to  the  phenomena  displayed  at  great 
depths  we  are  forced  to  employ  the  dangerous  method  of  extrapola- 
tion, and  our  conclusions  can  not  be  verified. 

VOLCANIC  EXPLOSIONS. 

It  is  generally  admitted  that  the  volcanic  gases  are  the  chief  agents 
in  producing  volcanic  explosions.  This  is  emphasized  by  E.  Reyer,2 
by  A.  C.  Lane,3  by  S.  Arrhenius,4  and  more  recently  by  C.  Doelter.5 
Lane  and  Doelter  especially  regard  the  deep-seated  magmas  as 
impregnated  by  gaseous  mixtures  which  explode  upon  relief  of  pres- 
sure. As  interpreted  by  Lane,  these  gases  were  absorbed  by  the 
early  earth  as  original  and  necessary  constituents  of  every  magma, 
and  their  retention  is  essential  to  the  development  and  crystallization 
of  plutonic  and  dike  rocks.  Their  sudden  escape,  due  to  the  for- 
mation of  cracks  in  the  earth’s  crust,  is  a prime  cause  of  volcanic 
eruptions.  Hypotheses  of  this  order,  varying  only  in  detail,  have 
been  widely  accepted,  but  they  are  not  in  complete  harmony  with 
the  conclusions  of  either  Gautier  or  Brun. 

It  is  plain  that  the  consideration  of  the  volcanic  gases  is  directly 
connected  with  various  current  speculations  concerning  the  origin  of 

1 G.  A.  Daubr6e,  Etudes  synthetiques  de  geologie  experimental,  1873,  pp.  235-241. 

2 Beitrag  zur  Fysik  der  Eruptionen,  Wien,  1877. 

3 Bull.  Geol.  Soc.  America,  vol.  5, 1893,  p.  259. 

4 Geol.  Foren.  Forhandl.,  vol.  22, 1900,  p.  411. 

6 Sitzungsb.  Akad.  Wien,  vol.  112, 1903,  p.  681. 


286 


THE  DATA  OF  GEOCHEMISTRY. 


the  earth;  and  whether  we  incline  to  the  nebular  hypothesis  or  to 
the  planetesimal  conception,  lately  developed  by  T.  C.  Chamberlin, 
we  must  take  them  into  account.  Chamberlin  and  R.  D.  Salisbury  1 
regard  the  gases  as  originally  entangled  in  the  meteoroidal  matter, 
from  which,  according  to  the  planetesimal  hypothesis,  the  earth  was 
formed,  and  they  are  therefore  true  additions  to  the  atmosphere  and 
hydrosphere.  These  authors  admit  that  lavas  in  rising  to  the  surface 
may  encounter  rocks  saturated  with  moisture,  and  so  generate  some 
steam;  but  they  argue  that  large  accessions  of  water,  such  as  infil- 
trations from  the  sea,  would  absorb  more  heat  than  the  molten 
magma  could  afford  to  lose.  Could  Stromboli,  for  instance,  which 
has  been  in  continual  activity  for  more  than  two  thousand  years, 
have  retained  its  heat  under  such  adverse  conditions  ? The  question 
is  pertinent,  but  not  final,  for  we  know  nothing  about  the  relative 
quantities  of  water  and  lava  which  are  supposed  to  take  part  in  the 
eruptions.  A large  molten  reservoir  and  a moderate  infiltration  of 
water,  a supply  of  heat  greater  than  the  wastage,  are  conceivable; 
and  it  is  also  to  be  remembered  that  some  water  lowers  the  melting 
point  of  a rock  and  so  helps  to  preserve  its  fluidity.  A considerable 
degree  of  cooling  is  not  incompatible  with  aqueo-igneous  fusion  and 
would  not  necessarily  check  the  outflow  of  a lava  stream  or  the  visi- 
ble activity  of  a volcano.  Arrhenius  2 claims  that  a continuous  activ- 
ity, like  that  of  Stromboli,  would  be  impossible  without  a steady  sup- 
ply of  water,  and  he  regards  the  sea  bottom  as  equivalent  to  a semi- 
permeable  membrane  through  which,  by  osmotic  pressure,  the  water 
is  forced.  This  pressure  at  a depth  of  10,000  meters  would  amount 
to  1,700  atmospheres.  It  is  not  as  a liquid,  however,  but  as  a vapor, 
far  above  its  critical  temperature,  that  the  water  enters  the  magma, 
in  which  it  is  absorbed  much  as  ordinary  water  is  taken  up  by  cal- 
cium chloride.  During  an  eruption  it  is  emitted  as  steam.  The 
reverse  movement  of  magma  to  the  ocean  is  prevented,  according  to 
Arrhenius,  by  the  impermeability  of  the  intervening  septum  to  the 
larger  and  heavier  molecules  of  which  the  molten  rock  is  composed, 
and  especially  to  the  amorphous  silica  which  the  entering  water  is 
supposed  to  set  free.  Here  the  nature  of  the  fluid  magma  itself  is  in 
question — a subject  which  will  be  taken  up  more  fully  in  the  next 
chapter. 

So  far,  then,  we  have  several  distinct  hypotheses  to  account  for 
the  gaseous  exhalations  of  volcanoes.  Arrhenius  and  Daubree,  as 

1 Geology,  vol.  1,  pp.  588-594,  602-618,  1904.  See  also  ante,  Chap.  II,  p.  56.  According  to  Chamberlin 
and  Salisbury,  crystallization  has  much  to  do  with  the  evolution  of  volcanic  gases.  When  crystals  form 
within  a lava,  they  give  up  their  gaseous  load,  which  overcharges  the  still  fluid  portions  of  the  magma, 
thereby  causing  increased  pressure  and  provoking  explosions.  See  analyses  by  R.  T.  Chamberlin,  of  gases 
from  the  rocks  and  phenocrysts  of  a small  tuff  cone,  Red  Mountain,  Ariz.,  cited  by  W.  W.  Atwood,  Jour. 
Geology,  vol.  14,  p.  138, 1906. 

2 Geol.  Foren.  Forhandl.,  vol.  22,  p.  411, 1900. 


VOLCANIC  GASES  AND  SUBLIMATES. 


287 


well  as  many  earlier  writers,  derive  them  from  infiltrations  of  sea 
water,  Arrhenius  assuming  osmotic  pressure  and  Daubree  capillary 
attraction  as  the  method  by  which  entrance  to  the  magma  was 
effected.  Chamberlin  and  Lane  regard  the  gases  as  original  inclo- 
sures within  the  earth,  now  issuing  from  great  depths.  Gautier, 
Moissan,  and  Brun  assign  their  origin  to  reactions  within  the  rocks 
themselves,  but  differ  as  to  the  details  of  the  process. 

Of  all  these  differing  views,  that  of  Gautier  involves  the  smallest 
amount  of  hypothesis,  and  it  also  has  the  merit  of  simplicity.  It  is 
not,  however,  as  we  have  already  seen,  absolute  and  final,  but  it  cer- 
tainly represents  a part  of  the  truth,  and  possibly  the  major  portion. 
On  the  experimental  side  it  needs  further  investigation,  for  it  is  dif- 
ficult to  suppose  that  a fluid  magma,  saturated  with  gas  and  water, 
could  emerge  from  a volcano  and  solidify  without  retaining  some 
gaseous  occlusions.  In  fact,  the  experiments  of  R.  T.  Chamberlin 
seem  to  prove  that  such  occlusions  exist,  and  the  extent  to  which 
Gautier’s  conclusions  can  be  accepted  depends  upon  their  magnitude. 
Here  we  may  properly  resort  to  some  evidence  from  analogy. 
Gaseous  occlusions  are  taken  up  by  iron,  steel,  and  slags  in  ordinary 
furnace  operations,  and  among  them  hydrogen  is  the  most  con- 
spicuous.1 Data  relative  to  the  absorption  of  hydrogen  by  iron  are 
abundant,2  and  meteoric  iron  seems  always  to  contain  it.3  From  the 
Lenarto  iron  T.  Graham  obtained  2.85  times  its  volume  of  gas, 
containing  86  per  cent  of  hydrogen.  From  the  Augusta  iron  Mallet 
extracted  3.17  volumes,  in  which  hydrogen,  carbonic  oxide,  carbon 
dioxide,  and  nitrogen  were  present.  There  is,  to  be  sure,  one  adverse 
experiment  by  M.  W.  Travers,4  on  meteoric  iron  of  unstated  origin, 
which  is  not  quite  conclusive.  By  heating  this  iron,  hydrogen  was 
obtained;  upon  dissolving  the  iron  in  copper  sulphate  solution,  none 
was  evolved.  The  failure  to  develop  hydrogen  in  the  second  experi- 
ment is  held  by  Travers  to  prove  its  absence,  at  least  as  a gaseous 
occlusion.  The  possibility  that  hydrogen  from  a metallic  hydride 
might  be  expended  in  the  precipitation  of  copper  seems  not  to  have 
been  investigated.  The  weight  of  evidence,  so  far,  is  that  meteoric 
irons  do  occlude  hydrogen,  while  meteoric  stones  yield  a larger  propor- 
tion of  carbon  dioxide.  The  Kold  Bokkeveld  carbonaceous  meteorite 


1 See  table  given  by  A.  C.  Lane  in  his  paper,  Geological  activity  of  the  earth’s  originally  absorbed  gases: 
Bull.  Geol.  Soc.  America,  vol.  5,  1893,  p.  264.  See  also  references  cited  by  G.  Tschermak,  Sitzungsb. 
Akad.  Wien,  vol.  75, 1877,  pp.  170-174. 

2 See,  for  example,  L.  Troost  and  P.  Hautefeuille,  Compt.  Rend.,  vol.  76, 1873,  p.  562;  L.  Cailletet,  idem, 
vol.  61,  1865,  p.  850;  and  Thoma,  Zeitschr.  physikal.  Chemie,  vol.  3,  1891,  p.  91.  Thoma’s  paper  gives 
many  references  to  literature.  H.  Wedding  and  T.  Fischer  (Ber.  V Internat.  Kong,  angew.  Chemie,  vol. 
2, 1904,  p.  25)  have  summed  up  the  subject  quite  thoroughly.  The  papers  by  J.  Parry  (Am.  Chemist,  vol. 
4, 1873-74,  p.  225;  vol.  6, 1875-76,  p.  107)  are  also  important. 

3 T.  Graham,  Proc.  Roy.  Soc.,  vol.  15, 1866-67,  p.  502.  J.  W.  Mallet,  idem,  vol.  20, 1871-72, p.  365.  A.  W. 
Wright,  Am.  Jour.  Sci.,3dser.,  vol.  9, 1875,  p.294;  vol.  10, 1875, p.  44;  vol.  11, 1876, p.253;  vol.  12, 1876, p.  166; 
3.  Dewar  and  G.  Ansdell,  Proc.  Roy.  Inst.,  vol.  11  1886,  p.445.  See  also  R.T,  Chamberlin,  lqc.cit. 

4 Proc.  Roy.  Soc.,  vol.  64,  p.  130,  1898-99. 


288 


THE  DATA  OF  GEOCHEMISTRY. 


gave  thirty  times  its  volume  of  gas,  in  which  carbon  dioxide  pre- 
dominated. The  terrestrial  native  iron  from  Ovifak,  in  Greenland, 
gives  off  when  heated,  according  to  Woehler,1  more  than  one  hundred 
times  its  volume  of  gas,  which  is  mainly  carbon  monoxide  with  a 
little  dioxide.  If  Chamberlin’s  theory  of  the  earth’s  origin  is  correct, 
we  have  in  these  gases  an  adequate  supply  for  the  maintenance  of  all 
volcanic  phenomena.  Or,  if  the  earth  itself  is  equivalent  to  a huge 
meteorite,  as  many  thinkers  have  supposed,  the  analogy  between  it 
and  the  smaller  bodies  accounts  for  nearly,  if  not  quite,  all  volcanic 
gases.  From  this  point  of  view  they  are  occlusions,  forced  out  by 
pressure  and  the  resulting  mechanical  heat.  Between  this  suppo- 
sition and  that  of  Chamberlin  there  is  little  essential  difference,  at 
least  upon  the  chemical  side  of  the  problem.  The  analogy  between 
the  expulsion  of  a gas  from  the  interior  of  our  globe  and  its  evolution 
from  meteorites  has  been  well  developed  by  G.  Tschermak,2  who 
regards  volcanism  as  a cosmic  phenomenon,  of  which  the  typical 
example  is  fco  be  found  in  the  terrific  gaseous  upheavals  that  are  seen 
on  the  surface  of  the  sun. 

For  each  of  the  theories  so  far  proposed  relative  to  the  origin  of 
volcanic  gases  strong  arguments  can  be  adduced,  and  no  one  should 
be  exclusively  adopted.  The  phenomena  are  probably  complex,  and 
many  activities  contribute  to  their  development.  Some  gas  must  be 
derived  from  reactions  like  those  described  by  Travers  and  Gautier; 
some  must  originate  from  percolating  waters;  and  a portion  of  the 
supply  may  possibly  come  from  deep-seated  sources.  Whether  we 
assume  that  the  earth  was  once  a molten  globe  or  that  it  was  formed 
by  the  accretion  of  meteoric  masses,  gases  must  be  retained  within  its 
interior,  and  their  escape  from  time  to  time  would  seem  to  be  unavoid- 
able. Molten  matter,  whether  metallic  or  stony,  is  known  to  dis- 
solve gases  in  large  amounts,  as  silver  dissolves  oxygen,3  and  they  are 
expelled  in  great  measure  during  solidification.  They  are,  moreover, 
expelled  explosively,  a fact  which  can  be  verified  in  any  laboratory; 
but  that  the  expulsion  is  complete  is  extremely  improbable.  Some 
gas,  it  may  be  much  or  little,  is  retained  by  the  solid  mass,  and  modi- 
fies its  properties.  All  of  these  elements  contribute  to  the  phenomena 
of  volcanism,  but  their  relative  magnitudes  can  not  now  be  evaluated. 
Speculation  upon  them  may  help  to  stimulate  research,  but  so  long 
as  the  temperatures  and  pressures  within  a volcano  are  unmeasured 
the  problems  suggested  by  the  hypotheses  must  remain  unsolved. 
The  question  of  volcanic  temperatures,  of  which  more  will  be  said  in 
the  next  chapter,  is  particularly  important  in  the  investigation  of 

1 Ann.  Chem.  Pharm.,  vol.  163,  1872,  p.  250.  A similar  observation  by  M.  Berthelot  is  recorded  by  A. 
Daubr^e,  Compt.  Rend.,  vol.  74,  1872,  p.  1541. 

2 Sitzungsb.  Akad.  Wien,  vol.  75,  1877,  p.  151. 

3 One  volume  of  molten  silver  can  absorb  22  volumes  of  oxygen,  which  escapes  explosively  when  the  metal 
cools.  This  ‘'spitting”  of  melted  silver  is  familiar  to  all  assayers. 


VOLCANIC  GASES  AND  SUBLIMATES. 


289 


volcanic  explosions.  The  latter  are  due  in  part  to  cooling  and  the 
violent  expulsion  of  gases  following  relief  of  pressure,  but  chemical 
combination  may  also  be  manifest  in  them.  If  the  temperature  in 
the  depths  of  a volcano  is  high  enough  to  dissociate  water  into  its 
elements,  then  the  issuing  gases  will  form  an  explosive  mixture  of 
tremendous  energy.  The  moment  such  a mixture  reached  the  surface 
of  the  molten  lava  it  would  have  become  cool  enough  to  ignite,  and 
the  characteristic  detonations  would  follow.  Hydrogen  alone,  emerg- 
ing into  the  air,  might  form  with  the  latter  a similar  mixture  and 
produce  the  same  phenomena.  E.  W.  von  Siemens,1  observing  a series 
of  explosions  at  Vesuvius,  ascribed  them  to  this  cause.  That  hydro- 
gen does  issue  from  volcanoes  is  established;  under  certain  conditions 
it  burns  quietly,  and  under  others  it  gives  rise  to  explosions;  but  in 
either  case  it  develops  much  heat  and  so  retards  the  cooling  of  its 
surrounding  matter.  One  gram  of  hydrogen,  burning  to  form  water, 
liberates  a quantity  of  heat  represented  by  34,000  calories;  that  is,  it 
would  raise  the  temperature  of  34,000  grams  of  water  from  0Q  to  1°  C. 
This  reaction  alone,  this  combustion  of  hydrogen  in  air,  evidently 
plays  a very  large  part  in  the  thermodynamics  of  volcanism. 

SUMMARY. 

That  the  volcanic  gases  appear  in  a certain  regular  order  has  been 
shown  by  the  various  researches  upon  their  composition,  and  espe- 
cially by  the  labors  of  Deville  and  Leblanc.  What,  now,  in  the  light 
of  all  the  evidence,  is  that  order,  and  what  do  the  chemical  changes 
mean? 

First.  The  gases  issue  from  an  active  crater  at  so  high  a tempera- 
thre  that  they  are  practically  dry.  They  contain  superheated  steam, 
hydrogen,  carbon  monoxide,  methane,  the  vapor  of  metallic  chlorides, 
and  other  substances  of  minor  importance.  Oxygen  may  be  present 
in  them,  with  some  nitrogen,  argon,  sulphur  vapor,  and  gaseous  com- 
pounds of  fluorine. 

Second.  The  hydrogen  burns  to  form  more  water  vapor,  and  the 
carbon  gases  oxidize  to  carbon  dioxide.  From  the  sulphur,  sulphur 
dioxide  is  produced.  The  steam  reacts  upon  a part  of  the  metallic 
chlorides,  generates  hydrochloric  acid,  and  so  acid  fumaroles  make 
their  appearance. 

Third.  The  acid  gases  of  the  second  phase  force  their  way  through 
crevices  in  the  lava  and  the  adjacent  rocks,  and  their  acid  contents 
are  consumed  in  effecting  various  pneumatolytic  reactions.  The 
rocks  are  corroded,  and  where  sulphides  occur  hydrogen  sulphide  is 
set  free.  If  carbonate  rocks  are  encountered,  carbon  dioxide  is  also 
liberated. 


i Monatsb.  K.  prouss.  Akad.,  1878,  p.  558. 


97270°— Bull.  616—16 19 


290 


THE  DATA  OF  GEOCHEMISTRY. 


Fourth.  Only  steam  with  some  carbon  dioxide  remains,  and  even 
the  latter  compound  soon  disappears. 

This  seems  to  be  the  general  course  of  events,  although  it  is  modi- 
fied in  details  by  local  peculiarities.  All  of  the  substances  enumer- 
ated in  the  lists  of  gases  and  sublimates  given  in  the  earlier  portions 
of  this  chapter  may  take  part  in  the  reactions,  but  they  do  not 
seriously  affect  the  larger  processes  which  have  just  been  described. 
The  order  is  essentially  that  laid  down  by  Deville  and  Leblanc, 
except  that  the  early  evolution  of  hydrogen  and  carbonic  oxide  is 
taken  into  account.  The  current  of  events  may  be  disturbed,  so  to 
speak,  by  ripples  and  eddies — that  is,  by  subsidiary  and  reversed 
reactions — but  its  main  course  seems  to  be  clearly  indicated.1 


1 For  a summary  of  our  knowledge  concerning  the  magmatic  gases  previous  to  the  work  of  Bran  and 
Chamberlin,  see  F.  C.  Lincoln,  Econ.  Geology,  vol.  2, 1907,  p.  258.  Lincoln  gives  a good  table  of  analyses 
and  proposes  a classification  of  the  volcanic  exhalations.  For  a theoretical  discussion  relative  to  “gas 
mineralizers  ” in  magmas  see  P.  Niggli,  Zeitschr.  anorg.  Chemie,  vol.  75,  p.  161 , and  vol.  77, 1912,  p.  321.  Also 
Centralbl.  Min.,  Geol.  u.  Pal.,  1912,  p.  321;  and  Geol.  Rundschau,  vol.  3, 1912,  p.  472. 


CHAPTER  IX. 

THE  MOLTEN  MAGMA. 

TEMPERATURE. 


In  the  chapter  upon  volcanic  gases  the  question  of  temperatures 
was  purposely  left  vague,  and  only  the  bare  fact  that  they  must  be 
high  was  taken  into  account.  For  an  intelligent  study  of  the  mag- 
mas, however,  some  more  definite  estimates  of  temperatures  are  essen- 
tial, even  though  their  inferior  limits  can  alone  be  determined  with 
any  degree  of  certainty.  We  can  measure  the  temperature  at  which 
lavas  and  their  component  minerals  fuse,  under  ordinary  conditions 
of  pressure;  but  these  melting  points  are  modified  by  various  agencies 
within  the  depths  of  the  earth,  and  it  is  not  yet  possible  to  strike  a 
definite  balance  between  the  opposing  forces.  By  pressure,  which 
steadily  increases  as  we  descend  into  the  earth,  the  melting  points 
must  be  raised,1  but  on  the  other  hand  the  gases  that  we  know  to  be 
present  in  the  molten  mass  tend  to  lower  them,  and  the  latter  tend- 
ency is  probably  the  stronger.  The  fact  that  pressure  tends  to 
prevent  the  escape  of  dissolved  vapors,  and  so  to  increase  fluidity, 
must  also  be  taken  into  account.  It  should  be  remembered,  more- 
over, in  any'  reasoning  upon  the  unerupted  magma,  that  the  tempera- 
ture at  which  it  can  retain  the  liquid  state  is  a minimum,  and  that 
actually  it  may  be  very  much  hotter.  The  temperature,  furthermore, 
is  believed  to  increase  with  the  depth;  but  we  can  do  no  more  than 
to  surmise  what  the  conditions  may  be  miles  below  the  apparent 
surface  of  the  lava  column.2  Although  the  characteristics  of  the  in- 
dividual rock-forming  minerals  will  not  be  generally  discussed  until 
the  next  chapter  is  reached,  our  knowledge  of  their  melting  points 
may  properly  be  summed  up  here.  It  is  only  within  recent  years 
that  anything  like  accurate  measurements  of  high  temperatures  have 
been  possible,  and  therefore  the  few  and  scattered  older  data  can  be 
ignored.3  The  development  of  the  thermocouple  by  C.  Barus  in 
the  United  States  Geological  Survey,  and  by  H.  Le  Chatelier  in 
France,  and  the  use  of  the  Seger  cones  in  the  ceramic  industry,  have 


1 Estimates  of  the  change  in  fusibility  due  to  pressure  have  been  made  by  Lord  Kelvin,  Philos.  Mag., 
5th  ser.,  vol,  47,  p.  66;  C.  E.  Stromeyer,  Mem.  Manchester  Lit.  Philos.  Soc.,  vol.  44,  No.  7,  1900,  and 
J.  H.  L.  Vogt,  Min.  pet.  Mitt.,  vol.  27,  1908,  p.  105.  The  fundamental  data,  however,  are  few  and  unsat- 
isfactory. On  the  influence  of  pressure  in  producing  chemical  changes  in  deep-seated  rocks,  see  J.  W. 
Judd,  Jour.  Chem.  Soc.,  vol.  57,  1890,  p.  404. 

2 For  estimates  of  temperatures  far  within  the  earth,  see  Clarence  King,  Am.  Jour.  Sci.,  3d  ser.,  vol.  45, 
1893,  p.  7;  O.  Fisher,  idem,  4th  ser.,  vol.  11, 1901,  p.  414;  F.  R.  Moulton,  cited  by  T.  C.  Chamberlin,  Jour. 
Geology,  vol.  5,  1897,  p.  674;  and  A.  C.  Lunn,  in  Chamberlin  and  Salisbury’s  Geology,  vol.  1,  1904,  p.  552. 
All  the  estimates  reach  exceedingly  high  figures,  but  they  are  based  upon  very  doubtful  extrapolations. 
It  is  conceivable  that  the  increase  of  temperature  with  depth  may  reach  a limit  which  it  can  not  exceed. 

3 See,  for  example,  A.  Schertel  and  T.  Erhard,  Beiblatter,  1879,  p.  347;  and  Schertel,  idem,  1880,  p.  542. 

291 


292 


THE  DATA  OF  GEOCHEMISTRY. 


placed  high-temperature  pyrometry  upon  a new  footing  and  have 
made  practicable  the  class  of  determinations  which  we  now  require. 

In  1891  J.  Joly  1 described  an  instrument  (the  meldometer)  by 
means  of  which  the  melting  points  of  minerals  could  be  rapidly  and 
easily  determined,  and  several  years  later  R.  Cusack2  reported  a 
considerable  number  of  measurements  made  with  its  aid.  The  in- 
strument consisted  of  a thin  ribbon  of  platinum,  upon  which  the  min- 
eral to  be  examined,  in  very  fine  powder,  was  placed.  The  particles 
of  mineral  dust  were  observed  with  a microscope;  the  ribbon  was 
heated  with  an  electric  current;  and  from  the  expansion  of  the  plati- 
num, which  was  measurable,  the  temperature  was  ascertained.  For 
the  method  by  which  the  meldometer  was  calibrated  the  original 
memoir  may  be  consulted. 

C.  Doelter,3  in  recent  years,  has  made  many  melting-point  determi- 
nations by  means  of  a thermoelectric  couple.  In  his  earlier  work  the 
minerals  were  fused  in  a gas  furnace;  later  an  electric  furnace  was  used. 

The  determinations  by  A.  Brun  4 were  published  in  1902  and  1904. 
His  fusions  were  effected  in  a muffle  furnace,  heated  by  a mixture  of 
oxygen  and  illuminating  gas,  and  the  temperatures  were  measured  by 
comparison  with  Seger  cones.  The  crystallized  mineral  was  mounted 
on  a slender  peduncle  of  platinum,  and  so  placed  that  it  was  heated  by 
radiation  from  the  walls  of  the  muffle  out  of  contact  with  the  flame. 

In  all  of  the  determinations  represented  by  the  foregoing  investiga- 
tions the  subjective  element  has  been  large.  The  tested  samples  were 
watched  and  the  human  eye  was  trusted  to  determine  when  soften- 
ing began  and  when  fusion  was  complete.  Greater  exactness  has  been 
secured  in  the  researches  conducted  by  A.  L.  Day  and  his  colleagues5 6 
in  the  geophysical  laboratories  of  the  United  States  Geological 
Survey  and  the  Carnegie  Institution  upon  almost  ideally  pure 


1 Proc.  Roy.  Irish.  Acad.,  3d  ser.,  vol.  2, 1891,  p.  38. 

2 Idem,  vol.  4,  1896,  p.  399. 

s Min.  pet.  Mitt.,  vol.  20, 1901,  p.  211;  vol.  21,  1902,  p.  23;  vol.  23,  1903,  p.  297;  Sitzungsb.  Akad.  Wien, 
vol.  114,  1905,  p.  529;  vol.  115,  Abth.  1,  July,  1906.  The  determinations  cited  are  from  his  third  paper. 

* Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  13,  1902,  p.  552;  vol.  18, 1904,  p.  537.  For  the  details  of  Bran’s  deter- 
minations, see  his  volume  Recherches  sur  l’exhalaison  volcanique,  Geneva,  1911.  There  are  also  some 
determinations  by  W.  C.  Roberts- Austen,  cited  by  Lord  Kelvin,  Philos.  Mag.,  5th  ser.,  vol.  47,  1899,  p.  66 
others  by  J.  H.  L.  Vogt,  published  in  part  2 of  Die  Silikatschmelzlosungen,  and  a few  by  W.  Hempel; 
Ber.  V Internat.  Kong,  angew.  Chemie,  vol.  1, 1904,  p.  725.  For  data  on  shales  and  clays,  see  W.  C.  Heraeus, 
Zeitschr.  angew.  Chemie,  1905,  p.  49.  For  several  rare  minerals,  see  H.  L.  Fletcher,  Sci.  Proc.  Royal  Dub- 
lin Soc.,  vol.  13,  1913,  p.  443.  For  Japanese  minerals,  Y.  Yamashita  and  M.  Majima,  Sci.  Rept.  Tohuku 

Univ.,  vol.  2, 1913,  p.  175.  On  methods,  with  a compilation  of  data,  A.  L.  Day,  Fortschr.  Min.,  Kryst.  u. 
Pet.,  vol.  4, 1914,  p.  115. 

6 A.  L.  Day  and  E.  T.  Allen,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19,  1905,  p.  93,  on  the  feldspars.  E.  T.  Allen 
and  W.  P.  White,  idem,  vol.  21,  1906,  p.  100,  on  wollastonite.  A.  L.  Day  and  E.  S.  Shepherd,  idem,  vol. 
22,  1906,  p.  265,  on  the  lime-silica  series.  E.  T.  Allen,  F.  E.  Wright,  and  J.  K.  Clement,  idem,  vol.  22, 
1906,  p.  385,  on  magnesium  metasilicate.  E.  T.  Allen  and  W.  P.  White,  idem,  vol.  27,  1909,  p.  1,  on  diop- 
side,  etc.  E.  S.  Shepherd  and  G.  A.  Rankin,  idem,  vol.  28,  1909,  p.  293,  on  binary  systems  of  alumina 
with  silica,  lime,  and  magnesia.  For  a summary  of  these  determinations,  with  corrections,  see  A.  L.  Day 
and  R.  B.  Sosman,  Am.  Jour.  Sci.,  4th  ser.,  vol.  31,  1911,  p.  341.  The  corrected  figures  are  given  in  the 
following  table.  Later  papers  by  N.  L.  Bowen,  Am.  Jour.  Sci.,  4th  ser.,  vol.  33, 1912,  p.  554;  vol.  38, 1914, 
p.  218,  and  N.  L.  Bowen  and  O.  Andersen,  idem,  vol.  37, 1914,  p.  487,  are  also  important.  Mixtures 
similar  to  the  last  have  also  been  studied  by  R.  Rieke,  Chem.  Abst.,  vol.  2,  1908,  p.  985,  from  Stahl  u. 
Eisen,  vol.  28. 


THE  MOLTEN  MA&MA. 


293 


artificial  minerals,  and  with,  thermoelectric  couples  which  had  been 
calibrated  by  comparison  with  the  standards  at  the  Physikalische 
Reichsanstalt  at  Berlin.  In  these  measurements  the  melting  points 
were  determined  by  noting  the  exact  temperatures  at  which  abrupt 
absorptions  of  heat  occurred,  thus  avoiding  errors  of  judgment. 

From  the  great  mass  of  data  now  available  I have  compiled  the 
following  table,  which  well  exhibits  the  great  divergence  between  the 
older  and  the  newest  determinations.  The  table  might  be  greatly 
extended,  but  so  many  of  the  published  figures  relate  to  unanalyzed 
minerals  that  their  value  is  problematical.  Additional  data  will  be 
given  in  Chapter  X,  in  describing  individual  species. 

Melting  points  ( °C .)  of  various  minerals , as  determined  by  different  investigators. 


Feldspars  and  feldspatkoids. 


Mineral. 

Joly. 

Cusack. 

Doelter. 

Brun. 

Day  et  al. 

AnortMte,  natural 

1, 165-1,  210 

1,  490-1,  520 
1,  544-1,  562 

A north  it, a artificial 

1,  550 
1,  516 
1, 477 

An5Ab1?  artificial 

An2Ab!,  artificial 

Labradorite 

Andesine 

1,  230 

1,  223-1,  235 

1,  040-1,  210 
1, 155-1, 185 

1,  370 
1,  280 

ArijAbj,  artificial 

1, 430 
1,  375 
a 1,  340 

An1Ab2,  artificial 

An1Ab3,  artificial 

Oligoclase 

1,  220 
1, 175 

1, 135-1, 185 
1, 115-1, 170 
1, 185-1,  220 
1,  275-1.  315 
1, 105-1, 125 

1,  260 
1,  259 

Albite 

Orthoclase 

1, 172 

Leu  cite 

1,  298 
1,  059-1,  070 

1, 410-1, 430 
1,  270 

Nepheline,  artificial 

1,  526 

a Approximate.  Viscosity  prevents  exact  measurements. 


Miscellaneous  minerals. 


Mineral. 

Cusack. 

Doelter. 

Brun. 

Day  et  al. 

Enstatite 

1,  375-1,  400 

MgSi03,  artificial 

1,  557 

Wollastonite  a 

1,  203-1,  208 

1,  230-1,  255 

1,  366 
1,  515 
1,  270 

CaSi03,  artificial 

1,540 
& 1,  391 

Diopside,  natural 

Diopside,  artificial 

1, 187-1, 195 

1, 135-1,  265 

Augite 

1. 187- 1, 199 
1,  219-1,  223 

1. 187- 1,  200 
1,  342-1,  378 

1,  425 

1,  085-1,  200 
1,  200-1,  220 
1,  065-1, 155 
1,  265-1,410 

1,  230 
1,  270 
1,  060-1,  070 
1,  750 
1,  780 

Tremolite 

Hornblende 

Olivine 

Quartz  c 

1,  625 

Magnetite 

1, 190-1,  225 
1,  350-1, 400 

Hematite 

1,  300 
1,  270 

Fluorite 

d 1,  387 
1,  816 

Sillimanite 

a Wollastonite  lias  no  true  melting  point.  At  1,190°  it  passes  into  the  pseudohexagonal  form,  which 
melts  at  1,540°. 

b A much  lower  value,  1,225°,  was  given  by  Vogt. 

c More  properly  silica.  Quartz  is  transformed  into  cristobalite  or  tridymite  at  about  800°,  and  has  no 
true  meltmg  point  of  its  own.  Roberts- Austen  gives  the  melting  point  of  silica  as  1,775°  and  Hempel  as 
1,685°.  Alumina  (corundum?)  melts,  according  to  Hempel,  at  1,880°,  magnesia  at  2,250°,  and  lime  at 
1,900°.  According  to  C.  W.  Kanolt  (Jour.  Washington  Acad.  Sci.,  vol.  3, 1913,  p.  318),  A1203  melts  at  2,050°, 
MgO  at  2,800°,  CaO  at  2,570°,  and  Cr203  at  1,990°.  O.  Boudouard  (Jour.  Iron  and  Steel  Inst.,  1905,  pt.  1,  p. 
350)  puts  the  melting  point  of  silica  at  1,830°.  According  to  P.  D.  Quensel  (Centralbl.  Min.,  Geol.  u.  Pal., 
1906,  pp.  657, 728),  tridymite  melts  as  low  as  1,560°,  and  shows  incipient  fusion  at  1,500°. 
d Private  communication  from  A.  L.  Day;  determined  on  the  natural  mineral. 


294 


THE  DATA  OF  GEOCHEMISTRY. 


A few  other  interesting  determinations  of  melting  point  have  been 
given  by  G.  Stein,  who  used  the  Wanner  pyrometer.1  Quartz,  or 
rather  silica,  became  a viscous  semifluid  at  1,600°,  and  was  com- 
pletely liquid  at  1,750°.  Above  the  latter  temperature  it  sublimes. 
For  several  artificial  silicates,  corresponding  to  natural  minerals,  the 
following  melting  points  were  observed:  CaSi03,  1,512°;  MgSi03, 
1,565°;  FeSi03,  1,500°  to  1,550°;  MnSi03,  1,470°  to  1,500°;  Mg2Si04, 
below  1,900°;  Zn2Si04,  1,484°.  There  is  also  a research  by  E. 
Dittler,2  in  Doelter’s  laboratory,  in  which  the  work  of  Day  and  his 
colleagues  is  criticized,3  and  the  attempt  is  made  to  show  that  their 
melting  points  are  much  too  high.  For  example,  Dittler  gives  1,310° 
as  the  melting  point  of  artificial  anorthite,  and  1,200°  as  that  of  the 
natural  mineral.  What  Dittler  has  observed,  however,  seems  not  to 
be  the  melting  points  as  defined  by  Day,  but  rather  temperatures  at 
which  the  crystallized  substances  begin  to  show  transitions  into  the 
very  viscous  amorphous  forms.  This  is  suggested  by  the  second 
paper  of  Brun,  in  which  he  gives  the  following  determinations: 
Artificial  anorthite  melts,  as  measured  by  a calorimetric  method, 
between  1,544°  and  1,562°.  Japanese  anorthite  fused  at  1,490°, 
albite  at  1,259°,  olivine  at  about  1,750°,  wollastonite  at  1,366°,  and 
the  hexagonal  calcium  metasilicate  at  1,515°.  In  the  glassy  state 
the  artificial  anorthite  begins  to  show  deformation  at  1,083°  to  1,110°, 
and  it  crystallizes  between  1,210°  and  1,250°.  The  albite  glass 
softens  at  1,177°.  These  lower  temperatures  accord  fairly  with  those 
determined  by  Cusack,  Doelter,  and  Dittler,  who  seem  to  have  ob- 
served them  rather  than  the  true  melting  points.  Other  discordances 
are  due  to  differences  between  the  substances  examined,  for  natural 
minerals  are  rarely  pure,  and  in  the  pyroxene-hornblende-olivine 
series  the  variations  due  to  isomorphism  are  very  large.  One  augite, 
for  example,  contains  much,  another  little,  iron;  calcium  and  magne- 
sium also  vary  in  then  proportions,  and  so  on.  In  these  series,  gen- 
erally speaking,  the  melting  point  falls  as  the  percentage  of  iron 
increases.  The  presence  of  water  in  a mineral  has  also  a lowering 
effect  upon  the  melting  point,  and  this  impurity  is  not  often  entirely 
absent.  The  figures  given,  therefore,  do  not,  except  in  those  from 
the  Geophysical  Laboratory  and  in  one  or  two  other  cases,  refer  to 
ideally  pure  compounds,  but  to  the  natural  minerals  with  all  their 
defects  of  composition.  They  help  us  to  form  some  idea  of  the 
temperatures  which  govern  volcanic  phenomena,  but  we  can  not 
reason  upon  them  as  if  they  were  precise  and  definite.  They  also 
furnish  us  with  some  checks  that  we  can  use  in  studying-  the  order  of 
formation  of  minerals  when  a molten  lava  cools,  although  here  again 


1 Zeitschr.  anorg.  Chemie,  vol.  55,  1907,  p.  159. 

2 Idem,  vol.  69, 1911,  p.  273. 

3 For  a reply  to  criticisms  see  Day  and  Sosman,  Am.  Jour.  Sci.,  4th  ser.,  vol.  31, 1911,  p.  341. 


THE  MOLTEN  MAGMA. 


295 


the  data  should  be  handled  with  great  caution.  A comparison  of  the 
different  figures  for  the  melting  point  of  the  same  mineral,  say  for 
leucite  or  olivine,  will  show  how  great  the  existing  uncertainties 
really  are.  Furthermore,  many  of  the  published  melting  points  have 
no  real  significance.  Some  of  the  minerals  for  which  melting  points 
have  been  recorded  break  down  into  other  substances  before  or  during 
fusion,  a fact  of  which  Brun  has  taken  notice  in  a number  of  instances. 
The  micas,  for  example,  for  which  Doelter  gives  several  determina- 
tions, lose  water  and  are  transformed  into  other  silicates  or  mixtures 
of  silicates,  whose  precise  character  is  unknown.  Garnet,  when 
fused,  also  splits  up  into  two  or  more  compounds,  and  in  such  cases 
the  recorded  melting  points  are  meaningless. 

In  the  geological  interpretation  of  the  melting  points  there  is  one 
particularly  dangerous  source  of  error.  We  must  not  assume  that 
the  temperature  at  which  a given  oxide  or  silicate  melts  is  the  tem- 
perature at  which  a mineral  of  the  same  composition  can  crystallize 
from  a magma.  Many  substances  exist  in  more  than  one  modifica- 
tion, and  certain  forms,  which  often  correspond  to  natural  minerals, 
are  developed  only  at  temperatures  far  below  the  apparent  points  of 
fusion.  Quartz,  for  example,  ceases  to  be  quartz  and  becomes  tridy- 
mite  long  before  it  fuses;  wollastonite  is  transformed  into  a pseudo- 
hexagonal  substance  which  is  unknown  as  a mineral  species,  and  the 
melting  point  of  magnesium  metasilicate,  under  ordinary  conditions, 
is  not  that  of  the  orthorhombic  enstatite,  but  of  a monoclinic  variety. 
In  these  instances,  which  will  be  taken  up  in  detail  in  the  next  chap- 
ter, the  transition  temperatures,  at  which  one  form  changes  to 
another,  are  geologically  as  important  as  the  melting  points,  and 
perhaps  of  even  greater  value.  They  are  the  temperatures  above 
which  the  several  species  can  not  form,  and  therefore  they  are  of  the 
utmost  significance.  Silica  crystallizes  as  quartz  only  below  800°; 
wollastonite  can  not  exist  above  1,190°;  and  so  the  formation  of 
either  mineral  in  a rock  tells  us  something  of  the  conditions  under 
which  it  solidified.  As  yet  the  data  of  this  class  are  unfortunately 
few,  but  their  number  is  likely  to  become  much  greater  within  the 
near  future.1 

For  the  direct  study  of  the  igneous  rocks  themselves,  the  available 
melting-point  measurements  are  very  few.  Mixtures,  such  as  rocks, 
unless  they  happen  to  be  eutectic,  have  no  distinct  melting  points, 
and  two  temperatures  at  least  should  be  determined  for  each  example. 


1 For  a discussion  of  the  application  of  these  temperature  relations  to  geological  occurrences  see  J. 
Koenigsberger,  Econ.  Geology,  vol.  7, 1912,  p.  676,  and  Neues  Jahrb..  Beil.  Band  32, 1911,  p.  191. 


296 


THE  DATA  OF  GEOCHEMISTRY. 


The  following  temperatures,  observed  by  Doelter,1  will  serve  to 
illustrate  this  point: 

Melting  'points  (°C.)  of  various  igneous  rocks. 


Rock. 

Softens. 

Becomes  fluid. 

Granite,  Predazzo 

1, 150-1, 160 
1, 115-1, 125 
1,030-1,060 
962-970 
992-1,  020 
995-1,  000 
1,060 
1,040-1,060 

1,240 
1,190 
1,  080-1,  090 
1,  010-1,  040 
1,060-1,075 
1, 050-1,  060 
1,090 

1,  060-1, 100 

Monzonite,  Fredazzo 

Lava,  Vesuvius 

Lava,  Etna 

Basalt,  Ttemagen 

Limburgite 

Phonolite . ..  

Nepheline  syenite 

According  to  A.  Brun,1 2  the  basalt  from  Stromboli  begins  to  soften 
at  1,130°,  and  at  1,170°  it  becomes  pasty.  The  still  molten  rock  con- 
tains crystals  of  augite  whose  melting  point  he  places  at  1,230°.  The 
temperature  at  which  the  basalt  solidified,  therefore,  cannot  exceed 
that  figure,  and  may  have  been  much  lower.  Similar  reasoning  has 
been  employed  by  C.  Doelter,3  based  upon  the  presence  of  leucite  in 
Yesuvian  lava.  Doelter,  however,  assigned  to  leucite  a melting  point 
which  is  certainly  too  low,4  and  his  computations,  which  must  be 
revised,  need  not  be  considered  further.  All  we  can  now  say  with 
certainty  is  that  the  temperature  of  an  emerging  lava  must  be  above 
that  at  which  it  begins  to  solidify.  That  temperature  is  rarely,  if 
ever,  below  1,000°  C.,  and  the  actual  temperature  not  long  before 
emission  may  be  hundreds,  perhaps  a thousand,  degrees  higher.  The 
temperature  of  the  lava  pool  at  Kilauea,  as  determined  by  Day  and 
Shepherd,  was  ahnost  exactly  1,000°.  Lava  at  Torre  del  Greco,  says 
A.  Geikie,5  fused  the  sharp  edges  of  flints  and  decomposed  brass,  the 
copper  actually  crystallizing.  From  its  effect  on  flint,  it  would  seem 
that  its  temperature  could  hardly  be  below  1,600°,  at  which  point 
silica  softens.  If,  however,  the  apparent  fusion  was  due  to  a solvent 
action  of  the  molten  lava,  the  argument  in  favor  of  a high  tempera- 
ture breaks  down.  A careful  study  of  the  conditions  under  which 
silicates  have  been  sublimed  at  Vesuvius  might  shed  much  light  on 
the  problem.6 


1 Mia.  pet.  Mitt.,  vol.  21, 1902,  p.  23.  J.  A.  Douglas  (Quart.  Jour.  Geol.  Soc.,  vol.  63, 1907,  p.  145),  has 
also  made  a number  of  similar  determinations,  and  has  measured  the  increase  of  volume  which  minerals 
exhibit  in  passing  from  the  crystalline  to  the  glassy  phase.  Such  an  increase  is  probably  the  rule,  l ut  A. 
Fleischer  (Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  57, 19C5,  p.  201  (Monatsb.);  vol.  59, 1907,  p.  122)  has  shown 
that  molten  basalt  and  some  slags  expand  on  solidification.  See  also  A.  Earker,  Natural  history  of  igneous 
rocks,  p.  158. 

2 Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  13, 1902,  p.  367. 

s Sitzungsb.  Akad.  Wien,  vol.  112, 1903,  p.  681. 

4 See  preceding  table  of  melting  points.  Preliminary  experiments  by  A.  L.  Day  have  shown  that  the 

melting  point  of  leucite  is  certainly  above  1,500°. 

& Text-book  of  geology,  4th  ed.,  p.  304. 

6 On  temperatures  at  Etna  see  G.  Platania,  Atti  R.  accad.  Lincei,  ser.  5,  vol.  21  (1),  1912,  p.  499.  The 
figures  obtained  and  those  cited  from  others  are  very  variable.  Variations  in  the  composition  of  the  lava, 
and  especially  in  its  content  of  gases,  will  account  for  some  of  the  discrepancies. 


THE  MOLTEN  MAGMA. 


297 


INFLUENCE  OF  WATER. 

So  far  the  measurements  cited  in  this  chapter  relate  to  dry  fusion 
or  to  the  fusion  of  minerals  containing  only  insignificant  quantities 
of  hygroscopic  water.  Within  a volcano,  apparently,  the  conditions 
are  quite  different,  and  there  the  presence  of  water  must  be  taken 
into  account,  together  with  the  gases  which  are  so  powerfully  oper- 
ative in  producing  explosions.  The  magma,  before  eruption,  is  some- 
thing very  different  from  the  smoothly  flowing  stream  of  lava,  for  it 
is  heavily  charged  with  aqueous  vapor  and  other  gases,  under  great 
pressure,  exactly  as  the  soda  water  in  an  ordinary  siphon  bottle  is 
loaded  with  carbon  dioxide.  When  the  pressure  is  released  the  gases 
escape  with  explosive  force,  carrying  the  liquid  matter  with  them.1 
In  the  eruption  of  a volcano  this  process  produces  a great  quantity 
of  fiery  spray,  which  solidifies  in  the  form  of  volcanic  ash,  while 
other  portions  of  the  foaming  surface  of  the  lava  cool  to  pumice. 
When  the  lava  stream  itself  appears  its  effervescence  has  largely 
ceased,  and  it  exhibits  the  ordinary  phenomena  of  a cooling  liquid. 

The  condition  of  the  water  which  is  contained  within  a magma  is 
perhaps  best  explained  by  certain  experiments  of  C.  Barus,2  who 
found  that  colloid  substances,  in  presence  of  solvents,  swell  up  enor- 
mously, and  that  at  high  temperatures  the  swollen  coagulum  passes 
into  a clear  and  apparently  homogeneous  solution.  This  observation 
he’  extended  to  mixtures  of  ordinary  soft  glass  and  water,  which  he 
heated  in  closed  steel  tubes  to  210°  C.  Under  these  conditions  210 
grams  of  glass  with  50  grams  of  water  formed  a resinous  opalescent 
mass,  in  which  all  the  water  was  absorbed.  This  substance,  to  which 
Barus  gave  the  name  of  “water  glass/’  when  heated  in  air,  swells 
up  enormously,  loses  water,  and  forms  a true  pumice.  By  ordinary 
exposure  to  air  the  substance  slowly  disintegrates.  Salts  dissolved 
in  the  water  do  not  enter  the  glass,  which  acts  in  that  respect  like  a 
semipermeable  membrane.  Hard  glasses  are  more  refractory;  but 
it  is  probable  that  at  the  temperatures  and  pressures  existing  within 
a volcano,  all  of  the  silicates  would  act  in  a similar  way  and  give 
similar  solutions.  This  may  enable  us  to  form  some  notion  of  the 
unerupted  magma,  with  its  dissolved  gases,  and  the  changes  which 
it  undergoes  when  the  pressure  upon  it  is  relieved.  One  effect  of  the 
water  would  be  to  reduce  the  temperature  at  which  liquidity  could 
be  maintained.  An  obsidian,  in  presence  of  water,  was  found  by 

1 This  comparison  of  a volcano  with  a bottle  of  soda  water  or  champagne  has  been  developed  by  S. 
Meunier.  He  assumes  that  the  water  was  originally  occluded  or  combined  in  the  rocks  and  when  the 
latter,  by  displacement,  are  brought  into  the  region  of  high  temperature,  their  aqueous  content  is  set  free 
and  an  explosion  becomes  possible.  See  La  Nature,  vol.  30,  pt.  1,  1902,  p.  386.  Also  Jour.  Washington 
Acad.  Sci.,  vol.  4, 1914,  p.  213> 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  9, 1900,  p.  161.  The  name  “water  glass,”  as  used  by  Barus,  is  unfortunate, 
for  it  already  belonged  to  the  soluble  alkaline  silicates  and  had  been  in  current  use  for  many  years. 


298 


THE  DATA  OF  GEOCHEMISTRY. 


Barus  to  fuse  at  about  1,250°,  while  the  resulting  pumice  melted  at 
1,650°,  approximately.1 

MAGMATIC  SOLUTIONS. 

So  far  as  we  can  determine,  then,  the  magma,  previous  to  eruption, 
is  a mass  of  rock-forming  matter,  in  a state  of  fusion,  and  heavily 
charged  with  gases  under  enormous  pressure.  To  what  extent  and 
how  its  temperature  may  vary  we  do  not  know,  but  the  pressure  must 
fluctuate  widely.  It  is  through  overcoming  pressure  that  eruptions 
become  possible.  Then  gases  and  water  are  largely  expelled,  and  a 
fluid  or  viscous  lava,  very  different  from  the  original  magma,  remains. 
By  pressure,  furthermore,  the  temperature  needed  to  produce  com- 
plete fluidity  is  raised,  and  this  fact  is  emphasized  by  the  phenomena 
of  resorption.  A mineral — hke  quartz,  for  example — may  crystallize 
within  a viscous  magma,  but  when  the  pressure  is  reduced  its  temper- 
ature of  fusion  falls,  and  partial  or  complete  re-solution  may  take 
place.  These  partly  redissolved  minerals  are  familiar  objects  to  the 
petrologist.2 

Whether  the  magma  itself,  at  great  depths,  is  homogeneous  or  not 
is  an  open  question,  but  it  is  not  emitted  homogeneously.  Different 
lavas  issue,  not  only  from  neighboring  vents,  but  successively  from 
the  same  opening  during  a series  of  eruptions.  To  determine  the 
cause  of  these  differences  is  one  of  the  great  problems  of  petrology, 
and  many  solutions  of  it  have  been  proposed,  discussed,  and  either 
abandoned  or  partly  accepted.  To  discuss  these  attempts  in  detail 
does  not  fall  within  the  scope  of  this  memoir,  but  the  evidence  upon 
which  they  rest,  so  far  as  it  touches  chemistry,  must  be  briefly 
considered.3 

From  a physicochemical  point  of  view,  a molten  rock  is  to  be 
regarded  as  a solution,  behaving  in  all  essential  particulars  exactly 
hke  any  other  solution.  One  or  more  minerals  are  dissolved  in 
another,  as  salt  dissolves  in  water;  or,  better,  they  are  mutually 
dissolved,  hke  a mixture  of  water  and  alcohol.  We  can  not  ready 
say  that  in  such  a mixture  one  substance  is  the  solvent  and  the  others 
are  the  solutes,  for  the  distinction  is  not  a sound  one,  however  con- 

1 Compare  F.  Guthrie,  Philos.  Mag.,  5th  ser.,  vol.  18, 1884,  p.  117,  on  the  change  from  obsidian  to  pumice 
by  extrusion  of  water. 

2 A good  example  of  the  resorption  of  olivine  in  a basalt  is  given  by  C.  N.  Fenner,  Am.  Jour.  Sci.,  4th 
ser.,  vol.  29,  1310,  p.  230.  The  author  discusses  other  physicochemical  relations  of  a basaltic  magma  at 
some  length. 

3 For  good  summaries  on  magmatic  differentiation,  see  J.  P.  Iddings,  The  origin  of  igneous  rocks:  Bull. 
Philos.  Soc.  Washington,  vol.  12,  1892,  p.  89;  W.  C.  Brogger,  Die  Eruptivgesteine  des  Kristianiagebietes, 
pt.  3, 1898,  p.  334;  and  F.  Loewinson-Lessing,  Compt.  rend.  VII  Cong.  g6ol.  intemat.,  1897,  p.  308.  These 
are  only  a few  among  many  memoirs  dealing  more  or  less  fully  with  the  subject.  Loewinson- Lessing’s 
paper  is  rich  in  literature  references.  For  a criticism  adverse  to  the  idea  of  magmatic  differentiation  see 
F.  Fouqu4,  Bull.  Soc.  min.,  vol.  25, 1902,  p.  349.  On  magmatic  differentiation  in  Hawaii,  see  R.  A.  Daly, 
Jour.  Geology,  vol.  19, 1911,  pj»289. 


THE  MOLTEN  MAGMA. 


299 


venient  it  may  be  in  ordinary  cases.1  The  different  molten  substances 
dissolve  one  another,  and  if  there  are  any  limits  to  their  miscibility 
they  have  not  been  determined.  I speak  now,  of  course,  with  refer- 
ence to  the  constituents  of  an  ordinary  fluid  lava,  and  these  are 
mostly  silicates — that  is,  metallic  salts. 

The  more  familiar  aqueous  solutions  of  salts  are  electrolytes,  and 
in  them  the  compounds  are  believed  to  be  dissociated  into  their  ions. 
This  dissociation  is  complete  only  at  infinite  dilution ; in  concentrated 
solutions  it  is  partial,  and  in  a saturated  solution  its  amount  may  be 
comparatively  small.  In  a molten  magma  probably  all  of  these  con- 
ditions hold,  for  as  a solution  it  is  dilute  with  respect  to  its  minor 
components,  but  highly  concentrated  as  regards  the  more  essential 
minerals.  As  a solution  of  apatite  or  rutile  it  may  be  very  weak; 
as  a solution  of  quartz,  feldspar,  or  pyroxene,  very  strong.  It  is, 
however,  a conductor  of  electricity,  and,  therefore,  if  the  analogy 
between  it  and  ordinary  solutions  is  valid,  it  is  at  least  partially 
ionized.  This  is  the  view  adopted  by  C.  Barus  and  J.  P.  Iddings,2 
who  studied  the  electrical  conductivity  of  three  molten  rocks,  for 
which  the  following  condensed  descriptions  may  be  cited  here: 


Melting  points  and  silica  content  of  three  igneous  rocks. 


Rock. 

Approxi- 
mate melt- 
ing point. 

Percentage 
of  Si02. 

Basalt 

1,250 
1,400 
1,  500 

48.49 

Hornblende-mica  porphyry 

61.  50 

Rhyolite 

75.50 

At  1,300°  the  basalt  was  quite  fluid,  but  at  1,700°  the  rhyolite 
was  still  viscid,  and  yet  the  conductivity  increased  with  the  viscosity 
and  with  the  silica,  in  spite  of  the  fact  that  silica  alone  is  probably 
an  insulator.  In  other  words,  the  fused  rocks  are  electrolytes,  and 
the  silicates  in  them  are  probably  more  or  less  dissociated  into  their 
ions.3  What  these. ions  are  we  do  not  yet  know;  but  their  ultimate 
identification  is  not  hopeless.  The  extent  of  the  ionization  is  also 
unknown,  but  its  existence  seems  to  be  established.  Furthermore, 


1 G.  F.  Becker  (Twenty-first  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3,  1901,  p.  519)  proposes  to  regard  the 
eutectic  mixtures  as  the  true  solvents,  and  the  minerals  which  separate  from  them  as  the  solutes.  This 
suggestion  has  attracted  much  attention;  but  it  can  not  be  fully  utilized  until  we  know  what  the  eutectics 
really  are. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  44, 1892,  p.  242. 

3 The  coexistence  in  certain  rocks  of  antagonistic  minerals  like  quartz  and  magnetite  may  be  an  evidence 
of  dissociation.  They  should  react  to  form  a silicate  of  iron,  but  we  can  readily  imagine  a highly  viscous 
melt  as  solidifying  so  rapidly  that  all  of  the  ions  are  unable  to  find  their  proper  partners.  The  free  oxides 
therefore  appear  in  the  solid  product.  I offer  this  merely  as  a suggestion.  H.  J.  Johnston-Lavis,  Bull. 
Soc.  beige  gdol.,  vol.  22,  1908,  p.  103,  has  attributed  the  quartz  in  a particular  basalt  to  included  gneiss. 
Doelter  (Sitzungsb.  Akad.  Wien,  vol.  113,  1904,  p.  169)  ascribes  the  early  separation  of  oxides  and  alumi- 
nates  from  cooling  magmas  to  dissociation. 


300  THE  DATA  OF  GEOCHEMISTRY. 

since  the  several  silicates  are  present  in  a magma  in  different  degrees 
of  concentration,  they  must  be  differently  ionized,  and  some  of  them 
to  a much  greater  extent  than  others. 

When  a salt  dissolves  in  water  the  temperature  of  solidification 
is  changed.  Water,  for  example,  freezes  at  0°  C.,  but  the  addition 
of  23.6  per  cent  of  sodium  chloride  to  it  reduces  the  melting  or 
solidifying  point  to  —22°.  This  depression  of  the  melting  point 
is  quite  a general  phenomenon,  and  from  it,  by  formulae  which  need 
not  be  considered  here,  the  molecular  weight  of  the  dissolved  sub- 
stance can  be  calculated.  In  alloys  a similar  change  can  be  observed, 
and  in  some  cases  it  is  very  striking;  the  well-known  fusible  alloys, 
for  instance,  melt  at  temperatures  below  the  boiling  point  of  water. 

An  igneous  rock,  so  far  as  our  data  now  go,  exhibits  the  same 
peculiarity,  and  becomes  fluid  at  temperatures  below  the  average 
meiting  point  of  its  constituent  minerals,  and  sometimes  lower  than 
the  lowest  among  the  latter.  Doelter’s  figures,  as  cited  on  page  296, 
serve  to  illustrate  this  point,  although  the  depression  is  not  so  marked 
as  in  the  more  familiar  cases  just  mentioned.  The  experiments  by 
Michaela  Vucnik1  and  Berta  Vukits,2  who  fused  together  minerals  of 
supposedly  known  melting  points  and  observed  those  of  the  mixtures, 
tell  the  same  story.  In  some  cases,  however,  the  interpretation  of 
the  observations  is  complicated  by  chemical  reactions,  which  pro- 
duced new  salts;  and  it  is  also  affected  by  the  liability  of  glasses 
to  supercooling.  Attempts  to  compute  molecular  weights  from  the 
observed  depressions  gave  unsatisfactory  results,  and  led  to  no  defi- 
nite conclusions. 

1ST.  V.  KultaschefFs  investigations,3  although  not  rigorously  com- 
parable with  natural  phenomena,  point  in  the  same  direction.  Mix- 
tures of  Na2Si03  and  CaSi03  were  studied,  the  first  salt  melting  at 
1,007°  and  the  second  at  a temperature  above  1,400°.4  A mixture 
of  80  per  cent  of  the  sodium  salt  with  20  per  cent  of  the  calcium  com- 
pound fused  at  938°,  and  even  greater  depressions  were  produced  by 
additions  of  the  still  less  fusible  silica.  Upon  adding  only  6.5  per 
cent  of  silica  to  the  sodium  silicate,  the  melting  point  was  reduced  to 
820°.  It  was  also  found  that  the  two  silicates  united  to  form  at 
least  two  double  salts,  a fact  which  complicates  the  interpretation 
of  the  phenomena.5 


1 Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  pp.  295,  340,  364. 

2 Idem,  pp..  705,  739. 

3 Zeitschr.  anorg.  Chemie,  vol.  35,  1903,  p.  187. 

4 1,540°  according  to  Allen  and  White.  See  table  of  melting  points,  p.  293. 

& A similar  study  of  several  binary  mixtures  of  silicates  is  reported  by  R.  C.  Wallace,  Zeitschr.  anorg 
Chemie,  vol.  63,  1909,  p.  1.  The  mixtures  examined,  however,  with  one  or  two  exceptions,  do  not  corre- 
spond to  natural  minerals. 


THE  MOLTEN  MAGMA. 


301 


EUTECTICS. 

When  a fused  rock,  or  mixture  of  similar  character,  solidifies,  it 
can  do  so  in  either  one  of  two  ways.  It  may  solidify  as  a unit, 
forming  a glass,  in  which  no  individualization  of  its  constituents  can 
be  detected,  or  it  may  solidify  as  a mass  of  crystalline  minerals,  each 
one  exhibiting  its  own  peculiarities.  Between  these  extremes  many 
intermediate  conditions,  due  to  partial  crystallization,  are  possible, 
ranging  from  glass  containing  a few  crystals  to  a crystalline  mass 
with  some  glassy  remainder  left  over — that  is,  both  processes  may 
go  on  in  the  same  cooling  magma,  and  both,  of  course,  incompletely. 
The  more  viscous  the  lava  the  less  easily  its  materials  can  crystallize, 
and  hence  glasses  are  most  commonly  derived  from  magmas  rich  in 
silica.  Obsidian  has  essentially  the  composition  of  rhyolite. 

Let  us  now  consider  what  will  happen  when  a solution  solidifies  to 
a crystalline  aggregate.  Take  for  example  a solution  of  common 
salt  in  water,  which  freezes  at  — 22°  C.  with  a definite  proportion — 
namely,  23.6  per  cent — of  sodium  chloride  in  the  mixture.  Upon 
cooling  such  a solution,  if  less  than  that  proportion  of  salt  is  present, 
ice  will  crystallize  first,  but  when  the  indicated  concentration  and 
temperature  have  been  reached  the  entire  mass — salt  and  water — will 
solidify.  If,  on  the  other  hand,  salt  is  in  excess  of  23.6  per  cent,  its 
hydrate,  NaC1.2H20,  will  first  appear  and  continue  to  be  deposited 
until  the  point  of  equilibrium  has  been  attained.  Then  the  same  mix- 
ture will  solidify  as  in  the  other  case.  This  minimum  temperature, 
with  its  definite,  corresponding  concentration  of  salt  and  water,  is 
known  as  the  eutectic  point,  and  at  that  point  the  solution  and  the 
solid  have  the  same  composition.1  Above  the  eutectic  point  either 
salt  or  water  may  crystallize  out,  that  substance  being  first  deposited 
which  is  in  excess  of  the  eutectic  ratio — the  ratio,  that  is,  of  23.6 
NaCl  to  76.4  H20.  In  the  freezing  of  sea  water  the  separation  of 
nearly  pure  ice  is  seen,  because  the  water  is  largely  in  excess  of  the 
eutectic  proportions. 

When  two  salts  are  fused  together  and  allowed  to  solidify,  the  same 
order  of  phenomena  appears,  provided  that  certain  conditions  are 
satisfied.  First,  the  fused  salts  must  be  miscible — that  is,  soluble  in 
one  another.  If  this  condition  is  not  fulfilled  the  melt  will  separate 
into  layers.  Secondly,  they  must  not  be  capable  of  acting  upon  each 
other  chemically,  for  in  that  case  new  compounds  are  produced. 
Finally,  they  should  not  be  isomorphous  salts,  for  then  no  eutectic 
mixture  is  possible.  The  feldspars  albite  and  anorthite,  for  example, 
crystallize  togther  in  all  proportions,  and  the  melting  points  of  the 


1 F.  Guthrie  regarded  these  saline  mixtures  with  water  as  definite  compounds,  which  he  termed  cryohy- 
drates.  See  Philos.  Mag.,  4th  ser.,  vol.  49,  1875,  pp.  1,  206,  266;  5th  ser.,  vol.  17, 1884, p. 462.  See  also  M. 
Roloff,  Zeitschr.  physical.  Chemie,  vol.  17, 1895,  p.  325. 


302 


THE  DATA  OF  GEOCHEMISTRY. 


mixed  crystals  form  a series  with  no  eutectic  depression.  This  differ- 
ence between  isomorphous  and  eutectic  mixtures  is  fundamental. 

Since,  now,  the  fusing  point  of  a lava  generally  falls  below  the 
average  melting  point  of  its  constituent  minerals,  the  foregoing  con- 
siderations may  be  applied  to  its  investigation.  Some  of  its  compo- 
nents will  form  isomorphous  mixtures,  but  a part  of  it  will  represent 
eutectic  proportions  which  differ  with  the  varying  composition 
of  different  rocks.  In  each  case  the  substances  that  are  in  excess 
of  the  eutectic  ratios  are  likely  to  crystallize  first,  and  the  eutectic 
mixture  itself  will  probably  be  found  in  the  groundmass,  or  solidi- 
fied mother  liquor,  from  which  the  crystals  have  separated.  From 
this  point  of  view  the  study  of  the  eutectics  becomes  fundamentally 
important  in  the  study  and  classification  of  igneous  rocks,  for  they 
chiefly  determine  the  character  and  order  of  deposition  of  the  pheno- 
crysts.  There  are  doubtless  other  factors  in  the  problem,  but  this  one 
is  the  most  fundamental  and  characteristic.  So  far  none  of  the 
eutectics  in  question  have  been  positively  identified,  although 
various  attempts  to  indicate  them  are  on  record,  with  results  which 
may  or  may  not  be  verified.  In  Kultascheffs  experiments  with 
sodium  and  calcium  silicates  two  eutectic  points  were  noted,  which 
represented,  however,  not  a single  natural  mixture,  but  a series  of 
artificial  mixtures  wherein  both  of  the  original  compounds  and  two 
double  salts  took  part.  H.  O.  Hofman’s  work  1 on  artificial  slags, 
containing  iron  and  calcium  silicates,  also  tells  us  something  about 
possible  eutectic  points,  and  other  valuable  data  are  given  in  the 
memoir  by  A.  L.  Day  and  E.  S.  Shepherd 2 on  the  compounds  of  lime 
and  silica.  The  mixtures  studied  in  the  latter  investigation,  how- 
ever, do  not  correspond  to  any  known  natural  associations. 

F.  Guthrie,3  to  whom  the  expression  “eutectic”  is  due,  was  the  first 
to  point  out  the  applicability  of  his  researches  to  the  study  of  igneous 
rocks,  and  of  late  years  his  suggestions  have  received  much  attention. 
J.  J.  H.  Teall 4 was  one  of  the  first  to  develop  the  subject,  and  he 
indicated  a micropegmatite,  with  62.05  per  cent  of  feldspar  and  37.95 
per  cent  of  quartz,  as  a possible  eutectic  mixture.  This  possibility  has 
been  discussed  by  several  writers,  and  especially  by  J.  H.  L.  Vogt,5 
who  regards  a mixture  of  74.25  per  cent  of  orthoclase  with  25.75  per 
cent  of  quartz  as  the  true  eutectic  in  this  particular  instance,  and 
shows  that  it  is  very  close  to  the  average  micropegmatite  in  composi- 


1 Technology  Quart.,  vol.  13, 1900,  p.  41. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  22, 1906,  p.  265. 

3 Philos.  Mag. , 4th  ser.,  vol.  49,  1875,  p.  20. 

4 British  Petrography,  1888,  pp.  395-419. 

5 Die  Silikatschmelzlosungen , pt.  2, 1904,  pp.  113-128.  See  also  Vogt,  Min.  pet.  Mitt.,  vol.  24, 1906, p.  437; 
vol.  25, 1906,  p.  361;  vol.  27, 1908,  p.  105.  A.  C.  Lane,  Jour.  Geology,  vol.  12, 1904,  p.  23.  H.  E.  Johansson, 
Geol.  Foren.  Forhandl.,  vol.  27,  1905,  p.  119;  and  A.  Bygd6n,  Bull.  Geol.  Inst.  Upsala,  vol.  7, 1904-5,  p.  1. 
The  subject  of  eutectics  is  also  fully  discussed  in  Harker’s  Natural  history  of  igneous  rocks,  and  Elsden’s 
Chemical  geology. 


THE  MOLTEN  MAGMA. 


303 


tion.  This  is  not  far  from  the  molecular  ratio  3AlKSi308:5Si02, 
although  simple  molecular  ratios  can  not  necessarily  be  assumed  in 
eutectic  mixtures.  The  latter,  so  far  as  present  evidence  goes,  are 
not  definite  compounds.  The  water-salt  eutectic  is  not  a hydrate,  but 
a mixture  of  salt  and  ice,  which,  however,  happens  to  approximate 
rather  closely  in  composition  to  NaCl+10H2O. 

In  the  first  of  the  memoirs  just  cited,  which  is  rich  in  data  relative 
to  the  physical  constants  of  molten  rocks,  minerals,  and  slags,  Vogt 
attempts  to  fix  the  composition  of  a number  of  eutectic  mixtures. 
Some  of  them  are  as  follows,  the  figures  referring  to  percentages: 

68  diopside  with  32  olivine. 

74  melilite  with  26  olivine. 

65  melilite  with  35  anorthite. 

40  diopside  with  60  akermanite. 

74.25  anorthite  with  25.75  quartz. 

75  albite  with  25  quartz. 

The  last  two  ratios  are  practically  identical  with  the  orthoclase- 
quartz  ratio  as  given  above.  It  is,  however,  a grave  question 
whether  in  a strict  sense  eutectics  of  feldspar  and  quartz  are  possible. 
Quartz  is  capable  of  formation  only  below  800°,  and  one  modifica- 
tion of  it  only  below  575°.  In  the  pegmatites  of  Maine,  as  described 
by  E.  S.  Bastin,1  the  quartz  is  often  of  the  low  temperature  variety, 
and  crystallization  was  further  modified  by  the  presence  of  gaseous 
or  vaporous  constituents  in  the  magma.  Fluid  inclusions  are  also 
common  in  the  quartz.  The  solidification  of  these  pegmatites  was 
therefore  a complex  process,  and  by  no  means  so  simple  as  the  theory 
of  eutectics  would  seem  to  demand.  A feldspar-silica  eutectic,  on 
the  other  hand,  in  which  during  prolonged  cooling  a gradual  develop- 
ment of  the  silica  as  quartz  occurred  may  be  conceivable.2 

The  entire  subject  of  eutectics,  in  reference  to  rock  formation,  is 
elaborately  discussed  by  Vogt,  who  considers  them  in  connection 
with  the  melting  points,  and  the  specific  and  latent  heats  of  the  com- 
ponent minerals.  These  data,  however,  are  more  or  less  crude,  and 
Vogt’s  results  are  therefore  to  be  regarded  merely  as  first  approxima- 
tions to  the  solution  of  the  problems  proposed,  and  as  subject  to  very 
critical  revision.  Vogt  also  sought  to  determine  the  molecular 
weights  of  several  silicates  from  the  observed  melting  point  depres- 
sions, and  concluded  that  they  were  represented  by  their  simplest 
empirical  formulae.  The  fused  minerals,  as  such,  exist  in  the  fluid 
magma,  although  they  are  partly  subject  to  electrolytic  dissociation. 
The  latter  phenomenon  has  also  been  much  studied  by  Doelter.3 
The  essential  point  in  Vogt’s  and  also  in  Doelter’s  work  is  that  they 

1 Jour.  Geology,  vol.  18, 1910,  p.  297.  Also,  more  in  detail,  in  Bull.  U.  S.  Geol.  Survey  No.  445 , 1911. 

2 For  the  conditions  under  which  quartz  can  form  see  the  section  on  that  mineral  in  the  following  chapter. 

» Monatsh.  Chemie,  vol.  28,  1907,  p.  1313;  Sitzungsb.  Akad.  Wien,  vol.  117,  1908,  pt.  1;  Zeitschr.  Elektro- 

chemie,  1908,  p.  552. 


304 


THE  DATA  OF  GEOCHEMISTRY. 


attempt  to  apply  modern  physicochemical  methods  to  the  investiga- 
tion of  magmas,  and  whether  their  conclusions  are  maintained  or  not 
they  are  at  least  suggestive. 

Up  to  this  point  we  have  considered  only  simple  cases  to  which  the 
theory  of  eutectics  is  easily  applied.  In  salt  and  water  we  have 
merely  a system  of  two  components,  and  the  examples  given  by  Vogt 
are  of  like  simplicity.  But  igneous  rocks  are,  as  a rule,  much  more 
complex,  and  may  contain  from  three  to  many  component  minerals- 
For  conditions  like  these  the  theoretical  treatment  is  as  yet  undevel. 
oped,  although  the  researches  of  Van’t  Hoff  on  the  Stassfurt  salts 
suggest,  with  their  diagrams,  certain  analogies  which  may  be  followed 
in  the  future.  The  laws  of  equihbrium  must  apply  to  all  possible 
cases  of  solution,  even  though  we  may  be  unable  as  yet  to  trace  the 
details  of  their  working.  Just  as  the  Stassfurt  problem  is  complicated 
by  the  deposition  of  hydrates  and  double  salts,  so  from  the  magma 
complex  silicates  can  form,  and  the  exact  conditions  under  which 
each  may  develop  are  so  far  only  partially  determined.  The  diffi- 
culties that  confront  us  here  are  well  pointed  out  by  Roozeboom  1 in 
his  great  work  on  the  phase  rule,  where  he  calls  attention  to  the  fact 
that  an  igneous  rock  represents  many  components  and  many  solid 
phases.  Some  of  the  latter  are  definite  compounds,  and  some  are 
mixed  crystals  from  isomorphous  series.  If  the  cooling  of  the  magma 
has  been  too  rapid,  supersaturation  may  have  occurred,  with  a change 
in  the  order  of  deposition  of  the  minerals  and  the  formation  of  some 
undifferentiated  glass  base.  Furthermore,  lava  rising  from  a great 
depth  undergoes  a change  of  pressure,  which  modifies  the  relative 
solubility  of  its  components  and  alters  the  position  of  the  eutectic 
point. 

SEPARATION  OF  MINERALS. 

It  is  evident,  from  what  has  been  said,  that  no  universal  concrete 
rule  can  be  laid  down  to  determine  the  order  in  which  the  different 
minerals  will  separate  from  a cooling  magma.  The  broad,  general 
principles  are  clear  enough,  but  their  application  to  the  problem 
under  consideration  is  an  affair  of  the  future.  For  the  present, 
therefore,  we  must  depend  upon  accurate  observations  and  experi- 
ments, and  in  that  way  accumulate  data  for  theory  to  work  upon. 
The  much-cited  phase  rule,  with  its  diagrams,  gives  us  a mathe- 
matical method  of  dealing  with  our  facts,  but  it  is  inoperative  with- 
out them.  When  accurate  numerical  data  have  been  obtained,  then 
the  rule  will  become  applicable  to  the  relatively  simpler  cases;  but 


i H.  W.  Bakhuis  Roozeboom,  Die  heterogenen  Gleichgewichte  vom  Standpunkte  der  Phasenlehre, 
vol.  2,  Braunschweig,  1904,  pp.  240  et  seq.  For  a simple  application  of  a phase-rule  diagram  to  a system 
of  two  components  see  W.  Meyerhoffer,  Zeitschr.  Kryst.  Min.,  vol.  36,  1902,  p.  592.  T.  T.  Read  (Econ. 
Geology,  vol.  1,  1905,  p.  101)  has  discussed  the  application  of  the  phase  rule  to  the  study  of  magmas,  but 
his  suggestions  have  been  criticized  by  A.  L.  Day  and  E.  S.  Shepherd  (idem,  p.  286).  C.  Doelter  (Min. 
pet.  Mitt.,  vol.  25,  1907,  p.  79)  has  studied  what  he  calls  the  “stability  fields”  of  certain  minerals. 


THE  MOLTEN  MAGMA. 


305 


anything  more  complex  than  a four-component  system  is  likely  to 
be  unmanageable.  At  present,  however,  we  can  see  some  of  the  con- 
ditions which  are  involved  in  the  general  problem.  First,  the  entire 
composition  of  the  magma  must  be  taken  into  account,  together 
with  the  pressure  under  which  it  solidifies.  An  ordinary  lava, 
cooling  on  the  surface  of  the  earth,  will  behave  very  differently 
from  similar  material  which  solidifies  at  a great  depth  to  form  a 
laccolith  or  batholith.  In  the  latter  case  its  gaseous  contents  are  not 
so  completely  lost,  and  they,  especially  the  water  vapor,  play  an 
important  part  in  determining  the  order  of  mineral  deposition.  The 
retention,  under  pressure,  of  boric  acid  and  fluorine  will  cause  the 
formation  of  compounds  which  do  not  appear  in  surface  eruptions, 
and  such  minerals  as  tourmaline  and  the  micas  become  possible. 

If  in  any  given  case  we  regard  the  eutectic  mixture  as  the  solvent, 
the  minerals  that  are  in  excess  of  its  ratios  will  be  the  first  to 
crystallize.  Their  order  of  deposition  will  , then  depend  upon  three 
essential  conditions — namely,  their  relative  abundance,1  their  solu- 
bility in  the  eutectic,  and  their  points  of  fusion.  Other  things  being 
equal,  the  less  soluble  and  less  fusible  substances  will  be  formed 
earliest.  With  an  excess  of  alumina,  corundum  and  spinel  may 
form,  and  as  a general  rule  the  so-called  accessory  minerals,  the 
more  trivial  constituents  of  a rock,  are  among  the  first  separations. 
Apatite,  sulphides,  and  the  titanium  minerals  belong  in  this  class. 
Although  the  sulphides  are  more  easily  fusible  than  the  silicates, 
their  insolubility  in  a silicate  magma  causes  their  early  precipitation. 
According  to  J.  H.  L.  Vogt,2  the  sulphides  are  much  more  soluble 
in  very  hot  magmas  than  they  are  at  lower  temperatures,  and  this 
order  of  difference  is  one  which  should  be  taken  into  account.  Solu- 
bility varies  with  temperature,  and  differently  with  different  sub- 
stances. It  also  varies  with  the  solvent,  and  J.  Morozewicz3  has 
shown  that  alumosilicates  rich  in  soda  dissolve  alumina  much  more 
freely  than  the  corresponding  potash  compounds,  in  which  it  is  little 
soluble,  if  at  all.  So  also  the  sulphides,  as  Vogt  has  pointed  out,  are 
more  soluble  in  femic  magmas  than  in  the  salic  varieties.  They  are 
consequently  more  abundant  in  basalts  and  diabases  than  they  are 
in  quartz  porphyry  or  rhyolite.  We  have  here,  apparently,  a case 
of  limited  miscibility  between  fused  sulphides  and  fused  silicates, 
while  on  the  other  hand  the  silicates  themselves  seem  to  be  miscible 
in  all  proportions.  At  least,  in  the  latter  case,  no  limitation  has 

1 F.  Loewinson-Lessing  (Compt.  rend.  VII  Cong.  g4ol.  intemat.,  1897,  pp.  352-353)  has  called  attention 
to  the  fact  that  relative  abundance  is  fundamentally  important;  that  is,  silica  will  divide  itself  among 
the  several  bases  in  accordance  with  the  law  of  mass  action;  or,  in  other  words,  that  law  will  determine 
what  silicates  can  form.  Its  detailed  application,  however,  is  perhaps  not  practicable. 

2 Die  Silikatschmelzlosungen,  pt.  1,  1903,  pp.  96-101. 

3 Min.  pet.  Mitt.,  vol.  18, 1888-89,  pp.  56,  57. 

97270°— Bull.  616—16 20 


306 


THE  DATA  OF  GEOCHEMISTRY. 


been  observed,  except  in  so  far  as  chemical  reactivity  renders  the 
mutual  presence  of  certain  species  impossible.  In  an  actual  magma 
these  incompatibilities  do  not  exist,  nor  do  they  become  evident 
when  we  fuse  together  several  oxides  to  form  an  artificial  melt. 
When,  however,  we  fuse  mixtures  of  minerals,  as  in  the  researches  of 
J.  Lenarcic,1  M.  Vucnik,2  and  B.  Yukits  3 the  limitations  of  this  class 
become  evident.  For  instance,  when  magnetite  is  fused  with  labra- 
dorite  it  is  absorbed,  and  upon  cooling  the  melt,  augite  crystals 
appear.  With  magnetite  and  anorthite,  hercynite  may  be  formed; 
leucite  and  acmite  give  magnetite,  leucite,  and  glass;  and  so  on. 
Again,  leucite  and  nephelite  are  incompatible  with  quartz,  which 
converts  them  into  feldspars;  and  a multitude  of  such  conditions 
help  to  determine  what  compounds  shall  crystallize  from  any  given 
magma.  In  a magma  of  defined  composition  certain  compounds 
are  capable  of  formation,  others  are  not;  and  these  limitations  are 
imperative.  In  the  next  chapter,  upon  rock-forming  minerals,  they 
will  be  considered  more  in  detail. 

In  ordinary  solutions  two  substances  having  an  ion  in  common 
diminish  the  solubility  of  each  other.  How  far  this  rule  may  apply 
to  magmas  is  uncertain,  and  especially  so  because  of  our  ignorance 
as  to  what  the  ions  actually  are.4  Still  we  may  assume  that  olivine, 
Mg2Si04,  and  enstatite,  MgSiOs,  have  magnesium  ions  in  common,, 
and  with  them  the  rule  ought  to  work.5  Each  should  be  less  soluble 
in  presence  of  the  other  than  it  is  when  present  alone,  and  the  same 
condition  ought  to  hold  for  the  two  potassium  salts  leucite  and  ortho- 
clase,  or  the  sodium  couple  albite  and  nepheline.  With  mixtures  of 
several  possible  silicates  the  rule  is  more  difficult  to  apply,  for  then 
complex  ions  are  likely  to  form.  For  instance,  in  a magma  capable 
of  yielding  olivine,  enstatite,  albite,  and  anorthite  the  ions  may  be 
Mg,  Ca,  Na,  Si03,  Si04,  AlSi04,  and  AlSi308.  Even  in  such  a case, 
which  is  purely  hypothetical,  two  of  the  supposed  minerals  have  an 
ion  in  common,  and  olivine  and  enstatite  should  be  the  first  to  sepa- 
rate. Here  we  have  a suggestion  of  what  really  happens  in  a vast 
number  of  cases,  possibly  in  a large  majority  of  cooling  magmas. 
The  order  in  which  the  minerals  are  deposited  is  essentially  that 

1 Centralbl.  Min.,  Geol.  u.  Pal.,  1903,  pp.  705,  743. 

2 Idem,  1904,  pp.  295,  340,  364;  1906,  p.  132. 

3 Idem,  1904,  pp.  705,  739.  See  also  memoirs  by  B.  K.  Schmutz,  Neues  Jahrb.,  1897,  Band  2,  p.  124;  K. 
Bauer,  idem,  Beil.  Band  12,  p.  535, 1899;  K.  Petrasch,  idem,  Beil.  Band  17,  p.  498, 1903;  H.  H.  Reiter,  idem, 
Beil.  Band  22, p.  183, 1906;  R.  Freis, idem,  Beil.  Band 23,  p.  43, 1907;  V.  Poschl,  Centralbl.  Min.,  Geol.  u.  Pal., 
1906,  p.  571;  Min.  pet.  Mitt.,  vol.  26, 1908,  p.  412;  H.  Schleimer,  Neues  Jahrb.,  1908,  Band  2,p.  1;  M.Urbas, 
idem,  Beil.  Band,  vol.  25, 1908,  p.  261;  M.  Hauke,  idem,  1910,  p.  1;  Vera  Hammerle,  idem,  Beil.  Band,  vol. 
29, 1910,  p.  719;  and  H.  Andesner,  idem,  Beil.  Band,  vol.  30, 1910,  p.  467. 

4 For  a discussion  of  this  subject  in  greater  detail  see  J.  H.  L.  Vogt,  Min.  pet.  Mitt.,  vol.  27,  1908,  p.  133. 

6 This  example  is  perhaps  not  perfect,  for  N.  L.  Bowen  (Am.  Jour.  Sci.,  4th  ser.,  vol.  37, 1914,  p.  487)  has 

shown  that  enstatite  on  fusion  breaks  up  into  forsterite  and  free  silica.  Still,  it  serves  to  illustrate  the 
principle. 


THE  MOLTEN  MAGMA. 


307 


laid  down  by  H.  Rosenbusch,1  namely,  ores  and  oxides  first,  then 
the  ferromagnesian  minerals,  then  the  feldspars,  and  finally,  if  an 
excess  of  silica  is  present,  quartz.  The  rule,  however,  is  not  and  can 
not  be  universal,  and  to  it  there  are  many  exceptions.  Its  common 
validity  must  be  ascribed  to  the  fact  that  most  igneous  rocks  are 
formed  from  relatively  few  components,  with  a correspondingly  mod- 
erate number  of  possibihties.  So  far  as  they  are  of  the  same  general 
nature  they  consolidate  most  commonly  in  the  same  general  way. 

To  a limited  degree  minerals  are  deposited  from  a magma  in  the 
reverse  order  of  their  fusibility,  the  more  infusible  first;  but  the  rule, 
as  we  have  seen,  is  by  no  means  general.  In  certain  cases,  however, 
it  holds,  especially  in  the  formation  of  the  successive  members  of  an 
isomorphous  series.  Plagioclase  feldspars,  for  example,  often  exhibit 
a zonal  structure,  with  the  less  fusible  lime  salts  concentrated  at  the 
crystalline  centers,  and  the  more  fusible  soda  salts  proportionally 
more  abundant  around  their  outer  surfaces.  The  order  of  fusibility 
seems  to  be  rather  a minor  factor  in  the  process  of  mineral  formation 
during  magmatic  cooling.  The  early  crystallization  of  leucite  and 
olivine  may  be  due  either  to  their  relative  infusibility,  to  their  insolu- 
bdity  in  the  remainder  of  the  magma,  or,  as  Doelter  2 supposes,  to 
their  superior  stability  at  high  temperatures.  Viscosity,  supersatu- 
ration, undercooling,  and  rate  of  cooling  all  play  their  respective  parts 
in  the  solidification  of  a magma,  and  the  interpretation  of  the  evidence 
in  any  particular  instance  is  not  a simple  matter.3 

DIFFERENTIATION. 

The  question  whether  there  is,  within  the  earth,  a single,  sensibly 
homogeneous  magma  is  one  that  concerns  geology  but  does  not 
seem  to  be  directly  approachable  through  chemical  evidence.  If, 
however,  we  consider  the  problem  locally  with  reference  to  effusions 
from  one  definite  volcanic  center,  the  chemist  may  have  something 
to  say.  Even  here  the  discussion  must  be  mainly  physical,  but  chem- 
ical principles  are  also  involved  in  its  settlement,  for  the  reason  that 
chemical  differences  characterize  the  lavas,  and  they  demand  con- 
sideration. 


1 Neues  Jahrb.,1882,  Band  2,  p.  1.  Compare  papers  by  J.  Joly,  Proc.  Roy.  Soc.  Dublin,  vol.  9, 1900,  p. 
298;  J.  A.  Cunningham,  idem,  1901,  p.  383;  and  W.  J.  Sollas,  Geol.  Mag.,  1900,  p.  295.  On  the  order  of  con- 
solidation of  magmatic  minerals  there  is  a copious  literature. 

2 Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  113,  1904,  p.  495.  Doelter  gives  many  data  on  the  separation  of 
minerals  during  the  cooling  of  melts  of  known  composition.  The  different  species  were  first  fused  together. 

3 The  importance  of  discriminating  between  the  fusibility  of  a mineral  and  its  solubility  in  a magma 
is  strongly  emphasized  by  A.  Lagorio,  in  Zeitschr.  Kryst.  Min.,  vol.  24,  1895,  p.  285.  Minerals  may  dis- 
solve at  temperatures  far  below  their  melting  points,  just  as  salt  dissolves  in  water.  It  is  also  necessary 
to  distinguish  between  simple  solution  and  chemical  reactivity.  In  the  one  process  a body  dissolves 
and  recrystallizes  from  solution  without  change.  In  the  other  it  dissolves  because  of  reactions  with  the 
solvent,  and  new  compounds  are  generated.  In  either  process,  however,  a solution  may  become  saturated, 
and  then  its  solvent  action  ceases.  On  viscosity  as  related  to  chemical  composition  in  silicate  fusions  see 
E.  Greiner,  Inaug.  Diss.,  Jena,  1907. 


308 


THE  DATA  OF  GEOCHEMISTRY. 


It  is  now  a commonplace  of  petrology  that  within  a given  area 
there  may  be  a variety  of  igneous  rocks  exhibiting  a relationship  to 
one  another  and  indicating,  by  their  mode  of  occurrence,  that  they 
had  a common  origin.  To  what  is  this  “ consanguinity/ ’ as  Iddings 
calls  it,  due  ? If  the  lavas,  which  may  differ  widely,  came  from  one 
and  the  same  fissure  or  crater,  how  were  their  differences  brought 
about  ? To  this  question  there  have  been  many  answers,  hut  its  dis- 
cussion still  continues  voluminously,  and  the  last  word  is  not  yet 
said.  If  distinct  magmas  exist,  which  are  ejected  sometimes  sepa- 
rately and  sometimes  commingling,  the  problem  becomes  apparently 
simple,  and  this  method  of  solution  has  been  repeatedly  proposed. 
Bunsen  assumed  the  existence  of  two  such  magmas,  the  normal 
pyroxenic  and  the  normal  trachytic,  and  Durocher  has  put  forth 
similar  views.  Other  petrologists  have  thought  that  there  are  more 
than  two  fundamental  magmas,  but  such  a multiplication  of  assump- 
tions can  only  end  in  confusion.  The  conception  is  simple  enough, 
but  its  application  to  observed  phenomena  is  quite  the  reverse.  With 
this  phase  of  the  question  chemistry  has  little  to  do.  The  prevalent 
modern  opinion  favors  the  idea  that  at  each  specified  locality  there  is 
one  essentially  homogeneous  magma,  from  which,  by  some  process 
of  differentiation,  the  various  rock  species  of  the  region  have  been 
derived.  Under  what  conditions  and  by  what  processes  can  such 
a differentiation  be  produced?  Upon  this  problem,  presented  in 
this  form,  physical  chemistry  has  some  suggestions  to  offer,  regardless 
of  the  antecedent  assumptions  or  of  the  geological  evidence  upon 
which  it  is  based.1 

It  is  not  necessary  for  us  now  to  consider  the  historical  aspect  of 
the  discussion,  for  that  has  been  well  done  by  several  other  writers. 
J.  P.  Iddings,  especially,  in  his  memoir  upon  the  origin  of  igneous 
rocks,2  and  more  recently  W.  C.  Brogger  3 and  F.  Loewinson-Less- 
ing  4 have  done  full  justice  to  this  side  of  the  question.  We  need 
only  take  up  broadly  the  hypotheses  which  have  been  suggested  in 
order  to  explain  the  observed  differentiation  and  examine  them  as  to 
their  validity.  An  exhaustive  discussion  of  details  is  out  of  the 
question. 

Although  R.  W.  Bunsen  was  the  first  to  show  that  a magma  is  really 
a solution,  little  attention  was  paid  to  this  consideration  until  A.  La- 
gorio,5  in  1887,  published  his  famous  memoir  on  the  nature  of  the 

1 Harker,  in  his  Natural  history  of  igneous  rocks,  devotes  a chapter  to  '‘hybridism” — that  is,  to  rocks 
formed  by  the  commingling  of  magmas.  Another  chapter  is  given  to  the  question  of  differentiation. 
Elsden,  in  his  Chemical  geology,  also  discusses  the  general  problem  at  some  length. 

2 Bull.  Philos.  Soc.  Washington,  vol.  12, 1892,  p.  89. 

3 Die  Eruptivgesteine  des  Kristianiagebietes,  pt.  3,  1898,  pp.  276  et  seq. 

4 Compt.  rend.  VII  Cong.  geol.  internat.,  1897,  p.  308. 

6 Min.  pet.  Mitt.,  vol.  8, 1887,  p.  421.  This  memoir  is  rich  in  references  to  former  literature. 


THE  MOLTEN  MAGMA. 


309 


u glass  base”  or  groundmass.  In  developing  his  fundamental  con- 
ception Lagorio  called  attention  to  “Soret’s  principle,”  which  asserts 
that  when  two  parts  of  the  same  solution  are  at  different  temperatures 
there  will  be  a concentration  of  the  dissolved  substance  in  the  cooler 
portion.  Through  the  operation  of  this  process,  namely,  unequal 
cooling,  it  was  thought  that  a homogeneous  molten  mass  might  be- 
come heterogeneous,  the  substances  with  which  a magma  was  most 
nearly  saturated  tending  to  accumulate  at  the  cooler  points,  leaving 
the  warmer  portions  with  an  excess  of  the  solvent  material.  This 
view  was  speedily  adopted  by  many  petrographers,  but  objections 
to  it  were  soon  found,  and  it  is  now  generally  abandoned.  G.  F. 
Becker  1 showed  that  to  produce  the  observed  phenomenon  in  so 
viscous  a medium  as  molten  lava  by  such  a process  of  molecular 
diffusion  would  require  almost  unlimited  time;  and  H.  Backstrom  2 
pointed  out  that  although  the  operation  of  Soret’s  principle  might 
cause  changes  in  the  absolute  concentration,  it  could  no  more  alter 
the  relative  proportions  of  the  dissolved  substances  than  it  could  in 
a mixture  of  gases. 

Another  process  which  surely  plays  some  part,  great  or  small,  in 
the  differentiation  of  magmas  is  the  solution  of  foreign  material.  The 
molten  lava,  as  it  rises  from  the  depths  to  the  surface  of  the  earth,  is 
inclosed  between  walls  of  rock  upon  which  it  exerts  a solvent  action. 
This  action  may  be  very  slight  or  it  may  be  important;  and  its  extent 
will  depend  on  the  character  of  the  magma,  the  character  of  the  rock 
with  which  it  is  in  contact,  the  temperature,  and  the  pressure.  Not 
one  of  these  factors  can  be  set  aside  as  negligible.  The  absorbed 
rock  may  be  either  igneous  or  sedimentary ; the  effect  produced  upon 
it  may  be  limited  to  a thin  contact  zone  or  it  may  permeate  large 
masses  of  material;  and  no  general  rule  governs  the  process  entirely. 
The  wall  rock  varies  in  solubility  with  respect  to  the  magma,  and 
this  condition,  modified  as  it  must  be  by  variations  in  temperature, 
is  of  prime  importance.  If  a magma  is  saturated  with  respect  to  the 
substances  contained  in  its  walls,  its  solvent  action  will  be  slight;  if 
unsaturated,  its  activity  must  be  greater.  A basaltic  magma  should 
take  up  silica ; a siliceous  magma  might  absorb  bases.  For  example, 
blocks  of  limestone,  more  or  less  altered  by  contact  with  the  molten 
magma,  are  ejected  from  some  volcanoes,  and  may  be  found  embedded 
in  the  solidified  lavas.  In  extreme  cases  they  may  disappear  en- 
tirely, leaving  a local  enrichment  in  lime  salts  as  evidence  of  their 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  3,  1897,  p.  21. 

2 Jour.  Geology,  vol.  1,  1893,  p.  773.  See  also  F.  Loewinson-Lessing,  Compt.  rend.  VII  Cong.  g<5ol. 
internat.,  1897,  p.  390. 


310 


THE  DATA  OF  GEOCHEMISTRY. 


former  nature.1  This  general  process,  this  assimilation  of  extraneous 
material,  is  given  much  weight  by  Johnston-Lavis  and  Loewinson- 
Lessing  in  their  discussions  of  magmatic  differentiation;  but  its 
effectiveness  is  by  no  means  universally  admitted.  R.  A.  Daly,2  a 
recent  advocate  of  the  assimilation  theory,  has  sought  to  explain  the 
mechanism  of  igneous  intrusions  by  a process  which  he  calls  “ mag- 
matic stoping.”  He  supposes  that  a batholithic  magma  eats  its  way 
up  by  solvent  action  on  the  invaded  rocks.  Blocks  of  the  latter, 
loosened  by  this  process,  sink  into  the  fluid  mass  and  are  gradually 
dissolved.  Thus  the  composition  of  the  magma  is  altered.  Daly 
also  argues  in  favor  of  the  view  that  such  a magma,  by  “gravitative 
adjustment,”  will  separate  into  layers,  the  denser  submagma  below, 
the  lighter  above.  The  latter  conception  is  not  new,  and  has  had 
many  supporters. 

The  hypothesis  advanced  by  A.  Michel-Levy3  that  differentiation 
is  brought  about  chiefly  by  a circulation  at  high  temperatures  and 
under  great  pressures  of  the  so-called  “fluides  mineralisateurs  ” — that 
is,  of  water  and  the  other  vapors  or  gaseous  contents  of  the  magma — 
is  one  which  deserves  serious  consideration.  These  agents  are  sup- 
posed to  entangle  certain  other  constituents,  the  lighter  substances  of 
the  magma,  and  to  concentrate  them  in  the  upper  layers  of  the  fused 
mass.  Silica  and  the  feldspathic  minerals  would  thus  accumulate 
near  the  top  of  a volcanic  reservoir,  leaving  the  ferromagnesian  miner- 
als in  greater  proportion  at  the  bottom — an  order  corresponding  with 
a common  order  of  ejectment  during  eruptions.  This  order,  how- 
ever, is  not  invariable,  and  in  Great  Britain,  according  to  A.  Geikie,4 
it  was  generally  reversed.  There  the  femic  rocks  represent  the  earli- 
est outflows  and  the  salic  rocks  came  later.  A progressive  enrich- 
ment in  silica  took  place,  instead  of  the  impoverishment  that  Michel- 
Levy’s  process  would  imply.  In  the  Yellowstone  Park,  according  to 


1 See,  for  example,  H.  J.  Johnston-Lavis,  The  ejected  blocks  of  Monte  Somma:  Trans.  Edinburgh  Geol. 
Soc.,  vol.  6,  1892-93,  p.  314.  Also  a paper  in  Natural  Science,  vol.  4,  1894,  p.  134.  F.  Loewinson-Lessing 
(loc.  cit.)  gives  many  other  references  to  literature  on  this  subject.  For  experimental  data  on  the  solu- 
bility of  corundum,  emery,  andalusite,  kyanite,  kaolin,  pyrophyllite,  leucite,  and  quartz  in  magmas,  see 
A.  Lagorio  (Zeitschr.  Kryst.  Min.,  vol.  24,  1895,  p.  285);  also  C.  Doelter  and  E.  Hussak  (Neues  Jahrb.,  1884, 
Band  1,  p.  18),  who  operated  on  olivine,  pyroxene,  hornblende,  biotite,  feldspars,  quartz,  garnet,  iolite,  and 
zircon  in  much  the  same  way.  How  far  these  experiments,  conducted  on  small  samples  during  short 
times,  can  be  used  to  illustrate  natural  phenomena  is  doubtful,  but  they  do  give  some  information  of  value. 
On  the  absorption  of  limestone  by  granite  see  A.  Lacroix,  Compt.  Rend.,  vol.  123, 1896,  p.  1021. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  15,  1903,  p.  269;  vol.  16, 1903,  p.  107;  vol.  20, 1905,  p.  185;  vol.  26, 1908,  p.  17, 
and  in  the  Rosenbusch  “Festschrift,”  1906,  p.  203.  See  also  Bull.  U.  S.  Geol.  Survey  No.  209, 1903,  p.  104, 
on  the  rocks  of  Mount  Ascutney.  A discussion  of  Daly’s  views,  mainly  adverse,  at  a meeting  of  the  Geo- 
logical Society  of  Washington,  is  reported  in  Science,  vol.  25, 1907,  p.  621.  J.  H.  L.  Vogt  (Die  Silikatschmelz- 
losungen,  pt.  2, 1904,  p.  225)  regards  the  assimilation  theory  as  quite  untenable.  Daly’s  views  have  been 
accepted  by  J.  Barrell,  Prof.  Paper  U.  S.  Geol.  Survey  No.  57,  1907,  pp.  155-156;  E.  C.  Andrews,  Rec. 
Geol.  Survey  New  South  Wales,  vol.  8,  1905,  p.  126;  and  A.  P.  Coleman,  Jour.  Geology,  vol.  15,  1907,  p.  773, 
On  magmatic  assimilation  in  the  Adirondacks  see  W.  J.  Miller,  Bull.  Geol.  Soc.  America,  vol.  25,  p.  243, 1914. 

3 Bull.  Soc.  g<§ol.  France,  3d  ser.,  vol.  25,  1897,  p.  367. 

4 The  ancient  volcanoes  of  Great  Britain,  vol.  2, 1897,  p.  477. 


THE  MOLTEN  MAGMA. 


311 


J.  P.  Iddings,1  lavas  of  medium  composition  were  emitted  first,  and 
the  differentiation  was  a splitting  up  of  the  magma  into  femic  and 
salic  portions.  The  sequence  of  lavas,  then,  appears  to  have  been 
different  in  different  regions,  and  the  irregularities  remain  to  be 
explained.  Apart  from  this  digression,  however,  the  suggestions  of 
Michel-Levy  should  be  borne  in  mind.  The  magmatic  vapors  must 
exert  an  important  influence  upon  the  process  of  differentiation,  for 
they  tend  to  accumulate  in  the  upper  part  of  a lava  column  or  reser- 
voir and  to  modify  its  properties  locally.  It  is  quite  possible  that 
they  may  bring  to  the  top  some  of  the  more  easily  sublimable  oxides 
or  silicates,  together  with  decomposable  fluorides  and  chlorides,  and 
during  an  eruption  these  substances  would  be  ejected  first.  A com- 
plete segregation,  however,  is  not  assumed — only  a differential  con- 
centration of  the  magmatic  components.  It  is  obvious  that  a more 
important  function  of  the  tl  mineralizers  ” is  to  increase  the  fusi- 
bility of  the  magmatic  mass  and  to  diminish  its  viscosity,  thereby 
facilitating  crystallization. 

In  a later  paper  than  the  one  previously  cited  G.  F.  Becker2  has 
shown  that  fractional  crystallization  may  have  been  an  important 
factor  in  producing  differentiation.  This  is  a process  which  is  well  un- 
derstood, and  it  must  have  been  more  or  less  operative.  From  this 
point  of  view  magmatic  differentiation  becomes  a part  of  the  general 
cooling  process,  and  not  a phenomenon  to  be  considered  aside  from  the 
ordinary  solidification  of  a lava.  The  magma,  whether  it  is  forming  a 
dike  or  a laccolith,  is  inclosed  between  walls  which  are  cooler  than 
itself,  and  along  these  surfaces  the  less  fusible  or  less  soluble  minerals 
will  first  crystallize.  The  process  is  aided  by  the  circulation  of  con- 
vection currents;  and  that  portion  of  the  fused  mass  which  last 
solidifies,  the  mother  liquor,  will  be  the  portion  of  maximum  fusibility, 
and,  therefore,  approximate  to  a eutectic  mixture.  The  center  of 
the  dike  or  laccolith  will  thus  have  one  composition  and  its  outer  parts 
another.  In  his  memoir  upon  the  Highwood  Mountains  L.  V. 
Pirsson 3 discusses  the  process  in  some  detail  and  shows  how  convec- 
tion and  crystallization  may  go  on  together.  When  great  differences 
in  specific  gravity  exist,  as  in  the  separation  of  the  heavy  titaniferous 
magnetite  of  the  Adirondacks  from  the  lighter  rocks  of  the  same 
magmatic  mass,4  the  crystallizing  substances  may  settle  to  the  bot- 
tom and  form  a distinct  layer  quite  unlike  the  superincumbent 
material.  Even  very  moderate  differences  of  density  may  produce 

1 Bull.  Philos.  Soc.  Washington,  vol.  12,  1892,  p.  89.  Compare  J.  E.  Spurr,  Jour.  Geology,  vol.  8, 1900, 
p.  621,  on  the  succession  of  the  igneous  rocks  in  the  Great  Basin  of  Nevada.  Spurr  gives  a good  historical 
summary  of  the  subject,  beginning  with  the  pioneer  work  of  Richthofen. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  4, 1897,  p.  257. 

3 Bull.  U.  S.  Geol.  Survey  No.  237,  1905,  p.  183.  Compare  also  A.  Harker,  Quart.  Jour.  Geol.  Soc.,  vol. 
50, 1894,  p.  324,  and  T.  L.  Walker,  Am.  Jour.  Sci.,  4th  ser.,  vol.  6,  1898,  p.  410. 

4 See  J.  F.  Kemp,  Nineteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pi.  3,  1899,  p.  417. 


312 


THE  DATA  OF  GEOCHEMISTRY. 


similar  results,  although  in  less  degree.  For  example,  Loewinson- 
Lessing1  has  shown  that  in  certain  Vesuvian  lavas  leucite  crystals 
have  risen  to  the  top,  while  augite  sank  to  the  bottom.2  In  the  differ- 
entiation of  the  eruptive  iron  ores  of  Norway,  as  described  by  J.  H. 
L.  Vogt,3  the  same  process  may  operate,  although  Vogt  gave  another 
interpretation  to  the  phenomena.  In  cases  of  this  kind  the  liquation 
hypothesis  of  J.  Durocher 4 may  be  partly  applicable,  and  we  can  easily 
conceive  of  the  cooling  magma  as  separating  into  lighter  and  heavier 
layers,  even  before  solidification  begins.  Kemp,  in  the  paper  just 
cited,  remarks  that  copper  matte  settles  out  almost  completely  from  a 
viscous  mixture  of  matte  and  slag,  although  in  a large  mass  of  magma 
convection  currents  might  hinder  the  perfect  working  of  such  a 
process.  Liquation,  then,  must  be  regarded  as  a possible  mode  of 
differentiation,  but  probable  only  in  certain  special  cases.  It  implies 
a limited  miscibility  of  the  magmatic  solutions,  and  that  does  not  often 
occur.  J.  Morozewicz,5  however,  in  his  experiments  upon  artificial 
magmas  observed  several  cases  in  which  his  melts  differed  in  com- 
position from  top  to  bottom,  the  undermost  portion  being  the  heav- 
iest. Similar  differences  of  density  are  well  known  to  the  glass 
makers,  as  shown  by  variations  in  refractive  capacity  between  the 
top  and  bottom  portions  of  their  melts.  Such  a “gravitative  adjust- 
ment” is  presumably  most  effective  in  slowly  cooling  magmas, 
especially  when  partial  crystallization  has  occurred.  The  minerals 
first  formed  must  have  time  to  sink.  The  rate  of  cooling,  therefore, 
is  a distinct  factor  in  the  differentiation  of  igneous  rocks. 

To  these  agencies  in  the  process  of  differentiation  must  be  added 
that  of  pressure.  This  has  been  taken  into  account  by  Martin 
Schweig,6  whose  views  may  be  briefly  summarized  or  paraphrased 
as  follows:  In  a molten  magma,  under  great  pressure,  partial  crystal- 
lization occurs ; the  crystals  formed  sink  within  the  fluid  mass,  while 
their  mother  liquor  accumulates  above  them.  An  eruption  takes 
place,  the  mother  liquor  is  ejected,  and  with  the  consequent  relief  of 
pressure  the  fusibility  of  the  separated  crystalline  matter  is  increased. 
The  latter,  remelted,  is  expelled  by  a later  explosion,  and  in  this  way 
the  magma,  originally  homogeneous,  gives  rise  to  two  or  more  differ- 
ent lavas  emitted  from  the  same  vent.  The  separation  is  effected  in 
the  first  place  by  fractional  crystallization,  aided  by  gravity;  and 
then,  under  reduced  pressure,  the  crystalline  layer  again  liquefies. 

1 Studien  ueber  die  Eruptivgesteine,  St.  Petersburg,  1899,  p.  155. 

2 Similar  observations  are  recorded  by  much  earlier  workers,  as,  for  instance,  Charles  Darwin,  in  Geo- 
logical observations  on  volcanic  islands,  1844,  p.  117,  and  P.  Scrope  in  his  treatise  Volcanos,  1872,  p.  125. 

3 See  summary  by  J.  J.  H.  Teall  in  Geol.  Mag.,  1892,  p.  82. 

4 Annales  des  mines,  5th  ser.,  vol.  11,  1857,  p.  217. 

3 Min.  pet.  Mitt.,  vol.  18,  1888-89,  p.  233.  N.  L.  Bowen  (Am.  Jour.  Sci.,  4th  ser.,  vol.  39, 1915,  p.  175),  in 
some  experiments  upon  the  magnesian  silicates,  has  found  that  in  a melt  olivine  and  pyroxene  crystallize 
out  and  sink,  while  tridymite  floats. 

6 Neues  Jahrb.,  Beil.  Band,  vol.  17,  1903,  p.  516.  Originally  published  as  a doctoral  dissertation.  The 
paper  contains  a good  summary  down  to  1903  of  the  entire  subject  of  differentiation. 


THE  MOLTEN  MAGMA. 


313 


This  is  a plausible  hypothesis,  but  it  leaves  some  things  out  of 
account.  Pressure,  in  the  first  instance,  raises  the  melting  points  of 
the  fused  minerals,  but  the  water  and  gases  dissolved  in  the  magma 
act  in  the  opposite  way.  They  tend  to  make  the  magma  more  fusible. 
When,  by  eruption,  these  gases  escape,  there  will  be  a decrease  of  fusi- 
bility to  offset  the  gain  from  reduced  pressure,  and  what  the  alge- 
braic sum  of  this  gain  and  loss  may  be  no  man  can  say.  The  oppos- 
ing tendencies  may  balance,  but  it  is  more  probable  that  one  or  the 
other  will  be  the  stronger,  and  beyond  this  point,  with  the  available 
evidence,  our  reasoning  can  not  go.  During  an  eruption  the  com- 
position of  a magma,  its  gaseous  load,  its  temperature,  and  the  pres- 
sure on  it  are  all  varying;  some  of  the  variations  are  slow  and 
gradual,  others  are  rapid;  heat  may  be  lost  by  cooling1  or  evolved  by 
chemical  change;  and  no  equation  can  yet  be  written  in  which  each 
of  these  factors  shall  receive  its  proper  valuation.  After  eruption  the 
phenomena  are  less  complex;  but  even  then  we  are  only  able  to 
follow  them  partially.  Fractional  crystallization,  liquation,  the  in- 
fluence of  dissolved  vapors,  and  the  assimilation  of  foreign  material 
are  all  intelligible  processes,  but  the  first  one  named  is  the  most 
general  and  presumably  the  most  important  of  all.  Even  its  influ- 
ence is  variable,  however,  becoming  zero  in  eutectic  mixtures  and 
increasing  in  potency  as  we  recede  from  the  eutectic  point.  The 
more  closely  the  composition  of  a magma  approaches  eutectic  ratios 
the  less  capable  of  fractionation  it  becomes. 

RADIOACTIVITY. 

This  chapter  would  be  incomplete  without  some  reference  to  recent 
speculations  and  investigations  relative  to  the  sources  of  volcanic 
heat.  That  heat  hitherto  has  been  commonly  referred  either  to  the 
molten  matter  left  over  after  the  consolidation  of  the  lithosphere  or 
to  a generation  from  mechanical  sources,  such  as  pressure  and  the 
friction  due  to  movements  within  the  crust.  The  discovery  of 
radium,  however,  which  emits  heat  continuously,  has  led  to  new  con- 
ceptions that  are  at  least  worth  mentioning.2 

The  quantity  of  heat  emitted  by  radium  has  been  measured  by  sev- 
eral investigators.  The  subjoined  table  gives  most  of  the  results 
obtained,  expressed  in  gram  calories  per  gram  of  pure  radium  per 
hour : 


1 The  sudden  expansion  of  the  gases  released  at  the  beginning  of  a volcanic  eruption  must  exert  a note- 
worthy cooling  effect  on  the  residual  magma. 

2 A discussion  of  the  purely  physical  or  mechanical  sources  of  heat  does  not  fall  within  the  scope  of  this 
treatise. 


314 


THE  DATA  OF  GEOCHEMISTRY. 


Heat  emitted  by  radium. 


Authority. 

Reference. 

Small  calories. 

P.  Curie  and  A.  Laborde 

Compt.  Rend.,  vol.  136,  1903,  p. 
673. 

100  approx. 

E.  Rutherford  and  II.  T.  Barnes. 

Philos.  Mag.,  6th  ser.,  vol.  7,  1904, 

p.  202. 

100  approx. 

C.  Runge  and  J.  Precht 

Jour.  Chem.  Soc.,  vol.  86  (2),  1904, 
p.  7. 

105. 

F.  Paschen 

Physikal.  Zeitschr.,  vol.  5,  1904, 
p.  563. 

126. 

J.  Precht 

Annalen  der  Physik,  4th  ser.,  vol. 
21,  1906,  p.  595. 

134.4. 

E.  v.  Schweidler  and  V.  F.  Hess. 

Monatsh.  Chemie,  vol.  29,  1908, 
p.  853. 

118. 

W.  Duane 

Compt.  Rend.,  vol.  148,  1909,  p. 
1448. 

120. 

W.  Duane 

Am.  Jour.  Sci.,  4th  ser.,  vol.  31, 
1911,  p.  247. 

104  to  117. 

H.  Pettersson 

Chem.  Abstracts,  vol.  5,  p.  2365, 
1911. 

116.4. 

The  differences  between  these  determinations  are  due  partly  to 
differences  in  the  atomic  weight  assigned  to  radium  and  partly  to 
different  methods  of  measurement;  but  they  are  immaterial  in  respect 
to  the  present  discussion.  It  is  enough  to  note  that  1 gram  of 
radium  spontaneously  emits  heat  enough  every  hour  to  raise  the 
temperature  of  more  than  100  grams  of  water  1°  Centigrade,1  an 
enormous  quantity  in  comparison  with  the  energy  displayed  in  even 
the  most  violent  chemical  reactions.  How  large  a part  does  this 
evolution  of  heat  play  in  volcanic  phenomena  or  in  maintaining  the 
temperature  of  the  earth  ? 

The  principal  radioactive  elements,  so  far  as  present  knowledge 
goes,  are  uranium,  radium,  and  thorium.  Actinium,  ionium,  and 
polonium  are  also  known,  but  their  thermal  efficiency  is  yet  to  be 
determined.  Potassium  and  rubidium  are  feebly  radioactive.  Ra- 
dium, which  is  a derivative  of  uranium,  is  by  far  the  most  important 
radioactive  element  so  far  discovered,  and  for  immediate  purposes  is 
the  only  one  which  need  be  taken  into  account.  It  has  been  sug- 
gested that  the  atomic  degradation  which  characterizes  the  elements 
above  named  is  probably  a general  property  of  all  matter,  but  that 
is,  as  yet,  only  an  unproved  speculation.2  It  may  or  may  not  be 
sustained  by  future  investigators. 

The  materials  forming  the  crust  of  the  earth,  whether  igneous  or 
sedimentary,  are  now  known  to  be  measurably  radioactive.  This 

1 The  most  probable  value  is  118  cal. 

2 N.  R.  Campbell  (Philos.  Mag.,  6th  ser.,vol.  9, 1905,  p.  531;  vol.  11,  1906,  p.  206)  claims  to  have  discov- 
ered radioactivity  in  several  common  metals.  H.  Greinacher  (Annalen  der  Physik,  4th  ser.,  vol.  24, 1907, 
p.  79)  attempted  to  determine  the  radioactivity  of  common  substances  by  a calorimetric  method,  and 
obtained  negative  results.  If  it  exists,  its  intensity  is  too  small  to  be  measured  by  any  known  method.  See 
also  W.  W.  Strong,  Am.  Chem.  Jour.,  vol.  42,  1909,  p.  147;  M.  Levin  and  R.  Ruer,  Physikal.  Zeitschr.,  vol. 
10, 1909,  p.  576. 


THE  MOLTEN  MAGMA. 


315 


radioactivity  is  even  communicated  to  the  waters1  and  the  atmos- 
phere, but  is  most  marked  in  the  older  rocks,  and  it  is  mainly  attrib- 
uted to  the  widespread  diffusion  of  radium  in  exceedingly  minute 
traces.  The  other  unstable  elements,  doubtless,  play  their  part,  but 
radium  appears  to  be  the  principal  agent  in  producing  the  phenom- 
enon. The  measurements  of  what  may  be  called  geochemical  radio- 
activity are  therefore  commonly  stated  in  terms  of  radium. 

The  decay  of  radium  is  through  a series  of  stages  in  which  a num- 
ber of  products  are  successively  formed.  The  first  of  these  products, 
the  radium  emanation,  to  which  the  name  niton  has  recently  been 
given,  is  a gas  belonging  to  the  helium-argon  group.  By  decompos- 
ing a rock  and  bringing  it  into  solution  this  gaseous,  radioactive 
substance  can  be  isolated,  and  its  amount  determined  by  its  action 
upon  the  air  within  an  electroscope.  The  details  of  the  operation 
need  not  be  considered  here.  They  are  given  by  Strutt  in  his  papers 
upon  radium  in  rocks,  and  are  also  summed  up  by  Joly  in  his  treatise 
upon  Radioactivity  and  Geology.  The  amount  of  emanation  is 
strictly  proportional  to  the  amount  of  radium  from  which  it  was 
generated,  provided  enough  time  is  allowed  for  it  to  accumulate  until 
its  rate  of  production  and  rate  of  decay  are  in  exact  equilibrium. 
These  rates  are  known  to  a fair  degree  of  approximation,  and  hence 
measurements  of  the  emanation  are  easily  restated  in  equivalent 
quantities  of  radium. 

Since  1906  numerous  determinations  of  radium  in  rocks  have  been 
made,  especially  by  R.  J.  Strutt  and  J.  Joly.2  From  Strutt’s  meas- 
urements, as  corrected  by  Eve  and  McIntosh,  the  radium  in  28  igneous 
rocks  ranges  from  0.30  X 10-12  to  4.78  X 10-12  grams  per  gram  of  mate- 
rial. The  average  is  1.7  XlO-12.  The  highest  values  were  obtained 
from  granites,  the  lowest  from  basalts  and  olivine  rocks.  For  sedi- 
mentary rocks  the  average  of  17  determinations  gave  1.1  XlO-12 

1 The  radioactivity  of  many  spring  waters  has  already  been  noted  in  the  chapter  on  mineral  springs. 
According  to  J.  Joly  (Radioactivity  and  geology,  p.  48),  sea  water  is  radioactive  to  an  extent  equivalent 
to  an  oceanic  content  of  20,000  tons  of  radium.  The  deep-sea  sediments  are  much  more  radioactive.  A.  S. 
Eve,  however  (Philos.  Mag.,  6th  ser.,  vol.  18,  1909,  p.  102),  found  much  smaller  amounts  of  radium  in  sea 
water  than  Joly— in  fact,  only  about  one-seventeenth  as  much.  For  a reply  by  Joly  see  the  same  volume, 
p.  396.  F.  Himstedt  (Physikal.  Zeitschr.,  vol.  5, 1904,  p.  210)  attributes  the  radioactivity  of  thermal  waters 
to  deep-seated  radioactive  minerals. 

2 See  Radioactivity  and  geology,  already  cited.  For  Strutt’s  papers  see  Proc.  Roy.  Soc.,  ser.  A,  vol.  77, 
1906,  p.  472;  vol.  78, 1906,  p.  150;  vol.  80,  1908,  p.  572;  vol.  84,  1910,  p.  377.  The  figures  given  by  Strutt  in  the 
first  of  these  papers  involved  an  erroneous  constant  and  were  corrected  by  A.  S.  Eve  and  D.  McIntosh,  Philos. 
Mag.,  6th  ser.,  vol.  14,  1907,  p.  231.  These  authors  also  measured  the  radioactivity  of  various  rocks  near; 
Montreal.  See  also  memoirs  by  C.  C.  Farr  and  D.  C.  H.  Florance,  Philos.  Mag.,  6th  ser.,  vol.  18, 1909,  p.  812 
A.  L.  Fletcher,  idem,  vol.  20,  1910,  p.  36;  vol.  21,  1911,  pp.  102,  770;  vol.  23,  1912,  p.  279;  A.  Gockel,  Jour. 
Chem.  Soc.,  vol.  100,  pt.  2, 1911,  p.  174,  abstract;  E.  H.  Buchner,  idem,  p.  243,  abstract;  and  vol.  102,  pt.  2, 
1912,  p.  525,  abstract.  Recent  papers  by  Joly,  partly  upon  radium  and  partly  upon  thorium,  are  in  Philos. 
Mag.,  6th  ser.,  vol.  17,  1909,  p.  760;  vol.  18,  1909,  pp.  140,  577;  vol.  20,  1910,  pp.  125,  353;  vol.  23,  1912,  p.  201; 
vol.  24, 1912,  p.  694.  On  the  radioactivity  of  pitchblende  see  H.  H.  Poole,  idem,  vol.  19, 1910,  p.  314.  On 
Australian  minerals,  D.  Mawson  and  T.  H.  Laby,  Chem.  News,  vol.  92,  1905,  p.39.  On  lavas,  O.  Scarpa, 
Atti  R.  accad.  Lincei,  5th  ser.,  vol.  16, 1907,  p.  44;  R.  Nasini  and  M.  G.  Levi,  idem,  vol.  15, 1906,  p.  391;  vol.  17, 
p.  432;  and  G.  T.  Castorina,  Neues  Jahrb.,  1907,  p.  11  (abstract).  J.  W.  Waters  (Philos.  Mag.,  6th  ser.,  vol. 
19,  1910,  p.  903)  has  studied  the  presence  of  radioactive  minerals  in  common  rocks.  On  radiothorium  see 
G.  A.  Blanc,  idem,  vol.  13, 1907,  p.  378;  vol.  18, 1909,  p.  146. 


316  THE  DATA  OF  GEOCHEMISTRY. 

grams  per  gram,  the  mean  of  the  two  averages  being  1.4  XlO-12. 
This  amount  is  equivalent  to  an  emission  of  heat,  the  heat  given  out 
by  radium,  about  28  times  as  great  as  is  needed  to  account  for  the 
observed  temperature  gradient  within  the  crust  of  the  earth. 

Joly’s  figures  are  much  higher  than  those  of  Strutt,  and  cover  a 
much  larger  number  of  determinations.  As  summed  up  by  him,1 
the  mean  radium  content  of  igneous  rocks  is  5.5 XlO-12  grams  per 
gram,  and  that  of  sedimentary  rocks  4.3 XlO-12.  Joly,  moreover, 
finds  only  slight  differences  (as  compared  with  Strutt’s  results) 
between  the  plutonic  rocks  and  those  of  volcanic  origin.  The  dis- 
cordance between  Strutt  and  Joly  I cannot  attempt  to  explain;  but 
it  seems  probable  that  the  granitic  rocks  and  perhaps  also  the  nephe- 
line  syenites  should  show  the  highest  values.  In  them  the  minerals 
of  uranium,  radium,  and  thorium  are  principally  concentrated.2 
The  radioactivity  of  the  sedimentary  rocks  may  be  due  to  a distri- 
bution of  the  radium  emanation  by  circulating  waters,  in  which  the 
gas  is  soluble.  That  of  mineral  springs  is  explicable  in  the  same 
way. 

An  attempt  to  compute  the  total  amount  of  radioactive  matter  in 
the  earth  and  its  thermal  significance  would  be  obviously  premature. 
The  available  data  are  too  scanty,  too  discordant,  and  in  some 
respects  too  incomplete  for  such  a purpose.  According  to  Strutt, 
the  radium  must  be  mainly  within  an  outer  shell  of  rock  of  relatively 
moderate  thickness;  for  if  it  were  uniformly  diffused  throughout  the 
earth  the  earth  would  be  growing  warmer,  which  is  highly  improb- 
able.3 Its  precise  distribution,  however,  can  only  be  determined 
after  many  more  experiments  have  been  made,  in  which  the  radio- 
activity of  each  rock  mass  shall  be  correlated  with  its  exact  petrologic 
nature.  An  apparent  “granite,”  for  example,  may  be  really  a meta- 
morphic  rock  in  masquerade,  and  not  a true  plutonic.  The  thorough 
geologic  and  petrologic  study  of  each  sample  of  rock  should  go  hand 
in  hand  with  its  radioactive  measurement.4 

On  the  purely  qualitative  side  of  the  problem  more  can  be  said. 
It  is  proved  that  the  surface  rocks  of  the  earth  contain  diffused  ra- 
dium, and  that  must  be  emitting  heat  at  a definite  rate.  On  this 
basis  of  fact  Maj.  C.  E.  Dutton5 6  has  suggested  that  volcanic  heat 
may  be  developed  by  radioactivity  in  limited  tracts  from  1 to  3 and 
not  over  4 miles  below  the  surface  of  the  earth.  Heat  thus  developed 
might  so  accumulate  as  to  fuse  the  rocks  in  which  it  was  generated. 
In  time,  when  enough  material  was  melted,  the  water  inclosed  in  the 


1 Radioactivity  and  geology,  p.  275. 

2 G.  von  dem  Borne  (Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  58,  1906,  p.  1)  has  found  the  granite  of  the 
Erzgebirge  to  be.strongly  radioactive. 

3 See  also  C.  Liebenow,  Physikal.  Zeitschr.,  vol.  5,  1904,  p.  625. 

* See  A.  Holmes  (Sci.  Progress,  vol.  9,  p.  12, 1914),  for  an  interesting  paper  on  the  distribution  of  radium 

in  the  earth. 

6 Jour.  Geology,  vol.  14,  1906,  p.  259. 


THE  MOLTEN  MAGMA. 


317 


magma  thus  produced  would  become  explosive,  and  an  eruption 
would  follow.  Then  a period  of  quiet  would  ensue,  more  heat  would 
be  released  by  the  subterranean  radium,  and  another  explosion  would 
occur.  Thus  Dutton  explains  the  periodicity  of  eruptions,  and  he 
argues  that  no  permanent  reservoirs  of  molten  magma  are  required 
in  order  to  account  for  volcanic  phenomena.  Dutton’s  views  have 
been  opposed  by  G.  D.  Louderback,1  partly  on  geologic  grounds,  and 
partly  because  radiferous  minerals,  such  as  uraninite,  are  not  found 
among  volcanic  products.  On  the  other  hand  Joly2  is  inclined  to 
favor  Dutton’s  suggestion,  having  found  Vesuvian  lavas  to  be  highly 
radioactive.  His  figures,  for  the  lavas  emitted  since  1621,  give,  in 
mean,  12.3  X 10~12  grams  of  radium  per  gram  of  rock,  an  astonishingly 
high  figure,  which  seems  to  need  verification. 

In  speculations  of  this  order  there  is  a certain  fascination,  but  also 
a tendency  to  push  the  conclusions  too  far.  It  is  extremely  proba- 
ble that  radioaction  may  account  for  part  of  the  heat  emitted  from 
volcanic  vents,  but  whether  it  is  the  greater  part  or  not  is  more  uncer- 
tain. In  any  case,  the  reported  radioactivity  of  potassium 3 must  be 
taken  into  account,  a metal  millions  of  times  more  abundant  than 
radium,  which  fact  may  offset  its  feeble  intensity.  Mechanical  agen- 
cies and  chemical  reactions  also  count  for  something  in  volcanic 
phenomena,  and  the  heat  due  to  them  should  not  be  ignored.  It  is 
much  more  likely  that  the  phenomena  are  produced  by  a combination 
of  causes,  than  that  they  are  ascribable  to  any  one  cause  alone. 

The  final  degradation  products  of  radium,  and  therefore  of  its 
parent,  uranium,  are  helium 4 and  probably  lead.  The  elementary 
pedigrees  are  somewhat  long,  and  their  consideration  in  detail  would 
be  out  of  place  here.  The  rate  at  which  helium  is  generated  is  fairly 
well  known,  and  upon  that  constant  a method  of  determining  the  age 
of  minerals  has  been  based.5  Given  the  amount  of  uranium  or 
radium  in  a rock  or  mineral,  and  also  the  amount  of  helium  which  it 
contains,  and  the  length  of  time  required  to  generate  the  helium  is 
easily  calculated. 

1 Jour.  Geology,  vol.  14,  1906,  p.  747. 

2 Philos.  Mag.,  6th  ser.,  vol.  18,  1909,  p.  577.  The  possible  relation  of  volcanism  to  radioactivity  is  also 
discussed  by  F.  von  Wolff,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  60,  1908,  p.  431. 

3 See  N.  R.  Campbell  and  A.  Wood,  Proc.  Cambridge  Philos.  Soc.,  vol.  14, 1906-1908,  p.  15;  and  Campbell, 
idem,  pp.  211,  557.  Also  E.  Henriot,  Compt.  Rend.,  vol.  148,  1909,  p.  910;  Henriot  and  G.  Varon,  idem, 
vol.  149,  p.  30;  J.  C.  McLennan  and  W.  T.  Kennedy,  Physikal.  Zeitschr.,  vol.  9, 1908,  p.  510.  M.  Levin  and 
R.  Ruer  (idem,  vol.  10,  1909,  p.  576)  studied  many  elements  other  than  those  strongly  radioactive  and 
found  only  K and  Rb  to  emit  undoubted  radiations.  W.  W.  Strong  (Am.  Chem.  Jour.,  vol.  42,  1909, 
p.  147)  obtained  similar  results  and  also  found  radioactivity  in  erbium.  R.  J.  Strutt  (Proc.  Roy.  Soc., 
vol.  81A,  1908,  p.  278)  suggests  that  the  helium  in  the  Stassfurt  salts  may  be  derived  from  potassium. 

* According  to  F.  Soddy  (Philos.  Mag., 6th  ser.,  vol.  16, 1908, p.  513)  uranium  and  thorium  both  yieldhelium. 

5 See  E.  Rutherford,  Radioactive  transformations,  p.  187.  For  applications  of  the  method,  see  R.  J. 
Strutt,  Proc.  Roy.  Soc.,  ser.  A,  vol.  81, 1908,  p.  272;  vol.  83, 1909,  pp.  96,  298;  vol.  84, 1910,  pp.  194, 379.  For 
criticisms  of  the  method,  see  M.  Levin,  Zeitschr.  Elektrochemie,  vol.  13,  1907,  p.  390;  G.  F.  Becker,  Bull. 
Geol.  Soc.  America,  vol.  19, 1908,  p.  113;  J.  Joly,  Radioactivity  and  geology,  ch.  11;  J.  Koenigsberger,  Geol. 
Rundschau,  vol.  1,  1910,  p.  245;  and  A.  Holmes,  Proc.  Roy.  Soc.,  vol.  85A,  1911,  p.  248.  Holmes’s  book, 
The  age  of  the  earth,  London,  1913,  is  an  excellent  summary  of  the  subject.  See  also  recent  papers  by  Joly 
in  Philos.  Mag.,  6th  ser.,  vol.  22, 1911,  p.  358,  and  Sci.  Progress,  vol.  9, 1914,  p.  37 


318 


THE  DATA  OF  GEOCHEMISTRY. 


By  this  method  Rutherford  computed  the  ages  of  a fergusonite 
and  a uraninite  at  something  over  500,000,000  years;  the  figures 
being  minima  because  some  helium  might  have  escaped.  Joly, 
revising  the  calculations  by  means  of  a different  value  for  the  rate 
of  change  of  uranium  into  radium,  reduced  the  estimate  to  241,000,000 
years.  By  the  same  method  Strutt  found  the  age  of  thorianite  from 
Ceylon  to  be  above  280,000,000  years,  and  of  a Canadian  sphene 
710,000,000  years.  For  more  modern  minerals  Strutt  found  much 
smaller  ages.  Sphaerosiderite  from  the  Oligocene  was  found  to  be 
8,400,000  years  old;  hematite  from  the  Eocene  31,000,000;  and 
hematite  from  the  Carboniferous  150,000,000  years.  He  also  studied 
a number  of  phosphatic  nodules,  which  gave  still  lower  figures,  in 
one  case  225,000  ye’ars.  The  order  of  the  geological  formations  was 
approximately  followed,  the  oldest  minerals  being  found  in  the  oldest 
rocks. 

Assuming  that  lead  is  the  final  product  of  the  degradation  of 
uranium,  B.  B.  Boltwood  1 has  sought  to  determine  the  age  of  cer- 
tain minerals  from  the  ratio  between  the  two  metals  when  both 
are  present.  The  ratio  multiplied  by  10 10  gives  the  approximate 
age.  By  this  method  Boltwood  found  ages  for  various  minerals, 
ranging  between  410,000,000  years  for  a uraninite  from  Connecticut 
to  2,200,000,000  years  for  Ceylonese  thorianite,  the  last  figure  being 
several  times  larger  than  that  given  by  Strutt.  The  great  uncertainty 
of  such  calculations,  however,  has  been  clearly  pointed  out  by  G.  F. 
Becker,2  who  has  applied  it  to  the  rare-earth  minerals  from  Baringer 
Hill,  Llano  County,  Texas,  with  the  following  results : 

Yttrialite  (Mackintosh) 11,470,000,000  years. 

Yttrialite  (Hillebrand) 5,136,000,000  years. 

Mackintoshite  (Hillebrand) 3,894,000,000  years. 

Nivenite  (Mackintosh) 1,671,000,000  years. 

Fergusonite  (Mackintosh) 10,350,000,000  years. 

Fergusonite  (Mackintosh) 2,967,000,000  years. 

The  list  might  be  extended  still  further,  but  it  is  full  enough  as  it 
stands.  The  minerals  are  all  from  one  deposit,  which  is  of  about  the 
same  geologic  age  as  the  Connecticut  uraninite  studied  by  Ruther- 
ford, and  yet  the  figures  vary  enormously,  even  for  a single  species. 
The  assumption  that  lead  is  derived  from  uranium  may  be  correct; 
but  that  all  the  lead  in  a given  mineral  had  that  origin  is  most  doubt- 
ful. In  the  evolution  of  the  chemical  elements  lead  probably  existed 
before  uranium,  and,  being  more  stable,  was  developed  in  larger 
quantities.  Magmatic  lead,  as  represented  by  galena,  is  common 
in  pegmatites,  and  may  easily  have  become  entangled  with  other 
minerals  as  an  occluded  impurity  when  crystallization  first  took 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  23,  1907,  p.  86. 

2 Bull.  Geol.  Soc.  America,  vol.  19, 1908,  p.  134.  See  also F. Zambonini,  Atti  R. accad.  Lincei,  5th  ser.,  vol. 
20,  pt.  2, 1911,  p.  131;  and  R.  W.  Lawson,  Univ.  Durham  Phil.  Soc.  Proc.,  vol.  5, 1913,  p.  26. 


THE  MOLTEN  MAGMA. 


319 


place.  This  possibility  is  pointed  out  by  Becker  very  clearly.  The 
uranium-lead  ratio  is  of  very  questionable  value  in  computing  the 
age  of  minerals. 

Similar  objections  apply  to  the  use  of  the  helium-radium  ratio 
when  it  is  assumed  that  all  the  helium  was  generated  by  radioactive 
decay.  Helium  is  found  in  the  nebulas,  the  hotter  stars,  and  the  sun; 
and  the  sun  contains  lead  also;  but  uranium,  thorium,  and  radium 
have  not  yet  been  recognized  in  the  solar  spectrum.  B.  Hasselberg  1 
in  a careful  comparison  of  the  solar  spectrum  with  that  of  uranium 
failed  to  detect  its  presence.  P.  G.  Nutting 2 was  similarly  unsuc- 
cessful when  he  compared  Exner  and  Haschek’s  table  of  the  spectrum 
of  uranium  with  a 30-foot  reproduction  of  the  solar  spectrum.3 

Furthermore,  helium  is  not  only  found  in  minerals  containing 
uranium,  but  also  under  other  conditions.  For  example,  in  certain 
beryls  Strutt4  found  much  helium  but  no  radioactive  parent  from 
which  it  might  have  been  generated.  The  helium  in  such  cases  may 
have  originated  from  unknown  radioactive  substances  of  such  great 
instability  that  no  trace  of  them  remains  unchanged,  but  this  is  pure 
speculation.  A.  Piutti5  found  that  helium  is  generally  present  in 
minerals  containing  glucinum,  but  with  no  regular  ratio  between 
the  two  elements.  He  has  also  6 shown  that  helium  is  absorbed 
by  certain  melted  salts  and  minerals,  and  that  its  presence  therefore 
tells  nothing  of  their  age. 

The  permeability  of  quartz  to  helium,  which  is  perceptible  at  220° 
and  very  great  at  1,100°,  may  have  some  bearing  on  the  problem 
now  before  us.7  That  minerals  should  differ  in  their  permeability, 
and  also  in  their  capacity  for  retaining  helium  is  almost  beyond 
question.  Another  difficulty  is  suggested  by  the  work  of  Ellen 
Gleditsch,8  who  has  shown  that  the  ratio  between  radium  and  uranium 
in  minerals  is  not  constant.  That  ratio  enters  into  many  of  the 
calculations  relative  to  the  age  of  radioactive  minerals.  A still 
greater  difficulty  appears  when  we  take  into  consideration  the 
presence  of  helium  in  the  waters  of  many  springs.  From  one  spring 
at  Santenay,  in  France,  according  to  C.  Moureu  and  A.  Lepape,9 
17,845  liters  of  helium  are  brought  to  the  surface  in  one  year.  To 
supply  this  quantity  the  radioactive  decay  of  not  less  than  91  metric 

1 K.  Svensk.  Vet.  Akad.  Handl.,  vol.  45,  No.  5,  p.  63, 1910. 

2 See  Becker,  Bull.  Geol.  Soc.  America,  vol.  19,  p.  123,  1908. 

3 F.  W.  Dyson  (Astron.  Nachrichten,  vol.  192,  p.  82,  1912)  has  reported,  somewhat  doubtfully,  lines  of 

radium  in  the  spectrum  of  the  solar  chromosphere.  H.  Giebeler  (idem,  vol.  191,  p.  401, 1912)  has  detected 
radium  and  its  emanation  in  the  spectrum  of  the  star  Nova  Geminorum  2.  These  observations  need  con- 
firmation. Recent  investigations  have  failed  to  support  them. 

* Proc.  Roy.  Soc.,  vol.  80A,  1908,  p.  572. 

6 Atti  R.  accad.  Lincei,  5th  ser.,  vol.  22,  pt.  1, 1913,  p.  140. 

s Jour.  Chem.  Soc.,  vol.  100,  pt.  2,  p.  88, 1911  (abstract). 

7 See  A.  Jaquerod  and  F.  L.  Perrot,  Compt.  Rend.,  vol.  139,  1904,  p.  789;  vol.  144,  1907,  p.  135. 

8 Idem,  vol.  148,  1909,  p.  1451;  vol.  149,  1909,  p.  267. 

9 Idem,  vol.  155, 1912,  p.  197. 


320 


THE  DATA  OF  GEOCHEMISTRY. 


tons  of  radium,  or  500,000,000  tons  of  pitchblende  or  thorianite 
would  be  required.  From  all  these  considerations  it  is  evident  that 
primordial  or  “fossil”  helium  must  be  taken  into  account,  and  also 
the  possibility  that  the  reaction  by  which  uranium  decays  may  be 
reversed  under  the  enormous  pressures  and  high  temperatures  exist- 
ing within  the  earth.1  On  the  basis  of  that  supposition  we  can 
imagine  that  some  of  the  helium  found  in  minerals  may  be  only  left- 
over material  from  the  original  reactions  in  which  the  heavier  elements 
were  formed. 

One  other  method  for  computing  the  age  of  minerals  is  based  on 
radioactive  phenomena.  In  certain  minerals,  micas  for  example, 
little  colored  rings  are  observed,  surrounding  a presumably  radio- 
active nucleus.  From  measurements  of  those  “pleochroic  haloes” 
J.  Joly  and  others2  have  computed  ages  comparable  with  those 
derived  from  the  helium  and  lead  ratios.  The  data,  however,  are 
not  sharp,  and  it  is  doubtful  whether  much  weight  can  be  given  to 
the  calculations. 

Finally,  the  discordance  between  the  foregoing  computations  and 
other  methods  of  ascertaining  the  age  of  the  earth  is  extraordinary. 
From  chemical  denudation,  from  paleontological  evidence,  and  from 
astronomical  data  the  age  has  been  fixed  with  a noteworthy  degree 
of  concordance  at  something  between  50  and  100  millions  of  years.3 
The  high  values  found  by  radioactive  measurements  are  therefore  to 
be  suspected  until  the  discrepancies  shall  have  been  explained.4 

In  his  presidential  address  before  the  Geological  Society  of  America 
in  December,  1914,  G.  F.  Becker  brings  forward  strong  arguments 
against  the  radioactive  method  of  computing  the  age  of  the  earth. 

1 This  possibility  is  recognized  by  Rutherford,  op.  cit.,  p.  194;  by  M.  Levin,  Zeitschr.  Elektrochemie, 
vol.  13, 1907,  p.  390;  and  also  by  Becker  in  the  paper  just  cited. 

2 See  J.  Joly  and  A.  L.  Fletcher,  Philos.  Mag.,  6th  ser.,  vol.  19, 1910,  p.  630;  and  J.  Joly  and  E.  Rutherford, 
idem,  vol.  25, 1913,  p.  694. 

3 See  G.  F.  Becker,  Smithsonian  Misc.  Coll.,  vol.  56,  No.  6, 1910. 

« See  J.  Marckwald,  Ber.  Deutsch.  chem.  Gesell.,  vol.  41,  1908,  p.  1559,  for  a summary  of  the  subject  of 
radioactivity.  Madame  M.  S.  Curie’s  Traite  de  radioactivity,  2 vols.,  Paris,  1910,  is  also  most  important. 
In  Zeitschr.  Elektrochemie,  vol.  13,  1907,  pp.  369-406,  is  a series  of  papers  forming  a symposium  upon  the 
subject.  A curious  attempt  to  reconcile  radioactive  and  erosional  methods  of  computing  time  is  due  to 
F.  C.  Brown  (Le  Radium,  October,  1912,  p.  352),  who  suggests  that  the  sodium  of  the  ocean  may  have  been 
derived  from  some  unknown  radioactive  parent.  This  is  speculation  pure  and  simple. 


CHAPTER  X. 

ROCK-FORMING  MINERALS. 

PRELIMINARY  STATEMENT. 

When  a magma  solidifies,  it  may  do  so  either  as  a glass  or  as  an 
aggregate  of  crystalline  minerals.  In  the  latter  process,  which  is  the 
first  step  in  the  general  process  of  magmatic  differentiation,  and  in 
which  molecular  diffusion  plays  an  important  part,  each  mineral  is 
distinctly  marked  off  in  space  and  occupies  a region  of  its  own.  It 
may  not  be  pure;  it  may  entangle,  during  its  formation,  particles  of 
other  substances,  but  its  definiteness  and  integrity  are  none  the  less 
clear. 

Although  more  than  a thousand  distinct  mineral  species  are  known 
to  science,  only  a relatively  small  number  of  them  are  in  any  sense 
abundant  or  to  be  reckoned  as  essential  constituents  of  rocks.  An 
igneous  rock  is  usually  a mixture  of  silicates,  containing,  as  basic 
metals,  potassium,  sodium,  calcium,  magnesium,  iron,  and  aluminum, 
with  oftentimes  free  silica.  Other  substances  are  present  only  in 
quite  subordinate  proportions.  There  may  be  small  quantities  of 
phosphates,  especially  apatite,  some  fluorides,  various  free  oxides,  the 
titanium  minerals,  zircon,  sulphides  in  trivial  amount,  and  sometimes 
free  elements,  such  as  graphite  or  metallic  iron;  but  these  constitu- 
ents of  a rock  have  only  minor  significance,  except  in  some  exceed- 
ingly rare  instances.  The  exceptions  need  not  be  considered  now. 

Each  mineral  species,  using  the  word  in  its  rigorous  sense,  is  a defi- 
nite chemical  entity,  capable  of  formation  only  under  certain  distinct 
conditions,  and  liable  to  alteration  in  various  ways.  Each  one  may 
be  studied  as  it  exists  in  nature,  with  the  alterations  which  it  there 
undergoes;  or  it  may  be  investigated  synthetically,  with  reference  to 
its  possible  modes  of  origin,  or  by  analytical  methods  in  order  to 
determine  what  transformations  it  is  likely  to  experience.  Both 
methods,  the  experimental  and  the  observational,  furnish  legitimate 
lines  of  attack  upon  geological  problems.  A mineral,  with  its  associa- 
tions, is  a record  of  chemical  changes  that  have  taken  place,  but  they 
do  not  end  its  history.  It  is  still  subject  to  decay — that  is,  to  trans- 
formations into  other  forms  of  matter,  and  their  study,  chemically 
or  in  the  field,  constitutes  an  important  part  of  metamorphic  geology. 
Alteration  products  are  highly  significant,  but  their  investigation 
demands  extreme  caution.  Errors  of  diagnosis  have  been  common  in 
97270°— Bull.  616—16 21  321 


322 


THE  DATA  OF  GEOCHEMISTRY. 


the  past,  both  as  to  the  nature  of  substances  and  with  regard  to  their 
implications;  and  each  reported  case  of  alteration,  therefore,  should 
be  submitted  to  the  severest  scrutiny.  A compact  muscovite,  for 
example,  may  easily  be  mistaken,  on  superficial  examination,  for  talc 
or  serpentine ; and  errors  of  that  kind  may  deprive  an  otherwise  good 
observation  of  all  its  meaning. 

Many  compounds,  identical  with  natural  minerals,  have  been  pre- 
pared by  laboratory  methods,  which  may  either  reproduce  the  condi- 
tions existing  in  nature  or  vary  widely  from  them.  Each  substance 
can  be  made  in  several  different  ways,  and  so  the  results  of  experi- 
ment may  or  may  not  have  geological  significance.  In  one  process 
the  conditions  of  a cooling  magma  are  exactly  paralleled;  whereas 
another  may  have  no  relation  to  the  phenomena  observed  by  the 
geologist.  The  correct  interpretation  of  laboratory  experiments  is, 
therefore,  an  affair  demanding  nicety  of  judgment;  and  the  discrim- 
ination between  relevant  and  irrelevant  data  is  not  always  easy.  The 
synthesis  of  a mineral  may  be  chemically  important,  and  yet  shed 
no  light  upon  the  problems  of  geology.  Still,  indirect  testimony  is 
often  of  value,  and  none  of  it  should  be  rejected  hastily. 

In  the  following  pages  the  more  important  minerals  of  the  igneous 
and  metamorphic  rocks  will  be  considered  individually,  from  the 
various  points  of  view  indicated  in  the  preceding  paragraphs.  Im- 
portance and  abundance,  however,  do  not  always  go  together.  A 
relatively  infrequent  mineral  may  be  important  for  what  it  signifies 
and  therefore  receive  more  attention  here  than  some  of  the  commoner 
species.  In  a general  way  the  usual  order  of  mineral  classification  will 
be  followed,  but  not  rigorously.  In  some  cases,  for  petrographic 
purposes,  two  minerals  may  be  studied  consecutively  which  in  a text- 
book upon  mineralogy  would  be  widely  separated.  The  problems 
of  par  agenesis,  which  are  all-important  here,  are  quite  independent 
of  mineraiogical  classification.  The  titanium  minerals — rutile,  ilmen- 
ite,  perofskite,  and  titanite,  for  example — can  be  properly  considered 
successively,  although  one  is  an  oxide,  two  are  titanates,  and  the 
fourth  is  a titanosilicate.  Petrographically  they  belong  together; 
mineralogically  they  do  not.  So  much  premised,  we  may  go  on  to 
study  the  individual  species,  as  follows,  beginning  with  the  free  ele- 
ments, carbon  and  iron.  The  inclusion  of  diamond  in  this  category 
may  be  justified  by  the  fact  that  it  is  essentially  a mineral  of  mag- 
matic origin. 

DIAMOND  AND  GRAPHITE. 

Diamond. — Pure  or  nearly  pure  carbon.  Isometric.  Atomic 
weight,  12;  molecular  weight,  unknown.  Specific  gravity,  3.5. 
Atomic  volume,  3.4.  Hardness,  10.  Colorless  to  black,  with  various 
shades  of  yellow,  green,  blue,  red,  and  brown.  The  black  carbonado 


ROCK-FORMING  MINERALS. 


323 


has  a specific  gravity  slightly  below  that  of  the  pure  diamond,  rang- 
ing from  3.15  to  3.29.  Fusibility  unknown,  probably  above  3,000°. 
Combustible  at  high  temperatures,  between  800°  and  850°,  according 
to  H.  Moissan,1  although  oxidation  begins  at  a point  somewhat 
lower. 

The  diamond  has  been  produced  artificially  in  several  ways. 
R.  S.  Marsden,2  in  1880,  claimed  to  have  obtained  minute  crystals 
from  the  solution  of  amorphous  carbon  in  molten  silver.  J.  B. 
Hannay,3  by  heating  amorphous  carbon  with  bone  oil  and  metallic 
lithium,  under  great  pressure,  also  secured  a few  crystals  of  carbon 
which  appeared  to  be  in  the  form  of  diamond.  Moissan,4  however, 
was  the  first  to  obtain  unimpeachable  results.  He  dissolved  carbon 
in  melted  iron,  and  cooled  the  mass  suddenly  under  pressure.  From 
the  cooled  iron,  undoubted  crystals  of  diamond  were  isolated. 
J.  Friedlander 5 dissolved  graphite  in  fused  olivine  and  obtained 
small  diamonds,  and  R.  von  Hasslinger,6  by  solution  of  amorphous 
carbon  in  an  artificial  magnesium  silicate  magma,  was  similarly 
successful.  A little  later  R.  von  Hasslinger  and  J.  Wolff 7 repeated 
and  varied  this  experiment,  using  different  magmas  in  order  to 
determine  under  what  conditions  the  diamonds  would  be  formed. 
Magnesia  and  lime  appeared  to  favor  the  crystallization  of  the 
carbon,  but  a high  proportion  of  silica  in  the  magma  seemed  to 
act  adversely.  According  to  Hasslinger  and  Wolff,  a carbide  is 
probably  first  produced,  from  which,  later,  the  carbon  separates 
in  adamantine  form.  L.  Franck  and  Ettinger8  claim  to  have 
found  diamonds  in  hardened  steel,  and  A.  Ludwig9  observed  their 
formation  when  an  electric  current  was  passed  through  an  iron 
spiral  embedded  in  powdered  gas  carbon,  in  an  atmosphere  of 
hydrogen  and  under  great  pressure.  In  a later  investigation  Lud- 
wig 10  fused  a mixture  of  carbon  and  iron  in  an  electric  stream, 
and  then  suddenly  chilled  the  mass  by  admission  to  it  of  water 
under  a pressure  of  2,200  atmospheres.  Under  these  conditions 
of  pressure  and  instantaneous  cooling  the  fused  carbon  solidified 
in  the  form  of  minute  diamonds.  With  slow  cooling  the  more 
stable  graphite  is  produced.  These  observations  accord  with  the 


1 Compt.  Rend.,  vol.  135,  1902,  p.  921. 

2 Proc.  Roy.  Soc.  Edinburgh,  vol.  11,  1880-81,  p.  20.  K.  Chrustchofl  (Zeitschr.  anorg.  Chemie,  vol.  4, 
1893,  p.  472)  also  obtained  diamonds  from  solution  in  silver.  Molten  silver,  he  says,  can  dissolve  about  6. 
per  cent  of  carbon. 

3 Proc.  Roy.  Soc.,  vol.  30,  1880,  pp.  188,  450. 

* Compt.  Rend.,  vol.  116, 1893,  p.  218.  Also  C.  Friedel,  idem,  p.  224.  See  also  Q.  Majorana,  Atti  R.  accad. 

Lincei,  5th  ser.,  vol.  6,  pt.  2,  1897,  p.  141. 

6 Abstract  in  Geol.  Mag.,  1898,  p.  226. 

6 Monatsh.  Chemie,  vol.  23,  1902,  p.  817. 
i Sitzungsb.  Akad.  Wien,  vol.  112, 1903,  p.  507. 

8 Chem.  Centralbl.,  1896,  pt.  2,  p.  573.  From  Stahl  u.  Eisen,  vol.  16,  p.  585. 

9 Chem.  Zeitung,  vol.  25,  1901,  p.  979. 

19  Zeitschr.  Elektrochemie,  vol.  8,  1902,  p.  273. 


324 


THE  DATA  OF  GEOCHEMISTRY. 


recent  conclusions  of  Moissan,1  who  finds  that  when  carbon  is 
raised  to  a high  temperature  at  atmospheric  pressure  it  volatilizes 
without  fusion  and  on  cooling  always  yields  graphite  alone.  In 
Moissan’s  work,  however,  external  pressure  is  not  applied.  It  is 
generated  by  internal  expansion  within  the  iron,  when  the  surface 
of  the  latter  is  suddenly  cooled.  The  addition  of  a little  ferrous 
sulphide  tQ  the  fused  iron  seems  to  increase  the  yield  of  diamonds. 

According  to  G.  Rousseau,2  diamond  is  formed  at  ordinary  pres- 
sures when  acetylene,  generated  from  calcium  carbide,  is  decomposed 
by  an  electric  current  at  a temperature  of  about  3,000°.  C.  V.  Bur- 
ton 3 claims  to  have  obtained  diamond  crystals  from  solution  in 
molten  lead  to  which  about  1 per  cent  of  calcium  had  been  added. 
Finally,  Sir  William  Crookes  4 has  detected  diamonds  in  the  ash  of 
cordite  which  had  been  exploded  in  closed  vessels.  In  the  last 
instance  the  pressure  generated  must  have  been  very  high. 

In  nature  the  diamond  is  ordinarily  found  in  gravels  and  until 
recently  little  was  known  of  its  parent  rock.  It  has  also  been 
discovered  in  several  meteorites,  as  in  the  meteoric  stones  of  Novo- 
Urei,  Russia,5  and  Carcote,  Chile,6  and  the  meteoric  iron  of  Canyon 
Diablo.7  The  Novo-Urei  stone  is  essentially  a mixture  of  oh  vine, 
67.48  per  cent,  with  augite  23.82  per  cent,  and  therefore  resembles 
a peridotite.  The  Canyon  Diablo  iron  contains  nodules  of  iron 
sulphide,  troilite,  which  recall  Moissan’s  latest  experiments,  and 
also  graphite.  For  each  occurrence  the  artificial  production  of 
diamonds  furnishes  a parallel — Hasslinger’s  work  in  one  case, 
Moissan’s  in  the  other. 

The  origin  of  the  diamond  as  a mineral  seems  to  be  clearly  indi- 
cated by  the  foregoing  data.  It  is  formed  by  crystallization  from  the 
solution  of  carbon  in  a fused  magma,  and  the  latter,  in  most  cases, 
seems  to  have  had  the  composition  of  a peridotite — an  association 
which  is  also  seen  in  the  Novo-Urei  meteorite.  In  the  South  African 
mines  the  diamonds  occur  in  or  near  volcanic  pipes,  embedded  in  a 
decomposed  rock,  which  has  been  described  as  a peridotitic  tuff  or 
breccia.8  The  volcanic  character  of  this  matrix  or  “blue  ground” 
was  early  recognized,  and  several  authorities,  notably  the  late  H. 

1 Compt.  Rend.,  vol.  140,  1903,  p.  277.  See  also  Annales  chim.  phys.,  8th  ser.,  vol.  5,  1905,  p.  174.  On 
diamonds  in  blast-furnace  slag  and  the  conditions  of  their  possible  formation,  see  H.  Fleissner,  Oesterr. 
Zeitschr.  Berg-u.  Hiittenw.,  vol.  58, 1910,  pp.  521,  539,  550,  570.  See  also  P.  Neumann,  Zeitschr.  Elek- 
trochemie,  vol.  15, 1909,  p.  817.  W.  von  Bolton  has  reported  the  recrystallization  of  diamond  dust,  under 
the  influence  of  mercury  vapor  derived  from  sodium  amalgam,  Zeitschr.  Electrochemie,  vol.  17,  p.  971, 1911. 

2 Compt.  Rend.,  vol.  117,  1893,  p.  164. 

3 Nature,  vol.  72, 1905,  p.  397. 

« Proc.  Roy.  Soc.,  vol.  76  A,  1905,  p.  458. 

5 M.  Erofeef  and  P.  Latschinoff,  Jour.  Russ.  Chem.  Soc.,  vol.  20,  1888,  p.  185.  Abstract  in  Jour.  Chem. 
Soc.,  vol.  56, 1889,  p.  224. 

e W.  Will  and  J.  Pinnow,  Ber.  Deutsch.  chem.  Gesell.,  vol.  23,  1890,  p.  345. 

7 G.  A.  Koenig  and  A.  E.  Foote,  Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  413. 

8 See  E.  Cohen,  5 Jahresb.  Ver.  Erdkunde,  Metz,  1882,  p.  129. 


ROCK-FORMING  MINERALS. 


325 


Carvill  Lewis,1  have  ascribed  the  origin  of  the  diamonds  to  the  sol- 
vent action  of  the  molten  peridotite  magma  upon  the  carbonaceous 
shales  through  which  it  has  penetrated.  In  some  cases,  however, 
these  shales  are  absent,  and  W.  Luzi 2 has  shown  that  when  "blue 
ground”  is  fused  at  a temperature  of  about  1,770°  the  diamonds 
which  it  contains  are  perceptibly  corroded.  That  is,  the  magma  itself 
is  proved  to  be  a solvent  of  carbon  which  may  just  as  well  have  come 
from  below  as  from  contact  metamorphism.  In  Lewis’s  papers  it  is 
pointed  out  that  in  a number  of  other  regions  diamonds  are  asso- 
ciated more  or  less  closely  with  rocks  of  serpentinous — that  is,  perido- 
titic — character.  T.  G.  Bonney,3  however,  has  sought  to  prove  that 
the  true  matrix  of  the  Cape  diamond  is  eclogite,  from  which  he 
says  the  mineral  has  crystallized  as  an  original  constituent,  just  as 
zircon  crystallizes  from  granite.  The  very  intimate  association  of 
these  diamonds  with  garnet  lends  support  to  this  view.  On  the 
other  hand,  G.  F.  Williams  4 states  that  he  crushed  and  examined  20 
tons  of  eclogite  at  Kimberley  and  found  no  trace  of  diamonds.  He 
also  reports  a Kimberley  diamond  which  contained  an  inclusion  of 
apophyllite.  If  the  diagnosis  was  correct,  it  throws  doubt  upon  the 
igneous  origin  of  the  gem,  for  apophyllite  is  a highly  hydrous  mineral. 
According  to  H.  ,S.  Harger5  the  Vaal  Kiver  diamonds  are  derived 
from  andesitic  lava,  and  H.  Merensky  6 reports  them  in  pegmatite  and 
diabase.  The  diamonds  recently  discovered  in  Arkansas,  however, 
are  associated  with  a peridotitic  rock  closely  resembling  kimberlite.7 

1 Papers  before  the  British  Association  in  1886  and  1887.  In  full,  edited  by  T.  G.  Bonney,  in  Papers 
and  notes  on  the  genesis  and  matrix  of  the  diamond,  London,  1897.  The  suggestion  that  the  shales  are 
the  source  of  the  carbon  is  adopted  from  E.  J.  Dunn,  Quart.  Jour.  Geol.  Soc.,  vol.  37,  1881,  p.  609.  See 
also  L.  De  Launay,  Les  diamants  du  Cap,  Paris,  1897;  G.  F.  Williams,  The  diamond  mines  of  South 
Africa,  New  York,  1905,  2 vols.;  Sir  William  Crookes,  Diamonds,  London  and  New  York,  1909;  and  P.  A. 
Wagner,  Die  diamantfiihrenden  Gesteine  Siidafrikas,  Berlin,  1909.  Wagner  gives  a full  bibliography 
relative  to  South  African  diamonds.  An  English  edition  appeared  in  1914.  For  bibliographic  notes  on 
diamond  see  J.  A.  Thomson,  Econ.  Geology,  vol.  5,  1910,  p.  64.  Other  memoirs  on  the  South  African 
diamonds  are  by  R.  Beck,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  59,  1907,  p.  275;  F.  H.  Hatch,  Nature,  vol. 
77, 1908,  p.  224;  J.  P.  Johnson,  Trans.  Inst.  Min.  and  Met.,  vol.  17,  1908,  p.  277;  and  F.  W.  Voit,  Eng.  and 
Min.  Jour.,  vol.  87,  1909,  p.  789.  For  a review  of  several  memoirs  upon  South  African  diamond,  see  E. 
Kaiser,  Zeitschr.  Kryst.  Min.,  vol.  51,  p.  399, 1912. 

2 Ber.  Deutsch.  chem.  Gesell.,  vol.  25, 1892,  p.  2470. 

s Proc.  Roy.  Soc.,  vol.  65,  1899,  p.  223.  Bonney’s  view  is  accepted  by  A.  L.  Du  Toit,  Eleventh  Ann. 
Rept.  Geol.  Commission,  Cape  of  Good  Hope,  1907,  p.  135.  G.  S.  Corstorphine  (Trans.  Geol.  Soc.  South 
Africa,  vol.  10,  1907,  p.  65)  shows  that  the  supposed  eclogite,  in  which  he  found  diamonds,  consists  really 
of  garnet-pyroxene  nodules  which  are  inclosed  in  the  kimberlite.  These  nodules  are  concretionary  in 
character. 

4 Trans.  Am.  Inst.  Min.  Eng.,  vol.  35,  1905,  p.  440.  Ann.  Rept.  Smithsonian  Inst.,  1905,  p.  193.  On  an 

inclusion  of  garnet  in  diamond  see  J.  R.  Sutton,  Nature,  vol.  75,  1907,  p.  488. 

6 Trans.  Geol.  Soc.  South  Africa,  vol.  12, 1910,  p.  139.  See  also  E.  H.  V.  Melvill,  idem,  p.  205,  on  stones 
from  the  Roberts-Victor  mine. 

e Zeitschr.  prakt.  Geologie,  1908,  p.  155. 

7 See  G.  F.  Kunz  and  H.  S.  Washington,  Am.  Jour.  Sci.,  4th  ser.,  vol.  24,  1907,  p.  275;  and  H.  D.  Miser, 
Bull.  U.  S.  Geol.  Survey  No.  540,  1914,  p.  534. 


326 


THE  DATA  OF  GEOCHEMISTRY. 


In  Brazil  diamonds  are  associated  with  hydromica  schists  and  the 
peculiar  form  of  quartzite  known  as  itacolumite;  and  O.  A.  Derby  1 
finds  no  evidence  of  olivine  rocks  anywhere  in  the  diamond-bearing 
region.  Similar  conclusions  have  been  reached  by  J.  C.  Br armor, 2 
who  states  that  the  diamonds  are  not  only  obtained  from  gravels, 
but  also  directly  from  decomposing  quartzite.  He  also  gives  a full 
list  of  the  associated  minerals.  Furthermore,  near  Bellary,  Madras 
Presidency,  India,  M.  Chaper 3 found  the  diamond  to  be  apparently 
derived  from  a pegmatite  consisting  of  rose-colored  orthoclase  and 
epidote.  Near  Inverell,  New  South  Wales,  T.  W.  Edgeworth 
David  4 found  diamonds  in  a matrix  of  hornblende  diabase.  In 
short,  though  much  evidence  points  to  an  igneous  origin  for  the 
diamond,  it  is  not  necessary  to  assume  that  the  same  magma  has 
yielded  it  in  all  cases.5 

Graphite. — Carbon,  more  or  less  impure.  Rhombohedral.  Atomic 
weight,  12;  molecular  weight  probably  below  that  of  diamond. 
Specific  gravity,  2.255.  Atomic  volume,  5.5.  Hardness,  1 to  2.  Color, 
steel  gray  to  black.  Fusibility  unknown,  probably  above  3,000°. 
Combustible  at  temperatures  between  650°  and  700°.6 

Graphite  is  easily  produced  artificially.  It  is  a common  constituent 
of  furnace  slags,  being  derived  from  the  fuel.  On  a commercial  scale 
it  is  made  by  heating  coke  in  the  electric  furnace,  in  which  process, 
according  to  E.  G.  Acheson,7  a carbide,  possibly  carborundum,  SiC, 
is  first  formed.  0.  Mulhauser  8 has  shown  that  when  carborundum  is 
strongly  heated  the  silicon  is  vaporized,  leaving  graphitic  carbon 
behind.  These  reactions,  connected  with  Moissan’s  discovery 9 of  car- 
borundum in  the  Canyon  Diablo  meteorite,  associated  with  graphite 
and  diamond,  may  have  some  geological  significance.  The  fact  that 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  24,  1882,  p.  34;  Jour.  Geology,  vol.  6,  1898,  p.  121.  For  the  minerals  asso- 
ciated with  Brazilian  diamond  see  E.  Hussak,  Min.  pet.  Mitt.,  vol.  18, 1898-99,  p.  334;  and  also  in  Zeitschr. 
prakt.  Geologie,  1906,  p.  318.  According  to  Hussak,  the  minerals  of  the  Brazilian  diamond  sands  are  those 
derived  from  granites,  gneisses,  and  older  schists,  such  as  amphibolite.  An  important  earlier  paper  upon 
Brazilian  diamonds  is  by  C.  Heusser  and  G.  Claraz,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  11,  1859,  p.  448. 
Two  later  papers  by  Derby,  relative  to  the  genesis  of  the  diamond,  are  in  Jour.  Geology,  vol.  19,  p.  627, 
1911;  vol.  20,  1912,  p.  451. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  31, 1911,  p.  480. 

3 Compt.  Rend.,  vol.  98,  1884,  p.  113.  More  fully,  in  Bull.  Soc.  g6ol.  France,  3d  ser.,  vol.  14,  1885-86,  p. 
330.  The  description  of  this  pegmatite  suggests  a resemblance  to  the  unakite  of  Virginia  and  North 
Carolina. 

4 Rept.  Brit.  Assoc.  Adv.  Sci.,  1906,  p.  562.  See  also  Chem.  News,  vol.  96,  1907,  p.  146.  According  to  J. 
A.  Thompson  (Geol.  Mag.,  1909,  p.  492),  the  matrix  of  the  Inverell  diamonds  is  dolerite. 

5 An  excellent  monograph  on  the  diamond,  by  E.  Boutan,  forms  a volume  in  Fremy’s  Encyclopedic 
chimique,  Paris,  1886.  It  concludes  with  a very  full  bibliography.  On  diamonds  in  California,  see  H.  W. 
Turner,  Am.  Geologist,  vol.  23,  1899,  p.  182.  For  a theoretical  discussion  on  the  genesis  of  the  diamond,  see 
A.  Koenig,  Zeitschr.  Elektrochemie,  vol.  12,  1906,  p.  441. 

6 H.  Moissan,  Compt.  Rend.,  vol.  135, 1902,  p.  921.  On  the  specific  gravity  of  graphite  see  H.  Le  Chatelier 
and  S.  Wologdine,  Compt.  Rend.,  vol.  146,  1908,  p.  49.  On  its  coefficient  of  expansion,  A.  L.  Day  and 
R.  B.  Sosman,  Jour.  Washington  Acad.  Sci.,  vol.  2, 1912,  p.  284.  These  two  papers  relate  to  the  definiteness 
of  graphite  as  a species. 

7 Jour.  Franklin  Inst.,  vol.  147,  1899,  p.  475. 

8 Zeitschr.  anorg.  Chemie,  vol.  5,  1894,  p.  111. 

9 Compt.  Rend.,  vol.  140,  1903,  p.  405. 


ROCK-FORMING  MINERALS. 


327 


graphite  is  often  found  in  meteorites  proves  that  it  has  not  neces- 
sarily an  organic  origin,  an  assumption  which  is  sometimes  made. 

Graphite  has  also  been  prepared  by  passing  vapors  of  carbon  bisul- 
phide or  carbon  tetrachloride  over  hot  iron,  but  these  processes  seem 
to  have  little  or  no  geological  significance.  Whether  such  sub- 
stances occur  in  volcanic  emanations  is  so  far  a matter  of  pure  specu- 
lation. So  also  is  E.  Weinschenk’s  suggestion  1 that  metallic  car- 
bonyls, rising  from  geat  depths,  may  yield  graphite  by  their  decom- 
position. None  of  these  compounds  has  been  identified  in  nature, 
and  it  is  more  than  doubtful  whether  they  could  exist  at  magmatic 
temperatures.  J.  Walther  2 is  inclined  to  attribute  the  Ceylon  graph- 
ite to  derivation  from  carboniferous  vapors  rising  from  the  interior 
of  the  earth,  and  it  is  possible  that  hydrocarbons  might  yield  the 
mineral.  M.  Diersche,3  studying  the  same  field,  ascribes  the  forma- 
tion of  the  graphite  to  the  infiltration  of  liquid  hydrocarbons  and 
their  decomposition  by  heat. 

W.  Luzi 4 has  shown  that  amorphous  carbon  can  be  converted  into 
graphite  by  strong  heating  in  melted  potash  glass  containing  calcium 
fluoride  and  water.  In  other  words,  graphite  can  occur  in  a silicate 
magma,  either  in  consequence  of  its  contact  with  carbonaceous  matter 
or  as  an  original  constituent  brought  up  from  below.  In  fact,  graph- 
ite often  originates  as  a product  of  contact  metamorphism.  L. 
Jaczewski 5 regards  the  Siberian  mineral  as  having  been  formed  by 
just  such  a transformation  of  coaly  matter  in  eruptive  magmas;  but 
there  are  many  occurrences  of  graphite  that  can  not  be  accounted  for 
in  this  way.  Weinschenk,6  for  example,  cites  instances  of  an  associa- 
tion of  graphite  with  the  higher  oxides  of  iron  and  manganese,  which 
amorphous  carbon  or  the  hydrocarbons  distilled  during  contact  of  a 
magma  with  coal  would  reduce  to  lower  forms.  In  these  cases  the 
metamorphosis  of  carbonaceous  shales  can  hardly  be  assumed.7 

From  what  has  been  said  it  is  evident  that  graphite  may  originate 
in  diverse  ways,  and  that  in  some  cases  its  mode  of  formation  is 
exceedingly  obscure.  Its  commonest  occurrences  are  in  the  crystal- 
line schists,  in  which  it  often  seems  to  replace  mica.  Graphitic 
granite,  gneiss,  mica  schist,  and  quartzite  are  all  well  known,  and  the 
Laurentian  limestones  of  Canada  contain  large  quantities  of  the 
mineral.  The  graphite  of  the  adjacent  Adirondack  region  is  attrib- 
uted by  E.  S.  B as  tin  8 to  the  dynamic  metamorphism  of  carbonaceous 

1 Compt.  rend.  VIII  Cong.  g6ol.  intemat.,  vol.  1, 1900,  p.  447. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  41, 1889,  p.  359.  For  a full  account  of  the  Ceylon  graphite  see  A.  K. 
Coom&ra-Swamy,  Quart.  Jour.  Geol.  Soc.,  vol.  56, 1900,  p.609.  This  paper  contains  a valuable  bibliography. 

3 Jahrb.  K.-k.  geol.  Reichsanstalt  Wien,  vol.  48,  1898,  p.  274. 

* Ber.  Deutsch.  chem.  Gesell.,  vol.  24,  1891,  p.  4093.  Zeitschr.  Naturwissenschaften,  vol.  64,  1891,  p.  224. 

5 Neues  Jahrb.,  1901,  Band  2,  ref.,  p.  74. 

« Compt.  rend.  VIII  Cong.  g6ol.  intemat.,  vol.  1,  1900,  p.  447. 

2 On  the  formation  of  graphite  in  certain  soils  see  W.  Heinisch,  Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  120, 
Abth.  II  b,  1911,  p.  85. 

3 Econ.  Geology,  vol.  5, 1910,  p.  134. 


328 


THE  DATA  OF  GEOCHEMISTRY. 


sediments.  T.  H.  Holland,1  however,  has  described  an  elseolite  syenite 
from  India  in  which  graphite  appears  to  be  an  original  mineral;  and 
Moissan  2 examined  a pegmatite  of  unknown  locality  and  reached  a 
similar  conclusion.  Graphite  is  also  found  in  the  iron-bearing  basalts 
of  Ovifak,  Greenland,  embedded  in  feldspar  and  associated  with 
native  iron.3  Graphite,  then,  sometimes  appears  as  a direct  separa- 
tion from  a magma,  under  conditions  which  preclude  the  supposition 
of  an  organic  origin,  or  interpretation  as  a result  of  metamorphic 
action. 

NATIVE  METALS. 

Native  iron. — Isometric.  Atomic  weight,  55.9;  molecular  weight 
unknown.  Specific  gravity,  7.3  to  7.8,  dependent  upon  the  impuri- 
ties. Atomic  volume,  7.2.  Color,  steel  gray  to  black.  Malleable. 
Luster,  metallic.  Hardness,  4 to  5.  Magnetic. 

Minute  grains  of  native  iron  are  not  uncommon  in  certain  eruptive 
rocks,  especially  in  basalts.  They  were  first  identified  by  T.  Andrews 4 
in  the  basalt  of  Antrim,  Ireland.  More  recently  they  have  been  found 
by  G.  H.  Cook  5 in  the  trap  rocks  of  New  Jersey;  by  G.  W.  Hawes  6 in 
the  dolerite  of  Dry  River,  near  Mount  Washington,  New  Hampshire; 
by  F.  Navarro  7 in  the  basalt  of  Gerona,  Spain;  and  by  F.  F.  Horn- 
stein  8 in  basalt  near  Cassel,  Germany.  In  the  New  Hampshire 
locality  they  occur  inclosed  in  grains  of  magnetite,  suggesting  a 
secondary  derivation  of  the  latter  mineral  from  the  metal.  There  are 
also  a number  of  other  European  occurrences.9  E.  Hussak 10  found 
particles  of  native  iron  in  an  auriferous  gravel  in  Brazil;  and  A. 
Daubree  and  S.  Meunier 11  have  described  small  masses  of  the  metal 
from  gold  washings  near  Berezovsk,  in  the  Ural.  These  masses  were 
notable  because  of  the  fact  that  they  contained  traces  of  platinum, 
but  no  nickel.  Their  specific  gravity  was  7.59. 

The  most  remarkable  occurrence  of  native  iron,  however,  is  that 
discovered  by  A.  E.  Nordenskiold12  in  1870,  at  Ovifak,  Disco  Island, 


1 Mem.  Geol.  Survey  India,  vol.  30, 1901,  p.  201. 

2 Compt.  Rend.,  vol.  121, 1895,  p.  538. 

3 See  K.  J.  V.  Steenstrup,  Mineralog.  Mag.,  vol.  6,  1884,  p.  1;  and  J.  Lorenzen,  idem,  p.  14.  Graphite 
from  inclusions  in  basalt  is  also  described  by  R.  Brauns,  Centralbl.  Min.,  Geol.  u.  Pal.,  1908,  p.  97.  On 
inorganic  graphite  from  Lapland,  see  O.  Stutzer,  idem,  1907,  p.  433.  In  Zeitschr.  prakt.  Geologie,  1910, 
p.  10,  Stutzer  has  a long  article  on  graphite  deposits  and  their  origin.  See  also  A.  N.  Winchell,  Econ. 
Geology,  vol.  6, 1911,  p.  218.  On  the  graphite  of  southeastern  Pennsylvania,  of  metamorphic  origin,  see 

B.  L.  Miller,  Econ.  Geology,  vol.  7, 1912,  p.  762.  On  the  conversion  of  amorphous  carbon  into  graphite  see 

C.  W.  Arsem,  Jour.  Ind.  Eng.  Chem.,  vol.  3, 1911,  p.  799. 

4 Rept.  Brit.  Assoc.,  1852,  pt.  2,  p.  34. 

5 Ann.  Rept.  Geol.  Survey  New  Jersey,  1874,  p.  56. 

e Am.  Jour.  Sci.,  3d  ser.,  vol.  13, 1877,  p.  33. 

7 Geol.  Centralbl.,  vol.  7,  1905,  p.  184. 

8 Centralbl.  Min.,  Geol.  u.  Pal.,  1907,  p.  276. 

8 See  for  example,  A.  Schwantke,  Centralbl.  Min.,  Geol.  u.  Pal.,  1901,  p.  65,  and  M.  Seebach,  idem,  1910, 
p.  641. 

10  Bol.  Comm.  geog.  e geol.  Sao  Paulo,  No.  7. 1890,  p.  14. 

11  Compt.  Rend.,  vol.  113, 1891,  p.  172. 

12  Geol.  Mag.,  1872,  pp.  460,  516. 


ROCK-FORMING  MINERALS. 


329 


Greenland.  Here  large  masses  of  iron,  up  to  20  tons  in  weight,  had 
been  weathered  out  like  bowlders  from  the  basalt,  and  in  the  rock 
itself  lenticular  and  disklike  pieces  of  the  metal  were  still  embedded. 
At  first  the  iron  was  thought  to  be  meteoric,  but  it  has  since  been 
proved  to  be  of  terrestrial  origin.1  In  nearly  all  respects  it  resembled 
meteoric  iron,  for  it  gave  the  Widmannstatten  figures  when  etched, 
contained  iron  chloride,  and  was  associated  with  magnetic  pyrites 
and  graphite.  Schreibersite,  the  iron  phosphide,  which  is  common  in 
meteorites,  is,  however,  absent  from  the  Ovifak  masses.  In  the 
sample  examined  by  Moissan 2 graphite,  amorphous  carbon,  and 
grains  of  corundum  were  found. 

This  Ovifak  iron  is  somewhat  variable  in  composition,  as  the 
numerous  analyses  of  it  show.3  The  following  analyses  by  J.  Law- 
rence Smith  are  enough  to  indicate  its  general  character: 

Analyses  of  native  iron  from  Ovifak , Greenland. 

A.  External  oxidized  coating  of  a large  mass.  Specific  gravity,  5. 

B.  Particles  of  iron  from  interior  of  the  mass  A.  Specific  gravity,  6.42. 

C.  Malleable  nodule  from  dolerite.  Specific  gravity,  7.46. 

D.  An  irregular  mass.  Specific  gravity,  6.80. 


A 

B 

c 

D 

FeoCL  

76. 21 

Fe 

16.  56 

93. 16 

90. 17 

88. 13 

Ni 

1.  08 

2.  01 

6.50 

2. 13 

Co 

.48 

.80 

.79 

1.  07 

Cu 

.08 

.12 

.13 

.48 

s. 

1. 12 

.41 

.36 

P 

.14 

.32 

.25 

c 

1.36 

2.  34 

2.33 

Cl  

.02 

. 08 

MgO 

Trace. 

Si02  

1.54 

Silicates 

4.  20 

H20 

4.  50 

101.  53 

99. 18 

99. 13 

99.  03 

The  terrestrial  nature  of  this  iron  is  abundantly  proved  by  the 
observations  of  Steenstrup,  who  found  it  disseminated  throughout 
large  bodies  of  basalt  in  place.  It  is,  therefore,  a part  of  the  rock 
itself,  but  concerning  its  origin  there  has  been  much  discussion.  Was 
it  present  in  the  original  magma  or  reduced  by  carbonaceous  matter 
on  its  way  up  from  below?  The  latter  supposition  is  admissible, 
for  Daubree,4  by  fusing  a Iherzolite  with  carbon,  obtained  pellets  of 

1 There  is  abundant  literature  on  this  subject.  See  especially  K.  J.  V.  Steenstrup,  Mineralog.  Mag., 
vol.  6, 1884,  p.  1;  J.  Lorenzen,  idem,  p.  14;  J.  Lawrence  Smith,  Annales  chim.  phys.,  5th  ser.,  vol.  16, 1879, 
p.  452;  and  A.  Daubree,  Etudes  synthetiques  de  geologie  experimentale,  1879,  p.  555. 

2 Compt.  Rend.,  vol.  116,  1893,  p.  1269. 

3 See  the  memoirs,  already  cited,  by  Nordenskiold,  Lorenzen,  and  Smith.  Also  E.  S.  Dana,  System  of 
mineralogy,  6th  ed.,  p.  28. 

4 Etudes  synthetiques  de  geologie  experimentale,  1879,  pp.  517,  574. 


330 


THE  DATA  OF  GEOCHEMISTRY. 


metallic  iron,  containing  nickel  and  almost  identical  in  composition 
with  the  specimens  from  Greenland.  Furthermore,  as  Daubree 
observes,  beds  of  lignite  are  found  on  Disco  Island,  and  graphite  is 
closely  associated  with  the  native  iron.  The  other  alternative,  how- 
ever, is  not  excluded  from  consideration,  and  it  may  be  that  the  iron 
came  as  such  from  great  depths  below  the  surface  to  teach  us  that 
the  earth  is  essentially  a vast  meteorite  and  that  its  interior  is  rich 
in  uncombined  metals.1  If  the  reduction  theory  held,  we  should 
expect  to  find  similar  occurrences  of  native  iron  wherever  basalts  or 
peridotite  had  penetrated  carbonaceous  strata.  The  rarity  of  the 
substance  would  seem  to  indicate  a profounder  origin. 

In  several  localities  metallic  grains  or  nodules  which  approach 
native  nickel  in  composition  have  been  found  in  gravels.  In  mete- 
orites the  nickel  rarely  exceeds  6 or  7 per  cent,  but  in  these  terrestrial 
products  its  proportion  is  usually  much  higher.  From  the  drift  of 
Gorge  Fiver  on  the  west  coast  of  New  Zealand  W.  Skey  2 obtained 
grains  of  this  character,  which  were  associated  with  magnetite,  tin- 
stone, native  platinum,  etc.  This  awaruite,  as  Skey  named  it,  is 
derived,  according  to  G.  H.  F.  Ulrich,3  from  neighboring  serpentines 
or  peridotites.  The  j osephinite  of  W.  H.  Melville  4 from  placer  gravels 
in  Josephine  and  Jackson  counties,  Oregon,  forms  pebbles  up  to  sev- 
eral grams  in  weight  and  also  occurs  near  large  masses  of  serpentine. 
Its  specific  gravity  is  6.204.  In  the  sands  of  the  Elvo,  near  Biella, 
Piedmont,  A.  Sella  5 found  minute  grains  of  a similar  substance,  but 
its  geological  origin  was  not  determined.  Their  specific  gravity  was 
7.8.  Souesite  consists  of  similar  grains,  found  by  G.  C.  Hoffmann  6 
in  sands  of  the  Fraser  Fiver,  in  British  Columbia.  They  were  asso- 
ciated with  native  platinum,  iridosmine,  gold,  etc.,  and  had  a specific 
gravity  of  8.215.  These  grains  are  doubtless  derived  from  perido- 
tite. Still  more  recently  a similar  nickel  iron  from  the  south  fork  of 
Smith  Fiver,  Del  Norte  County,  California,  has  been  described  by 
G.  S.  Jamieson,7  who  has  also  reexamined  the  mineral  from  Oregon. 
The  analyses  are  as  follows: 

1 See  also  E.  B.  de  Chancourtois,  Bull.  Soc.  geol.  France,  vol.  29, 1872,  p.  210.  C.  Winkler  (Ber.  Math, 
phys.  Classe,  K.  sachs.  Gesell.  Wiss.,  February  5,  1900)  suggests  that  iron  and  nickel  may  have  been 
brought  up  from  below  as  carbonyls,  Ni(CO)4,  Fe(CO)5,  and  Fe2(CO)7 — compounds  which  decompose 
easily,  depositing  their  metals  in  the  free  state.  Compare  Weinschenk’s  suggestion  as  to  graphite,  ante, 
p.  327. 

2 Trans.  New  Zealand  Inst.,  vol.  18,  1885,  p.  401. 

3 Quart.  Jour.  Geol.  Soc.,  vol.  46,  1890,  p.  619. 

4 BuH.  U.  S.  Geol.  Survey  No.  113,  1893,  p.  54. 

sCompt.  Rend.,  vol.  112, 1891,  p.  171. 

6 Am.  Jour.  Sci.,  4th  ser.,  vol.  19, 1905,  p.  319. 

7 Idem,  p.  413.  Jamieson  urges  that  the  original  name  awaruite  should  be  used  for  all  these  irons. 
Awaruite  is  also  reported  from  the  Yukon  by  R.  A.  A.  Johnston,  Summary  Rept.  Geol.  Surv.  Canada, 
1910-11,  p.  256. 


ROCK-FORMING  MINERALS. 


331 


Analyses  of  nickel  iron. 


A.  Awaruite,  Skey.  B.  JosepMnite,  Melville.  C.  Josephinite,  Jamieson,  D.  Del  Norte  County,  Jamie- 
son. E.  Souesite,  Hoffmann.  F.  Piedmont.  Analyzed  for  Sella  by  Mattirolo. 


A 

B 

c 

D 

E 

F 

Ni 

67.  63 

60. 45 

68.  61 

68.  46 

75.  50 

75.2 

Co  

. 70 

.55 

1.  07 

1.07 

None. 

Fe  

31.02 

23.22 

19.  21 

18.  97 

22.02 

26.6 

Fe7S8 

.55 

s 

.22 

.05 

.05 

Cu 

.50 

.59 

.56 

1.20 

As 

.23 

P 

.04 

.04 

Chromite  and  magnetite 

.12 

Si02 

.43 

.10 

.19 

Silicates 

12.26 

1. 16 

Insoluble 

9. 45 

9.  97 

MgO 

.50 

.44 

H20  at  100° 

.81 

H20  above  100° 

1. 12 

Cl 

.04 

co2 

Tracer 

Volatile  matter 

. 70 

100.  00 

100.  55 

99.  62 

99.  75 

99.  88 

101.8 

The  silicate  in  Melville’s  analysis  was  mainly  serpentine,  with  what 
appeared  to  be  an  impure  bronzite.  The  probable  derivation  of  the 
nodules  from  peridotite  is  thus  materially  emphasized.  With  these 
substances  two  meteorites  only,  or  supposed  meteorites,  can  be  com- 
pared. That  found  in  an  Indian  mound  in  Oktibbeha  County,  Mis- 
sissippi, contained  59.69  per  cent  Ni  and  37.97  per  cent  Fe;  and  that 
from  Santa  Catarina,  Brazil,  carried  63.69  Fe  with  33.97  Ni.  These 
masses,  however,  are  only  presumably,  not  certainly,  meteoric. 

Occasionally  native  iron  is  found  of  secondary  origin  produced  by 
the  obvious  reduction  of  iron  compounds.  On  North  Saskatchewan 
River,  70  miles  from  Edmonston,  beds  of  lignite  have  burned,  reduc- 
ing the  neighboring  clay  ironstone  to  metallic  iron.  According  to 
J.  B.  Tyrrell,1  masses  of  iron  which  weigh  from  15  to  20  pounds  can 
be  picked  up  in  this  locality.  G.  C.  Hoffmann 2 has  described  spher- 
ules of  iron  in  limonite,  found  in  fissures  in  quartzite  on  St.  Josephs 
Island,  Lake  Huron;  and  again  from  a pegmatite  of  Cameron 
Township,  Ontario.3  The  exact  origin  of  these  Canadian  irons  is 
not  clear.  Finally,  E.  T.  Allen  4 has  analyzed  soft,  malleable  iron 
from  borings  at  three  points  in  Missouri,  where  it  occurred  in  sedi- 
mentary rocks  not  far  from  beds  of  coal.  The  following  analyses 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  33, 1887,  p.  73. 

2 Trans.  Roy.  Soc.  Canada,  vol.  8,  pt.  3,  1890,  p.  39. 

3 Ann.  Rept.  Geol.  Survey  Canada,  vol.  6,  1895,  p.  23  R. 

4 Am.  Jour.  Sci.,  4th  ser.,  vol.  4, 1897,  p.  99.  Other  occurrences  of  naturally  reduced  ironare  reported  by 
A . A . Inostranzeff , Geol.  Zentralbl. , 1908,  p . 611 , from  Russian  Island,  near  Vladivostok,  and  by  E . Pf  iwosnik, 
Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  vol.  58,  1910,  p.  327,  from  Shotley  Bridge,  England.  On  iron 
formed  under  peat  by  the  reduction  of  bog  iron  ore  see  A.  E.  Kupffer,  Chem.  Zentralbl.,  1913,  p.  55. 


332 


THE  DATA  OF  GEOCHEMISTRY. 


of  these  products  will  serve  to  show  the  great  difference  between  them 
and  the  supposedly  magmatic  irons  described  in  the  preceding  pages: 

Analyses  of  native  iron  of  secondary  origin. 

A.  From  St.  Josephs  Island,  Hoffmann.  Specific  gravity,  6.8612. 

B.  From  Cameron  Township,  Ontario.  Analysis  by  Johnston  for  HofEmann.  Specific  gravity,  7.257. 

C.  From  Cameron,  Missouri,  Allen. 

D.  From  Weaubleau,  Missouri,  Allen. 

E.  From  Holden,  Missouri,  Allen. 


A 

B 

c 

D 

E 

Fe 

88.00 

.10 

.21 

.51 

.09 

.12 

.96 

(?) 

90.45 

Trace. 

None. 

.75 

None. 

Undet. 

Undet. 

99.16 

99.39 

97.10 

Ni 

Co 

Mn 

Cu 

S 

P 

.207 

.065 

.37 

Undet. 

.13 

.31 

Undet. 

.176 

1.65 

c 

Si02 

Insoluble 

9.76 

Undet. 

7.26 

Organic  matter 

99.75 

98.46 

99. 802 

99.83 

98. 926 

Not  only  iron  but  other  native  metals  may  occur  as  primary  con- 
stituents of  igneous  rocks.  Platinum,  with  its  companions,  osmium, 
iridium,  rhodium,  ruthenium,  and  palladium,  are  associated  with 
chromite  and  olivine  in  peridotites.1  W.  Moricke  2 has  found  pri- 
mary gold  in  a pitchstone  from  Guanaco,  Chile,  and  G.  P.  Merrill3 
* has  described  a granite  from  Sonora  in  which  it  also  appears.  Still 
other  examples  are  cited  by  R.  Beck.4  The  metallic  constituents  of 
magmas,  however,  have  received  very  little  attention  so  far,  and  their 
number  may  be  greater  than  it  is  now  supposed  to  be. 

SULPHIDES. 

Pyrite. — Isometric.  Composition,  FeS2.  Molecular  weight,  120. 

Specific  gravity,  4.95  to  5.10.  Molecular  volume,  24.  Color,  brass- 
yellow;  luster,  metallic.  Hardness,  6 to  6.5. 

Pyrrhotite. — Hexagonal  and  orthorhombic.  Two  modifications  are 
known.  Composition  uncertain,  varying  from  Fe7S8  to  FeuS12.  Specific 
gravity,  4.6.  Color,  bronze-yellow  to  copper-red;  luster,  metallic. 
Magnetic.  Hardness,  3.5  to  4.5.  Whether  troilite,  FeS,  which  is  a 
common  mineral  in  meteorites,  is  identical  with  pyrrhotite  or  not  is  a 
disputed  question.5 

£ 

1 See  J.  F.  Kemp,  Bull.  U.  S.  Geol.  Survey  No.  193, 1902,  for  a complete  summary  of  our  knowledge  con- 
cerning native  platinum,  with  many  bibliographic  references. 

2 Min.  pet.  Mitt.,  vol.  12, 1891,  p.  195. 

3 Am.  Jour.  Sci.,  4th  ser.,  vol.  1, 1896,  p.  309. 

4 Lehre  von  den  Erzlagerstatten,  2d  cd.,  1903.  See  also  W.  H.  Weed,  Eng.  and  Min.  Jour.,  vol.  77, 1904, 
p.  440,  and  R.  W.  Brock,  idem,  p.  511. 

6 See  S.  Meunier,  Annales  chim.  phys.,  4th  ser.,  vol.  17, 1869,  p.  36,  and  G.  Linck,  Ber.  Deutsch.  chem. 
Gesell.,  vol.  32, 1899,  p.  895. 


ROCK-FORMING  MINERALS. 


333 


Both  pyrite  and  pyrrhotite  are  common  though  minor  accessory 
constituents  of  igneous  rocks.  Pyrite  is  found  under  a great  variety 
of  associations,  but  pyrrhotite  is  more  characteristic  of  the  ferromag- 
nesian  varieties,  such  as  gabbro,  diabase,  diorite,  and  basalt. 

Pyrrhotite  has  been  observed  as  a furnace  product,  and  both  species 
can  be  made  artificially  by  various  processes.  Those  which  explain 
the  formation  of  sulphides  in  sedimentary  rocks  will  be  considered 
in  another  connection,  but  the  following  experimental  data  bear  upon 
their  occurrence  in  igneous  formations. 

J.  Durocher,1  by  mingling  the  vapor  of  iron  chloride  with  hydrogen 
sulphide  in  a porcelain  tube  heated  to  redness,  obtained  small  crystals 
of  pyrite.  By  heating  magnetite  to  whiteness  in  hydrogen  sulphide, 
T.  Sidot 2 produced  crystals  which  appeared  to  be  identical  with 
troilite.  Troilite  was  also  formed  by  R.  Lorenz,3  who  heated  iron 
to  redness  in  a stream  of  H2S.  C.  Doelter,4  on  the  other  hand,  by 
the  same  reaction,  and  also  with  amorphous  ferric  oxide  or  hematite 
instead  of  metallic  iron,  obtained  pyrite.  When  ferrous  carbonate 
or  sulphate  was  used,  troilite  was  formed.  All  of  these  methods  are 
general.  With  other  metals  or  their  salts  other  crystallized  sulphides, 
identical  with  natural  minerals,  can  be  produced.  In  brief,  gases  or 
vapors  which  exist  in  volcanic  exhalations  can  so  react  upon  one 
another  as  to  develop  crystalline  sulphides.  The  latter  appear  in  or 
upon  the  solidified  rocks,  but  preferably  in  rocks  which  have  cooled 
under  pressure.  By  pressure  the  reacting  vapors  are  confined  within 
the  magma,  and  can  not  readily  escape. 

Metallic  sulphides,  fairly  crystallized,  can  also  be  formed  in  the  wet 
way,  when  appropriate  mixtures  are  heated  together  in  sealed  tubes. 
H.  de  Senarmont 5 heated  various  metallic  solutions  with  hydrogen 
sulphide  or  alkaline  sulphides  in  this  manner  with  great  success,  and 
when  iron  salts  were  taken  pyrite  was  formed.  C.  Geitner  6 also  ob- 
tained pyrite  by  heating  powdered  basalt  with  water  and  sulphurous 
acid  to  200°.  Doelter 7 prepared  pyrite  by  heating  hematite,  mag- 
netite, or  siderite  with  hydrogen  sulphide  and  water  for  72  hours  to 
80°  or  90°.  When  the  same  investigator  8 heated  ferrous  chloride 
with  sodium  carbonate,  water,  and  hydrogen  sulphide  for  16  days  to 
200°  he  obtained  pyrrhotite,  provided  that  air  was  excluded  from  his 
tubes.  In  presence  of  air  pyrite  was  formed. 

1 Compt.  Rend.,  vol.  32, 1851,  p. 823.  For  an  earlier  synthesis  of  pyrite  see  F.  Wohler,  Liebig’s  Annalen, 
vol.  17,  p.  260, 1836. 

a Idem,  vol.  66, 1868,  p.  1257. 

* Ber.  Deutsch.  chem.  Gesell.,  vol.  24,  1891,  p.  1504. 

4 Zeitschr.  Kryst.  Min.,  vol.  11,  1886,  p.  30. 

6 Compt.  Rend.,  vol.  32, 1851,  p.  409. 

s Ann.  Chem.  Pharm.,  vol.  129, 1864,  p.  350. 

7 Zeitschr.  Kryst.  Min.,  vol.  11,  1886,  p.  30. 

8 Min.  pet.  Mitt.,  vol.  7, 1885-86,  p.  535. 


334 


THE  DATA  OF  GEOCHEMISTRY. 


According  to  W.  Feld,1  when  iron  salts  are  precipitated  by  an 
alkaline  polysulphide,  ferrous  sulphide  and  sulphur  are  thrown  down. 
If  the  solution  is  then  neutralized,  or  made  very  feebly  acid,  and 
boiled,  the  precipitate  is  rapidly  transformed  into  the  bisulphide. 
Alkaline  substances  retard  or  hinder  the  transformation,  reducing 
agents  hasten  it.  In  all  formations  of  pyrite  by  the  wet  way  the 
monosulphide  seems  to  be  first  produced.  In  a still  more  elaborate 
investigation  E.  T.  Allen,  J.  Johnston,  J.  L.  Crenshaw,  and  E.  S. 
Larsen 2 report  that  pyrrhotite  is  formed  by  the  direct  union  of  iron 
and  sulphur  and  also  by  the  dissociation  of  pyrite  in  an  atmosphere 
of  H2S  at  a temperature  of  550°.  At  575°,  the  reverse  change  takes 
place,  and  pyrite  is  again  formed.  Pyrrhotite  exists  in  two  modifica- 
tions, hexagonal  below  138°,  orthorhombic  above  that  transition 
temperature.  The  variation  of  pyrrhotite  from  troilite  is  ascribed  to 
the  presence  of  sulphur  in  “ solid  solution”  in  the  monosulphide.3 
In  meteorites  the  excess  of  metallic  iron  renders  the  formation  of  pure 
troilite  possible. 

Pyrite  was  produced  by  Allen  and  his  colleagues  not  only  from 
pyrrhotite,  but  also  by  the  action  of  hydrogen  sulphide  upon  solutions 
of  iron.  From  acid  solutions,  at  100°,  under  pressure,  its  relatively 
unstable  isomer,  marcasite  was  formed.  Warmer  alkaline  solutions 
yielded  pyrite.  At  450°  marcasite  is  transformed  into  pyrite, 
and  therefore  it  can  not  occur  as  a magmatic  mineral.  Marcasite 
is  only  found  in  sedimentary  formations  and  metalliferous  veins. 
Fossil  shells  consisting  entirely  of  marcasite  are  well  known,  and  inte- 
mediate  mixtures  of  pyrite  and  marcasite  are  common.  The  two 
species  probably  differ  in  molecular  arrangement,  but  the  evidence 
upon  this  point  is  far  from  conclusive.  Various  structural  formulae 
have  been  proposed  for  them,  but  none  has  been  definitely  estab- 
lished.4 

Pyrrhotite  and  marcasite  both  alter  into  pyrite  and  all  three  species 
alter  into  limonite,  goethite,  hematite,  and  sulphates  of  iron.  Perfect 
pseudomorphs  of  limonite  after  pyrite  are  common.5 

Another  modification  of  FeS2,  black  and  amorphous,  has  been  de- 
scribed by  B.  Doss,6  who  names  it  melnikovite. 

1 Zeitschr.  angew.  Chemie,  vol.  24, 1911,  p.  97. 

2 Yearbook  Carnegie  Inst.  Washington,  1910,  p.  104;  Am.  Jour.  Sci.,  4th  ser.,  vol.  33,  p.  169, 1912.  Many 
references  to  literature  are  given.  See  also  Allen,  Jour.  Washington  Acad.  Sci.,  vol.  1,  p.  170, 1911;  and 
Allen  and  Crenshaw,  Am.  Jour.  Sci.,  4th  ser.,  vol.  38,  p.  393,  1914. 

s The  variation  may  possibly  be  due  rather  to  admixtures  of  a higher  sulphide  of  iron,  Fe2S3  or  Fe3S4, 
compounds  which  are  not  definitely  known  but  are  theoretically  rational. 

* See  E.  Weinschenk,  Zeitschr.  Rryst.  Min.,  vol.  17, 1890,  p.  501;  A.  P.  Brown,  Proc.  Am.  Philos.  Soc.,  vol. 
33, 1894,  p.  225;  and  H.  N.  Stokes,  Bull.  U.  S.  Geol.  Survey  No.  186, 1901.  Stokes  describes  many  elaborate 
experiments  upon  the  relative  solubility  of  pyrite  and  marcasite  in  chemical  reagents.  See  also  G.  W. 
Plummer,  Thesis,  Univ.  Pennsylvania,  1910. 

5 For  a full  discussion  of  the  alterations  of  pyrite  see  A.  A.  Julien,  Annals  New  York  Acad.  Sci.,  vol.  3, 
1886,  p.365;  vol.  4, 1887,  p.  125.  A paper  on  the  origin  of  pyrite,  by  A.  R.  Whitney,  is  in  Econ.  Geology, 
vol.  8, 1913,  p.  455. 

6 Neues  Jahrb.,  Beil.  Band  33, 1912,  p.  662. 


EOCK-FORMING  MINERALS. 


335 


Each  of  these  synthetic  processes  finds  some  equivalent  in  nature. 
Dry  gases,  wet  gases,  and  alkaline  solutions  charged  with  hydrogen 
sulphide  can  assist  in  producing  the  minerals  which  are  now  under 
consideration,  with  other  rarer  species  of  the  same  class.  The  magmas 
contain  the  reagents,  and  the  reactions,  or  reactions  like  those  just 
described,  naturally  follow.  In  most  cases  the  sulphides  appear  as 
secondary  minerals,  but  they  are  sometimes  primary.  J.  H.  L.  Vogt 1 
has  shown  that  sulphides  are  actually  soluble  in  silicate  magmas, 
especially  at  the  higher  temperatures,  and  that  they  are  among  the 
earliest  minerals  to  crystallize.  Certain  of  the  pyrrhotite  deposits  of 
Norway  he  regards  as  the  direct  products  iof /.m«igm^,tic  segregation. 

Several  other  sulphides  occasionally  appear ras  priuto^y -minerals 
in  igneous  rocks.  Molybdenite,  MoS2,  is  common  in  granites,  and 
J.  F.  Kemp,2  in  a pegmatite  dike  in  British  Columbia,  found  masses 
of  bomite,  which  appeared  to  be  an  original  constituent  of  the  rock. 
In  the  augite  syenite  of  Stoko,  near  Brevik,  Norway,  the  arsenide, 
lollingite,  FeAs2,  appears  to  have  crystallized  before  the  feldspar. 
The  pegmatites  of  that  region,  as  described  by  W.  C.  Brogger,  also 
contain  molybdenite,  zinc  blende,  pyrite,  galena,  and  chalcopyrite.3 
Some  of  these  occurrences,  and  many  occurrences  of  pyrite  also,  are 
doubtless  secondary. 

FLUORIDES. 

Fluorite. — Isometric.  Composition,  CaF2.  Molecular  weight,  78.1. 
Specific  gravity,  3.18.  Molecular  volume.  24.5.  Hardness,  4. 
Colorless,  yellow,  red,  blue,  green,  purple,  violet,  etc. 

Fluorite,  although  most  abundant  as  a vein  mineral  and  in  sedi- 
mentary formations,  is  also  found  as  a minor  accessory  in  granite, 
gneiss,  quartz  porphyry,  syenite,  elseolite  syenite,  and  the  crystalline 
schists.  W.  C.  Brogger4  reports  it,  both  as  an  early  separation  in 
the  augite  syenites  of  Norway  and  also  as  a contact  mineral.  It 
sometimes  appears  on  volcanic  lavas  as  a sublimation  product,  or  as 
the  result  of  the  action  of  fluoriferous  gases  upon  other  minerals.5 6  It 


1 Die  Silikatschmelzlosungen,  pt.  1, 1903,  p.  96.  See  also  Zeitschr.  prakt.  Geologie,  1898,  p.  45;  and  Trans. 
Am.  Inst.  Min.  Eng.,  1901,  p.  131.  For  sulphides  in  slags,  see  J.  H.  L.  Vogt,  Mineralbildung  in  Schmelz- 
massen,  Christiania,  1892.  See  also  J.  E.  Spurr,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  33, 1903,  p.  306,  on  Alaskan 
pyrrhotite.  A remarkable  peridotite  at  East  Union,  Maine,  containing  21.5  per  cent  of  pyrrhotite,  is 
described  by  E.  S.  Bastin  in  Jour.  Geology,  vol.  16,  1908,  p.  124. 

2 Trans.  Am.  Inst.  Min.  Eng.,  vol.  31,  1901,  p.  182.  See  also  W.  H.  Emmons,  Bull.  U.  S.  Geol.  Survey 
No.  432,  1910,  p.  42,  on  molybdenite  in  the  granites  of  Maine.  R.  Brauns  (Centralbl.  Min.,  Geol.  u.  Pal., 
1908,  p.  97)  found  molybdenite  in  inclusions  in  basalt.  O.  Stutzer  (Zeitschr.  prakt.  Geologie,  1907,  p.  371) 
has  described  magmatic  bomite  from  South  Africa.  Chalcopyrite  and  bomite  as  primary  minerals  in  a 
monzonitic  dike  near  Apex,  Colorado,  havebeen  reported  by  E.  S.  Bastin  and  J.  M.  Hill.  Econ.  Geology, 
vol.  6,  p.  468,  1911.  See  also  E.  Howe,  Econ.  Geology,  vol.  10, 1915,  p.  298. 

3 See  Zeitschr.  Kryst.  Min.,  vol.  16,  pt.  2,  1890,  pp.  5-11.  For  very  complete  analyses  of  Norwegian 

pyrite,  see  E.  Boettker,  Rev.  gdn.  chim.  pure  et  app.,  vol.  9,  p.  323. 

* Zeitschr.  Kryst.  Min.,  vol.  16,  pt.  2, 1890,  p.  56. 

6 Idem,  vol.  7,  1883,  p.  630.  Abstract  of  memoir  by  A.  Scacchi.  For  a study  of  the  gases  occluded 
by  fluorite,  see  H.  W.  Morse,  Proc.  Am.  Acad.,  vol.  41,  1906,  p.  587.  According  to  H.  Becquerel  and 
H.  Moissan  (Bull.  Soc.  chim.,  3d  ser.,  vol.  5, 1891,  p.  154)  free  fluorine  is  sometimes  present  W.  J.  Hum- 
phreys (Astrophys.  Jour.,  vol.  20, 1904,  p.  266)  found  spectroscopic  traces  of  yttrium  and  ytterbium  in  many 
fluorspars.  G.  Urbain  (Compt.  Rend.,  vol.  143,  1906,  p.  826)  also  found  terbium,  gadolinium,  dysprosium, 
and  samarium. 


336 


THE  DATA  OF  GEOCHEMISTRY. 


is  also  produced  as  a secondary  mineral  from  the  decomposition  of 
various  fluosilicates.  It  alters  into  calcite,  being  attacked  by  perco- 
lating waters  containing  calcium  bicarbonate  or  alkaline  carbonates. 
Crystallized  calcium  fluoride  has  been  prepared  by  several  processes, 
but  they  shed  little  light  upon  its  presence  in  igneous  rocks.1 

Several  other  fluorides  are  found  associated  with  granites  or  peg- 
matites, such  as  tysonite,  fluocerite,  yttrocerite,  etc.  More  important 
by  far  is  the  mineral  cryolite,  which  forms  a large  bed  in  Greenland. 
According  to  F.  Johnstrup,2  it  is  a concretionary  secretion  in  eruptive 
granite.  A more  recent  writer,  It.  Baldauf,3  regards  the  cryolite  as 
having  been  formed  by  the  action  of  fluoriferous  gases  upon  the 
original  granitic  magma.  Cryolite  is  also  found  sparingly  at  Miask, 
in  the  Urals,  and  in  the  granites  of  Pikes  Peak,  Colorado.4  It  is  a 
double  fluoride  of  aluminum  and  sodium,  Na3AlF6.  Fluorine  com- 
pounds, it  must  be  observed,  are  rarely  found  in  eruptive  rocks. 
They  are  especially  characteristic  of  the  deep-seated  or  plutonic  rocks, 
where  the  gaseous  exhalations  have  been  retained  under  pressure, 
and  are  commonly  regarded  as  of  pneumatolytic  origin. 

CORUNDUM. 

Bhombohedral.  Composition,  aluminum  oxide,  A1203.  Specific 
gravity,  3.95  to  4.10;  of  the  purest  material,  4.0;  molecular  weight,5 
102 ; molecular  volume,  25.5.  Colorless  when  pure,  but  ordinarily  col- 
ored yellow,  gray,  green,  red,  or  blue  by  traces  of  impurity.  Emery 
is  a mixture  of  corundum  with  magnetite  or  hematite,  and  sometimes 
spinel.  Fusible  at  2,050°  C.,  according  to  C.  W.  Kanolt.6  Hard- 
ness, 9,  thus  ranking  among  natural  minerals  next  to  diamond. 

Crystallized  alumina,  artificial  corundum,  has  been  produced  by 
various  methods.  These  are  well  summarized  in  the  works  of  Bour- 
geois and  Fouque  and  Levy,  and  in  the  memoir  by  J.  Morozewicz.7 
They  may  be  briefly  grouped  as  follows:  First,  by  direct  fusion  of 
amorphous  alumina.  Second,  by  the  crystallization  of  alumina  from 
solution  in  various  molten  fluxes,  such  as  potassium  bichromate, 
sodium  molybdate,  borax,  lead  oxide,  etc.  Most  of  these  processes 
find  no  equivalent  in  nature.  Third,  by  the  decomposition  of  alum- 
inum chloride  or  fluoride  by  water  at  high  temperatures — methods 

1 See  the  works  by  Brauns,  Bourgeois,  and  Fouqud  and  Ldvy  cited  elsewhere  in  this  chapter. 

2 Cited  by  F.  Zirkel,  Lehrbuch  der  Petrographie,  vol.  3,  p.  444.  The  original  memoir  by  Johnstrup  is 
not  within  my  reach. 

3 Zeitschr.  prakt.  Geologie,  1910,  p.  432.  Baldauf  gives  a good  description  of  the  rarer  minerals  associated 

with  the  cryolite.  See  also  O.  B.  Boggild,  Zeitschr.  Kryst.  Min.,  vol.  51,  1913,  pp.  591,  614. 

* W.  Cross  and  W.  F.  Hillebrand,  Bull.  U.  S.  Geol.  Survey  No.  20. 

& The  ordinary  rounded-off  atomic  weights  may  be  used  for  computations  of  molecular  weights  and 
volumes. 

6 Jour. Washington  Acad.  Sci.,vol.  3,  1913,  p.  315.  Other  determinations  of  the  melting  point  are:  Hem- 
pel,  1,880°;  Moissan,  2,250°;  and  Ruff,  2,010°. 

7 Fouqud  and  Levy,  Synthese  des  mindraux  et  des  roches,  Paris,  1882.  L.  Bourgeois,  Reproduction  arti- 
ficielle  des  mindraux,  in  Fremy’s  Encyclopddie  chimique,  vol.  2,  1st  appendix.  Morozewicz,  Min.  pet. 
Mitt.,  vol.  18,  1898,  p.  23. 


ROCK-FORMING  MINERALS. 


337 


which  may  shed  some  light  upon  the  formation  of  corundum  as  a 
contact  mineral,  or  as  a constituent  of  metamorphic  rocks.  In  some 
of  these  reactions  boric  acid  plays  a part.  Fourth,  by  the  decomposi- 
tion of  other  minerals,  such  as  muscovite.  Finally,  by  crystallization 
of  artificial  magmas. 

It  is  not  necessary  for  our  purposes  to  examine  these  processes  in 
detail.  It  is  enough  to  select  from  among  them  those  which  seem  to 
be  the  most  significant.  P.  Hautefeuille  and  A.  Perrey,1  for  example, 
dissolved  alumina  in  melted  nepheline,  and  found  that  upon  cooling 
the  greater  part  of  it  crystallized  out  as  corundum.  The  association 
of  corundum  with  certain  nepheline  syenites  can  be  rationally  studied 
in  the  light  of  this  observation.  With  leucite  a similar  result  was 
obtained;  but  an  artificial  potassium  nepheline  gave  no  similar  reac- 
tion. A.  Brun  2 prepared  corundum,  together  with  anorthite,  by 
heating  a mixture  of  40  parts  silica,  37  lime,  and  120  alumina  to 
whiteness  for  three  hours.  Fusion  of  the  mixture,  however,  gave 
him  only  glass.  When  the  alumina  was  reduced  to  23  parts,  zoisite 
was  formed.  W.  Bruhns  3 obtained  corundum  in  the  wet  way  by 
heating  alumina  for  10  hours  to  300°  in  a platinum  tube  with  water 
containing  a trace  of  ammonium  fluoride;  but  at  250°  no  crystalliza- 
tion took  place.  By  similar  reactions  hematite,  quartz,  tridymite, 
and  ilmenite  were  prepared.  These  experiments  strengthen  the  sup- 
position that  the  fluorine  compounds  contained  in  volcanic  exhala- 
tions may  assist  the  natural  formation  of  the  minerals  named.  P. 
Hautefeuille’s  synthesis  of  corundum 4 by  the  action  of  moist  hydro- 
fluoric acid  upon  alumina  at  a red  heat  is  another  illustration  of  the 
same  principle.  It  is  typical  of  a considerable  number  of  mineral 
syntheses.  That  the  fluorides  are  not  essential  to  the  formation  of 
corundum,  however,  is  shown  by  the  experiments  of  G.  Friedel.5 
When  amorphous  alumina  is  heated  to  450-500°  with  a solution  of 
soda,  corundum  and  diaspore,  HA102,  are  both  produced.  At  530- 
535°  corundum  alone  formed,  and  at  400°  only  diaspore.  If  the 
alumina  contained  a little  silica,  crystals  of  quartz  appeared.  By  a 
similar  reaction  between  ferric  hydroxide  and  soda  solution,  Friedel 
obtained  crystals  of  hematite.  E.  S.  Shepherd  and  G.  A.  Kankin  6 
converted  precipitated  alumina  into  crystalline  corundum  by  simple 
heating  at  about  200°. 

From  a geological  standpoint  some  very  important  experiments 
upon  the  genesis  of  corundum  are  those  of  Morozewicz,7  who  studied 

1 Bull.  Soc.  min.,  vol.  13,  1890,  p.  147. 

2 Arch.  sci.  phys.  nat.,  3d  ser.,  vol.  25, 1891,  p.  239. 

8 Neues  Jahrb.,  1889,  Band  2,  p.  62. 

4 Annales  chim.  phys.,  4th  ser.,  vol.  4, 1865,  p.  153. 

8 Bull.  Soc.  min.,  vol.  14, 1891,  p.  8. 

9 Am.  Jour.  Sci.,  4th  ser.,  vol.  28,  1909,  p.  321. 

T Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  22-83.  Also  Zeitschr.  Kryst.  Min.,  vol.  24, 1895,  p.  281. 

97270°— Bull.  616—16 22 


338 


THE  DATA  OF  GEOCHEMISTRY. 


the  conditions  of  its  deposition  from  a cooling  magma.  He  worked 
with  artificial  magmas  upon  a rather  large  scale,  using  the  furnaces 
of  a glass  factory  in  preparing  his  melts;  and  he  found  that  when- 
ever the  alumina,  in  comparison  with  the  other  bases,  exceeded  a cer- 
tain ratio,  the  excess,  upon  cooling  the  fused  mass,  crystallized  out 
completely  either  as  corundum,  as  spinel,  as  sillimanite,  or  as  iolite.1 
The  qualifying  conditions  are  as  follows: 

An  alumosilicate  magma  in  which  the  molecular  ratio  of  the 
bases  CaO,  K20,  Na20  is  to  A1203  as  1:1  is  said  to  be  saturated  with 
respect  to  alumina.  If  more  alumina  is  present,  the  magma  is  super- 
saturated, and  the  excess  will  be  deposited  as  one  or  another  of  the 
above-named  minerals.  If  we  write  the  general  formula  for  the 
magma  of  H0.mAl203.7iSi02  the  following  rules  are  found  to  apply: 
First,  if  magnesia  and  iron  are  absent,  and  the  value  of  n lies 
between  2 and  6,  the  excess  of  alumina  will  crystallize  wholly  as 
corundum;  but  if  n is  greater  than  6,  sillimanite,  or  sillimanite  and 
corundum,  will  form.  With  magnesia  or  iron  present  in  an  amount 
above  0.5  per  cent,  and  with  n<  6,  spinel  is  produced,  or  spinel  and 
corundum  together.  With  n>6,  the  magnesia  and  the  excess  of 
alumina  will  go  to  form  iolite,  or  iolite  and  spinel.  In  each  case  the 
alumina  in  excess  of  the  ratio  RO : Al203 : : 1 : 1 is  completely  taken 
up  in  the  formation  of  the  several  species  named.  The  balance  of  the 
alumina — the  normal  alumina,  so  to  speak — will  obviously  appear  in 
other  minerals,  such  as  anorthite,  nepheline,  alkali  feldspars,  etc., 
whose  nature  will  depend  upon  the  bases  which  happen  to  be  asso- 
ciated with  it,  and  also  upon  the  proportion  of  silica. 

Previous  to  the  appearance  of  Morozewicz’s  memoir  it  was  com- 
monly supposed,  but  without  good  reason,  that  corundum  was  not  a 
true  pyrogenic  mineral.  It  was  best  known  as  occurring  with  meta- 
morphic  rocks,  and  especially  in  limestones;  and  it  had  been  observed 
as  a product  of  contact  action,  although  rarely.2  When  corundum 
was  found  in  igneous  rocks  it  was  regarded  as  derived  from  acci- 
dental inclusions,  and  not  as  a primary  separation  from  the  magma. 
The  work  of  Morozewicz  modified  these  beliefs  and  shed  new  light 
upon  the  problems  of  petrology.  The  common  association  of  corun- 
dum with  spinel,  iolite,  sillimanite,  andalusite,  and  kyanite  at  once 
became  significant,  and  in  accordance  with  the  rules  developed  by 
Morozewicz. 

Pyrogenic  corundum,  according  to  A.  Lagorio,3  is  found  in  alumo- 
silicate rocks  only  when  the  latter  contain  over  30  per  cent  alumina, 


1 Cordierite.  The  name  iolite  has  priority  and  is  given  preference  by  Dana. 

* K.  Busz  (Geol.  Mag.,  1896,  p.  492)  found  corundum  in  contacts  between  granite  and  clay  slate  on  Dart- 
moor in  Devonshire.  A.  K.  Coom&ra-Sw&my  (Quart.  Jour.  Geol.  Soc.,  vol.  57, 1901,  p.  185)  observed  it  at 
contacts  between  granite  and  micaceous  quartzite  near  Morlaix,  France.  The  corundum  was  there  asso- 
ciated with  sillimanite,  andalusite,  spinel,  etc.  On  an  occurrence  of  corundum  in  basalt  see  E.  Schurmann, 
Sitzungsb.  naturhist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  1911,  pt.  2,  p.  63  A. 

8 Zeitschr.  Kryst.  Min.,  vol.  24, 1895,  p.  285.  This  memoir  contains  abundant  literature  references  upon 
the  occurrence  of  corundum  in  igneous  rocks. 


ROCK-FORMING  MINERALS. 


8S9 


and  such  rocks  are  rare.  Lagorio  cites  analyses  of  several  examples, 
and  Morozewicz  1 himself  describes  others.  Kvschtymite  is  an  anor- 
thite  rock  containing  up  to  59.5  per  cent  of  corundum;  a corundum 
syenite  with  18.5  per  cent  consists  largely  of  orthoclase  and  albite, 
and  a corundum  pegmatite  with  35.4  per  cent  has  similar  composi- 
tion. All  these  rocks  are  from  the  Ural  Moun tarns.  A corundum 
anorthosite  analogous  to  kyschtymite  has  been  described  by  W.  G. 
Miller 2 from  Canada ; and  corundum-bearing  nepheline  syenites, 
according  to  A.  P.  Coleman,3  are  also  found  in  the  same  region.  In 
the  Coimbatore  district,  Madras  Presidency,  India,  T.  H.  Holland  4 
found  large  crystals  of  corundum  in  an  albite-orthoclase  rock  near  its 
contact  with  elseolite  syenite.  They  were  associated  with  chrysoberyl 
and  zinc  spinel,  zinc  oxide  and  glucina  having  here  played  the  part 
usually  assigned  to  magnesia  in  the  commoner  magmas.  In  the  Bid- 
well  Bar  quadrangle,  California,  A.  C.  Lawson  5 found  a dike  of  an 
oligoclase-corundum  rock  cutting  peridotite. 

The  solubility  of  alumina  in  peridotite  magmas — that  is,  in  mag- 
mas free  from  lime  and  alkalies — seems  not  to  have  been  experimen- 
tally investigated.  The  corundum  of  North  Carolina  and  Georgia, 
however,'  is  associated  with  rocks  of  this  class,  and  whether  it  was 
derived  by  fractional  crystallization  from  the  olivine  rock,  dunite, 
or  from  contact  action  with  adjacent  gneisses  is  an  open  question. 
The  latter  view,  which  is  that  of  the  earlier  writers  upon  these  locali- 
ties, was  advocated  by  T.  M.  Chatard,6  but  J.  H.  Pratt 7 argues  in 
favor  of  a pyrogenic  origin.  According  to  Pratt,  the  corundum 
crystallized  from  the  fused  dunite  along  the  cooler  surfaces  of  con- 
tact with  the  surrounding  rocks.  In  these  deposits  spinel  occurs  but 
rarely.  The  corundum,  emery,  and  iron  spinel  of  the  “Cortlandt 

1 Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  212, 219.  For  present  purposes  the  minor  accessory  minerals  in  these 
rocks  may  be  ignored. 

2 Am.  Geologist,  vol.  24, 1899,  p.  276. 

3 Jour.  Geology,  vol.  7, 1899,  p.  437.  A syenite  from  Montana,  containing  31  per  cent  of  corundum  has 
been  described  by  A.  F.  Rogers,  Jour.  Geology,  vol.  19, 1911,  p.  748. 

* Mem.  Geol.  Survey  India,  vol.  30,  1901,  pp.  201,  205.  For  Indian  corundum  in  general,  see  Holland, 
Manual  of  geology  of  India,  Economic  geology,  pt.  1;  F.  R.  Mallet,  Rec.  Geol.  Survey  India,  vol.  5,  1872, 
p.  20;  vol.  6, 1873,  p.  43;  and  C.  S.  Middlemiss,  idem,  vol.  29, 1896,  p.  39.  Mallet  describes  beds  of  corundum 
in  gneiss.  A remarkable  corundum  rock  from  India  is  described  by  J.  W.  Judd  in  Mineralog.  Mag.,  voL 
11, 1895,  p.  56.  For  Burmese  occurrences,  see  C.  B.  Brown  and  Judd,  Proc.  Roy.  Soc.,  vol.  57,  1895,  p.  387. 
On  the  corundum  granulite  of  Waldheim,  Saxony,  see  E.  Kalkowsky,  Abhandl.  Naturwiss.  Gesell.  Isis, 
July-Dee.,  1907,  p.  47. 

5 Bull.  Dept.  Geology  Univ.  California,  vol.  3, 1903,  p.  219. 

6 Bull.  U.  S.  Geol.  Survey  No.  42, 1887,  p.  45.  Chatard  gives  abundant  references  to  literature.  See  also 
F.  P.  King’s  report  upon  Georgia  corundum  (Bull.  Geol.  Survey  Georgia  No.  2,  1894),  which  contains  a 
bibliography  of  American  publications  upon  the  subject.  A similar  publication  by  J.  V.  Lewis,  on  North 
Carolina  corundum,  forms  Bull.  No.  11  of  the  North  Carolina  Geol.  Survey,  1896.  Vol.  1 of  the  North  Caro- 
lina Geol.  Survey,  1905,  by  Pratt  and  Lewis,  is  a valuable  monograph  on  corundum  and  chromite. 

7 Am.  Jour.  Sci.,  4th  ser.,  vol.  6, 1898,  p.  49;  vol.  8, 1899,  p.  227.  In  Mineralog.  Mag.,  vol.  12,  1899,  p.  139, 
J.  W.  Judd  and  W.  E.  Hidden  have  a paper  upon  North  Carolina  ruby;  also  in  Am.  Jour.  Sci.,  4th  ser 
vol.  8,  1899,  p.  370. 


340 


THE  DATA  OE  GEOCHEMISTRY. 


series”  in  New  York  were  regarded  by  G.  H.  Williams1  as  segre- 
gations in  norite.2 

At  Yogo  Gulch,  in  the  Little  Belt  Mountains  of  Montana,  corun- 
dum is  found  in  dikes  of  lamprophyre  which  contains  too  little 
alumina  to  satisfy  the  conditions  laid  down  by  Morozewicz.  The 
occurrence  has  been  carefully  studied  by  W.  H.  Weed  3 and  L.  Y. 
Pirsson,4  who  believe  that  the  corundum  was  not  in  this  case  a con- 
stituent of  the  original  magma,  but  that  is  has  been  produced  by  the 
action  of  the  latter  upon  inclosed  fragments  of  clay  shale  or  lime- 
stone. This,  of  course,  is  a sort  of  contact  action,  but  its  mechanism 
is  not  clearly  worked  out.  The  thermal  decomposition  of  minerals, 
especially  of  silicates,  has  so  far  been  inadequately  studied.  Under 
what  neutral  conditions  can  alumina  be  liberated  from  its  silicates  ? 
This  is  a question  which  demands  investigation,  but  it  may  be  noted 
here  that  Vernadsky,5  by  fusing  muscovite,  obtained  sillimanite  and 
corundum.  Natural  corundum  evidently  may  originate  in  more 
than  one  way,  and  no  single  process  can  account  for  all  of  its  occur- 
rences. 

Notwithstanding  the  fact  that  corundum  is  one  of  the  most  refrac- 
tory of  minerals  toward  aqueous  solvents,  being  insoluble  in  even  the 
strongest  acids,  it  is  not  absolutely  unalterable  by  them.  S.  J. 
Thugutt 6 found  that  corundum,  upon  prolonged  heating  with  water 
to  about  230°  in  a platinum  digester,  became  appreciably  hydrated. 
The  product  of  the  reaction  after  336  hours  contained  5.14  per  cent 
of  combined  water.  Even  at  100°  in  an  open  vessel,  some  hydration 
occurred.  A similar  prolonged  treatment  of  corundum  with  a solu- 
tion of  the  silicate  K2Si205  converted  it  into  a substance  having  the 
composition  of  orthoclase,  while  sodium  silicate  produced  a com- 
pound resembling  analcite.  In  nature  reactions  of  this  kind  are 
conceivably  possible,  but  they  must  be  very  slow;  in  the  laboratory 
the  acceleration  due  to  temperature  and  pressure  accounts  for  much 
of  the  change.  However,  alterations  of  corundum  are  common,  and 
Thugutt’s  experiments  give  us  some  notion  of  the  way  in  which  they 
were  probably  effected.  By  water  alone  corundum  may  be  trans- 
formed into  diasp  ore,  HA102,  which  is  one  of  its  frequent  associates. 
By  further  or  coincident  action  of  salts  dissolved  in  percolating 
waters  the  alteration  of  corundum  can  be  modified,  and  a consider- 


1 Am.  Jour.  Sci.,  3d  ser.,  vol.  33,  1887,  p.  194. 

2 For  an  account  of  the  emery  mine  at  Chester,  Massachusetts,  see  B.  K.  Emerson,  Mon.  U.  S.  Geol.  Sur- 
vey, vol.  29, 1898,  p.  117.  In  Bull.  U.  S.  Geol.  Survey  No.  269, 1906,  J.  H.  Pratt  gives  a very  complete  account 
of  the  corundum  and  emery  of  the  United  States,  together  with  much  information  upon  foreign  localities. 
For  the  emery  of  Naxos,  see  S.  A.  Papavasiliu,  Geol.  Centralbl.,  vol.  8, 1905,  p.  99. 

3 Twentieth  Ann.  Kept.,  U.  S.  Geol.  Survey,  pt.  3,  1900,  p.  454. 

4 Idem,  p.  552;  Am.  Jour.  Sci.,  4th  ser.,  vol.  4, 1897,  p.  421.  See  also  G.  F.  Kunz,  Am.  Jour.  Sci.,  4th  ser., 

vol.  4,  1887,  p.  417. 

6 Cited  by  Morozewicz,  Min.  pet.  Mitt.,  vol.  18,  1898,  p.  25. 

6 Mineralchemische  Studien,  Dorpat,  1891,  p.  104. 


BOCK-FORMING  MINERALS. 


341 


able  number  of  other  minerals  may  be  produced.1  Among  them 
gibbsite,  spinel,  sillimanite,  kyanite,  andalusite,  pyrophyllite,  musco- 
vite, paragonite,  chloritoid,  margarite,  zoisite,  feldspars,  tourmaline, 
and  various  vermiculites  and  chlorites  have  been  recorded.2  Some  of 
these  reported  alteration  products  are  doubtless  secondary  and  not 
due  to  the  direct  transformation  of  corundum,  but  on  this  subject 
there  is  much  uncertainty.  The  envelopment  of  one  mineral  by 
another  does  not  necessarily  establish  the  derivation  of  the  second 
from  the  first.  The  field  observations  and  the  study  of  natural  speci- 
mens need  to  be  reenforced  by  experiments  in  the  laboratory  before 
accurate  conclusions  concerning  the  alterations  can  be  drawn. 

THE  SPINELS. 

Spinel. — Isometric.  Composition,  MgAl204.  Molecular  weight, 
142.5.  Specific  gravity,  3.5.  Molecular  volume,  40.7.  Usually 
colored  violet,  green,  or  red  by  impurities.  Ha/dness,  8. 

Hercynite. — Isometric.  Composition,  FeAl204.  Molecular  weight, 
174.1.  Specific  gravity,  3.93.  Molecular  volume,  44.3.  Color,  black. 
Hardness,  7.5  to  8. 

These  minerals,  together  with  gahnite,  ZnAl204,  magnetite, 
Fe//Fe'//204,  magnesioferrite,  MgFe204,  franklinite,  and  chromite, 
form  a natural  isometric  group,  in  which  there  are  many  intermediate 
mixtures.  In  the  general  formula  R"R'"204,  R"  may  be  mag- 
nesium, ferrous  iron,  zinc,  or  manganese;  and  R'"  is  represented  by 
aluminum,  ferric  iron,  trivalent  manganese,  and  chromium.  In 
pleonaste  we  have  an  intermediate  magnesium  iron  spinel,  and  in 
picotite  chromium  appears.  Structurally  the  formula  of  spinel  is 
commonly  written  0 = A1  — O — Mg  — O— A1  = 0,  but  this  should  not 
be  taken  as  a finality.  It  is  not  the  only  expression  possible,  nor  has 
its  validity  been  proved. 

1 For  a discussion  of  the  reactions  which  are  supposed  to  produce  the  alterations  of  corundum,  see  C.  R. 
Van  Hise,  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  pp.  223-225. 

2 F.  A.  Genth,  Proc.  Am.  Philos.  Soc.,  vol.  13,  1873,  p.  361;  voL  20,  1882,  p.  381;  Am.  Jour.  Sci.,  3d  ser., 
vol.  39. 1890,  p.  47.  These  papers  are  full  of  details  regarding  alteration  products  of  corundum. 


842 


THE  DATA  OF  GEOCHEMISTRY. 


The  following  analyses  of  spinels  show  the  wide  variations  in  their 
composition: 


Analyses  of  spinels. 


A.  Rose  spinel,  Ceylon.  Analysis  by  H.  Abich. 

B . From  V esuvius.  Analysis  by  H.  Abich.  Analyses  A and  B cited  from  Dana’s  System  of  mineralogy, 
6th  ed.,  p.  222. 

C.  From  lherzolite,  Auvergne.  Analysis  by  F.  Pisani,  Compt.  Rend.,  vol.  63, 1866,  p.  49. 

D.  From  pyroxenite,  Montana.  Analysis  by  L.  G.  Eakins,  Bull.  U.  S.  Geol.  Survey  No.  220, 1903,  p.  20. 

E.  Pleonaste  from  near  Peekskill,  New  York.  Analysis  by  C.  A.  Wolle,  Am.  Jour.  Sci.,  2d  ser.,  vol.  48, 
1869,  p.  350. 

F.  Hercynite  from  the  Bohmerwald.  Analysis  by  B.  Quadrat,  Liebig’s  Annalen,  vol.  55, 1845,  p.  357, 


A 

B 

C 

D 

E 

F 

ALO, 

69. 01 
1. 10 

67. 46 

59.  06 

62.  09 
2.  62 
2. 10 
17.  56 
Trace. 
15.  61 
.16 
.55 

60.  79 

61.17 

OoO, 

Fe203 

10.  72 
13.  60 

5. 26 
21.  74 

FeO 

.71 

5.  06 

35.  67 

MnO 

MgO 

26. 31 

25.  94 

17. 20 

12.  84 

2.  92 

CaO 

Si02 

2.02 

2.  38 

99.  05 

100.  84 

100.  58 

100.  69 

100.  63 

99.  76 

Members  of  the  spinel  group  have  been  made  artificially  by 
methods  which  generally  recall  those  mentioned  under  corundum. 
For  example,.  S.  Meunier  1 fused  a mixture  of  alumina,  magnesia, 
cryolite,  and  aluminum  chloride,  and  obtained  spinel  crystals.  In 
another  investigation 2 he  produced  them  by  heating  aluminum 
chloride  and  water  with  metallic  magnesium  in  a sealed  tube.  These 
processes,  with  others  which  have  been  described,  may  perhaps  repre- 
sent in  a broad  way  the  pneumatolytic  methods  of  nature.  The  pro- 
duction of  spinel'by  the  fusion  of  appropriate  magmatic  mixtures  is, 
however,  the  process  of  greatest  importance  geologically,  and  some  of 
the  conditions  attending  its  formation  have  been  already  described 
under  corundum.  E.  S.  Shepherd  and  G.  A.  Rankin 3 have  pre- 
pared spinel  by  direct  fusion  of  its  constituent  oxides.  The  details 
of  Morozewicz’s  experiments  need  not  be  repeated  here.4 *  An  inter- 
esting emphasis  is  given  to  them  by  the  observations  of  G.  Linck,6 
who  found,  in  a German  gabbro,  spinel  associated  with  sillimanite 
and  corundum.6 

Spinels  are  also  formed  by  the  breaking  down  of  other  minerals, 
or  by  the  reactions  of  two  or  more  species  upon  one  another.  Accord- 


1 Compt.  Rend.,  vol.  104, 1887,  p.  1111. 

2 Idem,  vol.  90, 1880,  p.  701. 

» Am.  Jour.  Sci.,  4th  ser.,  vol.  28,^909,  p.  293. 

* See  also  J.  H.  L.  Vogt,  Mineralbildung  in  Schmelzmassen,  pp.  189-203. 

6 Sitzungsb.  X.  Akad.  Wiss.  Berlin,  1893,  p.  47. 

e See  also  W.  Salomon,  Zeitschr.  Deutsch.  geol.  Gesell. , vol.  42, 1890,  p.  525,  for  spinel  In  cordierlte  contact 
rocks  In  Itaij. 


ROCK-FORMING  MINERALS, 


343 


ing  to  Vernadsky,1  spinel  is  among  the  compounds  produced  by 
the  fusion  of  biotite,  an  observation  which  has  been  confirmed 
by  C.  Doelter.2  F.  W.  Clarke  and  E.  A.  Schneider 3 found  it  to  be 
formed  when  clinochlore  and  xanthophyllite  were  strongly  ignited, 
and  Doelter2  also  obtained  it  by  fusing  the  first-named  species. 
Tourmaline,  pyrope,  and  spessartite  also  yield  spinel  among  the 
products  of  their  fusion.4 

According  to  Fouque  and  Levy  5 spinel  and  melanite  are  formed 
when  nephelite  and  augite  are  fused  together,  and  Doelter  and 
Hussak6  obtained  spinel  from  a mixture  of  fayalite  and  sarcolite. 
M.  Vucnik 7 found  that  a mixture  of  magnetite  and  anorthite  gave 
recrystallized  anorthite,  hercynite,  and  glass,  the  magnetite  having 
disappeared.  Similar  observations  with  augite-elseolite  and  corun- 
dum-elseolite  mixtures  were  made  by  B.  Vukits.8 

Spinel,  especially  pleonaste,  is  a common  accessory  mineral  in 
gneisses  and  in  many  eruptive  rocks.  Picotite  is  more  character- 
istic of  the  peridotites  and  the  derived  serpentines.  Spinel  is  a 
frequent  companion  of  corundum  and  also  of  emery,  as  at  Chester, 
Mass.,  and  in  the  norite  at  Crugers,  N.  Y.9  A number  of  remarkable 
spinel  rocks  from  Elba  have  been  described  by  P.  Aloisi.10  A troc- 
tolite  from  Madagascar,  rich  in  spinel,  is  reported  by  A.  Lacroix.11 
Many  of  these  occurrences  are  easily  interpreted  in  the  light  of 
Morozewicz’s  experiments.  The  other  experiments,  cited  above, 
explain  the  appearance  of  spinel  as  a contact  mineral.  In  many 
cases  it  appears  in  limestones  as  a product  of  contact  metamorphism. 
Its  alterations  seem  to  have  been  little  studied,  but  a change  into 
steatite  is  mentioned  in  the  literature. 

Chromite. — Isometric.  Normal  composition,  FeCr204,  but  with 
variable  replacements  of  Fe"  by  Mg  and  of  Cr  by  Al  and  Fe'",  as 
in  the  other 'members  of  the  spinel  group.  Specific  gravity,  4.32 
to  4.57.  Color,  black.  Hardness,  5.5.  The  following  analyses  are 
fairly  typical : 12 


1 Cited  by  J.  Morozewicz,  Min.  pet.  Mitt.,  vol.  18, 1898,  p.  59. 

2 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

s BuU.  U.  S.  Geol.  Suivey  No.  113, 1893,  p.  30. 

* Doelter,  loe.  cit.,  for  tourmaline.  C.  Doelter  and  E.  Hussak,  Neues  Jahrb.,  1884,  Bandl,p.  157,  for 

garnets. 

6 Synth&se  des  min6raux  et  des  roches,  p.  64. 

6 Neues  Jahrb.,  1884,  Band  1,  p.  157. 

7 Centralbl.  Min.,  Geol.  u.  Pal.,  1904, p.  297.  Criticized  by  J.  Morozewicz  in  the  same  journal,  1905, p.  148. 

s Idem,  1904,  pp.  710,  743. 

» G.  H.  Williams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  33,  1887,  p.  194.  See  also  J.  n.  Pratt,  Bull.  U.  S.  Geol. 
Survey  No.  2C9,  1906,  p.  34. 

Proc.  verb.  Soc.  tosc.  sci.  nat.,  vol.  15,  p.  60. 

11  Bull.  Soc.  min.,  vol.  31, 1908,  p.  318. 

12  A very  complete  collection  of  chromite  analyses , down  to  1884 , with  literature  references , is  given  in  M. 
E.  Wadsworth’s  Lithological  studies:  Mem.  Mus.  Comp.  Zool.  Harvard  Coll.,  vol.  11,  1884.  A mineral 
from  Serbia,  of  composition  Fe20s.Cr203,  has  been  named  chromitite  by  M.  Z.  Jovitschitsch,  Monatsh. 
Chemie,  vol.  30,  1909,  p.  39.  Also,  later,  Bull.  Soc.  Min.,  vol.  35, 1911,  p.  511. 


844 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  chromite. 

A.  From  vicinity  of  Mundorff,  British  Columbia.  Chrompicotite.  Analysis  by  R.  A.  A.  Johnston,  for 
G.  C.  Hoffmann,  Am.  Jour.  Sci.,  4th  ser.,  vol.  13,  1902,  p.  242. 

B.  From  Corundum  Hill,  North  Carolina.  Analysis  by  C.  Baskerville,  for  J.  H.  Pratt,  Am.  Jour.  Sci., 
4th  ser.,  vol.  7,  1899,  p.  281. 

C.  From  Webster,  North  Carolina.  Analysis  by  H.  W.  Foote,  for  Pratt,  loc.  cit. 

D.  From  Port  au  Port  Bay,  Newfoundland.  Analysis  by  E.  Waller,  for  G.  W.  Maynard,  Trans.  Am. 
nst.  Min.  Eng.,  vol.  27,  1897,  p.  283. 

E.  From  Tampadal,  lower  Silesia.  Analysis  by  Laszczynski,  for  H.  Traube,  Zeitschr.  Deutsch.  geol. 
Gesell.,  vol.  46,  1894,  p.  60. 


A 

B 

C 

Do 

E 

Cr90o 

55. 90 

57.  80 

39.  95 

49. 23 

41.  23 

AloOq 

13. 83 

7. 82 

29.28 

7.  50 

24.  58 

Fe203 

2.  28 

FeO 

14.64 

25.  68 

13. 90 

17.  21 

16.  99 

MnO 

. 69 

Trace. 

.58 

MgO 

15. 01 

5.  22 

17. 31 

18.  66 

14.  77 

Si02 

.60 

2.  80 

6.  51 

99.  98 

100.  01 

100.  44 

99. 11 

100. 43 

oAlso  contains  traces  of  lime,  copper,  and  vanadium. 


The  earlier  syntheses  of  chromite  seem  to  have  little  or  no  geo- 
logical bearing.  S.  Meunier,1  however,  who  prepared  chromite  by 
oxidizing  an  alloy  of  iron  and  chromium,  attributes  its  origin  to  a 
similar  reaction  occurring  in  nature.  He  supposes  that  such  an 
alloy,  like  platinum  and  nickel  iron,  can  be  brought  up  from  the 
interior  of  the  earth  to  be  oxidized  by  vapors  when  it  nears  the 
surface.  Unfortunately,  no  such  alloy  has  yet  been  found  in  the 
rocks,  and  in  meteorites  chromite  itself  is  a common  mineral. 

Chromite  is  essentially  a constituent  of  peridotites  and  of  the 
serpentines  derived  from  them.  It  is  one  of  the  earliest  species 
formed  during  the  solidification  of  the  magma,  and  its  larger  deposits, 
when  it  occurs  in  ore  bodies,  are  now  generally  ascribed  to  magmatic 
differentiation  through  the  action  of  gravity.  J.  H.  L.  Vogt 2 thus 
interprets  the  chromite  deposits  of  Norway,  and  J.  H.  Pratt 3 has 
elaborated  the  same  conception  with  respect  to  the  chromic  iron 
ores  of  North  Carolina.  The  origin  of  corundum  and  of  chromite  in 
dunite  Pratt  explains  in  the  same  way.  When  a peridotite  alters  to 
serpentine,  the  refractory  chromite  remains  unchanged. 

Magnetite. — Isometric.  Composition,  Fe304,  but  with  variable 
impurities  and  replacements.  Molecular  weight,  231.7.  Specific 
gravity,  5.17.  Molecular  volume,  44.8.  Color,  black.  Hardness, 
5.5  to  6.5.  Magnesium,  manganese,  aluminum,  and  titanium  are 
common  impurities,  rutile,  ilmenite,  hematite,  and  the  spinels  being 

1 Compt.  Rend.,  vol.  110,  1890,  p.  424. 

2 Zeitschr.  prakt.  Geologie,  1894,  p.  384. 

s Trans.  Am.  Inst.  Min.  Eng.,  vol.  29, 1899,  p.  17.  For  a general  review  of  chromite  deposits,  see  Stelzner- 
Bergeat,  Die  Erzlagerstatten,  1904,  p.  33.  The  magmatic  view  is  adopted  in  this  work  and  also  in  Beck’s 
treatise  upon  ore  bodies. 


ROCK-FORMING  MINERALS. 


845 


frequent  admixtures  in  magnetite.  The  titaniferous  magnetites 
form  a well-known  subclass  of  ores.  In  a magnetite  from  the  Tyro- 
lese Alps,  T.  Petersen1  found  1.76  per  cent  of  nickel  oxide,  and  the 
magnetites  of  eastern  Ontario  may  contain  half  as  much.2 

Magnetite  is  often  observed  as  a furnace  product,  and  it  forms  the 
“iron  scale”  of  the  blacksmith.  W.  Miiller3  found  both  magnetite 
and  hematite  in  crystals  among  the  oxidation  products  of  the  iron- 
bearing residues  from  an  aniline  factory.  The  mineral  has  also  been 
produced  artificially  by  several  investigators.  J.  J.  Ebelmen  4 pre- 
pared it,  well  crystallized,  by  fusing  together  an  iron  silicate  and 
lime.  According  to  H.  Sainte-Claire  Deville,5  ferrous  oxide,  heated 
in  a stream  of  hydrochloric  acid,  forms  magnetite,  while  a mixture 
of  magnesia  and  ferric  oxide,  similarly  treated,  yields  magnesiofer- 
rite,  MgFe204.  T.  Sidot6  obtained  magnetite  by  the  calcination  of 
ferric  oxide  alone. 

In  artificial  magmas  magnetite  is  easily  formed,  especially  when 
the  proportion  of  silica  is  low.  Any  excess  of  iron  over  that  needed 
to  combine  with  silica  is  likely  to  be  deposited  in  the  form  of  mag- 
netite, although  the  conditions  of  its  appearance  are  not  so  simple 
as  in  the  separation  of  alumina  as  corundum.7  The  order  of  its 
crystallization  with  reference  to  other  minerals  is  by  no  means 
invariable. 

Like  the  spinels,  magnetite  may  be  formed  by  the  breaking  down 
of  other  species,  or  by  reactions  between  them.  In  other  words,  it 
may  be  a product  of  contact  metamorphism.  C.  Doelter,8  for  ex- 
ample, repeatedly  obtained  it  by  fusing  various  rocks  in  contact  with 
limestone — a procedure  which  recalls  Ebelmen’s  experiment.  Ac- 
mite  upon  fusion  yields  magnetite  and  a glass,9  and  glaucophane 
gives  similarly  a mixture  in  which  magnetite  appears.  By  melting 
together  biotite  and  microcline,  Fouqu6  and  Levy10  obtained  magne- 
tite, leucite,  and  olivine.  J.  Lenarcic 11  found  magnetite  in  the  mass 
produced  by  fusing  leucite  with  augite;  but  on  the  other  hand,  when 
magnetite  and  labradorite  were  taken,  the  former  mineral  was  dis- 
solved and  augite  appeared.  Similar  observations  were  made  by 
M.  Vucnik12  and  B.  Vukits,13  who  found  magnetite  among  the  fusion 


1 Neues  Jahrb.,  1867,  p.  836. 

2 W.  G.  Miller,  Rept.  British  Assoc.,  1897,  p.  600. 

3Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  45,  1893,  p.  63. 

4 Compt.  Rend.,  vol.  33,  1851,  p.  528. 

* Idem,  vol.  53,  1861,  p.  199. 

6 Idem,  vol.  69, 1869,  p.  201. 

7 See  J.  Morozewicz,  Min.  pet.  Mitt.,  vol.  18, 1898,  p.  84,  and  J.  ET.  L.  Vogt,  Minsralbildung  in  Schmelz- 
massen,  pp.  203-212. 

s Neues  Jahrb.,  1886,  Band  1,  p.  128. 

» Doelter,  Neues  Jahrb.  1897,  Band  1,  p.  1.  See  also  M.  Vutaik,  cited  below, 

w Synthase  des  mindraux  et  des  roches,  p.  77. 

u Centralbl,  Min.,  Geol  u.  Pal.,  1903,  pp.  705,  743. 

12  Idem,  1904,  pp.  300, 342,  344,  345, 366, 369. 

18  Idem,  1904,  pp.  705,  715,  743,  748. 


846 


THE  DATA  OF  GEOCHEMISTRY. 


products  of  anorthite  and  hedenbergite,  albite  and  hedenbergite, 
olivine  and  augite,  elseolite  and  augite,  and  ebeolite  and  diopside. 
Each  of  these  couples,  when  fused,  yielded  magnetite,  with  other 
products  which  varied  according  to  the  nature  of  the  mixture. 

Magnetite  occurs  as  an  accessory  mineral  in  rocks  of  all  classes, 
and  it  sometimes  rises  to  the  rank  of  a principal  constituent,  or  even 
forms  rock  masses  by  itself.  It  is  obviously  most  abundant  in  rocks 
rich  in  ferromagnesian  minerals,  such  as  norites,  diabases,  gabbro3, 
or  peridotites;  but  it  i3  also  associated  with  nepheline  rocks  and 
anorthites.  In  many  cases  it  forms  large  ore  bodies  that  are  regarded 
as  products  of  magmatic  differentiation;  and  these  deposits,  as  a 
rule,  are  highly  titaniferous.1  Some  ores  shade  from  magnetite  into 
ilmenite,  with  over  40  per  cent  of  titanic  oxide.  They  frequently 
contain  spinel,  and  sometimes,  also,  corundum. 

In  the  great  iron  deposits  of  the  Lake  Superior  region,  and  the 
adjacent  parts  of  Michigan,  Wisconsin,  and  Minnesota,  magnetite  is 
found  in  slates  and  cherts,  often  associated  with  grunerite  and  actino- 
lite.2  Here  the  mineral  is  not  of  direct  igneous  origin.  In  the  Mesabi 
district,  according  to  C.  K.  Leith,3  it  is  derived  from  the  leaching  of 
a hydrous  iron  silicate,  of  uncertain  composition,  to  which  he  has 
given  the  name  “greenalite.”  Other  silicates  may  yield  magnetite 
through  metamorphic  changes,  and  it  can  also  form,  says  C.  It.  Van 
Hise,4  from  marcasite  and  pyrite,  and  from  the  oxidation  of  siderite 
in  place.  By  further  oxidation  magnetite  can  alter  to  hematite  and 
limonite,  and  through  the  agency  of  carbonated  waters  it  may  be 
transformed  into  siderite  again. 

HEMATITE. 

Rhombohedral.  Composition,  Fe203.  Molecular  weight,  159.8. 
Specific  gravity,  5.2.  Molecular  volume,  30.7.  Color,  red  to  steel- 
gray  and  black.  Hardness,  5.5  to  6.5.  Hematite  has  been  prepared 
artificially  by  several  methods.  In  the  classical  experiment  of 
Gay-Lussac,5  the  vapor  of  ferric  chloride  was  decomposed  by  steam 
at  a high  temperature,  and  crystals  of  hematite  were  formed.  A. 


1 See  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1893,  p.  6;  1894,  p.  382;  1900,  pp.  234,  370;  1901,  pp.  9, 180, 
289,  327.  J.  F.  Kemp,  Nineteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3,  1899,  p.  377;  School  of  Mines 
Quart.,  vol.  20, 1899, p.  323;  vol.  21, 1900, p.  5G;  Zeitschr.  prakt.  Geologie,  1905,  p.  71.  W.  Lindgren,  Science, 
vol.  16, 1902,  p.  984.  G.  H.  Williams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  33, 1887,  p.  194.  R.  Beck,  Lehre  von  den 
Erzlagerstatten,  2d  ed.,  pp.  20-30.  Kemp’s  paper  in  the  School  of  Mines  Quarterly  is  a general  review  of 
the  titaniferous  magnetites,  with  many  analyses  and  copious  references  to  other  literature.  In  Zeitschr. 
prakt.  Geologie,  1907,  p.  86,  Vogt  describes  magmatic  iron  ores  in  granite.  On  magmatic  iron  ores  in  U tah, 
see  E.  P.  Jennings,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  35,  1905,  p.  338.  On  the  magmatic  magnetites  of 
Lapland,  see  O.  Stutzer,  Neues  Jahrb.,  Beil.  Band  24,  1907,  p.  548.  A magnetite  basalt  from  Colorado  is 
described  by  II.  S.  Washington  and  E.  S.  Larsen  in  Jour.  Washington  Acad.  Sci.,  vol.  3, 1913,  p.  449. 

2 See  C.  R.  Van  Hise,  W.  S.  Bayley,  II.  L.  Smyth,  and  J.  M.  Clements,  in  Mon.  U.  S.  Geol.  Survey,  vol. 
28, 1897;  vol.  36, 1889;  and  vol.  45,  1903. 

3 Mon.  U.  S.  Geol.  Survey,  vol.  43, 1903,  pp.  101-115. 

4 A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  p.  229. 

6 See  R.  Brauns,  Chemische  Mineralogie,  1896,  p.  231. 


ROCK-FORMING  MINERALS. 


347 


DaubrSe1  obtained  it  by  passing  ferric  chloride  vapor  over  lime;  and 
H.  Sainte-Claire  Deville 2 prepared  the  specular  variety  by  the  slow 
action  of  gaseous  hydrochloric  acid  upon  ferric  oxide  at  a red  heat. 
Hematite  is  also  produced,  according  to  H.  Arctowski,3  by  the  action 
of  vaporized  ammonium  chloride  upon  either  red-hot  iron  or  ferric 
oxide.  It  has  also  been  noted  as  a sublimation  product  in  the  salt- 
cake  furnaces  of  certain  chemical  works.4 *  Fine  crystals  of  hematite, 
grouped  in  rosettes,  have  been  formed  in  the  iron  heating  pipes  of  a 
Deacon  chlorine  apparatus  in  Philadelphia.  Some  of  the  crystals 
were  as  much  as  3 centimeters  in  diameter.  Their  formation  was  due 
to  the  action  of  heated  air  and  hydrochloric  acid  upon  the  iron. 
Ferric  chloride  was  probably  first  formed  and  then  transformed  into 
hematite  by  aqueous  vapor.  All  these  reactions  are  analogous  to,  if 
not  identical  with,  those  that  produce  the  so-called  “sublimed” 
hematite  which  is  seen  upon  volcanic  lavas.  A.  Arzruni,6  on  com- 
paring the  volcanic  mineral  with  the  artificial  product,  found  them 
to  be  crystallographically  identical.  W.  Bruhns's  experiment,7  in 
which  hematite  was  formed  by  heating  amorphous  ferric  oxide  with 
water  and  a trace  of  ammonium  fluoride  to  300°  in  a platinum  tube, 
seems  to  be  less  closely  related  to  geological  phenomena. 

Fouque  and  Levy8  repeatedly  obtained  hematite  from  artificial 
magmas,  and  similar  observations  have  been  made  by  others.  In 
ordinary  furnace  slags,  however,  according  to  J.  H.  L.  Vogt,9  hema- 
tite rarely  if  ever  occurs.  Ferric  oxide  can  crystallize  out  as  hematite 
only  when  ferrous  compounds  are  either  absent  or  present  in  quite 
subordinate  amounts,  for  ferrous  oxide  unites  with  it  to  form  mag- 
netite. The  latter  species,  therefore,  is  characteristic  of  rocks  rich  in 
ferromagnesian  minerals,  while  hematite  appears  chiefly  in  the  more 
siliceous  and  feldspathic  granites,  syenites,  trachytes,  rhyolites, 
andesites,  and  phonolites.  It  is  also  found  in  the  crystalline  schists; 
but  magnetite  is  by  far  the  more  common  as  a pyrogenic  mineral.  In 
igneous  rocks  generally  ferrous  oxide  exceeds  the  ferric  in  amount, 
the  average  percentages,  as  shown  by  961  analyses,10  being  3.46  FeO 
and  2.63  Fe203.  This  preponderance  of  the  lower  oxide  seems  to 
determine  the  frequent  formation  of  magnetite.  The  ferric  pyrite  and 
the  ferrous  pyrrhotite  appear  to  follow  the  same  rule  of  association, 

1 Compt.  Rend.,  vol.  39, 1854,  p.  135. 

2 Idem,  vol.  52, 1861,  p.  1264. 

s Zeitschr.  anorg.  Chemie,  vol. 6, 1894,  p.  377;  Bull.  Acad.  roy.  sci.  Belgique,  3d  ser.,  vol.  27, 1894,  p.  933. 

< See  H.  Vater,  Zeitschr.  Kryst.  Min.,  vol.  10, 1885,  p.  391;  and  B.  Doss,  idem,  vol.  20,  1892,  p.  566. 

6 C.  E.  Munroe,  Am.  Jour.  Sci.,  4th  ser.,  vol.  24,  1907,  p.  485. 

Zeitschr.  Kryst.  Min.,  vol.  18, 1891,  p.  46. 

1 Neues  Jahrb.,  1889,  Band  2,  p.  62. 

8 Synthase  des  min6raux  et  des  roches,  p.  236. 

9 Mineralbildung  in  Schmelzmassen,  pp.  215-217.  Cf.  also  J.  Morozewicz,  Min.  pet.  Mitt.,  vol.  18,  1898, 

p.  84. 

19  Bull.  U.  S.  Geol.  Survey  No.  228, 1904,  p.  17. 


348 


THE  DATA  OF  GEOCHEMISTRY. 


the  one  being  commonest  in  highly  silicic  rocks,  the  other  accom- 
panying the  ferromagnesian  minerals. 

Hematite  alters  into  limonite,  magnetite,  pyrite,  marcasite,  and 
siderite,1  and  in  metamorphic  rocks  it  may  be  derived  from  the  same 
species.  Limonite,  siderite,  and  magnetite  are  especially  liable  to 
yield  it.  The  derivation  of  hematite  from  silicates  is  probably  always 
indirect,  one  or  another  of  the  above-named  species  having  been 
formed  first.  Titanium  is  a common  impurity  in  hematite,  and  L.  J. 
Igelstrom,2  in  a Swedish  ore,  found  molybdenum  in  very  appreciable 
amounts. 

TITANIUM  MINERALS. 

Tlmenite. — Rhombohedral.  Composition,  FeTi03.  Molecular 

weight,  152.  Specific  gravity,  4.5  to  5.  Molecular  volume,  30.4. 
Color,  black;  luster,  submetallic.  Hardness,  5 to  6. 

Ilmenite,  menaccanite,  or  titanic  iron  has  been  little  investigated 
upon  the  synthetic  side.  W.  Bruhns  3 prepared  it,  mixed  with  some 
magnetite,  by  heating  finely  divided  metallic  iron,  ferric  oxide,  and 
amorphous  titanic  oxide  with  hydrochloric  acid  in  a platinum  tube 
to  270-300°.  In  nature,  however,  it  is  found  most  widely  diffused. 
It  occurs  with  or  replacing  hematite  in  granite  and  syenites  and  as  an 
essential  constituent  in  diorite,  diabase,  gabbro,  basalt,  etc.,  often 
with  magnetite.4  In  these  rocks  it  is  one  of  the  earliest  minerals  to 
separate.  It  i3  also  found  in  metamorphic  rocks,  such  as  gneiss, 
mica  schist,  and  amphibolite.  A.  von  Lasaulx  5 describes  ilmenite 
as  an  alteration  derivative  of  rutile. 

The  constitution  of  ilmenite  has  been  much  discussed.  Some  au- 
thorities have  regarded  it  as  an  isomorphous  mixture  of  Fe203  and 
Ti203;  but  C.  Friedel  and  J.  Guerin,6  who  prepared  the  latter  com- 
pound artificially,  do  not  favor  this  view.  Ti203  as  such  has  not  been 
found  as  an  independent  mineral.  T.  Konig  and  O.  von  der  Pfordten  7 
made  various  attempts  to  detect  Ti203  in  ilmenite  and  only  met  with 
failure.  Since  the  mineral  pyrophanite,  MnTi03,  isomorphous  with 
ilmenite,  is  known,  and  since,  as  S.  L.  Penfield  and  H.  W.  Foote8 
have  shown,  ilmenite  sometimes  contains  large  admixtures  of  the 
molecule  MgTiOs,  the  formula  FeTiOs  may  now  be  regarded  as  estab- 
lished for  titanic  iron.  In  an  ilmenite  from  Warwick,  New  York, 
Penfield  and  Foote  found  16  per  cent  of  magnesia.  In  fact,  the  com- 


1 C.  R.  Van  Hise,  A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  p.  226. 

2 Zeitschr.  Kryst.  Min.,  vol.  25, 1896,  p.  94. 

8 Neues  Jahrb.,  1889,  Band  2,  p.  65. 

4 See  the  papers  of  Vogt,  Kemp,  and  others  cited  under  magnetite.  The  titaniferous  magnetites  are 
mixtures  of  that  species  with  ilmenite.  See  also  A.  Cathrein,  Zeitschr.  Kryst.  Min.,  vol.  8, 1884,  p.  321. 

Urbainite  is  a rock  rich  in  ilmenite  found  at  St.  Urbain,  Canada.  Described  by  C.  H.  Warren,  Am.  Jour. 

Sci.,  4th  ser.,  vol.  33, 1912,  p.  263. 

4 Zeitschr.  Kryst.  Min.,  vol.  8, 1884,  p.  54. 

8 Annales  chim.  phys.,  5th  ser.,  vol.  8, 1876,  p.  38. 

r Ber.  Deutsch.  chem.  Gesell.,  vol.  22, 1889,  p.  1485.  See  also  W.  Manchot,  Zeitschr.anorg.  Chemie,  vol. 
74, 1912,  p.  79. 

8 Am.  Jour.  Sci.,  4th  ser.,  vol.  4,  1897,  p.  108. 


ROCK-FORMING  MINERALS. 


549 


pound  MgTiOa  is  independently  represented  by  the  mineral  geikie- 
lite  1 from  Ceylon.  An  excess  of  iron  in  ilmenite  may  be  due  to 
admixed  hematite  and  an  excess  of  titanium  to  rutile. 

Ilmenite  is  often  surrounded  by  a margin  of  white  or  even  reddish 
alteration  products,  which  is  commonly  known  by  the  name  of  leu- 
coxene.  According  to  A.  Cathrein,2  this  substance  is  essentially 
titanite,  sometimes  accompanied  by  rutile. 

Pseudobrookite. — Orthorhombic.  Composition,  ferric  orthotitan- 

ate,  Fe4(Ti04)3.  Molecular  weight,  559.9.  Specific  gravity,  4.39. 
Molecular  volume,  127.5.  Color,  dark  brown  to  black.  Hardness,  6. 

Pseudobrookite  is  a rare  accessory  mineral  in  certain  eruptive 
rocks,  such  as  andesite,  trachyte,  basalt,  and  nephelinite.  A similar 
mineral,  formed  by  “sublimation”  in  a salt-cake  furnace,  was  de- 
scribed by  B.  Doss,3  who  gave  it  the  formula  Fe2Ti05  and  made  it 
isomorphous  with  andalusite,  Al2Si05 . The  natural  mineral,  however, 
has  the  orthotitanate  formula,  as  given  above.4 

Perofskite. — Isometric  or  pseudoisometric.  Composition,  calcium 
titanate,  CaTi03.  Molecular  weight,  136.2.  Specific  gravity,  4. 
Molecular  volume,  34.  Color,  yellow,  ranging  through  orange  and 
brown  to  grayish  black.  Hardness,  5.5. 

Perofskite  has  been  prepared  synthetically  by  several  chemists. 
J.  J.  Ebelmen 5 obtained  it  by  fusing  titanic  oxide  with  lime  and 
potassium  carbonate;  and  later  6 by  the  action  of  lime  on  an  alkaline 
melt  containing  titanic  oxide  and  silica.  P.  Hautefeuille  7 heated  a 
mixture  of  calcium  chloride,  titanic  oxide,  and  silica  to  redness  in  a 
stream  of  moist  carbon  dioxide,  or  of  hydrochloric  acid,  and  obtained 
perofskite  crystals.  L.  Bourgeois 8 observed  its  deposition  from 
various  fused  mixtures  resembling  natural  magmas  in  composition. 
Finally,  P.  J.  Holmquist 9 prepared  perofskite  by  fusing  together 
sodium  carbonate,  calcium  carbonate,  and  titanic  oxide,  under  special 
manipulative  conditions. 

Perofskite  occurs  both  in  eruptive  and  metamorphic  rocks.  It  is 
found  in  melilite,  leucite,  and  nepheline  rocks,  and  in  some  perido- 
tites;10  and  is  among  the  earliest  secretions.  It  is  particularly  charac- 
teristic of  melilite  basalt,  being,  according  to  A.  Stelzner,11  the  most 
faithful  companion  of  melilite.  At  Catalao,  Brazil,  E»  Hussak12  found 

1 A description  of  geikielite  by  T.  Crook  and  B . M.  Jones  is  printed  in  Mineralog.  Mag. , vol.  14, 1906,  p.  160. 

2 Zeitschr.  Kryst.  Min.,  vol.  6, 1882,  p.  244. 

3 Idem,  vol.  20, 1892,  p.  566.  Doss  gives  a good  bibliography  of  pseudobrookite. 

4 Established  by  A.  Frenzel,  Min.  pet.  Mitt.,  vol.  14,  p.  121;  confirming  the  earlier  analyses  of  A.  Koch, 

G.  Lattermann,  and  A.  Cedarstrom.  See  E.  S.  Dana,  System  of  mineralogy,  6th  ed.,  p.  232. 

6 Compt.  Rend.,  vol.  32, 1851,  p.  710. 

e Idem,  vol.  33, 1851,  p.  528. 

7 Annales  chim.  phys.,  4th  ser.,  vol.  4, 1865,  p.  163. 

8 Idem,  5th  ser.,  vol.  29, 1883,  p.  479. 

0 Bull.  Geol.  Inst.  Upsala,  vol.  3, 1896-97,  p.  181. 

10 See  G.  H.  Williams,  Am.  Jour.  Sci.,3d  ser.,  vol.  34,  1887,  p.  137;  J.  S.  Diller,  ldem,vol.37, 1889,  p.  219. 

u Neues  Jahrb.,  Beil.  Band  2, 1883,  p.  390. 

12  Neues  Jahrb.,  1894,  Band  2,  p.  297. 


350 


THE  DATA  OF  GEOCHEMISTRY. 


a peculiar  rock  consisting  of  magnetite  and  perofskite;  a titaniferous 
magnetite  of  a new  kind.  A similar  rock  has  been  found  in  the  Un- 
compahgre  quadrangle  by  E.  S.  Larsen  and  analyzed  in  the  labora- 
tory of  the  United  States  Geological  Survey.  Perofskite  is  also  found 
in  chlorite  schist,  limestone,  quartz  gneiss,1  etc.  Hussak  observed  its 
alteration  into  titanic  oxide,  and  K.  Schneider 2 has  described  perof- 
skite as  derived  from  titanite. 

Titanite, — Monoclinic.  Composition,  CaTiSi05.  Molecular  weight, 
196.5.  Specific  gravity,  3.54.  Molecular  volume,  55.5.  Color,  yel- 
low, green,  red,  gray,  brown,  or  black.  Hardness,  5 to  5.5. 

Titanite,  or  sphene,  has  been  produced  artificially  by  several  experi- 
menters, but  it  does  not  seem  to  be  easily  formed.  P.  Hautefeuille  3 
prepared  it  by  fusing  a mixture  of  silica  and  titanic  oxide  with  cal- 
cium chloride.  L.  Bourgeois 4 obtained  it,  but  obscurely  developed, 
by  fusing  together  its  constituent  oxides,  silica,  titanic  oxide,  and 
lime.  L.  Michel 5 fused  ilmenite  with  calcium  sulphide,  silica,  and 
carbon,  which  yielded  a mixture  of  titanite,  garnet,  and  a subsulphide 
of  iron.  S.  Smolensky 6 prepared  titanite  by  Bourgeois’s  method  and 
determined  its  melting  point  as  1,221°. 

As  a pyrogenic  mineral  titanite  is  found  among  the  oldest  secre- 
tions in  the  more  siliceous  rocks,  such  as  granites,  diorites,  syenites, 
and  trachyte.  It  is  abundant  in  phonolites  and  elaeolite  syenites, 
and  is  also  common  as  a secondary  mineral,  derived  by  alteration 
from  rutile  or  ilmenite.  It  is  often  associated  with  chlorite.  At 
Green  River,  North  Carolina,  large  crystals  of  sphene  are  found  com- 
pletely or  partially  altered  into  a yellow,  friable,  earthy  substance 
which  has  been  given  the  name  of  xanthitane.  According  to  L.  G. 
Eakins,7  this  product  is  a hydrous  titanate  of  aluminum.  An  altera- 
tion of  titanite  into  rutile  has  been  observed  by  P.  Mann 8 in  the 
foyaite  of  the  Serra  de  Monchi que;  and  B.  Doss  9 has  reported  pseudo- 
morphs  of  anatase  after  sphene. 

Rutile. — Tetragonal.  Composition,  Ti02.  Molecular  weight,  80.1. 
Specific  gravity,  4.2.  Molecular  volume,  19.1.  Color,  commonly  red- 
dish to  brown  or  black.  Plardness,  6 to  6.5. 

Broolnte. — Orthorhombic.  Composition  and  molecular  weight  as 
for  rutile.  Specific  gravity,  4.  Molecular  volume,  20.  Color,  yel- 
lowish, reddish,  brown,  or  iron-black.  Hardness,  5.5  to  6. 

Octdhedrite  or  anatase. — Tetragonal.  Composition  and  molecular 
weight  the  same  as  for  rutile  and  brookite.  Specific  gravity,  3.82  to 

1 See  O.  Miigge,  Neues  Jahrb.,  Beil.  Band  4,  1886,  p.  581. 

2 Neues  Jahrb.,  1889,  Band  1,  p.  99. 

* Annales  chim.  phys.,  4th  ser.,  vol.  4,  1865,  p.  129. 

* Idem,  5th  ser.,  vol.  29, 1883,  p.  474. 

* Compt.  Rend.,  vol.  115, 1892,  p.  830. 

8 Zeitschr.  anorg.  Chemle,  vol.  73, 1912,  p.  302. 

2 Bull.  U.  S.  Geol.  Survey  No.  60, 1890,  p.  135. 

8 Neues  Jahrb.,  1882,  Band  2,  p.  200. 

9 Idem,  1895,  Band  1,  p.  128. 


ROCK-FORMING  MINERALS.  351 

3.95.  Molecular  volume,  20.5.  Color,  brown,  indigo-blue,  and  black. 
Hardness,  5.5  to  6. 

All  three  modifications  of  titanic  oxido  have  been  studied  synthet- 
ically. Crystals  of  brookite  were  obtained  by  A.  Daubree,1  by  the 
action  of  aqueous  vapor  upon  titanic  chloride  at  a red  heat.  By 
heating  amorphous  titanic  oxide  to  redness  in  a current  of  hydro- 
chloric acid  gas,  H.  Sainte-Claire  Deville  and  H.  Caron 2 transformed 
it  into  a crystalline  modification,  and  similar  results  were  obtained 
by  P.  Hautefeuille  and  A.  Pcrrey.3  By  the  prolonged  heating  of 
titanic  oxide  with  boric  acid  J.  J.  Ebelmen  4 obtained  rutile,  and  P. 
Hautefeuille  5 attained  the  same  end  when  sodium  tungstate  or  vana- 
date was  used  as  flux.  H.  Traube  6 also  crystallized  rutile  from  fused 
sodium  tungstate,  and  was  able  to  add  to  it  appreciable  quantities  of 
iron,  manganese,  and  chromium,  impurities  which  are  found  in  the 
natural  mineral.  Several  investigators  have  prepared  rutile  by  the 
same  general  process,  using  microcosmic  salt  as  the  solvent.  B.  Doss,7 
by  this  method,  prepared  both  rutile  and  anatase.  Deville  and 
Caron  8 also  prepared  rutile  by  heating  titanic  oxide  with  silica  and 
oxide  of  tin  to  redness.  By  heating  ilmenite  and  pyrite  together  at 
about  1,200°,  L.  Michel 9 obtained  a mixture  of  rutile  and  pyrrhotite. 

The  three  forms  of  titanic  oxide  were  reproduced  by  P.  Haute- 
feuille10 by  various  modifications  of  the  same  general  pneumatolytic 
process.  Potassium  titanate  and  calcium  chloride  were  heated  in  a 
current  of  hydrochloric  acid  mixed  with  air,  and  crystals  were  formed. 
Titanic  oxide  with  potassium  or  calcium  fluoride,  or  potassium  silico- 
fluoride,  similarly  treated,  gave  the  same  products,  which,  when  the 
operation  was  conducted  at  a strong  red  heat,  was  rutile.  Brookite 
was  formed  by  heating  potassium  titano fluoride  in  aqueous  vapor, 
and  by  the  action  of  hydrofluoric  acid  upon  titanic  chloride,  at  a 
temperature  not  higher  than  the  boiling  point  of  zinc.  A mixture 
of  titanic  oxide,  calcium  fluoride,  and  potassium  chloride,  heated  in 
a stream  of  hydrochloric  acid,  silicon  fluoride,  and  moist  hydrogen, 
also  gave  brookite,  and  so  did  titanic  oxide,  silica,  and  potassium 
silicofluoride  in  a current  of  hydrochloric  acid  alone.  When  titanic 
fluoride  was  decomposed  by  aqueous  vapor  at  a lower  temperature, 
at  or  near  the  boiling  point  of  cadmium,  octahedrite  was  produced. 
How  far  these  experiments  may  parallel  the  pneumatolytic  processes 
of  nature  is  doubtful;  but  they  show  that  rutile,  the  most  stable 

1 Compt.  Rend.,  vol.  29,  1849,  p.  227. 

8  Idem,  vol.  53, 1861,  p.  161. 

3 Idem,  vol.  110, 1890,  p.  1038. 

< Idem,  vol.  32, 1851,  p.  330. 

6 Cited  by  Bourgeois,  Reproduction  artiflcielle  des  min6raux,  1884,  p.  85. 

8 Neues  Jahrb.,  Beil.  Band  10, 1895-96,  p.  470. 

7 Idem,  1894,  Band  2,  p.  147. 

8 Compt.  Rend.,  vol.  53, 1861,  p.  161. 

9 Idem,  vol.  115,  1892,  p.  1020. 

io  Annales  chim.  phys.,  4th  ser.,  vol.  4, 1865,  p.  129. 


852 


THE  DATA  OF  GEOCHEMISTRY. 


modification  of  titanic  oxide,  is  formed  at  the  highest  temperatures, 
brookite  at  temperatures  considerably  lower,  and  anatase  at  a point 
still  lower  in  the  scale.  These  observations  are  in  harmony  with  the 
known  occurrences  of  the  three  species  as  rock-forming  minerals. 

Rutile  occurs  as  a pyrogenic  mineral  in  eruptive  rocks,  but  it  is 
more  common  in  gneiss,  mica  schist,  and  the  phyllites.  In  a horn- 
blende gneiss  from  Freiberg,  A.  Bergeat 1 observed  rutile,  ilmenite, 
and  titanite,  which  had  formed  as  a single  generation  and  crystallized 
before  the  biotite.  A remarkable  dike  rock  in  Nelson  County,  Vir- 
ginia, described  by  T.  L.  Watson  and  S.  Taber,2  consists  essentially  of 
rutile  and  apatite.  Rutile  is  also  found  as  a secondary  mineral, 
derived  from  ilmenite  and  titanite.  C.  Doelter  3 found  rutile  to  be 
slightly  soluble  in  water,  and  more  so  in  a solution  of  sodium  fluoride. 
From  such  a solution  after  heating  to  145°  during  thirty-four  days 
the  mineral  was  partially  recrystallized.  Possibly  some  secondary 
rutile  may  originate  from  solution  of  the  original  substance,  or  of 
titanic  oxide  leached  from  another  species. 

Brookite  is  not  found  in  fresh  eruptive  rocks,  but  generally  in 
decomposed  granite,  gneiss,  quartz  porphyry,  and  the  sedimentaries. 
Octahedrite  is  never  primary,  but  is  formed  by  the  alteration  of  other 
titanium  minerals.  It  has  been  observed  under  a great  variety  of 
conditions,  as  in  granite,  diabase,  quartz  porphyry,  diorite,  the  crys- 
talline schists,  shales,  sandsto  nes,  and  limestones.4 

Brookite  alters  into  rutile,  and  rutile  into  ilmenite,  anatase,  and 
sphene.  The  titanium  minerals  are  thus  closely  connected  with  one 
another,  and  transformations  are  possible  in  almost  every  direction. 
From  a magma  deficient  in  lime  and  iron,  titanic  oxide  may  separate 
as  rutile;  when  lime  is  abundant,  titanite  or  perofskite  may  form; 
in  presence  of  much  iron  ilmenite  or  pseudobrookite  will  be  deposited. 
Brookite  and  octahedrite  appear  only  as  secondary  minerals. 

CASSITERITE  AND  ZIRCON. 

Cassiterite. — Tetragonal.  Composition,  stannic  oxide,  Sn02.  Mo- 
lecular weight,  151.  Specific  gravity,  6.9.  Molecular  volume,  21.9. 
Color,  commonly  brown  to  black,  rarely  colorless,  red,  or  yellow. 
Hardness,  6 to  7. 

A.  Daubree  5 prepared  cassiterite  by  the  action  of  aqueous  vapor 
upon  tin  tetrachloride  in  a red-hot  porcelain  tube.  H.  Sainte-Claire 
Deville  6 obtained  it  by  passing  gaseous  hydrochloric  acid  over  the 

1 Neues  Jahrb.,  1895,  Band  1,  p.  232. 

2 Bull.  U.  S.  GeoL  Survey  No.  430, 1910,  p.  200. 

s Min.  pet.  Mitt.,  vol.  11, 1890,  p.  325. 

* For  a very  full  summary  of  the  occurrence  of  zircon  and  the  titanium  minerals,  especially  brookite  and 
anatase,  see  H.  Thiirach,  Verhandl.  Phys.  med.  Gesell.  Wlirzburg,  vol.  18,  No.  10, 1884.  On  the  rutile  of 
Nelson  County,  Virginia,  see  G.  P. Merrill,  Eng.  and  Min.  Jour.,  March  8,  1902,  and  T.  L.  Watson,  Eoon. 

Geology,  vol.  2, 1907,  p.  493. 

6 Compt.  Rend.,  vol.  29,  1849,  p.  227. 

6 Idem,  vol.  63, 1861,  p.  101. 


EOCK-FORMTNG  MINERALS. 


353 


amorphous  oxide  of  tin  at  a high  temperature,  and  also  by  acting 
upon  stannous  chloride  with  aqueous  vapor.  According  to  A.  Ditte,1 
stannic  oxide  may  be  crystallized  by  fusion  with  calcium  chloride; 
and  its  crystallization  is  mentioned  by  Deville  and  H.  Caron  2 as 
having  been  effected  by  heating  a fluoride  of  tin  with  boric  oxide. 
The  formation  of  cassiterite  as  a furnace  product  has  several  times 
been  observed,  most  recently  by  A.  Arzruni 3 and  J.  H.  L.  Vogt.4 
In  this  case  it  was  produced  during  the  manufacture  of  pulverulent 
stannic  oxide,  by  the  slow  oxidation  of  metallic  tin.  With  this  excep- 
tion, the  syntheses  of  cassiterite  point  to  its  origin  as  a pneumato- 
lytic  mineral,  and  its  commoner  associations  tell  a similar  story.  It 
is  almost  invariably  accompanied  by  minerals  containing  boric  oxide 
or  fluorine,  such  as  topaz,  tourmaline,  lepidolite,  and  apatite.5 

Cassiterite  is  rarely  found  as  an  original  rock-forming  mineral. 
M.  von  Miklucho-Maclay  6 has  reported  it  accompanied  by  rutile, 
topaz,  apatite,  and  tourmaline,  as  an  inclusion  in  the  mica  of  a gran- 
ite. According  to  R.  Beck,7  it  is  also  an  original  constituent  of 
granite  on  the  islands  of  Banca  and  Billiton.  It  also  occurs,  but 
sparingly,  in  the  lithia-bearing  pegmatites  of  Maine  and  California, 
and,  according  to  L.  C.  Graton,8  as  an  original  constituent  of  pegma- 
tite in  the  Carolinas.  The  relations  of  cassiterite  as  a vein  mineral 
will  be  considered  in  another  connection  later. 

Zircon . — Tetragonal.  Composition,  zirconium  orthosilicate,  ZrSi04. 
Molecular  weight,  183.  Specific  gravity,  4.6  to  4.8.  Molecular  vol- 
ume, 38.7.  Color,  commonly  brown,  but  also  colorless,  yellow,  red, 
bluish,  green,  etc.  Hardness,  7.5. 

Zircon  has  been  repeatedly  produced  synthetically.  H.  Sainte- 
Claire  Deville  and  H.  Caron  9 obtained  it  by  heating  zirconia  in  a 
current  of  silicon  fluoride.  Deville 10  also  prepared  it  by  heating  zir- 
conia with  quartz  in  the  same  gas.  In  the  latter  process,  which  is 
identical  in  character  with  the  former,  zirconium  fluoride  is  formed, 
which  reacts  upon  the  quartz,  regenerating  the  silicon  fluoride.  A 
small  quantity  of  the  latter  substance  may  therefore  generate  an 
indefinite  amount  of  zircon.  P.  Hautefeuille  and  A.  Perrey 11  obtained 
zircon  when  a mixture  of  silica,  zirconia,  and  lithium  molybdate  was 

1 Compt.  Rend.,  vol.  96,  1883,  p.  701. 

2 Idem,  vol.  46, 1858,  p.  766. 

s Zeitschr.  Kryst.  Min.,  vol.  25,  1896,  p.  467. 

4 Idem,  vol.  31, 1899,  p.  279. 

3 For  a list  of  tlie  minerals  occurring  with  cassiterite,  see  W.  Kohlmann,  Zeitschr.  Kryst.  Min.,  vol.  24, 

1895,  p.  350. 

6 Neues  Jahrb.,  1885,  Band  2,  p.  88. 

1 Zeitschr.  Kryst.  Min.,  vol.  33,  1900,  p.  205. 

8 Bull.  U.  S.  Geol.  Survey  No.  293, 1906. 

* Compt.  Rend.,  vol.  46,  1858,  p.  764. 

M Idem,  vol.  52,  1861,  p.  780. 

ii  Idem,  vol.  107,  1888,  p.  1000. 

97270°— Bull.  6i6— 16 23 


354 


THE  DATA  OF  GEOCHEMISTRY. 


heated  to  800°.  Finally,  K.  Chrustschoff 1 effected  the  synthesis  of 
zircon  by  heating  gelatinous  silica  and  gelatinous  zirconia  together, 
under  pressure,  to  a temperature  near  redness.  Deville’s  work  indi- 
cates a possible  pneumatolytic  origin  for  zircon  in  some  instances; 
the  other  processes  seem  to  be  unrelated  to  the  ordinary  occurrences 
of  the  mineral. 

Zircon  is  one  of  the  commonest  accessory  constituents  in  all  classes 
of  igneous  rocks.  It  is  especially  common  in  the  more  silicic  species, 
such  as  granite,  syenite,  diorite,  etc.,  and  in  all  the  younger  eruptives. 
It  is  very  characteristic  of  the  nepheline  syenites.2  It  is  one  of  the 
earliest  minerals  to  crystallize  from  the  cooling  magmas,  and  the 
first  one  among  the  silicates.  With  or  in  place  of  zircon  some  more 
complex  silicates,  such  as  the  zircon  pyroxenes,  may  form.  These 
substances,  however,  are  exceedingly  rare  and  quite  imperfectly 
known. 

PHOSPHATES. 

Apatite. — Hexagonal.  Composition  variable,  two  compounds  being 
included  in  the  species.3  They  are  Ca5(P04)3F  and  Ca5(P04)3Cl. 
Molecular  weight,  504.5  for  fluorapatite  and  521  for  chlorapatite. 
Specific  gravity,  3.17  to  3.23.  Molecular  volume,  159.1  to  161.6. 
Color,  white,  green,  blue,  red,  yellow,  gray,  or  brown.  Hardness,  5. 

The  first  synthesis  of  apatite  was  effected  by  A.  Daubree,4  who 
obtained  it  in  crystals  by  passing  the  vapor  of  phosphorus  trichloride 
over  red-hot  lime.  N.  S.  Manross  5 fused  sodium  phosphate  either 
with  calcium  chloride,  calcium  fluoride,  or  both  together,  and  so 
obtained  chlorapatite,  fluorapatite,  or  a mixture  of  the  two,  resembling 
natural  apatite,  at  will.  This  process,  slightly  modified,  was  also 
adopted  by  H.  Briegleb  6 successfully.  G.  Forchhammer 7 prepared 
chlorapatite  by  fusing  calcium  phosphate  with  sodium  chloride. 
When  bone  ash  or  marl  was  used  instead  of  the  artificial  calcium  phos- 
phate, a mixed  apatite  was  formed.  Similar  results  were  reported  by 
Deville  and  Caron,8  who  fused  bone  ash  with  ammonium  chloride 
and  either  calcium  chloride  or  fluoride,  and  also  by  A.  Ditte,9  who 
repeated  Forchhammer’s  experiment.  By  heating  calcium  phosphate 

1 Neues  Jahrb.,  1892,  Band  2,  p.  232. 

2 For  an  elaborate  discussion  of  the  natural  occurrences  of  zircon,  see  H.  Thiirach,  Verhandl.  Phys. 
med.  Gesell.  Wurzburg,  vol.  18,  No.  10,  1884.  For  zircon  in  the  augite  syenites  of  Norway,  see  W.  C. 
Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16,  1890,  p.  101.  A zirconiferous  sandstone  found  near  Ashland,  Vir- 
ginia, has  been  described  by  T.  L.  Watson  and  F.L.  Hess,  Bull.  Philos.  Soc.  University  of  Virginia,  vol.  1, 
1912,  p.  267. 

3 For  complete  analyses  of  apatite,  with  a discussion  of  its  variations,  see  J.  A.  Voelcker,  Ber.  Deutsch. 
chem.  Gesell.,  vol.  16, 1883,  p.  2460.  For  manganese,  magnesium,  cerium,  etc.,  in  apatite,  see  E.  S.  Dana, 

System  of  mineralogy,  6th  ed.,  pp.  764, 765. 

* Compt.  Rend.,  vol.  32, 1851,  p.  625. 

6 Liebig’s  Annalen,  vol.  82, 1852,  p.  353. 

6 Idem,  vol.  97, 1856,  p.  95. 

2 Idem,  vol.  90,  1854,  pp.  77,  322. 

8 Compt.  Rend.,  vol.  47,  1858,  p.  985. 

9 Idem,  vol.  94,  1882,  p.  1592. 


ROCK-FORMING  MINERALS. 


355 


with  calcium  chloride  and  water,  under  pressure,  at  250°,  H.  Debray  1 
prepared  chlorapatite.  E.  Weinschenk 2 also  produced  it  by  heating 
calcium  chloride,  ammonium  phosphate,  and  ammonium  chloride  at 
temperatures  of  150°  to  180°  in  a sealed  tube.  F.  K.  Cameron  and 
W.  J.  McCaughey 3 prepared  fluorapatite  by  dissolving  calcium 
fluoride  in  fused  disodium  phosphate  and  lixiviating  the  cooled  melt. 
Chlorapatite  was  formed  when  dicalcium  phosphate  was  added  in 
excess  to  molten  calcium  chloride.  When  precipitated  calcium  phos- 
phate was  used,  chlorspodiosite  was  obtained,  Ca3(P04)2.CaCl2. 
B.  Nacken,4  by  fusing  calcium  fluoride  or  chloride  with  calcium  phos- 
phate, obtained  both  species  of  apatite,  and  also  mixed  crystals. 
Apatite  has  been  reported  as  present  in  lead-furnace  slags  by  W.  M. 
Hutchins  5 and  J.  H.L.  Vogt.6  The  composition  of  these  slag  prod- 
ucts, however,  seems  not  to  have  been  verified  by  analysis. 

Apatite  is  found  in  all  classes  of  rocks — igneous,  metamorphic,  and 
sedimentary.  In  the  eruptives  it  appears  as  one  of  the  oldest  secre- 
tions from  the  magma.  It  is  more  common  in  femic  rocks  than  in 
the  more  siliceous  varieties.  Titaniferous  magnetites,  like  those  of 
Norway  and  the  Adirondacks,  often  contain  apatite  in  large  amounts. 
Apatite  also  appears  as  an  important  vein  mineral;  and  in  these  occur- 
rences Vogt7  regards  it  as  having  been  formed  by  pneumatolytic 
agencies.  According  to  E.  Muller,8  apatite  is  strongly  attacked  by 
waters  containing  carbonic  acid.  Both  lime  and  phosphoric  acid 
pass  into  solution.  A carbonated  mineral  allied  to  apatite  has 
been  described  by  W.  Tschirwinsky,9  under  the  name  podolite.  Its 
composition  is  represented  by  the  formula  3Ca3P208.CaC03,  which  is 
that  of  apatite  with  calcium  fluoride  replaced  by  calcium  carbonate. 

Monazite. — Mono  clinic.  Composition,  normally,  cerium  phosphate, 
CeP04,  but  other  rare-earth  metals  are  always  present,  replacing 
cerium.  Molecular  weight,  235.25.  Specific  gravity,  5.  Molecular 
volume,  47.  Color,  yellow,  reddish,  and  brown.  Hardness,  5 to  5.5. 

Xenotime. — Tetragonal.  Composition,  yttrium  phosphate,  YtP04. 
Molecular  weight,  189.  Specific  gravity,  4.5.  Molecular  volume,  42. 
Color,  grayish  white,  yellowish,  reddish,  and  commonly  brown. 
Hardness,  4 to  5. 

Both  monazite  and  xenotime  have  been  prepared  artificially  by  F. 
Badominsky,10  who  fused  the  amorphous  phosphates  of  cerium  or 

1 Compt.  Rend.,  vol.  52,  1861,  p.  44. 

2 Zeitschr.  Kryst.  Min.,  vol.  17, 1890,  p.  489. 

8 Jour.  Phys.  Chem.,  vol.  15, 1911,  p.  464. 

* Centralbl.  Min.,  Geol.  u.  Pal.,  1912,  p.  545. 

6 Nature,  vol.  36,  1887,  p.  460. 

c Mineralbildung  in  Schmelzmassen,  p.  263. 

2 See  his  paper  in  Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  134,  and  also  papers  in  Zeitschr.  prakt. 
Geologie,  1894,  p.  458;  1895,  pp.  367,  444,  465. 

c Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  27,  Min.  pet.  Mitt.,  1877,  p.  25. 

a Centralbl.  Min.,  Geol.  u.  Pal.,  1907,  p.  279.  According  to  W.  T.  Schaller  (Am.  Jour.  Sci.,4thser.,  vol.  30, 
1910,  p.  309),  podolite  is  identical  with  dahllite,  which  was  described  much  earlier. 

M Compt.  Rend.,  vol.  80, 1875,  p.  304. 


356 


THE  DATA  OF  GEOCHEMISTRY. 


yttrium  with  the  corresponding  chlorides.  This  process,  however, 
sheds  no  light  upon  their  genesis  in  nature. 

According  to  O.  A.  Derby,1  these  two  species,  although  they  occur 
sparingly,  are  very  common  accessory  minerals  in  Brazilian  granites 
and  gneisses.  The  monazite  is  principally  found  associated  with 
zircon,  in  residues  from  granite,  syenite,  and  gneiss,  but  not  in  dia- 
base, diorite,  or  minette.  Xenotime  is  a fairly  constant  accessory  in 
muscovite  granite.  It  was  also  found  in  a biotite  gneiss,  but  was 
absent  from  phonolites  and  the  nepheline  or  augite  syenites.  O.  A. 
Derby2  also  reported  a titaniferous  magnetite  from  Brazil,  which 
contained  monazite,  and  still  another  association  of  monazite  with 
graphite.  On  examining  a number  of  granites  and  gneisses  from 
New  England,  Derby  3 found  several  occurrences  of  monazite,  and 
one  of  xenotime.  W.  Ramsay  and  A.  Illiacus4  also  report  the  pres- 
ence of  monazite  in  the  pegmatites  of  Finland.  W.  E.  Hidden5 
found  crystals  of  xenotime,  intergrown  with  zircon,  in  a decomposing 
granite  in  Henderson  County,  North  Carolina. 

Although  it  is  an  inconspicuous  mineral  in  rocks,  monazite  some- 
times accumulates  in  large  quantities  in  residual  sands,  which,  as  a 
source  of  the  rare  earths,  have  important  commercial  value.  The 
Brazilian  monazite  sands  are  described  by  E.  Hussak  and  J.  Reitin- 
ger,6  who  give  very  complete  analyses  of  several  samples.  In  North 
Carolina 7 the  sands  are  derived  from  gneiss,  and  W.  Lindgren 8 
reports  sands  of  granitic  origin  from  the  Idaho  Basin,  Idaho. 

THE  SILICA  MINERALS. 

Quartz. — Rhombohedral.  Composition,  silicon  dioxide,  Si02.  Mo- 
lecular weight,  60.4.  Specific  gravity,  2.65.  Molecular  volume,  22.8. 
Colorless  when  pure,  but  often  tinted  yellow,  violet,  red,  blue,  green, 
brown,  or  black.  Hardness,  7. 

Tridymite. — Hexagonal.  Composition  like  quartz,  Si02.  Specific 
gravity,  2.3.  Molecular  volume,  26.3.  Colorless  or  white.  Hard- 
ness, 7. 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  37, 1889,  p.  109;  vol.  41, 1891,  p.  308. 

2 Idem,  4th  ser.,  vol.  13, 1902,  p.  211. 

3 Proc.  Rochester  Acad.  Sci.,  vol.  1, 1891,  p.  198. 

4 Zeitschr.  Kryst.  Min.,  vol.  31, 1899,  p.  317. 

& Am.  Jour.  Sci.,  3d  ser.,  vol.  36, 1888,  p.  380. 

6 Zeitschr.  Kryst.  Min.,  vol.  37,  1903,  p.  550.  Another  memoir  on  the  Brazilian  sands,  by  A.  Lisboa, 
appears  in  Ann.  Escola  de  Minas,  No.  6,  Ouro  Preto,  1903. 

i See  report  on  monazite  by  H.  B.  C.  Nitze,  Sixteenth  Ann.  Kept.  U.  S.  Geol.  Survey,  pt.  4, 1895,  p.  667. 
This  memoir  contains  a valuable  bibliography.  Another  general  paper  upon  monazite,  thorite,  and  zircon, 
by  P.  Truchot,  may  be  found  in  the  Revue  g6n.  sci.,  vol.  9,  1898,  p.  145,  and,  translated  into  English,  in 
Chem.  News,  vol.  77,  pp.  135,  145. 

s Am.  Jour.  Sci.,  4th  ser.,  vol.  4,  1897,  p.  63.  Also  in  Eighteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3, 
1898,  p.  677.  On  monazite  sand  in  Queensland,  see  Bull.  Imperial  Inst.,  vol.  3,  1905,  p.  233;  and  in  the 
Malay  Peninsula,  idem,  vol.  4, 1906,  p.  301. 


ROCK-FORMING  MINERALS. 


357 


Cristobalite.1 — Pseudocubic.  Composition  like  quartz,  Si02.  Molec- 
ular weight,  60.4.  Specific  gravity,  2.348.  Molecular  volume,  25.7. 
Melting  point,  1,685°. 

The  fused  silica  forms  a glass,  which  can  be  worked  into  flasks, 
crucibles,  beakers,  etc.,  for  chemical  uses.  Quartz,  furthermore,  is 
distinctly  volatile  at  high  temperatures,  as  was  shown  in  a previous 
chapter.2 

Opal . — Amorphous  silica,  carrying  a variable  amount  of  water 
(from  2 to  13  per  cent).  Color,  white,  yellow,  red,  brown,  green, 
blue,  or  gray.  Specific  gravity,  1.9  to  2.3.  Hardness,  5.5  to  6.5. 

Free  silica  occurs  in  nature  in  many  forms,  quartz  and  opal  being 
peculiarly  variable  species.  Chalcedony,  jasper,  agate,  flint,  and 
other  similar  minerals  are  commonly  regarded  as  cryptocrystalline 
quartz  and  often  contain  admixtures  of  amorphous  or  soluble  silica,3 
with  other  impurities. 

The  different  modifications  of  silica  are  readily  prepared  by  simple 
laboratory  methods.  When  an  orthosilicate  is  decomposed  by  a 
strong  acid,  gelatinous  silica  is  formed,  which,  upon  drying,  becomes 
an  amorphous  mass  essentially  identical  with  opal.4  The  siliceous 
sinters  deposited  by  hot  springs  are  all  classed  as  opal.  At  the  hot 
springs  of  Plombi&res,  in  France,  common  opal  and  hyalite  have  been 
formed  by  the  action  of  the  waters  upon  an  ancient  Roman  cement.5 
The  precious  opal,  which  fills  seams  and  cavities  in  igneous  rocks, 
such  as  trachyte,  was  probably  formed  by  the  action  of  hot,  magmatic 
water  upon  the  silicates,  the  latter  being  first  decomposed  and  the 
liberated  silica  being  deposited  in  the  hydrous  form. 

On  the  artificial  production  of  quartz  and  tridymite  there  have  been 
many  researches.  P.  Schafhautl6  simply  heated  a solution  of  col- 
loidal silica  in  a Papin  digester,  and  obtained  a crystalline  deposit 
of  quartz.  H.  de  Senarmont 7 heated  gelatinous  silica  with  water 
and  carbonic  acid,  sometimes  also  with  hydrochloric  acid,  at  tempera- 
tures of  from  200°  to  300°,  with  similar  results.  A.  Daubree8  pro- 

1 See  G.  vom  Rath,  Neues  Jahrb.,  1887,  Band  1,  p.  198;  E.  Mallard,  Bull.  Soc.  min.,  vol.  13, 1890,  p.  172; 
P.  Gaubert,  idem,  vol.  27, 1904,  p.  242.  The  fusing  temperature  is  that  given  by  E.  Endell  and  R.  Rieke, 
Zeitschr.  anorg.  Chemie,  vol.  79, 1912,  p.  258.  According  to  N.  L.  Bowen  (Am.  Join1.  Sci.,  4th  ser.,  vol. 
38, 1914,  p.  218),  it  is  probably  somewhat  higher. 

2 See  also  A.  L.  Day  and  E.  S.  Shepherd  on  quartz  glass,  in  Science,  new  ser.,  vol.  23, 1906,  p.  670.  They 
found  that  quartz  began  to  vaporize  rapidly  at  about  the  temperature  of  melting  platinum— that  is,  be- 
tween 1,700°  and  1,750°. 

3 For  recent  discussions  upon  the  nature  of  chalcedony,  etc.,  see  A.  Michel  L6vy  and  E.  Munier-Chalmas, 
Bull.  Soc.  min.,  vol.  15, 1892,  p.  159;  and  F.  Wallerant,  idem,  vol.  20,  1897,  p.  52.  The  fibrous  varieties, 
quartzine  and  lutecite,  are  especially  considered.  See  also  H.  Hein,  Neues  Jahrb.,  Beil.  Band,  vol.  25, 1908, 
p.  182,  on  the  relation  of  fibrous  silica  to  quartz  and  opal.  According  to  C.  N.  Fenner  ( Jour.  Washington 
Acad.  Sci.,  vol.  2,  p.  476, 1912),  chalcedony  is  probably  a distinct  form  of  silica.  On  gelatinous  silica  in 
an  ore  body,  see  J.  H.  Levings,  Trans.  Inst.  Min.  Met.,  vol.  21,  p.  478, 1911-12. 

4 For  details  concerning  syntheses  of  opal,  see  L.  Bourgeois,  Reproduction  artificielle  des  mm£raux, 

1884,  p.  93. 

6  See  A.  Daubr6e,  Etudes  synth6tiques  de  g^ologie  expdrimentale,  1879,  p.  189. 

6 Cited  by  L.  Bourgeois,  Reproduction  artificielle  des  mindraux,  1884,  p.  80. 

7 Annales  chim.  phys.,  3d  ser.,  vol.  32,  1851,  p.  142. 

8 Compt.  Rend.,  vol.  39,  1854,  p.  135. 


358 


THE  DATA  OF  GEOCHEMISTRY. 


duced  quartz,  together  with  various  silicates,  by  the  action  of  silicon 
chloride  at  high  temperatures  upon  lime,  magnesia,  glucina,  or  alu- 
mina. He  also  obtained  quartz  by  heating  water  to  a temperature 
below  redness  in  a sealed  glass  tube ; 1 and  he  furthermore  observed 
its  deposition  from  the  waters  of  Plombieres.2  To  K.  Chrustschoff  3 
we  are  indebted  for  a series  of  experiments,  based  fundamentally 
upon  the  original  processes  of  Schafhautl  and  Senarmoilt.  He 
obtained  quartz  by  heating  an  aqueous  solution  of  colloidal  silica  to 
250°  for  several  months.  In  his  latest  research  he  added  hydro- 
fluoboric  acid  to  his  solution  of  silica  and  varied  the  temperature. 
At  180°  to  228°  he  obtained  regular  crystals,  resembling  the  form 
of  silica  known  as  cristobalite,  at  240°  to  300°  quartz  was  formed, 
and  at  310°  to  360°  tridymite.  C.  Friedel  and  E.  Sarasin4  pro- 
duced quartz  by  heating,  in  a steel  tube,  caustic  potash,  gelatinous 
silica,  and  amorphous  alumina  nearly  to  redness  during  14  to  38 
hours.  When  the  experiment  was  conducted  at  a higher  tempera- 
ture they  obtained  tridymite  and  quartz  side  by  side.  W.  Bruhns,5 
upon  heating  powdered  glass  to  about  300°  under  pressure,  with 
a weak  solution  of  ammonium  fluoride,  obtained  quartz;  when 
microcline  was  similarly  heated  with  hydrofluoric  acid  for  53  hours 
tridymite  was  formed.  E.  Baur6  obtained  quartz  and  tridymite 
simultaneously,  as  did  Friedel  and  Sarasin,  by  heating  a mixture 
of  silica,  sodium  alumina te,  and  water  for  six  hours  to  520°  in  a 
steel  bomb.  Both  species  and  also  a soda  feldspar  were  produced 
by  J.  Konigsberger  and  W.  J.  Muller7  when  glass  was  heated  to 
300°  and  upward  with  water  alone.  From  the  filtered  and  slowly 
cooled  solution  quartz  and  opal  were  deposited;  the  tridymite  and 
feldspar  were  found  in  the  decomposed  and  undissolved  residue. 
Exceptionally  fine,  doubly  terminated,  and  clear  crystals  of  quartz 
were  obtained  by  E.  T.  Allen8  when  a mixture  of  magnesium  ammo- 
nium chloride,  sodium  metasilicate,  and  water  was  heated  at  400° 
to  450°  during  three  days  in  a steel  bomb. 

All  the  foregoing  experiments  re1  ate  to  the  production  of  quartz 
and  tridymite  in  the  wet  way,  but  dry  methods  have  also  been  suc- 
cessfully employed.  B,.  S.  Marsden 9 reports  the  deposition  of  crystal- 

1 Etudes  synthdtiques  de  geologic  expSrimentale,  1879,  p.  158. 

2 Idem,  p.  175. 

3 Am.  Chemist,  vol.  3,  1873,  p.  281.  Compt.  Rend.,  vol.  104, 1887,  p.  602.  Neues  Jahrb.,  1897,  Band  1,  p. 
240,  Refer  ate. 

4 Bull.  Soc.  min.,  vol.  2, 1879,  pp.  113, 158. 

6 Neues  Jahrb.,  1889,  Band  2,  p.  62. 

6 Zeitschr.  physikal.  Chemie,  vol.  42, 1903,  p.  572.  Questioned  by  A.  L.  Day  and  E.  S.  Shepherd,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  22,  1906,  p.  276. 

2 Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  pp.  339, 353.  The  authors  discuss  at  length  the  relations  between 
quartz  and  tridymite. 

8 Cited  by  Day  and  Shepherd,  op.  cit.,  p.  297. 

9 Proc.  Roy.  Soc.  Edinburgh,  vol.  11,  1880,  p.  37. 


ROCK-FORMING  MINERALS. 


359 


lized  silica  from  solution  in  molten  silver,  but  the  first  definite  work 
upon  this  branch  of  the  subject  is  due  to  G.  Rose.1  He  fused  adularia 
with  microcosmic  salt,  and  amorphous  silica  with  a deficiency  of 
sodium  carbonate,  with  borax,  and  with  wollastonite,  and  in  each  case 
obtained  tridymite.  He  also  observed  the  transformation  of  quartz 
into  tridymite  by  simple  ignition,  whereas  upon  fusion  it  yielded  only 
a glass.  K.  Chrustschoff 2 by  fusing  a rock  rich  in  quartz  also 
obtained  tridymite;  and  K.  B.  Schmutz,3  who  melted  together  a 
granite,  sodium  chloride,  and  sodium  tungstate,  found  plagioclase, 
augite,  and  tridymite  in  the  subsequently  cooled  mass.  H.  Schulze 
and  A.  Stelzner 4 found  tridymite  as  an  accidental  product  in  the 
muffle  of  a zinc  furnace;  and  C.  Velain 5 observed  it  with  anorthite  and 
wollastonite  in  the  glass  formed  by  the  ashes  of  wheat  and  oats  during 
the  combustion  of  a grain  mill.  It  has  also  been  reported  by  A. 
Schwantke6  as  produced  by  the  action  of  lightning  upon  a roofing 
slate.  S.  Meunier7  fused  silica,  caustic  potash,  and  aluminum 
fluoride  together  and  obtained  tridymite.  P»  Hautefeuille  8 heated 
amorphous  silica  with  sodium  or  lithium  tungstate  to  750°,  when 
quartz  was  formed;  but  at  temperatures  from  900°  to  1,000°  tridy- 
mite alone  appeared.  F.  Parmentier,9  repeating  this  experiment  with 
sodium  molybdate,  produced  both  quartz  and  tridymite,  and  so,  too, 
did  P.  Hautefeuille  and  J.  Margottet 10  with  lithium  chloride  as  the 
flux. 

A.  Brun 11  has  transformed  quartz  glass  into  crystallized  quartz  by 
heating  it  in  the  vapors  of  alkaline  chlorides  to  a temperature  between 
700°  and  750°.  Above  800°  and  below  1,000°  tridymite  is  formed 
These  experiments  show  that  quartz  may  be  produced  without  the 
intervention  of  water,  but  it  is  not  always  so  formed.  Quartz 
crystals  often  contain  water  bubbles,  especially  in  pegmatites. 
Rhyolitic  quartz  may  perhaps  conform  to  Brun’s  observations. 

In  recent  years  several  investigations  have  been  reported  which 
had  for  their  purpose  the  determination  of  the  transition  point 
between  quartz  and  tridymite.  C.  Johns  12  found  that  quartz  sand 
was  transformed  to  tridymite  at  1,500°,  and  suggested  that  the  true 
inversion  temperature  might  be  200°  lower.  P.  D.  Quensel13  prepared 

1 Ber.  Deutsch.  chem.  Gesell.,  vol.  2,  1869,  p.  388. 

2 Neues  Jahrb.,  1887,  Band  1,  p.  205. 

3 Idem,  1897,  Band  2,  p.  147. 

* Idem,  1881,  Band  1,  p.  145. 

6 Bull.  Soc.  min.,  vol.  1,  1878,  p.  113. 

6 Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  p.  87.  On  tridymite  and  cristobalite  in  fire-brick,  see  P.  G.  Holm- 
quist,  Geol.  For.  Forhandl.,  vol.  33,  p.  245,  1911. 

7 Compt.  Rend.,  vol.  Ill,  1890,  p.  509. 

s Bull.  Soc.  min.,  vol.  1, 1878,  p.  1. 

9 Cited  by  L.  Bourgeois,  Reproduction  artificielle  des  mindraux,  1884,  p.  81. 

m Bull.  Soc.  min.,  vol.  4, 1881,  p.  244. 

11  Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  25,  1908,  p.  610.  See  also  Vogt,  Min.  pet.  Mitt.,  vol.  25,  1906,  p.  408. 

12  Geol.  Mag.,  1906,  p.  118. 

13  Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  pp.  657,  728.  Quensel  puts  the  melting  point  of  tridymite  as  low 
as  1,560°  and  claims  to  have  observed  incipient  fusion  at  1,500°. 


360 


THE  DATA  OF  GEOCHEMISTRY. 


both  minerals;  first  by  heating  a mixture  of  oligoclase  and  quartz  with 
tungstio  oxide  and  later  from  amorphous  silica  and  the  same  flux. 
According  to  his  data,  quartz  formed  below  1;000°  and  tridymite 
above.  The  figures  obtained  by  A.  L.  Day  and  E.  S.  Shepherd  1 are, 
however,  much  more  precise.  They  found  that  quartz  is  the  unstable 
form  of  silica  at  all  temperatures  above  800°,  and  will  go  over  into 
tridymite  whenever  the  conditions  are  favorable.  On  the  other  hand, 
when  tridymite  is  fused  with  a mixture  of  potassium  chloride  and 
lithium  chloride,  quartz  begins  to  appear  at  about  750°.  When 
quartz  glass  was  devitrified  at  1,200°,  or  crystalline  quartz  was  heated 
to  the  same  temperature,  homogeneous  cristobalite  was  formed. 
According  to  E.  S.  Shepherd,  G.  A.  Rankin,  and  F.  E.  Wright,2  cristo- 
balite can  be  generated  in  pure  melts  of  silica.  More  recently  also 
in  the  same  geophysical  laboratory,  C.  N.  Fenner  3 has  studied  the 
stability  relations  of  the  silica  minerals  in  much  greater  detail  and 
reached  the  following  conclusions:  At  870°  ± 10°,  quartz  is  trans- 
formed to  tridymite.  At  1,470°  ± 10°,  tridymite  passes  over  into 
cristobalite.  The  melting  point  of  cristobalite  is  put  by  Fenner  at 
1,625°,  much  lower  than  the  figure  already  cited  from  Endell  and 
Rieke;  that  of  quartz  is  at  least  155°  lower  still. 

It  is  possible  to  go  even  further  in  the  use  of  1 ‘ quartz  as  a geologic 
thermometer/ ’ to  use  the  significant  expression  of  F.  E.  Wright  and 
E.  S.  Larsen.4  Quartz  exists  in  two  modifications,  which  differ  in 
their  optical  properties,  and  which  also  yield  different  etch  figures  on 
treatment  with  cold  hydrofluoric  acid.  One  of  these,  a quartz, 
exists  only  below  575°;  above  that  temperature  it  passes  into  ft 
quartz,  the  change  being  reversible.  At  ordinary  temperatures  all 
quartz  is  a quartz;  but  if  at  auy  time  it  has  been  heated  above  575°. 
the  fact  is  recorded  in  its  structure  as  shown  by  its  etch  figures. 
Quartz,  therefore,  in  any  rock,  must  have  been  formed  below  800°, 
and  its  peculiarities  indicate  whether  it  was  crystallized  below  or 
above  575°.  Vein  quartz,  and  the  quartz  of  some  pegmatites,  were 
formed  at  the  lower  range  of  temperature;  granitic  and  porphyry 
quartzes  in  the  higher  portion  of  the  scale.  Like  quartz,  tridymite 
and  cristobalite  exist  each  in  two  modifications,  a and  /?;  which, 
with  their  transition  temperatures  have  been  studied  by  Fenner  and 
others.  Silica,  then,  is  known  in  at  least  six  forms,  and  possibly  even 
more. 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  22,  1906,  p.  276.  Cf.  also  G.  Stein,  Zeitschr.  anorg.  Chemie,  vol.  55, 1907, 
p.  159. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  28, 1909,  p.  293. 

3 Idem,  vol.  36,  1913,  p.  331.  See  also  valuable  memoirs  by  K.  Endell  and  R.  Rieke,  Zeitschr. 
anorg.  Chem.,  vol.  79, 1912,  p.  239;  Min.  pet.  Mitt.,  vol.  31, 1912,  p.  501;  A.  Smits  and  K.  Endell,  Zeitschr. 
anorg.  Chem.,  vol.  80, 1913,  p.  176.  The  literature  is  very  voluminous  and  can  only  be  superficially 
treated  here.  The  several  authors  named  give  many  bibliographic  references. 

4 Am.  Jour.  Sci.,  4th  ser.,  vol.  28, 1909,  p.  421.  The  two  modifications  of  quartz  were  first  recognized  by 
H.  Le  Chatelier,  Compt.  Rend.,  vol.  108, 1889,  p.  1046.  See  also  O.  Miigge,  Neues  Jahrb.,  Festband,  1907, 
p.  181,  and  other  authorities  cited  by  Wright  and  Larsen. 


ROCK-FORMING  MINERALS. 


361 


In  all  probability  quartz,  tridymite,  and  cristobalite  are  polymers 
of  the  fundamental  molecule  Si02.  Tridymite  and  cristobalite  are 
the  lower,  less  complex  polymers,  and  therefore  are  more  stable  at 
high  temperatures.  They  are,  moreover,  less  dense  than  quartz,  and 
quartz  glass,  with  still  lower  density,  probably  approximates  most 
nearly  to  the  simple  molecule  Si02.  The  true  formula  of  quartz  is 
probably  not  less  than  Si306,  and  may  be  much  higher.1  The  syn- 
thetic data  all  bear  out  these  conclusions  and  show  the  difficulty  of 
preparing  pyrogenic  quartz  from  magmatic  mixtures. 

J.  Morozewicz  2 has  shown  that  when  an  artificial  magma,  prefer- 
ably aluminous,  is  supersaturated  with  silica,  the  excess  of  the  latter 
separates  out  on  cooling,  partly  as  tridymite  and  partly  as  a pris- 
matic modification  which  has  not  been  further  examined.  A liparite 
magma,  however,  containing  about  1 per  cent  of  tungstic  acid, 
solidifies  as  a mixture  of  quartz,  sanidine,  and  biotite.  The  function 
of  the  tungstic  acid  seems  to  be  to  liberate  silica  at  the  lower  range 
of  temperatures  through  which  quartz  can  form,  while  at  higher  tem- 
peratures the  reverse  reaction  takes  place  and  silica  is  reabsorbed. 
These  conclusions,  as  stated  by  Morozewicz,  are  drawn  from  his  own 
observations,  in  connection  with  the  experiments  by  Hautefeuille, 
which  have  already  been  cited.  The  formation  of  still  a third, 
prismatic  modification  of  silica,  was  also  reported  by  Fouque  and 
Levy,3  who  obtained  it  by  fusing  an  excess  of  silica  with  the  elements 
of  augite,  enstatite,  or  hypersthene. 

Next  to  the  feldspars,  quartz  is  the  most  abundant  mineral  in  the 
crust  of  the  earth.  Tridymite  is  rare.  From  a discussion  of  about 
seven  hundred  analyses  of  igneous  rocks,  in  comparison  with  their 
mineralogical  characteristics,  quartz  appears  to  form  about  12  per 
cent  of  the  entire  lithosphere.4  It  occurs  in  many  forms  and  asso- 
ciations— as  a primary  mineral,  as  a secondary  deposition,  as  a 
cementing  substance,  and  as  the  chief  constituent  of  quartzites  and 
sandstones.  Porphyritic  quartz  is  found  in  such  eruptives  as  quartz 
porphyry,  rhyolite,  dacite,  etc.  Granitic  quartz,  which  is  massive, 
represents  the  youngest  secretion  in  granite,  syenite,  diorite,  etc., 
and  is  peculiarly  rich  in  liquid  or  gaseous  inclusions.  It  is  the  sur- 
plus of  silica  left  over  after  the  bases  have  been  satisfied,  and,  being 
probably  less  in  amount  than  the  eutectic  ratio  demands,  it  remains 
in  solution  to  near  the  end  of  the  solidifying  process.  We  have 
already  noted  and  criticized  Vogt's  conclusions,5  to  the  effect  that 
micropegmatite  is  a true  eutectic  mixture  of  feldspar  and  quartz, 
containing  about  25  per  cent  of  the  latter  mineral;  and  the  glass  base 

1 See  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588,  1914,  p.  13. 

2 Min.  pet.  Mitt.,  vol.  18,  1898,  pp.  158-166. 

3 Synthase  des  mineraux  et  des  roch.es,  pp.  88,  89. 

* F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  228,  1904,  pp.  19,  20. 

6 See  p.  302. 


362 


THE  DATA  OF  GEOCHEMISTRY. 


or  groundmass  of  many  rocks  has  similar  composition.  It  is  easy  to 
understand  from  a consideration  of  the  synthetic  experiments  why 
silica  should  form  glass  during  the  solidification  of  a magma,  but 
the  generation  of  quartz  is  a less  simple  matter.  Lavas  begin  to 
solidify  at  temperatures  above  the  transition  point  of  quartz,  and 
the  development  of  the  latter  in  such  a rock  as  rhyolite  is  probably 
a result  of  very  slow  cooling,  or  even  supercooling.  That  is,  the 
temperature  of  the  cooling  mass  is  probably  held  for  a long  time  just 
below  the  transition  point,  so  that  quartz  forms  instead  of  tridymite. 
The  formation  of  quartz,  especially  in  plutonic  rocks,  is  possibly  also 
conditioned  by  pressure,  and  it  is  likely  that  magmatic  water,  by 
reducing  the  temperature  of  fusion,  may  aid  in  its  deposition.  Under 
great  pressure  the  denser  quartz  should  tend  to  form  rather  than 
tridymite.  The  latter  mineral  is  characteristic  of  volcanic  rocks, 
especially  of  rhyohte,  trachyte,  and  andesite.  The  occurrence  of 
tridymite  in  Mont  Pelee  has  been  especially  studied  by  A.  Lacroix.1 
Rocks  collected  soon  after  the  eruptions  contained  none  of  this  min- 
eral, which  began  to  appear  about  six  months  later.  Lacroix  there- 
fore regards  tridymite  not  as  an  immediate  crystallization  from  the 
magma,  but  as  having  been  formed,  after  cooling,  by  the  action  of 
magmatic  gases  on  the  andesitic  paste.  In  recent  lavas  quartz 
occurs  but  rarely.  In  some  cases,  however,  quartz  has  been  observed 
in  basalts — that  is,  in  rocks  which  are  capable  of  assimilating,  as  sili- 
cates, more  silica  than  they  contain — but  in  most  instances  this 
quartz  is  regarded  as  foreign  and  representing  accidental  inclusions. 
There  are  quartz  basalts,  however,  in  which  the  quartz  appears  to  be 
an  original  and  early  secretion  from  the  magma,  and  these  examples 
are  not  easy  to  explain.  In  fact,  no  final  explanation  of  them  has 
yet  been  proposed.2  The  dissociation  hypothesis,  offered  in  the  pre- 
ceding chapter  to  account  for  the  coexistence  of  quartz  and  mag- 
netite, has  perhaps  the  maximum  of  probability. 

Secondary  quartz  may  be  produced  by  several  processes.  Certain 
hydrous  silicates,  like  talc  and  pectohte,  are  broken  down  by  mere 
ignition,  with  liberation  of  free  silica.  Possibly  this  fact  may  have 
some  bearing  upon  the  formation  of  quartz  as  a contact  mineral. 
Most  silicates  are  decomposable  by  percolating  waters,  and  we  have 
already  seen  that  silica,  in  a greater  or  less  amount,  is  almost  invari- 
ably present  in  springs  and  rivers.  Silica  so  dissolved  is  redeposited 
by  evaporation  as  opal,  but  when  alkalies  are  present,  according  to 

1 Bull.  Soc.  min.,  vol.  28, 1905,  p.  56.  See  also  Lacroix  on  tridymite  from  Vesuvius,  idem,  vol.  31,  1908, 
p.  323. 

2 See  J.  P.  Iddings,  Bull.  U.  S.  Geol.  Survey  No.  66, 1890,  and  Am.  Jour.  Sci.,  3d  ser.,  vol.  36, 1888,  p.  208, 
on  quartz  basalts  from  New  Mexico;  and  J.  S.  Diller,  Bull.  U.  S.  Geol.  Survey  No.  79, 1891 , on  quartz  basalts 
from  California.  Also  a note  by  Diller,  in  Science,  1st  ser.,  vol.  13, 1889,  p.  232,  on  porphyritic  quartz  in 
eruptive  rocks.  In  Bull.  No.  79  Diller  cites  many  references  to  similar  rocks  from  other  localities.  Iddings 
discusses  at  some  length  the  possible  origin  of  the  quartz  but  reaches  no  certain  conclusions. 


ROCK-FORMING  MINERALS. 


363 


G.  Spezia/  quartz  is  formed.  Spezia  also  observed  that  when  opal 
was  heated  with  a solution  of  an  alkaline  silicate  it  was  transformed 
into  an  aggregate  of  quartz  crystals.  At  high  temperatures  a dilute 
solution  of  sodium  silicate  dissolves  quartz  to  some  extent,  but  the 
latter  is  redeposited  at  lower  temperatures.1 2  A 5 per  cent  solution  of 
borax,  under  pressure  and  at  290°  to  315,°  attacks  quartz  strongly, 
but  at  12°  to  16°,  even  under  very  great  pressure,  no  solution  was 
noted.3  These  experiments  by  Spezia  shed  much  light  upon  the 
deposition  of  opal  or  quartz  as  a cementing  material.  There  is  also  a 
suggestive  experiment  reported  by  Ramsay  and  Hunter,4  who  heated 
amorphous  silica  with  water  to  200°  in  a sealed  tube.  In  two  days 
the  silica  had  caked  together  to  a granular  mass  of  glass.  The  quartz 
crystals  which  line  cavities  in  chalcedony  or  wood  opal  may  have  been 
formed  by  the  action  of  alkaline  silicates  upon  the  last-named  min- 
eral. Much  has  been  written  upon  the  solubility  of  quartz,  and  the 
corrosion  of  quartz  pebbles  has  repeatedly  been  noted.5 6  Quartz  may 
be  dissolved  and  replaced  by  pseudomorphs  of  other  minerals,  and 
silicates  are  often  decomposed  by  percolating  waters,  yielding  pseu- 
domorphs of  quartz.  Geological  literature  contains  innumerable 
references  to  replacements  of  this  order.  ✓ 

THE  FELDSPARS. 

Orthoclase. — Monoclinic.  Composition,  KAlSi308.  Molecular  weight, 
279.4.  Specific  gravity,  2.56.  Molecular  volume,  109.1.  Colorless, 
often  reddish  or  yellowish,  sometimes  gray  or  green.  Hardness, 
6 to  6.5. 

Microcline. — Triclinic.  Composition,  specific  gravity,  hardness, 
etc.,  like  orthoclase. 

Albite. — Triclinic.  Composition,  NaAlSi308.  Molecular  weight, 
263.3.  Specific  gravity,  2.605.  Molecular  volume,  101.1.  Colors  as 
in  orthoclase,  commonly  white.  Hardness,  6 to  6.5. 

Anorthoclase. — Triclinic.  Intermediate  in  composition  between 
albite  and  microcline. 

Anorthite. — Triclinic.  Composition,  CaAl2Si208.  Molecular  weight, 
279.1.  Specific  gravity,  2.765.  Molecular  volume,  100.9.  Fuses  at 
1,550°.  Color,  white,  grayish,  reddish.  Hardness,  6 to  6.5. 

1 Jour.  Chem.  Soc.,  vol.  76,  pt.  2,  1899,  p.  300. 

2 Idem,  vol.  78,  pt.  2, 1900,  p.  595. 

3 Idem,  vol.  80,  pt.  2,  1901,  p.  605.  For  Spezia’s  original  papers,  of  which  these  notes  are  abstracts,  see 
Atti.  Accad.  Torino,  vol.  31,  1896,  p.  196;  vol.  33,  1898,  pp.  289,  876;  vol.  35,  1900,  p.  750;  and  vol.  36,  1900- 

1901,  p.  631. 

* Rept.  British  Assoc.  Adv.  Sci.,  1882,  p.  239. 

6 See  C.  W.  Hayes,  Bull.  Geol.  Soc.  America,  vol.  8,  1896,  p.  213;  M.  L.  Fuller,  Jour.  Geology,  vol.  10, 

1902,  p.  815;  and  C.  H.  Smyth,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19, 1905,  p.  277.  On  the  chemical  reactivity  of 
quartz,  due  to  its  solubility,  see  F.  Rinne,  Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  p.  333.  On  the  solubility 
of  quartz  in  alkaline  solutions,  as  conditioned  by  the  fineness  of  its  subdivision,  see  G.  Lunge  and  C.  Mill- 
berg,  Zeitschr.'  angew.  Chemie,  1897,  p.  393.  R.  Schwarz  finds  (Zeitschr.  anorg.  Chemie,  vol.  76, 1912,  p.  422), 
that  the  three  silica  minerals  are  very  different  as  regards  solubility  in  reagents.  Tridymite  and  cris- 
tobalite  dissolve  more  easily  and  rapidly  than  quartz,  and  quartz  glass  more  easily  still. 


364 


THE  DATA  OF  GEOCHEMISTRY. 


There  are  several  minor  additions  to  be  made  to  this  list.  A 
monoclinic  equivalent  of  albite  appears  to  occur  as  an  admixture  in 
many  examples  of  orthoclase,  and  sometimes  is  in  excess  of  the  potas- 
sium compound.  According  to  P.  Barbier  and  A.  Prost 1 this  soda 
orthoclase  is  very  nearly  represented  by  a supposed  albite  from 
Kragero,  Norway.  Similarly,  sodium  may  replace  calcium  in  anor- 
thite,  forming  a triclinic  isomer  of  nephelite,  with  the  formula 
Na2Al2Si208.  This  compound  has  been  prepared  synthetically,  and 
also  identified  by  H.  S.  Washington  and  F.  E.  Wright2  as  a constit- 
uent of  a feldspar  from  the  Island  of  Linosa,  east  of  Tunis.  For  the 
sodium  anorthite  itself,  they  propose  the  name  carnegieite,  and  for 
the  mixed  feldspar,  in  which  it  is  associated  with  albite  and  anorthite, 
the  name  anemousite. 

The  mineral  celsian  may  be  a barium  anorthite,  BaAl2Si208. 
Hyalophane  is  another  barium  feldspar,  which,  however,  is  mono- 
clinic, and  appears  to  be  a mixture  of  a salt  like  celsian  with  ortho- 
clase. Traces  of  barium  are  often  found  in  feldspars. 

Albite  and  anorthite  form  the  extreme  ends  of  a series  of  minerals 
known  as  the  plagioclase  feldspars.  Several  stages  of  mixture  in  this 
series  have  received  distinctive  names,  as  shown  below.  The  symbols 
Ab  and  An  represent  albite  and  anorthite, respectively: 


Oligoclase AbA^i  to  AbaAn^ 

Andesine * AbaA^  to  AbjAnj. 

Labradorite Ab^A^i  to  AbjAng. 

Bytownite AbxAn3  to  AbjAiie. 


These  feldspars  are  generally  regarded  as  isomorphous  mixtures  of 
the  two  end  species;  but  some  authorities  consider  them  as  repre- 
senting definite  compounds,  which,  in  their  turn,  may  commingle 
isomorphously  in  any  proportion.3  The  prevalent  opinion,  however, 
seems  to  be  fully  confirmed  by  the  most  recent  investigations,  espe- 
cially by  those  of  A.  L.  Day  and  his  colleagues,  E.  T.  Allen,  R.  B. 
Sosman,  and  N.  L.  Bowen,4  whose  determinations  of  melting  points 
form  a regular  linear  series.  The  latest  figures,  representing  com- 
plete fusion,  by  Bowen,  are  as  follows : 


Melting  points  of  feldspar. 


°G. 

An 

1,550 

AbxAn5 

1,521 

AbiAn2 

1,490 

AbxAn! 

1,450 

°C. 

Ab2An! 

1,394 

AbgAn! 

1,362 

Ab4Ant 

1,334 

Ab5Ant 

1,265 

1 Bull.  Soc.  chim.,  4th  ser.,  vol.  3, 1908,  p.  894.  W.  T.  Schaller  (Am.  Jour.  Sci.,  4th  ser.,  vol.  30, 1910,  p. 
358)  proposes  to  name  this  soda  orthoclase  barbierite. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  29, 1910,  p.  52.  For  synthetic  data  see  N.  L.  Bowen,  Am.  Jour.  Sci.,  4th 
ser.,  vol.  33, 1912,  p.  551.  He  gives  references  to  earlier  literature. 

s See,  for  example,  W.  Tarrassenko,  Zeitschr.  Kryst.  Min.,  vol.  36,  p.  182, 1902. 

4 Day  and  Allen,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19,  1905,  p.  93.  Day  and  Sosman,  idem,  vol.  31, 1911,  p. 
341.  Bowen,  idem,  vol.  35, 1913,  p.  577. 


ROCK-FORMING  MINERALS. 


365 


These  figures  give  a regular  curve,  but  as  the  albite  end  of  the 
series  is  approached  the  mixtures  become  too  viscous  to  admit  of 
good  melting-point  measurements.  It  should  be  noted  that  the 
observations  were  made  upon  artificial  preparations  of  great  purity. 

Of  all  the  feldspars  anorthite  is  the  one  most  easily  made  pyro- 
genically.  In  the  investigation  by  Day  and  Allen  just  cited  it  was 
prepared  without  difficulty  by  simply  fusing  its  constituent  oxides 
together;  and  this  observation  is  in  accord  with  the  results  obtained 
by  previous  experimenters.  J.  H.  L.  Vogt 1 observed  its  formation 
in  slags,  and  J.  Morozewicz2  repeatedly  obtained  feldspars  varying 
from  labradorite  to  nearly  pure  anorthite  in  his  experiments  with 
artificial  magmas.  Fouque  and  Levy3  obtained  anorthite  directly 
from  its  constituents;  and  S.  Meunier,4  upon  fusing  silica,  lime,  and 
aluminum  fluoride  together,  found  sillimanite,  tridymite,  and  anor- 
thite in  the  resultant  mass.  Anorthite  is  also  formed  by  the  break- 
ing down  of  other  more  complex  silicates.  A.  Des  Cloizeaux,5  by  fus- 
ing garnet  and  vesuvianite,  obtained  crystals  which  Fouque  and  Levy 
identified  as  anorthite;  and  similar  results  are  reported,  with  much 
more  detail,  by  C.  Doelter  and  E.  Hussak.6  Doelter7  also  found 
anorthite  among  the  products  formed  by  fusing  epidote,  axinite,  chab- 
azite,  and  scolecite.  Finally,  C.  and  G.  Friedel8  prepared  anorthite 
in  the  wet  way  by  heating  muscovite  with  lime,  calcium  chloride,  and 
a little  water  to  500°  in  a steel  tube.  Feldspars  analogous  to  anor- 
thite, oligoclase,  and  labradorite,  but  containing  strontium,  barium, 
or  lead  in  place  of  calcium,  were  also  obtained  by  Fouque  and  Levy 9 
when  mixtures  of  silica,  alumina,  sodium  carbonate,  and  the  proper 
monoxide  were  heated  together  to  temperatures  a little  below  the 
point  of  fusion.  Plagioclase  feldspars  containing  potassium  have 
been  made  synthetically  by  E.  Dittler.10  A microcline  from  the 
Ilmen  Mountains,  described  by  W.  Vernadsky,11  contained  rubidium 
to  the  extent  of  3.12  per  cent  Rb20. 

All  attempts  to  prepare  the  alkali  feldspars  by  simple  dry  fusion 
have  failed.  Whether  the  constituent  substances  are  taken  or  the 
natural  minerals  themselves  are  fused,  the  product  is  always  a glass, 
without  any  distinct  evidences  of  crystallization.  Anorthite,  as  we 
have  seen,  crystallizes  easily,  and  the  intermediate  feldspars,  which 
form  without  difficulty  near  the  anorthite  end  of  the  series,  become 

1 Mineralbildung  in  Schmelzmassen,  p.  181. 

2 Min.  pet.  Mitt.,  vol.  18, 1898,  p.  156. 

3 Syntbese  des  mineraux  et  des  roches,  p.  138. 

4Compt.  Rend.,  vol.  Ill,  1890,  p.  509. 

5 Manuel  de  min4ralogie,  vol.  1, 1862,  pp.  277,  543. 

6Neues  Jahrb.,  1884,  Band  1,  p.  158. 

7 Idem,  1897,  Band  1,  p.  1;  Allgemeine  und  chemische  Mineralogie,  p.  183. 

8 Compt.  Rend.,  vol.  110, 1890,  p.  1170. 

0 Synthase  des  mindraux  et  des  roches,  p.  145. 

xo  Min.  pet.  Mitt.,  vol.  29, 1910,  p.  273. 

u Bull.  Soc.  min.,  vol.  36, 1914,  p.  258. 


366 


THE  DATA  OF  GEOCHEMISTRY. 


more  and  more  unmanageable  as  we  approach  albite.  This  fact  was 
observed  by  Fouque  and  Levy1  and  corroborated  by  Day  and  Allen, 
the  latter  having  also  shown  that  the  viscosity  of  the  alkaline  com- 
pounds impedes  their  crystallization,  at  least  within  any  reasonable 
time  which  can  be  allowed  for  a laboratory  experiment.  Allnte,  how- 
ever, may  be  recrystallized,  as  J.  Lenarcic2  has  shown,  when  it  is 
fused  with  half  its  weight  of  magnetite.  The  mixture  forms  a mobile 
liquid  in  which  crystallization  can  take  place.  Other  substances 
also  render  crystallization  possible.  P.  Hautefeuille 3 heated  an 
alkaline  alumosilicate  of  sodium  to  900°-l,000°  with  tungstic  acid 
and  obtained  albite.  A similar  experiment  with  a potassium  alumo- 
silicate yielded  orthoclase,4  and  a mixture  of  silica,  alumina,  and 
acid  potassium  tungstate  gave  the  same  result.  By  heating  a potas- 
sium alumosilicate  mixture  with  alkaline  phosphates  to  which  an 
alkaline  fluoride  had  been  added,  Hautefeuille  5 produced  both  quartz 
and  orthoclase,  and  a potassium  feldspar  was  also  obtained  by  Doel- 
ter  6 when  a mixture  corresponding  to  KAlSi04  was  fused  with  potas- 
sium fluoride  and  silicofluoride.  How  these  extraneous  substances 
act  is  not  clear.  Day  and  Allen,7  repeating  a part  of  Hautefeuille’s 
work,  heated  a powdered  albite  glass  with  sodium  tungstate  and 
succeeded  in  bringing  about  crystallization.  The  fragments  of  glass, 
however,  became  crystalline  without  change  of  form,  and  their  out- 
lines were  unaltered — that  is,  the  transformation  from  the  vitreous 
to  the  crystalline  modification  took  place  without  solution  of  the 
material.  The  mechanism  of  this  reaction  is  quite  unexplained. 

By  hydrochemical  means  the  alkali  feldspars  are  more  easily  pre- 
pared. C.  Friedel  and  E.  Sarasin 8 heated  gelatinous  silica,  precipi- 
tated alumina,  and  caustic  potash  together,  with  a little  water,  to 
dull  redness  in  a steel  tube.  Quartz  and  orthoclase  were  produced. 
In  a later  investigation  9 they  heated  a mixture  having  the  composi- 
tion of  albite,  with  an  excess  of  sodium  silicate,  to  about  500°  and 
obtained  albite.  The  same  process,  essentially,  was  followed  by  K. 
Chrustschoff  ,10  who  heated  an  aqueous  solution  of  dialyzed  silica  with 
a little  alumina  and  caustic  potash  to  300°  during  several  months, 
when  quartz  and  orthoclase  formed.  C.  and  G.  Friedel 11  also  pre- 
pared orthoclase  by  heating  muscovite  with  potassium  silicate  and 
water  to  500°.  In  a series  of  experiments  in  which  amorphous  silica 

1 Synthese  des  min4raux  et  des  roches,  pp.  142-145. 

2 Centralbl.  Min.,  Geol.  u.  Pal.,  1903,  p.  705. 

3 Compt.  Rend.,  vol.  84, 1877,  p.  1301. 

4 Idem,  vol.  85,  1877,  p.  952. 

3 Idem,  vol.  90, 1880,  p.  830. 

6 Neues  Jatirb.,  1897,  Band  1,  p.  1. 

7 Am.  Jour.  Sci.,  4th  ser.,  vol.  19, 1905,  p.  117. 

3 Compt.  Rend.,  vol.  92, 1881, p.  1374. 

8 Idem,  vol.  97, 1883,  p.  290. 

io  Idem,  vol.  104, 1887,  p.  602. 

u Idem,  vol.  110, 1890,  p.  1170, 


ROCK-FORMING  MINERALS. 


367 


was  heated  with  potassium  or  sodium  aluminate  and  water  to  520° 
in  a steel  bomb,  E.  Baur  1 determined  the  conditions  under  which 
quartz  alone,  feldspar  alone,  or  both  together,  could  form.  When 
the  silica  was  in  excess,  quartz  appeared ; with  silica  and  the  alumi- 
nate in  nearly  equal  proportions,  both  minerals  crystallized;  when 
the  aluminate  preponderated  in  the  mixture,  only  feldspar  formed. 

The  feldspars  are  by  far  the  most  abundant  of  all  the  minerals  and 
form  nearly  60  per  cent  of  the  material  contained  in  the  igneous 
rocks.2  Among  the  latter  only  the  pyroxenites,  peridotites,  leucitites, 
and  nephelinites  contain  no  feldspars,  or  at  most  contain  them  in 
quite  subordinate  quantities.  The  monoclinic  alkali  feldspars  are 
especially  characteristic  of  the  more  siliceous  plutonic  rocks,  although 
they  also  occur  in  many 'erup  fives  and  in  metamorphic  schists.  In 
granite,  for  example,  orthoclase,  quartz,  and  muscovite  are  the  con- 
spicuous minerals.  Albite  is  also  found  under  similar  conditions. 
In  the  less  siliceous  rocks,  such  as  gabbro  or  basalt,  the  plagioclases 
are  more  abundant,  and  the  feldspars  approach  anorthite  in  compo- 
sition as  the  proportion  of  silica  in  a magma  decreases.  This  state- 
ment, however,  must  he  construed  as  indicating  a tendency,  not  as 
the  formulation  of  a distinct  rule.  The  more  siliceous  rocks  contain 
preferably  the  more  siliceous  feldspars,  and  vice  versa.  Anorthite 
has  also  been  repeatedly  observed  in  meteorites,  and  it  is  not  uncom- 
mon as  a contact  mineral  in  limestones.3  Orthoclase,  probably  of 
aqueous  origin,  sometimes  occurs  as  a gangue  mineral  in  metalliferous 
fissure  veins.4 

The  feldspars  are  all  highly  alterable  minerals  and  their  alteration 
products  are  both  numerous  and  important.  They  are  attacked  by 
water  alone,  more  so  by  water  containing  carbon  dioxide,  and  still 
more  vigorously  by  acid  waters,  such  as  issue  from  volcanic  vents  or 
are  formed  by  the  oxidation  of  sulphides.  Alkaline  solutions  also 
exert  a powerful  decomposing  action  upon  this  group  of  silicates. 
Among  the  many  experiments  relative  to  this  class  of  reactions  those 
of  A.  Daubree  5 6 are  perhaps  the  most  classic.  Fragments  of  ortho- 
clase were  agitated  with  water  alone  by  revolution  in  a cylinder  of 
iron  during  192  hours.  From  5 kilograms  of  the  feldspar  12.6  grams 
of  K20  were  thus  extracted  and  found  in  the  filtered  solution.  To 
water  charged  with  carbon  dioxide  2 kilograms  of  orthoclase,  after 
10  days  of  agitation,  yielded  0.27  gram  of  K20,  with  0.75  gram  of 

1 Zeitschr.  physikal.  Chemie,  vol.  42,  1903,  p.  567.  The  paper  is  illustrated  by  diagrams  based  upon  the 
phase  rule. 

2 See  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  419, 1910,  p.  9. 

3 For  example,  crystals  of  anorthite  occur  with  epidote  in  the  limestone  of  Phippsburg,  Me.,  and  also 
with  garnet,  scapolite,  etc.,  at  Raymond,  Me.  See  Bull.  U.  S.  Geol.  Survey  No.  113,  1893,  p.  110,  and 
Bull.  No.  167, 1900,  p.  69.  C.  H.  Warren  (Am.  Jour.  Sci.,  4th  ser.,  vol.  11, 1901,  p.  369)  describes  crystals 
of  anorthite  from  the  limestone  of  Franklin,  N.  J.,  near  its  contact  with  granite. 

4 W . Lindgren  (Am.  Jour.  Sci., 4th  ser.,  vol.  5, 1898,  p.  418)  has  described  an  occurrence  of  this  kind  near 

Silver  City,  Idaho.  He  gives  a number  of  references  to  other  localities. 

6 Etudes  synthetiques  de  geologie  experimentale,  1879,  pp.  268-275. 


368  the  data  of  geochemistry. 

v 

free  silica.  With  alkaline  solutions,  especially  at  elevated  tempera- 
tures and  under  pressure,  the  changes  are  even  more  striking,  as  shown 
by  J.  Lemberg’s  investigations.1  Labradorite,  heated  324  hours  to 
215°  with  a sodium  carbonate  solution,  yielded  cancrinite.  Other 
feldspars,  similarly  treated,  but  with  variations  in  detail,  were  trans- 
formed into  analcite.  With  glasses  formed  by  the  fusion  of  feldspars, 
and  with  potassium  carbonate,  zeolites  of  the  chabazite  and  phillip- 
site  series  were  produced. 

The  end  products  of  the  alteration  of  feldspars  are  commonly 
kaolinite  and  quartz.  Other  hydrous  silicates  of  alumina  are  prob- 
ably also  formed.  When  the  alkalies  have  not  been  wholly  withdrawn 
muscovite  is  a common  alteration  product.  Many  of  the  zeolites  are 
generally  interpreted  as  hydrated  feldspars,  those  which  contain  lime 
having  been  derived  from  plagioclase.  From  anorthite  calcite  may 
be  formed.  Scapolites,2  epidote,  and  zoisite  are  also  not  uncommon 
derivatives  of  feldspars.  Finally,  by  substitution  of  bases,  one  feld- 
spar may  pass  into  another,  as  in  the  alteration  of  orthoclase  into 
albite.3 

LEUCITE  AND  ANALCITE. 

Leucite. — Isometric.  Composition,  KAlSi206.  Molecular  weight, 
219.  Specific  gravity,  2.5.  Molecular  volume,  87.6.  Color,  white  to 
gray.  Hardness,  5.5  to  6.  Fuses  at  about  1,420°. 

Analcite. — Isometric.  Composition*  NaAlSi206.H20.  Molecular 
weight,  220.9.  Specific  gravity,  2.25.  Molecular  volume,  98.2. 
Colorless  or  white,  sometimes  tinted  by  impurities.4  Hardness,  5 to 
5.5. 

Although  leucite  and  analcite  are  widely  separated  in  miner alogical 
classification,  one  being  placed  near  the  feldspars  and  the  other 
among  the  zeolites,  they  belong  chemically  together.  They  are  simi- 
lar in  form  and  in  composition,  and  are  connected  by  so  many  rela- 
tions that  they  can  not  be  adequately  studied  apart.  Analcite,  to  be 
sure,  differs  from  leucite  in  respect  to  hydration,  but  G.  Friedel 5 has 
shown  that  its  water  is  not  a part  of  the  essential  crystalline  molecule. 
When  heated  in  sealed  tubes  with  dissociating  ammonium  chloride, 
leucite  and  analcite  both  yield  the  same  ammonium  derivative,6 
NH4AlSi206.  Furthermore,  as  the  experiments  of  J.  Lemberg 7 and 
S.  J.  Thugutt 8 have  shown,  the  two  species  are  easily  convertible,  the 
one  into  the  other.  When  leucite  is  heated  to  180-195°  with  a solu- 


1 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  39,  1887,  p.  559. 

2 See  J.  W.  Judd,  Mineralog.  Mag.,  vol.  8, 1889,  p.  186,  on  the  alteration  of  plagioclase  into  scapolite. 

3 For  an  example  of  this  kind  see  F.  A.  Genth,  Proc.  Am.  Philos.  Soc.,  vol.  20, 1882,  p.  392. 

4 On  variations  in  the  composition  of  analcite,  see  H.  W.  Foote  and  W.  M.  Bradley,  Am.  Jour.  Sci.. 

4th  ser.,  vol.  33, 1912,  p.  433. 

6  Bull.  Soc.  min.,  vol.  19,  1896,  p.  363. 

6 F.  W.  Clarke  and  G.  Steiger,  Bull.  U.  S.  Geol.  Survey  No.  207, 1902. 

7 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  28, 1876,  pp.  537  et  seq. 

8 Mineralchemische  Studien,  Dorpat,  1901,  pp.  100, 101, 


ROCK-FORMING  MINERALS. 


369 


tion  of  sodium  chloride  or  sodium  carbonate,  analcite  is  formed. 
Analcite,  similarly  treated  with  potassium  salts,  is  converted  into 
leucite. 

Leucite  and  analcite  are  both  easily  prepared  synthetically.  Leu- 
cite can  be  formed  by  simply  fusing  together  its  constituent  oxides 
and  cooling  the  mass  slowly.  This  process  was  followed  by  Fouque 
and  Levy,1  who  also  formed  leucite,  with  other  minerals,  from  various 
artificial  magmas.2  By  fusion  of  its  constituents  with  potassium  van- 
adate, P.  Hautefeuille 3 obtained  measurable  crystals  of  leucite.  The 
same  result  followed  the  fusion  of  muscovite  with  potassium  vanadate. 
Syntheses  of  leucite  by  indirect  methods,  with  the  intervention  of 
fluorides  or  of  silicon  chloride,  have  also  been  effected  by  S.  Meu- 
nier 4 and  A.  Duboin.5  C.  Doelter,6  by  fusing  a mixture  equivalent 
to  AU03  + 2Si02  with  sodium  fluoride,  prepared  a soda  leucite, 

NaAlSi206- 

When  microcline  and  biotite  are  fused  together,  leucite  appears 
among  the  products;7  and  Doelter8  found  that  it  was  formed  when 
muscovite,  lepidolite,  or  zinnwaldite  was  fused  alone.  It  was  also 
produced  hydro  chemically  by  C.  and  G.  Friedel 9 when  muscovite  was 
heated  to  500°  in  a steel  tube  with  silica  and  a solution  of  potassium 
hydroxide. 

The  syntheses  of  analcite  have  all  been  effected  under  pressure,  and 
in  the  wet  way.  A.  de  Schulten10  heated  sodium  silicate,  caustic  soda, 
and  water,  in  contact  with  aluminous  glass,  at  a temperature  of  180° 
to  190°.  He  also  produced  analcite  by  heating  a solution  of  sodium 
silicate  with  sodium  aluminate,  in  proper  proportions,  to  180°  for 
eighteen  hours.11  C.  Friedel  and  E.  Sarasin12  prepared  analcite  by 
heating  precipitated  aluminum  silicate  with  sodium  silicate  and  water 
to  500°  in  a sealed  tube.  J.  Lemberg13  derived  analcite  from  andesine 
and  oligoclase  by  prolonged  heating  with  sodium  carbonate  solutions 
at  210°  to  220°.  These  transformations  illustrate  the  ready  formation 
of  analcite  as  a secondary  mineral.  They  are  not,  however,  all  strictly 
similar.  Analcite  derived  from  leucite  can  be  transformed  into  leucite 
again,  as  we  have  already  seen;  but  according  to  S.  J.  Thugutt14  the 

1 Synthese  des  min&aux  et  des  roches,  p.  153. 

2 Bull.  Soc.  min.,  vol.  2, 1879,  p.  Ill;  vol.  3, 1880,  p.  118. 

8 Cited  by  L.  Bourgeois,  Reproduction  artificielle  des  minOraux,  p.  130. 

4 Compt.  Rend.,  vol.  90,  1880,  p.  1009;  vol.  Ill,  1890,  p.  509. 

6 Idem,  vol.  114, 1892,  p.  1361. 

6 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

7 Fouqu6  and  L6vy,  Synthase  des  min&aux  et  des  roches,  p.  77. 

» Loc.  cit. 

9 Compt.  Rend.,  vol.  110, 1890,  p.  1170. 

i°  Idem,  vol.  90, 1880,  p.  1493;  Bull.  Soc.  min.,  vol.  3,  1880,  p.  150. 

m Idem,  vol.  94,  1882,  p.  96. 

12  Idem,  vol.  97,  1883,  p.  290. 

I8  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  39,  1887,  p.  559. 

14  Neues  Jahrb.,  Beil.  Band  9,  1894-95,  p.  604. 

97270°— Bull.  616—16 24 


370 


THE  DATA  OF  GEOCHEMISTRY. 


reaction  with  andesine  is  not  reversible.  The  two  alterations,  there- 
fore, are  chemically  unlike.  Analcite  may  also  be  generated  by  alter- 
ation from  elseolite  and  segirite.1  When  formed  with  other  zeolites, 
it  is  the  earliest  one  to  appear. 

Leucite  is  a mineral  characteristic  of  many  recent  lavas,  but  not 
found  in  the  abyssal  rocks.  Its  absence  from  the  latter  and  older 
depositions  may  be  due  to  its  easy  alteration  into  other  species;  but 
such  an  explanation  is  of  course  only  tentative.  Its  formation  takes 
place  only  when  the  potassium  of  a magma  is  in  excess  over  the 
amount  required  to  form  feldspars.  When  the  excess  is  small,  leucite 
and  feldspar  may  both  appear;  when  it  is  large  enough,  leucite  alone 
forms.  Comparatively  speaking,  it  is  rather  a rare  mineral;  a fact 
which  is  possibly  explained  by  some  observations  of  A.  Lagorio.2  In 
an  artificial  leucite-tephrite  magma,  kept  at  a red  heat,  the  difficultly 
fusible  leucite  crystallizes  out.  If,  then,  the  temperature  is  raised, 
the  mineral  redissolves ; if  lowered,  the  mass  becomes  so  viscous  that 
the  crystallization  of  leucite  ceases.  In  brief,  the  formation  of  leucite 
seems  to  be  possible  only  through  a very  narrow  range  of  tempera- 
tures, and  the  favorable  conditions  do  not  often  occur.3 

Analcite  is  most  frequently  found  as  a secondary  mineral,  the  prod- 
uct of  zeolitization;  and  until  recent  years  it  was  supposed  to  have 
no  other  origin.  It  was  often  noted  in  eruptive  rocks,  but  it  was 
supposed  to  be  always  a product  of  alteration.  It  is  now  generally 
recognized,  however,  that  analcite  may  occur  as  an  original  pyrogenic 
mineral;  but,  being  a hydrated  species,  it  can  so'  appeal*  only  in 
deep-seated  rocks,  where  it  has  been  formed  under  pressure.  W.  Lind- 
gren,4  for  example,  identified  it  in  the  sodalite  syenite  of  Square 
Butte,  Montana.  In  certain  rocks  analcite  has  probably  been  erro- 
neously identified  as  glass;  for  instance,  in  the  monchiquites,  which 
L.  V.  Pirsson 5 interprets  as  analcite  basalts  equivalent  to  the  similar 
leucite  lavas.  W.  Cross,6  has  described  an  analcite  basalt  from  near 
Pikes  Peak,  Colorado,  and  has  also  identified  primary  analcite  in  the 
phonolites  of  Cripple  Creek.7  The  groundmass  of  a tinguaite  from 
Manchester,  Massachusetts,  according  to  H.  S.  Washington,8  consists 
of  analcite  and  nepheline;  and  J.  W.  Evans  9 has  identified  the  min- 
eral in  a monchiquite  from  Mount  Girnar,  India.  In  the  last  instance 
some  of  the  analcite  has  been  transformed  into  a mixture  of  feldspar 
and  nepheline.  The  extreme  case  cf  an  analcite  rock,  however,  is 

1 See  W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16,  1890,  pp.  223, 333. 

2 Zeitschr.  Kryst.  Min.,  vol.  24,  1895,  p.  293. 

s On  the  formation  oi  leucite  in  igneous  rocks,  see  H.  S.  Washington,  Jour.  Geology,  vol.  15,  1907,  pp. 
257,  357. 

* Am.  Jour.  Sci.,  3d  ser.,  vol.  45,  1893,  p.  286. 

8 Jour.  Geology,  vol.  4,  1896,  p.  679. 

6 Idem,  vol.  5,  1897,  p.  684. 

7 Sixteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2,  1895,  p.  36. 

8 Am.  Jour.  Sci.,  4th  ser.,  vol.  6,  1898,  p.  182. 

9 Quart.  Jour.  Geol.  Soc.,  vol.  57, 1901,  p.  38. 


ROCK-FORMING  MINERALS. 


371 


the  heronite  from  Heron  Bay,  Lake  Superior,  described  by  A.  P. 
Coleman.1  This  is  a dike  rock  containing  analcite,  plagioclase,  ortho- 
clase,  and  segirine,  in  which  the  analcite  forms  47  per  cent  of  the  mass. 
In  the  analcite  diabase  described  by  H.  W.  Fairbanks,2  the  analcite 
may  have  been  derived  from  nepheline.  It  is  partly  replaced  by 
feldspar,  and  partly  altered  into  a mineral  which  may  be  prehnite. 
Analcite  also  alters  into  kaolin.3 

Alterations  of  leucite  into  analcite  have  been  repeatedly  observed, 
as  in  the  Saxon  Wiesenthal 4 and  in  the  Highwood  Mountains,  Mon- 
tana.5 The  most  notable  transformation  of  leucite,  however,  is  into 
pseudomorphs  of  mixed  orthoclase  and  nepheline.6  The  “pseudo- 
leucite”  crystals  of  Magnet  Cove,  Arkansas,  are  a mixture  of  this 
kind. 

THE  NEPHELITE  GROUP. 

Nephelite  or  elseolite. — Hexagonal.  Simplest  empirical  formula, 
NaAlSi04.  Corresponding  molecular  weight,  142.5.  Specific  grav- 
ity, 2.55  to  2.65.  Molecular  volume,  54.8.  Melting  point,  1,526°, 
Bowen.  Normally  white  or  colorless;  often  tinted  yellow,  gray, 
greenish,  or  reddish  by  impurities.  Hardness,  5.5  to  6. 

Kaliophilite  or  phacelite. — Hexagonal.  Composition,  KAlSi04. 
Molecular  weight,  158.6.  Specific  gravity,  2.5  to  2.6.  Molecular 
volume,  6.1.  Colorless.  Hardness,  6. 

Eucryptite.  — Hexagonal.  Composition,  LiAlSi04.  Molecular 
weight,  126.5.  Specific  gravity,  2.67.  Molecular  volume,  47.3. 
Colorless  or  white.  Only  known  as  produced  by  the  alteration  of 
spodumene. 

Kaliophilite  and  eucryptite  are  rare  minerals,  having  slight  geo- 
logical significance.  They  are  included  here  because  of  the  light  they 
shed  upon  the  composition  of  nephelite.  The  formula  given  for 
the  latter  species  is  analogous  to  the  formulae  of  kaliophilite  and 
eucryptite,  and  is  also  that  of  the  artificial  mineral.  Natural  neph- 
elite or  elseolite  always  varies  from  the  theoretical  composition,  and 
approximates  more  nearly  the  formula  Na6K2Al8Si9034.  This  varia- 
tion is  probably  due,  first,  to  isomorphous  admixtures  of  kaliophilite, 


1 Jour.  Geology,  vol.  7,  1899,  p.  431. 

2 Bull.  Dept.  Geology  Univ.  California,  vol.  1,  1895,  p.  273.  See  also  B.  R.  Young,  Trans.  Edinburgh 
Geol.  Soc.,  vol.  8,  1903,  p.  326,  on  analcite  diabase  in  Scotland;  C.  W.  Knight,  Canadian  Rec.  Sci.,  vol.  9, 
1905,  p.  265,  on  an  analcite- trachyte  tuff  from  southwestern  Alberta;  and  A.  Pelikan,  Min.  pet.  Mitt.,  vol. 
25,  1906,  p.  113,  on  two  analcite  phonolites  from  Bohemia.  Essexites  and  teschenites  from  Western  Scot- 
land, rich  in  primary  analcite,  are  described  by  G.  W.  Tyrrell,  Trans.  Geol.  Soc.  Glasgow,  vol.  13,  1909, 
p.  299,  and  Geol.  Mag.,  1912,  pp.  66,  120.  On  analcite  basalts  from  Sardinia,  see  H.  S.  Washington,  Boll. 
Soc.  geol.  ital.,  vol.  33,  1914,  p.  147.  A still  later  paper  on  primary  analcite,  by  J.  D.  MacKenzie,  is 
published  in  Am.  Jour.  Sci.,  4th  ser.,  vol.  39, 1915,  p.  571. 

3 W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16, 1890,  p.  199. 

4 See  A.  Sauer,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  37,  1885,  p.  452. 

5 W.  H.  Weed  and  L.  V.  Pirsson,  Am.  Jour.  Sci.,  4th  ser.,  vol.  2, 1896,  p.  315. 

8 See  Sauer,  loc.  cit.;  J.  F.  Williams,  Ann.  Rept.  Geol.  Survey  Arkansas,  1890,  vol.  2,  p.  267;  E.  Hussak, 
Neues  Jahrb.,  1890,  pt.  1,  p.  166;  and  E.  Scacchi,  Rendiconti  Accad.  Napoli,  vol.  24,  p.  315, 


872 


THE  DATA  OF  GEOCHEMISTRY. 


and  possibly  also  to  the  presence  of  silica  or  albite  as  impurities  in 
the  normal  orthosilicate.  This  supposition  is  put  in  more  definite 
shape  by  H.  W.  Foote  and  W.  M.  Bradley/  who  regard  natural 
nephelite  as  the  normal  compound  with  other  silicates  or  silica 
present  in  “solid  solution.”  The  same  hypothesis  may  explain  the 
similar  variations  in  cancrinite,  sodalite,  and  other  species.  The 
expression  “solid  solution,”  however,  should  be  used  with  caution. 
It  probably  confuses  a number  of  different  phenomena,  to  which 
specific  names  quite  properly  belong.  Isomorphous  mixtures  or 
mix-crystals  are  well  known;  occlusion  describes  another  form  of  im- 
purity; a solid  (or  solidified)  solution  like  glass  is  not  at  all  the  same 
as  either  of  the  others.  Under  the  name  pseudonephelite  F.  Zam- 
bonini1  2 has  described  a normal  isomorphous  mixture  from  Capo 
di  Bove  having  the  formula  (Na,K)AlSi04.  The  equivalency  of 
nephelite  and  kaliophilite  is  well  shown  by  an  experiment  of  J.  Lem- 
berg.3 He  heated  elssolite  one  hundred  hours  to  200°  with  a solution 
of  potassium  silicate,  and  obtained  an  amorphous  product  having 
the  composition  KAlSi04. 

P.  Hautefeuille  4 prepared  an  artificial  nephelite  by  fusing  a mix- 
ture of  silica  and  sodium  aluminate  with  a flux  of  lithium  vanadate. 
Fouque  and  Levy  5 obtained  the  mineral  more  directly  by  fusing  its 
constituents  together,  and  so,  too,  did  C.  Doelter.6  Doelter’s  prepara- 
tion agreed  closely  with  the  empirical  formula  NaAlSi04.  Accord- 
ing to  Fouque  and  Levy,  nephelite  is  one  of  the  minerals  which  crystal- 
lize most  easily  from  fusion.  S.  Meunier  7 prepared  nephelite  less 
simply,  by  fusing  silica,  alumina,  and  soda  with  cryolite;  and  A. 
Duboin  8 effected  the  synthesis  of  kaliophilite  when  potassium  fluor- 
ide, alumina,  and  silica  or  potassium  fluosilicate  were  fused  together. 
By  similar  processes  Doelter  9 obtained  both  nephelite  and  kaliophi- 
lite. C.  and  G.  Friedel 10  converted  muscovite  into  nephelite  by  heat- 
ing with  a solution  of  caustic  soda  to  500°  in  a steel  tube.  The  pres- 
ence of  nephelite  in  pseudomorphs  after  leucite  was  noted  in  the 
description  of  the  latter  mineral.  An  amorphous  silicate  having  the 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  31, 1911,  p.  25;  vol.  33, 1912,  p.  439.  Other  recent  discussions  of  the  con- 
stitution of  nephelite  are  by  J.  Morozewicz,  Bull.  Acad.  Sci.  Cracow,  1907,  p.  958;  Silvia  Hillebrand 
Sitzungsb.  Akad.  Wien,  vol.  119,  pt.  1, 1910;  S.  J.  Thugutt,  Compt.  Rend.  Soc.  Sci.  Warsaw,  1913,  p.  856; 
W.  T.  Schaller,  Zeitschr.  Kryst.  Min.,  vol.  50, 1912,  p. 343;  and  N.  L.  Bowen,  Am.  Jour.  Sci.,  4th  ser.,  vol.  33, 
1912,  p.  551. 

2 Jour.  Chem.  Soc.,  vol.  98,  pt.  2, 1910,  p.  1078.  Abst.  from  Rend.  acad.  sci.  fis.  mat.,  Napoli,  1910. 

a Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  37,  1885,  p.  966. 

* Cited  by  Fouqu£  and  L£vy,  Synthase  des  min6raux  et  des  roches,  p.  155. 

6 Loc.  cit. 

6 Zeitschr.  Kryst.  Min.,  vol.  9,  1884,  p.  321. 

i Compt.  Rend.,  vol.  Ill,  1890,  p.  509. 

s Idem,  vol.  115, 1892,  p.  56. 

9 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

10  Compt.  Rend.,  vol.  110,  1890,  p.  1170.  By  the  same  process,  using  caustic  potash  instead  of  soda, 
G.  Friedel  effected  the  synthesis  of  kaliophilite:  Bull.  Soc.  min.,  vol.  35,  p.  470,  1912.  Recent  syntheses  of 
nephelite,  kaliophilite,  and  eucryptite  by  direct  fusion  are  described  by  A.  S.  Ginsberg,  Zeitschr.  anorg, 
Chemie,  voL  73, 1912,  p 277. 


BOCK-FORMING  MINERALS. 


378 


composition  of  nephelite  was  obtained  by  R.  Hoffmann  1 when  kaolin 
and  dry  sodium  carbonate  were  heated  together,  and  a similar  result 
was  reached  by  A.  Gorgeu  2 and  P.  G.  Silber.3  When  Gorgeu  heated 
kaolin  with  potassium  iodide,  a salt  like  kaliophilite  was  formed.  In 
these  reactions  the  temperature  was  kept  below  that  at  which  the 
materials  would  sinter  together. 

Nephelite  is  rarely  found  except  in  igneous  rocks.4  The  glassy 
crystallized  variety  found  in  recent  lavas  is  commonly  known  by  the 
first  name  of  the  species;  the  massive,  opaque,  or  coarsely  crystalline 
mineral  of  the  older  rocks  is  called  elaeolite.  Phonolite,  nephelinite, 
nepheline  basalt,  and  elaeolite  syenite  are  among  the  important  rocks 
in  which  nephelite  is  an  essential  species.  Its  presence  indicates  an 
excess  of  soda  in  a magma  over  the  amount  required  to  form  feld- 
spars, and  it  is  one  of  the  latest  minerals  to  be  deposited.5 6  In  a 
nepheline  syenite  from  an  island  off  the  coast  of  Guinea,  A.  Lacroix 0 
found  crystals  of  sodium  fluoride,  NaF.  This  new  mineral  species 
he  named  villiaumite. 

Nephelite  and  elaeolite  are  peculiarly  subject  to  alteration.7  Na- 
trolite,  analcite,  hydronephelite,  thomsonite,  sodalite,  muscovite,  and 
kaolin  are  among  the  products  thus  formed.  Eucryptite  also  alters 
into  muscovite.8  This  indicates  that  the  simplest  empirical  for- 
mulae of  the  nephelite  minerals  should  be  tripled,  for  the  formula  of 
muscovite  is  Al3(Si04)3KH2. 

THE  CAN CRINITE-  S OD  AEITE  GROUP. 

Cancrinite. — Hexagonal.  Composition  uncertain,  but  probably 
best  represented  by  the  formula  Al3Na4HCSi3015.  Corresponding 
molecular  weight,  511.5.  Specific  gravity,  2.4.  Molecular  volume, 
213.  Color  commonly  yellow,  but  also  white,  gray,  greenish,  bluish, 
or  reddish.  Hardness,  5 to  6. 

Sodalite .9 — Isometric.  Composition  normally  Al3Na4Si3012Cl,  but 
variable.  Molecular  weight,  486.  Specific  gravity,  2.2.  Molecular 
volume,  221.  Color,  white,  gray,  greenish,  yellowish,  reddish,  very 
often  bright  blue.  Hardness,  5.5  to  6. 

Hauynite. — Isometric.  Composition,  Al3Na3CaSSi3016,  but  vary- 
ing in  the  relative  proportions  of  Na  and  Ca.  Molecular  weight, 

1 Liebig’s  Annalen,  vol.  194, 1878,  p.  5. 

2 Annales  chim.  phys.,  6th  ser.,  vol.  10, 1887,  p.  145. 

3 Ber.  Deutsch.  chem.  Gesell.,  vol.  14, 1881,  p.  941. 

* Nephelite  is  reported  by  Max  Bauer  (Neues  Jahrb.,  1896,  Band  1,  p.  85;  1897,  Band  1,  p.  258)  in  certain 

crystalline  schists,  and  also  associated  with  chlorite  in  jadeite. 

6 See  the  experiments  of  J.  Morozewicz,  Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  1, 105.  Compare  also  J.  LenarCifi, 
Centralbl.  Min.,  Geol.  u.  Pal.,  1903,  pp.  705,  743. 

6 Compt.  Rend.,  vol.  146,  1908,  p.  213. 

1 See  W.  C.  Brbgger,  Zeitschr.  Kryst.  Min.,  vol.  16, 1890,  pp.  223  et  seq. 

8 See  G.  J.  Brush  and  E.  S.  Dana,  Am.  Jour.  Sci.,  3d  ser.,  vol.  20, 1830,  p.  266. 

9 A variety  of  sodalite  containing  some  sulphur  has  been  named  hackmannite  by  L.  H.  BorgstrCm, 
Zeitschr.  Kryst.  Min.,  voL  37,  1903,  p.  284.  A sodalite  from  Monte  Somma  containing  molybdenum  Is 
described  by  F.  Zambonini,  Mineralogia  Vesuviana,  p.  214,  under  the  name  molybdosodalite. 


374 


THE  DATA  OF  GEOCHEMISTRY. 


563.6.  Specific  gravity,  2.4  to  2.5.  Molecular  volume,  230.  Color, 
blue,  green,  red,  or  yellow.  Hardness,  5.5  to  6. 

Noselite  or  nosean. — Isometric.  Composition  like  haiiynite,  but 
without  calcium,  Al3Na5SSi3016.  Molecular  weight,  569.5.  Specific 
gravity,  2.25  to  2.4.  Molecular  volume,  242.  Color,  gray,  bluish,  or 
brownish.  Hardness,  5.5. 

Chemically,  these  four  minerals,  together  with  lapis  lazuli  and  the 
rarer  microsommite,  are  to  be  classed  as  derivatives  of  nephelite 
with  which  they  are  commonly  associated.  Their  exact  composition 
is  still  somewhat  uncertain.  The  formula  assigned  to  cancrinite  is 
that  developed  by  F.  W.  Clarke ; 1 the  three  isometric  species  are 
written  as  interpreted  by  W.  C.  Brogger  and  H.  Backstrom,2  who 
have  shown  their  relationship  to  the  garnet  group.  Under  sodalite, 
however,  more  than  one  compound  may  be  included,  as  the  experi- 
ments of  J.  Lemberg 3 and  S.  J.  Thugutt 4 seem  to  indicate.  The  two 
last-named  authorities  regard  these  minerals  as  double  molecular 
compounds  of  a silicate  like  nephelite  with  sodium  carbonate,  chlo- 
ride, sulphate,  etc.  In  support  of  this  view  Thugutt  prepared  a large 
number  of  artificial  compounds  in  which  the  sodium  chloride  of  soda- 
lite was  replaced  by  other  salts ; but  the  new  substances  differed  from 
the  natural  minerals  in  containing  water  of  crystallization.5  A dis- 
cussion of  these  salts,  however,  would  lead  us  too  far  afield. 

An  artificial  cancrinite  was  obtained  by  Lemberg 6 when  alumina, 
sodium  silicate,  and  sodium  carbonate  solution  were  heated  together 
under  pressure;  and  also  by  the  action  of  sodium  carbonate,  fused  in 
its  water  of  crystallization,  upon  elseolite.7  Labradorite,  heated  to 
215°  with  sodium  carbonate  solution,  also  gave  him  cancrinite.8  C. 
and  G.  Friedel 9 prepared  a hydrous  cancrinite  by  heating  muscovite 
to  500°  in  a solution  of  sodium  carbonate  and  caustic  soda.  With 
sodium  sulphate  in  place  of  the  carbonate,  a hydrous  noselite  was 
formed.10  The  same  authors  obtained  sodalite  by  treating  muscovite 
at  500°  with  sodium  chloride  and  caustic  soda.11  Lemberg 12  produced 
sodalite  by  fusing  nephelite  with  common  salt;  and  the  fusion  of 
elaeolite  or  sodalite  with  sodium  sulphate  gave  noselite.13  In  short, 

1 Bull.  U.  S.  Geol.  Survey  No.  588, 1914,  p.  27. 

2 Zeitschr.  Kryst.  Min.,  vol.  18, 1891,  p.  209. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  37,  1885,  p.  969. 

* Mineralchemische  Studien,  Dorpat,  1891. 

6 A '‘chromate  sodalite,”  containing  Na2Cr04,  has  lately  been  described  by  Z.  Weyberg,  Centralbl.  Min. 
Geol.  u.  Pal.,  1904,  p.  727.  It  differs  from  the  hydrated  compound  prepared  by  Thugutt. 

« Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  35, 1883,  p.  593. 

7 Idem,  vol.  37,  1887,  p.  963. 

8 Idem,  vol.  39, 1887,  p.  559.  For  a recent  discussion  of  the  constitution  of  cancrinite  see  Thugutt,  Neues 
Jahrb.,  1911,  Band  1,  p.  25. 

9 Bull.  Soc.  min.,  vol.  14, 1891,  p.  71. 

w Idem,  vol.  13, 1890,  p.  238. 

nCompt.  Rend.,  vol.  110, 1890,  p.  1170. 

11  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  28, 1876,  p.  602. 

» Idem,  vol.  35, 1883,  p.  590. 


ROCK-FORMING  MINERALS. 


375 


the  experiments  of  Lemberg,  which  were  very  numerous,  proved  that 
compounds  of  this  class  could  be  derived,  by  simple  reactions,  from 
nephelite,  and  that  they  are  mutually  convertible,  one  into  another. 
Furthermore,  S.  J.  Thugutt 1 prepared  sodalite  by  heating  natrolite 
with  soda  solution  and  aluminum  chloride  to  195°  under  pressure; 
and  also  from  similar  treatment  of  kaolin  with  common  salt  and  caus- 
tic soda  at  about  212°.2  Sodalite,  then,  has  been  derived  by  artificial 
means  from  elseolite,  muscovite,  and  kaolin.  It  was  also  obtained  by 
Z.  Weyberg3  when  a mixture  of  silica,  alumina,  and  soda  was  fused 
with  a large  excess  of  common  salt. 

In  his  work  upon  artificial  magmas,  J.  Morozewicz 4 prepared 
noselite,  hauynite,  and  sodalite  by  purely  pyrochemical  methods, 
equivalent  to  those  which  produce  these  minerals  in  volcanic  rocks. 
The  fusions  were  effected  at  temperatures  not  exceeding  600°  to  700°, 
for  compounds  of  this  class  are  decomposed  by  an  excessive  heat. 
From  a mixture  of  kaolin,  sodium  carbonate,  and  sodium  sulphate, 
noselite  crystals  were  formed.  From  a more  complex  mixture, 
containing  also  calcium  silicate,  potassium  silicate,  iron  silicate, 
calcium  carbonate,  and  calcium  sulphate,  hauynite  was  produced. 
Kaolin  fused  with  sodium  carbonate  and  sodium  chloride  gave  a com- 
pound having  the  formula  already  assigned  to  sodalite;  elaBolite, 
similarly  treated,  yielded  a substance  richer  in  chlorine.  Moro- 
zewicz concludes  that  two  kinds  of  sodalite  exist;  to  one  he  gives 
the  formula  2(Na2Al2Si208)  +NaCl,  while  the  other  agrees  with 
3(Na2Al2Si208)+2NaCl. 

Cancrinite  occurs  only  in  elaeolite  syenite  and  allied  rocks,  closely 
associated  with  nephelite  and  sodalite.  W.  Ramsay  and  E.  T. 
Nyholm5  have  described  a cancrinite  syenite  in  which  cancrinite  is 
an  important  primary  mineral.  Cancrinite  alters  into  a zeolitic  sub- 
stance, “spreustein,”  in  which  natrolite  is  the  predominating  mineral.6 
Crystallized  sodalite  is  also  found  in  trachyte  and  phonolites,  in 
which  it  separates  after  augite.7  Sodalite  alters  into  hydronephelite 
and  natrolite.  Hauynite  and  noselite  form  in  various  leucitic  and 
nephilinic  rocks  among  the  younger  eruptives.  In  order  of  deposition 
they  are  the  oldest  of  the  feldspathoids. 


iNeues  Jahrb.,  Beil.  Band  9, 1894-95,  p.  576. 

2Mineialchemische  Studien,  p.  18. 

8Centralbl.  Min.,  Geol.  u.  Pal.,  1905,  p.  717. 

« Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  128-147. 

6 Bull.  Comm.  geol.  Finland,  vol.  1,1895,  No.  1.  See  also  I.  G.  Sundell,  idem,  1905,  No.  16. 

6 See  W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16, 1890,  p.  240;  also  L.  Saemannand  F.  Pisani,  Annales 
chim.  phys. , 3d  ser. , vol.  67, 1863,  p.  350. 

7 On  sodalite  syenite  from  Square  Butte,  Montana,  see  W.  Lindgren,  Am.  Jour.  Sci.,3d  ser.,  vol.  45, 1893, 
p.  286.  A sodalite  trachyte  from  Teneriffe  has  been  described  by  H.  Preiswerk,  Centralbl.  Min.,  Geol.  u. 
Pal.,  1909,  p.  393. 


878 


THE  DATA  OF  GEOCHEMISTRY. 


THE  PYROXENES. 

Enstatite. — Orthorhombic.  Composition,  MgSi03,  but  generally 
with  admixtures  of  FeSiOs.  When  10  to  12  per  cent  of  the  latter  salt 
is  present  the  mineral  is  known  as  bronzite.  Minimum  molecular 
weight,  100.8.  Specific  gravity,  3.1.  Molecular  volume,  32.5. 
Color  ranging  from  white  to  olive  green  and  brown.  Hardness,  5.5. 

Hypersthene. — Orthorhombic.  Composition  like  enstatite,  but 
with  FeSi03  predominating.  The  molecular  weight  of  the  latter 
compound  is  132.3.  Color,  greenish  and  brownish  to  black.  Specific 
gravity,  3.4  to  3.5.  Hardness,  5 to  6. 

Enstatite  and  hypersthene,  the  orthorhombic  members  of  the 
pyroxene  group,  are  to  be  regarded  as  mixtures  of  the  two  isomor- 
phous  salts  MgSi03  and  FeSiOs.  Hypersthene  is  also  modified  in 
many  cases  by  the  presence  of  a third  salt,  CaSi03,  but  in  very  subor- 
dinate quantities.  The  enstatite  of  the  Bishopville  meteorite  consists 
of  the  magnesian  silicate  very  nearly  pure.  The  formulae  given  above 
are  minima,  the  actual  formulae  being  multiples  of  them,  at  least 
double,  possibly  more. 

The  first  synthesis  of  supposed  enstatite  was  made  by  J.  J.  Ebel- 
men,1  who  fused  silica,  magnesia,  and  boric  oxide  together.  A. 
Daubree2  obtained  it  repeatedly  in  his  attempts  to  reproduce  the 
characteristics  of  meteorites,  when  meteoric  stones  and  magnesian 
eruptive  rocks  were  fused.  11  Enstatite”  recrystallized  on  cooling  the 
melts.  He  also  prepared  the  same  substance  by  fusing  olivine  with 
silica,  and  he  found  that  when  serpentine  was  melted  it  broke  down 
into  a mixture  of  enstatite  and  olivine.  The  latter  reaction  has 
been  verified  quantitatively  in  the  laboratory  of  the  United  States 
Geological  Survey.  P.  Hautefeuille 3 produced  a silicate  which  he 
identified  with  enstatite,  by  dissolving  amorphous  silica  in  molten 
magnesium  chloride,  and  S.  Meunier  4 * effected  its  synthesis  by  acting 
on  metallic  magnesium  with  silicon  chloride  and  water  vapor. 

Later  investigations,  however,  by  F.  Fouque  and  A.  Michel  Levy,6 
and  also  by  J.  H.  L.  Vogt,6  have  shown  that  the  foregoing  syntheses 
were  misinterpreted.  The  product  obtained  was  in  most  cases,  if 
not  in  all,  a monoclinic  magnesium  metasilicate,  instead  of  the 
orthorhombic  enstatite.  The  latter  form  was  obtained  by  Fouque 
and  Levy7  by  simply  fusing  silica,  magnesia,  and  ferric  oxide  together, 
but  it  was  more  or  less  mixed  with  the  monoclinic  variety. 


lAnnales  chim.  phys.,  3d  ser.,  vol.  33, 1851,  p.  58. 

iCompt.  Rend.,  vol.  62, 1866,  pp.  20C,  369,  660. 

« Annales  chim.  phys.,  4th  ser.,  vol.  4, 1865,  p.  174. 

« Compt.  Rend.,  vol.  90, 1880,  p.  349;  vol.  93, 1881,  p.  737. 

6 Synthase  des  mindraux  et  des  roches,  1882. 

c Mineralbildung  in  Schmeizmassen,  1892,  p.  71. 

7 Loc.  clt. 


ROCK-FORMING  MINERALS. 


877 


In  the  elaborate  research  by  E.  T.  Allen,  F.  E.  Wright,  and  J.  K. 
Clement,1  it  has  been  found  that  magnesium  metasilicate  exists  in 
four  modifications,  two  being  pyroxenes  and  two  amphiboles.  The 
monoclinic  pyroxene  is  formed  whenever  a melt  having  its  composi- 
tion is  allowed  to  crystallize  at  temperatures  a little  below  1,521°. 
It  can  be  crystallized  at  lower  temperatures  from  solution  in  molten 
calcium  vanadate,  magnesium  vanadate,  or  magnesium  tellurite. 
The  other  three  modifications  of  the  silicate  pass  into  this  variety 
when  heated  to  about  1,000°  in  molten  magnesium  chloride  trav- 
ersed by  a stream  of  dry  hydrochloric  acid  gas.  The  monoclinic 
pyroxene,  then,  is  the  most  stable  form  of  magnesium  metasilicate. 
According  to  N.  L.  Bowen  and  O.  Andersen,2  it  has  no  true  melting 
point  but  breaks  down  at  1,557°  into  forsterite  and  silica. 

When  a glass  having  the  composition  of  enstatite  is  devitrified  by 
heating  to  a temperature  above  1,000°  and  below  1,100°,  best  at 
about  1,075°,  the  orthorhombic  enstatite  is  formed.  In  this  way 
good  crystals  were  produced.  At  slightly  higher  temperatures  the 
monoclinic  pyroxene  begins  to  appear.  The  presence  of  enstatite 
in  an  igneous  rock  is  evidence  that  the  final  crystallization  took  place 
at  the  relatively  lower  temperatures,  for  above  them  it  can  not  exist. 
What  the  effect  of  iron  may  be  in  modifying  the  properties  of  these 
silicates  is  as  yet  undetermined. 

Enstatite  and  hypersthene  are  common  pyrogenic  minerals,  and 
occur  in  many  eruptive  rocks.  Enstatite  and  bronzite  are  often  con- 
stituents of  meteorites.  According  to  J.  Morozewicz 3 the  ortho- 
rhombic pyroxenes  separate  from  metasilicate  magmas  when  the 
ratio  Mg  + Fe:Ca.is  3:1  or  greater.  Both  species  undergo  altera- 
tion, through  hydration,  into  talc4  and  serpentine.  Bastite  is  an 
alteration  product  of  this  kind,  having  the  composition  of  serpentine. 

Wollastonite. — Monoclinic.  Composition,  CaSi03.  Minimum  mo- 
lecular weight,  116.5.  Specific  gravity,  2.85.  Molecular  volume, 
40.5.  Color,  white,  often  tinted  by  impurity.  Hardness,  4.5  to  5. 

Calcium  metasilicate  is  known  in  two  modifications — the  natural 
wollastonite  and  an  artificial  pseudohexagonal  form.  The  latter  is 
easily  produced  by  fusing  lime  and  silica  together 5 and  has  been 
repeatedly  observed  in  slags.6  Wollastonite  has  also  been  found  in 
slags,  but  rarely.7  E.  Hussak,8  however,  by  fusing  and  slowly  cool- 
ing a glass  containing  silica,  soda,  lime,  and  boric  acid,  obtained 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  22,  1906,  p.  385. 

2 Idem,  vol.  37, 1914,  p.  487. 

s Min.  pet.  Mitt.,  vol.  18, 1898,  p.  110. 

« See  C.  H.  Smyth,  School  of  Mines  Quart.,  vol.  17,  1896,  p.  333. 

c See  L.  Bourgeois,  Bull.  Soc.  min.,  vol.  5,  1882,  p.  13;  A.  Gorgeu,  idem,  vol.  10, 1S87,  p.  273;  and  C.  Doel- 
ter,  Neues  Jahrb.,  1886,  Band  1,  p.  119. 

c See  J.  H.  L.  Vogt,  Mineralbildung  in  Schmelzmassen,  1892,  pp.  34-80. 

i See  Vogt,  loc.  cit.,  and  P.  Heberdey,  Zeitschr.  Kryst.  Min.,  vol.  26, 1896,  p.  22. 

a Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  101. 


378 


THE  DATA  OF  GEOCHEMISTRY. 


crystals  of  wollastonite.  C.  Doelter  1 also  effected  the  synthesis  of 
wollastonite  by  fusing  calcium  metasilicate  with  sodium  fluoride. 

According  to  E.  T.  Allen  and  W.  P.  White,2  wollastonite  is  stable 
only  below  1,190°,  and  above  that  temperature  it  passes  into  the 
pseudohexagon al  modification.  By  heating  a glass  of  the  composi- 
tion CaSi03  to  between  800°  and  1,000°,  pure  wollastonite  was 
obtained.  The  reverse  change,  from  the  pseudo  variety  to  the 
normal,  was  brought  about  by  dissolving  the  former  in  molten  cal- 
cium vanadate  and  crystallizing  at  a temperature  between  800°  and 
900°.  The  melting  point  of  the  silicate  is  1,540°. 

The  pseudowoflastonite  has  not  yet  been  observed  as  a natural 
mineral,  but  wollastonite  is  common.  The  inference  from  this  fact, 
as  drawn  by  G.  F.  Becker,3  is  that  the  rocks  containing  free  calcium 
metasilicate  must  have  crystallized  at  temperatures  below  the  inver- 
sion point  of  wollastonite,  for  otherwise  its  isomer  would  have 
appeared. 

Although  wollastonite  is  usually  classed  with  the  pyroxenes,  its 
place  among  them  is  doubtful.  It  differs  from  them  in  being  easily 
decomposed  by  acids,  and  its  occurrences  in  nature  are  not  the  same. 
It  is  very  rare  in  eruptive  rocks,  and  is  commonly  found  as  a product 
of  contact  metamorphism,  especially  in  limestones.  It  occurs  also  in 
feldspathic  schists.  H.  Wulf 4 has  described  a rock  from  Hereroland, 
Africa,  which  consisted  of  wollastonite  and  diopside  in  nearly  equal 
proportions.  An  occurrence  of  wollastonite  in  aplite  is  recorded 
by  A.  Lacroix.5  The  alteration  of  wollastonite  to  ordinary  pyroxene 
is  reported  by  C.  H.  Smyth,6  and  an  alteration  to  apophyflite  by 
S.  J.  Thugutt.7  The  secondary  mineral  pectolite,  HNaCa2Si309,  is 
regarded  as  a derivative  of  wollastonite. 

Diopside. — Monoclinic.  Composition,  CaMgSi206.  Molecular  weight, 
217.3.  Specific  gravity,  3.2.  Molecular  volume,  68.  Color,  white, 
yellowish,  green,  and  nearly  black.  Hardness,  5 to  6.  Chrome  diopside 
is  a variety  containing  small  amounts  of  chromium. 

Hedenbergite. — Monoclinic.  Composition,  CaFeSi206.  Molecular 
weight,  248.8.  Specific  gravity,  3.5  to  3.6.  Molecular  volume,  70. 
Color,  grayish  green  to  black.  Hardness,  5 to  6. 

Between  diopside  and  hedenbergite  there  are  various  intermediate 
mixtures.  Schefferite  is  another  monoclinic  pyroxene  containing 

1 Min.  pet.  Mitt.,  vol.  10,  1888,  p.  83.  For  later  work  by  Doelter,  see  Sitzungsb.  K.  Akad.  Wiss.  Wien, 
yoI.  120,  Abth.  1,  p.  339,  1911. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  21, 1906,  p.  89.  See  also  A.  L.  Day,  E.  S.  Shepherd,  and  F.  E.  Wright, 
idem,  vol.  22,  p.  265.  The  synthetic  wollastonite  reported  by  L.  v.  Szathm&ry  (Foldt.  Kozl.,  vol.  39, 1909, 
p.  314)  was  the  pseudomineral.  See  B.  Mauritz,  idem,  p.  505. 

3 Prefatory  note  to  the  memoir  by  Allen  and  White. 

* Min.  pet.  Mitt.,  vol.  8, 1887,  p.  230. 

3 Bull.  Soc.  min.,  vol.  21,  p.  272,  1898. 

c Am.  Jour.  Sci.,  4th  ser.,  vol.  4,  1897,  p.  309. 

7 Centralbl.  Min.,  Geol.  u.  Pal.,  1911,  p.  764. 


ROCK-FORMING  MINERALS. 


879 


manganese,  up  to  over  8 per  cent  of  MnO.  Jeffersonite  is  another 
member  of  this  group  containing  zinc.  These  variations  may  repre- 
sent mixtures  of  the  simple  salts  MnSi03  and  ZnSi03  with  the  lime, 
magnesia,  and  iron  silicates;  but  the  commingled  salts  are  probably 
more  complex.  Rhodonite,  MnSiOs,  is  classed  also  as  a pyroxene, 
but  is  triclinic.  It  can  hardly  be  considered  as  a rock-forming  min- 
eral, at  least  not  in  the  usual  acceptance  of  the  term. 

Monoclinic  pyroxenes  of  the  diopside-hedenbergite  type  have  been 
repeatedly  observed  in  slags.1  A.  Daubree,2  on  heating  water  to 
incipient  redness  in  a glass  tube,  obtained  crystals  of  diopside.  G. 
Lechartier 3 effected  the  synthesis  of  these  pyroxenes  by  fusing  silica, 
lime,  and  magnesia  with  an  excess  of  calcium  chloride.  When  ferric 
oxide  was  added  to  the  mixture,  iron  pyroxenes  were  formed.  In 
the  experiments  of  J.  Morozewicz  4 with  artificial  magmas  these  min- 
erals were  deposited  when  the  ratio  Mg  + Fe:Ca  was  less  than  3:1. 
Clear  and  perfect  crystals  of  diopside  have  been  prepared  by  E.  T. 
Allen  and  W.  P.  White,5  who  heated  glass  of  the  theoretical  composi- 
tion in  a flux  of  calcium  chloride  and  an  atmosphere  of  hydrochloric 
acid  to  1,000°  for  several  weeks.  The  specific  gravity  of  the  artificial 
mineral  was  3.275  and  the  melting  point  1,380°.  They  found  that 
diopside  is  the  only  stable  compound  between  its  component  silicates, 
although  two  eutectics  were  observed. 

The  monoclinic  pyroxenes  are  common  in  eruptive  rocks  and  the 
crystalline  schists.  The  variety  known  as  diallage  is  especially 
characteristic  of  gabbro.  They  also  occur  as  secondary  minerals. 
R.  Brauns  6 has  observed  the  variety  salite,  as  formed  in  a picrite  by 
the  action  of  aqueous  solutions  upon  olivine  and  plagioclase. 

Acmite  or  segirite. — Monoclinic.  Normally  NaFe,//Si206,  but  often 
containing  ferrous  and  lime  silicates  in  isomorphous  admixture. 
Molecular  weight,  231.7.  Specific  gravity,  3.53.  Molecular  volume, 
65.6.  Color,  brownish,  greenish,  to  black.  Hardness,  6 to  6.5. 

Jadeite. — Monoclinic.  Composition,  NaAlSi206.  Molecular  weight, 
202.9.  Specific  gravity,  3.34.  Molecular  volume,  60.8.  Color,  white 
and- various  shades  of  green.  Hardness,  6.5  to  7. 

Spodumene. — Monoclinic.  Composition,  LiAlSi2Oc.  Molecular 

weight,  186.9.  Specific  gravity,  3.17.  Molecular  volume,  58.9. 
Color,  white,  yellow,  green,  and  amethystine.  Hardness,  6.5  to  7. 
Hiddenite  is  the  emerald-green  gem  spodumene  from  North  Carolina. 
Kunzite  is  the  amethystine  gem  variety  from  California. 

1 See  citations  in  L.  Bourgeois,  Reproduction  artiflcielle  des  min4raux,  pp.  115-116;  and  Fouqu4  and 

L4vy,  Synthase  des  min4raux  et  des  roches,  pp.  102-103.  Also  G.  J.  Brush,  Am.  Jour.  Sci.,  2d  ser.,  vol. 
39, 1865,  p.  13i 

3 Etudes  synth4tiques  de  geologie  exp4rimentale,  pp.  159-176. 

8 Compt.  Rend.,  vol.  67,  1868,  p.  41.  Compare  A.  Gorgeu,  Bull.  Soc.  min.,  vol.  10,  1887,  pp.  273,  276. 

4 Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  123  et  seq.  See  also  J.  H.  L.  Vogt,  Die  Silikatschmelzlosungen,  pt. 

1, 1903,  pp.  28-49. 

& Am.  Jour.  Sci.,  4th  ser.,  vol.  27,  1909,  p.  1. 

o Nenes  Jahrb.,  1898,  Band  2,  p.  79. 


380 


THE  DATA  OF  GEOCHEMISTRY. 


These  alkali  pyroxenes,  as  they  are  often  called,  are  interesting  on 
account  of  their  constitutional  similarity.  Acmite,  however,  is  the 
most  important  as  a rock-forming  mineral,  although  in  the  inter- 
pretation of  mixed  pyroxenes  the  jadeite  molecule  must  often  be 
taken  into  account.  Spodumene  occurs  only  sporadically — usually, 
if  not  always,  in  pegmatite — and  is  peculiarly  noticeable  on  account 
of  the  immense  size  which  its  crystals  may  attain.  Crystalline  faces 
of  spodumene  many  feet  in  length  have  been  observed  in  the  Black 
Hills  of  South  Dakota.  The  alteration  of  spodumene,  as  studied  by 
A.  A.  Julien,1  and  more  exhaustively  by  G.  J.  Brush  and  E.  S.  Dana,2 
is  very  instructive.  First,  by  the  action  of  percolating  solutions  con- 
taining soda,  it  is  transformed  into  a mixture  of  eucryptite,  LiAlSi04, 
and  albite,  NaAlSi308.  Then,  by  the  further  action  of  potassium 
salts,  the  eucryptite  i3  altered  into  muscovite,  KH2Al3Si3012.  Albite 
and  muscovite  are  the  final  products  of  these  metamorphoses.  The 
intimate  mixture  of  these  two  compounds  was  long  thought  to  be  a 
distinct  mineral,  cymatolite. 

Acmite  can  be  produced  synthetically,  but  its  constituent  oxides, 
when  fused  together,  commonly  yield  only  a glass  containing  crystals 
of  magnetite.  Acmite,  when  fused,  resolidifies  as  a mixture  of  mag- 
netite and  glass.3  C.  Doelter,4 *  however,  from  the  fusion  of  an  arti- 
ficial mixture  of  the  oxides,  obtained  some  acmite.  H.  Backstrom  6 
fused  silica,  ferric  oxide,  and  sodium  carbonate,  mingled  in  the 
proper  proportions,  together  and  held  the  solidified  mixture  at  a dull 
red  heat  for  three  days.  Under  those  conditions  acmite  was  formed. 
He  also  obtained  it  by  fusing  a leucite  phonolite  and  subjecting  the 
glass  to  a similar,  very  slow  devitrification.  Z.  Weyberg  6 also  ob- 
tained acmite  by  fusing  a mixture  of  the  composition  2Si02  + Fe208  + 
Na20  with  a large  excess  of  sodium  chloride.  According  to  J.  Moro- 
zewicz,7  the  acmite-j  adeite  compounds  form  in  metasilicate  magmas 
when  the  silica  amounts  to  less  than  50  per  cent.  The  exact  condi- 
tions of  their  generation,  however,  with  respect  to  temperature  and 
rate  of  cooling,  are  yet  to  be  determined. 

Several  attempts  have  been  made  toward  the  synthesis  of  spodu- 
mene. By  fusing  together  lithium  carbonate,  alumina  and  silica  K. 
Ballo  and  E.  Dittler 8 obtained  several  silicates,  one  having  the  com- 
position of  spodumene,  and  another  that  of  eucryptite.  The  artificial 
spodumene,  however,  differs  from  the  natural  mineral  in  its  optical 
properties,  and  is  designated  /?  spodumene.  The  natural,  a mineral 


1 Annals  New  York  Acad.  Sci.,  vol.  1,  1879,  p.  318. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  20,  1880,  p.  257. 

* M.  Vu6nik,  Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  p.  369. 

* Neues  Jahrb.,  1897,  Band  1,  p.  16. 

8 Bull.  Soc.  min.,  vol.  16, 1893,  p.  130. 

8 Centralbl.  Min.,  Geol.  u.  Pal.,  1905,  p.  717. 

7 Min.  pet.  Mitt.,  vol.  18,  1898,  p.  123. 

8 Zeitschr.  anorg.  Chemie,  vol.  76, 1912,  p.  39. 


BOCK-FORMING  MINERALS. 


381 


is  transformed  at  about  1,000°  into  the  other,  which  melts  at  1,380°. 
Similar  results  have  since  been  obtained  by  F.  M.  Jaeger  and  A.  Simek,1 
who  found  the  transition  temperature  from  a to  $ spodumene  to  be 
995°,  and  the  melting  point  1,417°.  Natural  kunzite  fused  at  1,428°, 
and  the  artificial  orthosilicate,  a pseudoeucryptite  ” at  1,388°. 

Acmite  is  a mineral  of  eruptive  rocks,  generally  of  those  which 
contain  leucite  or  nephelite.  It  is  especially  common  in  elseolite 
syenite.  Concerning  the  petrologic  relations  of  jadeite  less  is  known; 
but  S.  Franchi 2 has  identified  the  mineral  as  an  essential  constituent 
of  certain  eruptive  rocks  in  Piedmont.  Acmite  or  segirite,  according 
to  W.  C.  Brogger,3  alters  into  analcite.  J.  Lemberg,4  by  heating 
spodumene  or  jadeite  with  alkaline  solutions  under  pressure,  also 
obtained  analcite.  Jadeite  alone  is  slowly  attacked,  but  the  glass 
resulting  from  its  fusion  is  altered  readily.  It  is  noticeable  that 
jadeite  and  dehydrated  analcite  have  the  same  empirical  composition; 
but  the  denser  jadeite  molecule  is  doubtless  the  more  complex. 
The  one  is  a polymer  of  the  other.  These  alterations,  natural  or 
artificial,  emphasize  the  constitutional  similarity  of  the  three  alkali 
pyroxenes. 

Augite. — Monoclinic.  Composition  very  variable,  for  augite  is  an 
isomorphous  mixture  of  several  different  silicates.  Specific  gravity, 
2.93  to  3.49.  Color,  white,  green,  brown,  and  black.  Hardness,  5 
to  6. 

Augite  is  essentially  a metasilicate  of  lime,  magnesia,  and  ferrous 
iron,  plus  silicates  of  ferric  iron  and  alumina.  Manganese  and 
alkalies  are  often  present,  and  some  varieties  contain  titanic  oxide 
up  to  4.5  per  cent.  In  addition  to  silicate  molecules  analogous  to 
those  of  the  pyroxenes  already  described,  augite  is  supposed  to  con- 
tain a compound  of  the  form  R/'Al2Si06,  which,  however,  is  hypo- 
thetical. The  rare  mineral  komerupine  or  prismatine,  however,  has 
the  formula  MgAl2Si06,  and  may  represent  the  aluminous  con- 
stituent of  the  nonalkaline  augites.5 6  When  alkalies  are  present  they 
probably  represent  molecules  analogous  to  or  identical  with  acmite 
and  jadeite. 

1 Abst.in  Chem.  Zentralbl.,  1914,  ii,  pp.  1026,  1027.  See  also  K.  Endell  and  R.  Rieke,  Zeitschr.  anorg. 
Chemie,  vol.  74,  1912,  p.  33;  who  give  950°  as  the  melting  point  of  natural  spodumene.  For  an  earlier 
research  on  the  lithium-aluminum  silicates  see  P.  Hautefeuille,  Compt.  Rend.,  vol.  90, 1880,  p.  541. 

2 Rendiconti  R.  accad.  Lincei,  vol.  9,  pt.  1, 1900,  p.  349.  On  the  jadeite  of  Upper  Burma,  see  A.  W.  G. 

Bleeck,  Zeitschr.  prakt.  Geologie,  1907,  p.  341. 

s Zeitschr.  Kryst.  Min.,  vol.  16, 1890,  p.  333.  Brogger  cites  many  references  to  the  literature  of  acmite. 

< Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  39, 1887,  p.  584. 

6 A more  complex  formula,  NaHsMgeAlwSbO^,  has  been  assigned  to  kornerupine  by  J.  Uhlig,  Zeitschr. 
Kryst.  Min.,  vol.  47,  1910,  p.  215. 


382 


THE  DATA  OF  GEOCHEMISTRY. 


The  following  analyses  of  rock-forming  augite  1 were  all  made  in 
the  laboratory  of  the  United  States  Geological  Survey: 

Analyses  of  augite. 

A.  From  nepheline  basalt,  Black  Mountain,  Uvalde  quadrangle,  Texas.  W.  F.  Hillebrand,  analyst. 

B.  From  dolerite,  near  Valmont,  Colorado.  Analyzed  by  L.  G.  Eakins. 

C.  From  tinguaite,  Two  Buttes,  Colorado.  Analyzed  by  Hillebrand. 

D.  From  granite,  Silver  Cliff,  Colorado.  Eakins,  analyst. 

E.  From  a dyke,  Silver  Cliff.  Eakins,  analyst. 

F.  From  basalt,  Mount  Taylor  region,  New  Mexico.  Analyzed  by  T.  M.  Chatard. 


A 

B 

c 

D 

E 

F 

Si02 

45. 23 

49.10 

47.  54 

48.  72 

54.87 

47.  06 

Ti02 

4.  28 

3.00 

1.  82 

7.  73 

7.  95 

4. 14 

9. 27 

6. 34 

7.  77 

CrK 

Trace. 

Trace. 
1. 30 

Fe203 

2.  95 

5.  64 

3.  77 

2. 88 

FeO 

4.  07 

8. 30 

6. 42 

6.34 

4.  61 

8. 15 

MnO 

. 07 

.36 

.34 

.14 

.20 

MgO 

12.  25 

12.37 

10.  05 

14.  67 

14. 47 

13.  52 

CaO : 

23. 37 

22.  54 

21.  57 

16.  79 

15. 87 

19.  33 

Na20 

.47 

Trace.. 

1.  38 

.19 

.28 

.33 

K20 

.12 

Trace. 

. 12 

.11 

NiO 

.05 

Trace. 

Trace. 

F oOe 

None. 

.06 

.37 

.18 

.31 

.20 

2V  

100.  96 

100. 26 

100. 22 

100.  27 

99.  77 

99.  85 

Augite  is  a common  mineral  in  slags,2  and  is  easily  produced  from 
its  constituents  by  simple  fusion.3  It  was  repeatedly  obtained  by 
Fouque  and  Levy,4  both  by  itself  and  in  association  with  other  miner- 
als, in  their  classic  experiments  upon  the  synthesis  of  rocks.  J. 
Morozewicz5  also  has  found  both  ordinary  augite  and  the  alkaline 
varieties  in  the  products  yielded  by  his  artificial  magmas.  The  mole- 
cule RAl2Si06  is  generally  formed  from  magmas  containing  over  50 
per  cent  of  silica;  and  its  alumina  appears  to  be  the  residue  left  over 
after  the  feldspars,  feldspathoids,  and  micas  have  been  satisfied. 

When  garnet,  vesuvianite,  or  epidote  is  fused  augitic  minerals 
appear  among  the  compounds  produced.6  Biotite  and  clinochlore 
also  yield  it  among  the  products  of  their  thermal  decomposition.7 
C.  Doelter 8 found  that  augite  was  formed  when  diopside  was  fused 
with  alumina  or  ferric  oxide;  and  from  mixtures  of  silica  with  the 
proper  bases  he  obtained  crystals  rich  in  RAl2Si06.  According  to 
J.  Lenarcic,9  magnetite  and  labradorite,  fused  together,  yield  augite. 


1 From  Bull.  U.  S.  Geol.  Survey  No.  419, 1910,  pp.  262, 263. 

2 See  J.  H.  L.  Vogt,  Mineralbildung  in  Schmelzmassen,  p.  34. 

8 For  early  syntheses,  see  Fouqu6  and  Levy,  Synthese  des  min^raux  et  des  roches,  p.  102. 

<Op.  cit.,  pp.  60,  67,  105. 

8 Min.  pet.  Mitt.,  vol.  18,  1898,  pp.  107,  113, 120, 123, 124. 

8 C.  Doelter,  Allgemeine  chemische  Mineralogie,  pp.  182, 183. 

7Doelter,  Neues  Jalirb.,  1897,  Band  1,  p.  1. 

8Idem,  1884,  Band  2,  p.  51. 

Centraibl.  Min.,  Geol.  u.  Pal.,  1903,  pp.  705, 743. 


ROCK-FORMING  MINERALS. 


383 


So,  too,  does  hedenbergite  when  fused  with  anorthite,  albite,1  or 
corundum.2 

Several  other  minerals  in  addition  to  those  already  named  are 
classed  as  pyroxenes,  but  they  are  too  rare  to  need  more  than  a pass- 
ing mention  here.  The  so-called  zircon  pyroxenes,  rosenbuschite, 
lavenite,  wohlerite,  and  hiortdahlite  are  found  in  the  elaeolite  syenites 
of  Norway.  The  triclinic  babingtonite  is  interesting,  for  it  contains, 
in  addition  to  the  molecular  types  found  in  the  other  pyroxenes,  the 
ferric  silicate  Fe2Si309.  It  has  been  found  not  only  as  a natural 
mineral,  but  also  as  a furnace  product  in  slag.3 

Augite,  among  the  pyrogenic  minerals,  is  to  be  classed  as  one  of 
the  older  secretions.  It  is  common  in  igneous  rocks  of  nearly  all 
classes,  and  the  pyroxenes  in  general  are  the  most  important  of  the 
so-called  ferromagnesian  minerals.  Some  rocks,  the  pyroxenites,  con- 
sist of  pyroxenes  almost  entirely;  websterite,  for  instance,  is  formed 
of  bronzite  and  diopside.  The  most  striking  alteration  of  pyroxene 
is  into  hornblende,  but  it  also  alters  into  tremolite,4  chlorite,  serpen- 
tine, talc,  mica,  garnet,  epidote,  and  glauconite.  The  pyroxenes, 
furthermore,  occur  as  important  secondary  minerals  sometimes  as 
the  product  of  contact  metamorphism  in  limestones,  sometimes  as 
marginal  zones  derived  from  olivine.5  Diallage  and  hypersthene 
rocks  alter  into  amphibolites.6 

Note. — For  theoretical  discussions  upon  the  constitution  of  the  pyroxenes  see  G. 
Tschermak,  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  21,  1871,  Min.  pet.  Mitt.,  p.  17. 
C.  Doelter,  Min.  pet.  Mitt.,  vol.  2,  1879,  p.  193.  F.  W.  Clarke,  Bull.  U.  S.  Geol. 
Survey  No.  588,  1914.  J.  W.  Retgers,  Zeitschr.  physikal.  Chemie,  vol.  16,  1895, 
p.  614.  P.  Mann,  Neues  Jahrb.,  1884,  Band  2,  p.  172.  A.  Merian,  idem,  Beil.  Band  3, 
1884,  p.  252.  The  literature  upon  this  subject  is  very  voluminous. 

THE  AMPHIBOLES. 

Anthophyllite. — Orthorhombic.  Composition  like  enstatite  or 
bronzite  (Mg,Fe)  Si03,  with  the  magnesium  silicate  predominating. 
Specific  gravity,  3 to  3.2.  Color,  gray,  brown,  green,  and  intermedi- 
ate shades.  Hardness,  5.5  to  6.  Gedrite  is  a variety  containing  usu- 
ally more  iron  and  much  alumina.  As  an  amphibole,  anthophyllite 
corresponds  to  hypersthene  among  the  pyroxenes.7 

Tremolite. — Monoclinic.  Composition,  CaMg3Si4012.  Molecular 

weight,  370.1.  Specific  gravity,  2.9  to  3.1.  Molecular  volume,  123. 
Color,  white  to  gray.  Hardness,  5 to  6. 


i M.  Vufinik,  Centralbl.  Min.,  Geol.  u.  Pal.,  1904,  pp.  300,  342. 

2B.  Vukits,  idem,  1904,  p.  705. 

* See  L.  Buchrucker,  Zeitschr.  Kryst.  Min.,  vol.  18, 1891,  p.  626. 

* See  H.  Ries,  Annals  New  York  Acad.  Sci.,  vol.  9, 1896-97,  p.  124,  in  an  important  memoir  upon  the 
pyroxenes  of  New  York. 

8 See  G.  H.  Williams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  31, 1886,  p.  35,  and  F.  D.  Adams,  Am.  Naturalist,  vol. 
19, 1885,  p.  1087.  Williams  gives  a number  of  references  to  alterations  of  this  kind. 

8 Williams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  28, 1884,  p.  258. 

7 An  iron  anthophyllite,  FeSiC>3,  associated  with  the  fayalite  of  Rockport,  Massachusetts,  has  been 
described  by  C.  H.  Warren,  Am.  Jour.  Sci.,  4th  ser.,  vol.  16, 1903,  p.  337. 


384 


THE  DATA  OF  GEOCHEMISTRY. 


Adinolite. — Like  tremolite,  but  with  iron  partly  replacing  mag- 
nesium. Specific  gravity,  3 to  3.2.  Nephrite  is  a compact  variety  of 
actinolite.  True  asbestos  is  a fibrous  form  of  tremolite  or  actinolite; 
but  anthophyllite  and  crocidolite  are  also  found  asbestiform.  The 
Canadian  asbestos  of  commerce  is  serpentine.1 

Cummingtonite. — Monoclinic,  but  with  the  composition  of  an 
anthophyllite  containing  much  iron.  Specific  gravity,  3.1  to  3.3. 
Color,  gray  to  brown. 

The  foregoing  members  of  the  amphibole  group,  except  the  alumi- 
nous gedrite,  are  most  simply  interpreted,  like  the  corresponding 
pyroxenes,  as  mixtures  of  metasilicates  of  calcium,  magnesium,  and 
iron.  Griinerite  is  the  ferrous  silicate,  FeSiOa  alone.2  Dannemorite 
is  a similar  iron-manganese  metasilicate.  In  richterite,  which  has  a 
similar  general  formula,  alkalies  appear,  up  to  9 per  cent  or  more. 
Many  analyses  of  these  minerals  show  the  presence  of  water  in  them, 
and  also  of  fluorine. 

Anthophyllite  and  gedrite  are  essentially  Archean  minerals,  occur- 
ring especially  in  hornblende  gneisses  and  schists.  Tremolite  is  found 
as  an  accessory  mineral  in  metamorphic  limestones  and  dolomites. 
Actinolite  is  also  a mineral  of  the  metamorphic  rocks.  In  the 
iron  regions  near  Lake  Superior  actinolite-magnetite  schists  are 
common.3 

Anthophyllite,  tremolite,  and  actinolite  alter  easily  into  talc,  ser- 
pentine, and  calcite.  The  reverse  alteration,  of  talc  into  anthophyl- 
lite, has  been  reported  by  Genth.4  Uralite,  which  has  ordinarily  the 
composition  of  actinolite,  is  an  amphibole  derived  by  alteration  from 
similarly  constituted  pyroxenes.5 

Hornblende. — Monoclinic.  Composition  variable,  as  with  augite, 
of  which  hornblende  is  the  equivalent  among  the  amphiboles.  Horn- 
blende, however,  contains  a smaller  proportion  of  lime  and  more 
magnesia  plus  iron  than  augite.  It  also  contains  aluminous  silicates. 
The  fight-colored  hornblende,  with  little  iron,  is  called  edenite.  The 
darker  varieties  are  known  as  pargasite.  Specific  gravity,  3.0  to  3.47, 
depending  upon  the  proportion  of  iron.  Color,  white,  gray,  green, 
and  brown,  ranging  to  black.  Hardness,  5 to  6. 

The  subjoined  analyses  of  hornblende  are  given  in  the  memoir  by 
S.  L.  Penfield  and  F.  C.  Stanley.6  They  show  the  variability  in  com- 
position of  the  mineral,  and  also  the  predominance  of  magnesium  and 
iron  over  calcium,  the  reverse  condition  from  that  noted  in  augite. 


i See  G.  P.  Merrill,  Proc.  U.  S.  Nat.  Mus.,  vol.  18,  1896,  p.  281,  for  a good  summary  of  our  knowledge  of 
asbestos. 

* A.  C.  Lane  and  F.  F.  Sharpless  (Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  505)  have  applied  the  name 
griinerite  to  a ferromagnesian  amphibole  like  cummingtonite. 

a See  W.  S.  Bayley,  Am.  Jour.  Sci.,  3d  ser.,  vol.  46, 1893,  p.  176.  Also  C.  R.  Van  Hise,  C.  K.  Leith,  and 

others,  in  Mon.  U.  S.  Geol.  Survey,  vol.  28, 1897;  vol.  43, 1903. 

* Proc.  Am.  Philos.  Soc.,  vol.  20, 1882,  p.  393. 

6 On  the  theory  of  uralitization  see  L.  Duparc  and  T.  Homung,  Compt.  Rend.,  vol.  139,  1904,  p.  223. 
See  also  Duparc,  Bull.  Soc.  min.,  vol.  31, 1908,  p.  50. 

6 Am.  Jour.  Sci.,  4th  ser.#  vol.  23, 1907,  p.  23. 


ROCK-FORMING  MINERALS, 


385 


Analyses  of  hornblende. 

A.  From  Renfrew,  Ontario.  Stanley,  analyst. 

B.  From  Edenville,  New  York.  Stanley,  analyst. 

C.  From  Cornwall,  New  York.  J.  L.  Nelson,  analyst.  Am . Jour.  Sci.,  4th  ser.,  vol.  15,  1903,  p.  227. 
Fluorine  determination  added  to  Nelson's  analysis  by  Stanley. 

D.  From  Monte  Somma,  Italy.  Stanley,  analyst. 

E.  Basaltic  hornblende,  Bilin,  Bohemia.  Stanley,  analyst. 

F.  From  Grenville  Township,  Quebec.  Stanley,  analyst. 


A 

B 

C 

D 

E 

F 

SiOo 

43.  76 

41.  99 

36.  86 

39.  48 

39.  95 

45.  79 

Ti02 

.78 

1.46 

1.04 

.30 

1.  68 

1.20 

A1203 

8.  33 

11.  62 

12. 10 

12.  99 

17.  58 

11.37 

Fe203 

6.  90 

2.  67 

7. 41 

7. 25 

7.25 

.42 

FeO 

10.  47 

14.  32 

23.35 

10.  73 

2. 18 

.42 

MnO 

.50 

.25 

. 77 

1.00 

Trace. 

.39 

MgO 

12.  63 

11. 17 

1.90 

11.47 

14. 15 

21. 11 

CaO 

9.  84 

11.  52 

10.  59 

12.  01 

11.  96 

12.  71 

K20 

1.  28 

.98 

3.20 

2.39 

1.  98 

1.  69 

Na20 

3.  43 

2. 49 

1.20 

1.  70 

3. 16 

2.  51 

H20 

.65 

.61 

1.30 

.76 

.41 

. 67 

F 

1.  82 

.80 

.27 

.05 

.03 

2.  76 

Loss  at  110° 

.10 

.08 

.12 

.13 

0=F 

100.  49 
.76 

99.  96 
.33 

99.  99 
.11 

100.  25 
.02 

100.  46 
.01 

101.  04 
1. 16 

99.73 

99.  63 

99.  88 

100.  23 

100. 45 

99.  88 

The  synthesis  of  hornblende  was  first  effected  by  K.  Chrustschoff.1 
He  heated  a solution  containing  dialyzed  silica,  alumina,  and  ferric 
hydroxide,  with  some  ferrous  hydroxide,  magnesium  hydroxide,  and 
limewater,  for  three  months  to  550°  in  a closed  digester,  and  obtained 
crystals  of  amphibole.  C.  Doelter,2  by  using  fluxes  of  low  melting 
point,  also  succeeded  in  producing  the  mineral.  A mixture  of  mag- 
nesia, oxide  of  iron,  alumina,  and  silica,  fused  with  boric  acid,  gave 
the  desired  result.  He  also  succeeded  in  recrystallizing  amphiboles 
from  a flux  of  borax,  or  from  one  of  magnesium  chloride  and  calcium 
chloride;  but  in  most  of  his  experiments  augite,  sometimes  with 
olivine,  scapolite,  magnetite,  anorthite,  or  orthoclase,  was  produced. 
E.  T.  Allen,  F.  E.  Wright,  and  J.  K.  Clement,3  in  the  research  already 
cited  under  pyroxene,  found  that  when  magnesium  metasilicate  was 
heated  considerably  above  its  melting  point  and  then  rapidly  cooled, 
the  orthorhombic  amphibole  was  formed.  With  slow  cooling,  pyrox- 
enes are  produced.  By  heating  the  orthorhombic  amphibole  with 
water  at  375°  to  475°,  it  was  transformed  into  the  monoclinic  modi- 
fication. The  latter  was  also  obtained  when  solutions  of  magnesium 
ammonium  chloride  or  of  magnesium  chloride  and  sodium  bicarbonate 


1 Compt.  Rend.,  vol.  112, 1891,  p.  677. 

2 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

3 Am.  Jour.  Sci.,  4th  ser.,  vol.  22, 1906,  p.  385. 

97270°— Bull.  616—16 25 


386 


THE  DATA  OF  GEOCHEMISTRY. 


were  heated  with  sodium  silicate  or  amorphous  silica  during  three 
to  six  days  at  375°  to  475°  in  a steel  bomb.  Small  quantities  of 
quartz  and  of  forsterite  were  formed  at  the  same  time. 

According  to  A.  Becker,1  when  anthophyllite  or  hornblende  is  fused, 
a pyroxene,  sometimes  with  olivine,  is  formed.  According  to  A. 
Lacroix,2  alterations,  due  to  heat  alone  or  to  the  action  of  molten 
magmas,  of  hornblende  to  augite,  are  common  among  the  volcanic 
rocks  of  Auvergne.  The  amphiboles,  in  short,  are  unstable  at  high 
temperatures,  and  either  the  rapid  cooling  of  a magma,  the  presence 
of  water,  or  some  undetermined  influences  of  pressure,  conditions 
their  appearance  as  pyrogenic  minerals.  An  excess  of  magnesia  is 
also  favorable  to  their  development,  while  an  excess  of  lime  may 
determine  the  formation  of  pyroxene. 

Common  hornblende  is  very  widely  diffused,  as  in  granite,  syenite, 
diorite,  diabase,  gabbro,  and  norite,  and  in  the  metamorphic  gneisses, 
hornblende  schists,  and  amphibolites.  The  crystallized  “basaltic 
hornblende”  appears  as  an  early  secretion  in  andesite,  dacite,  phono- 
lite,  basalt,  etc.  Hornblende  alters,  not  only  into  pyroxenes  as  men- 
tioned above,  but  also  into  chlorite,  epidote,  biotite,  siderite,  calcite, 
and  quartz.  Pseudomorphs  of  hornblende  or  of  anthophyllite  after 
olivine  have  been  described  by  F.  Becke  3 and  B.  Kolenko.4 * 

Ordinarily,  the  constitution  of  the  hornblendes  is  supposed  to  be 
analogous  to  that  of  augite,  metasilicates  of  the  form  RSi03  being 
isomorphously  commingled  with  Tschermak’s  hypothetical  compound, 
RAl2Si06.  It  is  also  commonly  assumed  that  the  amphibole  mole- 
cules are  larger  than  those  of  the  pyroxenes,  as  shown  by  the  formulae 
of  diopside,  MgCaSi206,  and  tremolite,  CaMg3Si4012.  The  latter 
assumption,  however,  is  not  well  grounded,  for  the  amphiboles,  as  a 
rule,  are  lower  in  specific  gravity  than  the  corresponding  pyroxenes, 
which  indicates  that  their  molecules  are  really  less  condensed.  The 
true  molecular  weights  are  unknown;  and  it  is  quite  possible  that 
they  are  better  represented  by  polymeric  symbols,  such  as  R8Si8024 
in  the  pyroxene  series  and  R4Si4012  for  the  amphiboles.  The  way 
in  which  the  alkali  pyroxenes  alter  into  mixtures  of  orthosilicates 
and  trisilicates  offers  an  argument  in  favor  of  this  view.  In  fact, 
G.  F.  Becker  5 has  sought  to  explain  the  relations  between  the  two 
groups  of  minerals  upon  the  supposition  that  they  are  mixtures  of 
the  two  classes  of  salts  just  named.  There  are  still  other  interpreta- 
tions of  the  hornblendes.  R.  Scharizer 6 regards  them  as  mixtures  of 
actinolite  with  an  orthosilicate  isomeric  with  garnet,  R"3R"'2Si3012, 

1 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  37, 1885,  p.  10. 

2 Min6ralogie  de  la  France,  vol.  1, 1893-1895,  pp.  668-669. 

3 Min.  pet.  Mitt.,  vol.  4,  1882,  p.  450. 

4 Neues  Jahrb.,  Band  2, 1885,  p.  90. 

6 Am.  Jour.  Sci.,  3d  ser.,  vol.  38, 1889,  p.  154.  See  also  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588, 
1914. 

6 Neues  Jahrb.,  Band  2, 1884,  p.  143. 


ROCK-FORMING  MINERALS. 


387 


to  which  he  has  given  the  name  “syntagmatite.”  A hornblende 
from  Jan  Mayen  Island  agrees  very  nearly  with  the  supposed  syn- 
tagmatite  in  composition.  F.  Berwerth  1 also  assumes  the  presence 
of  orthosilicates  in  the  hornblendes,  and  attributes  part  of  their 
alumina  to  molecules  which  are  either  those  of  mic&s  or  isomeric  with 
them.  Another  portion  of  the  alumina  he  regards  as  forming  the 
metasilicate  Al2Si309,  a compound  which  is  not  known  to  occur  by 
itself  in  nature.  An  alkali  hornblende  from  Piedmont,  described  by 
F.  R.  Van  Horn,2  has  very  nearly  orthosilicate  ratios;  and  so  also 
has  a variety  from  Dungannon,  Ontario,  studied  by  F.  D.  Adams  and 
B.  J.  Harrington.3  Some  hornblendes,  however,  contain  a larger 
proportion  of  oxygen  than  orthosilicates  require;  and  to  explain 
their  constitution  it  is  necessary  to  assume  the  existence  of  basic 
salts — a condition  which  is  fulfilled  by  the  molecule  RAl2Si06.  The 
synthesis  of  such  a compound,  or  its  discovery  as  an  actual  mineral 
would  go  far  toward  settling  the  constitution  of  this  important 
group.4 

An  interpretation  of  the  amphiboles  quite  unlike  that  of  Tschermak 
has  been  proposed  by  S.  L.  Penfield  and  F.  C.  Stanley.5  They  assume 
the  existence  in  them  of  bivalent  molecules,  Al2OF2,  A120(0H)2, 
A1203R",  and  Al204R/,Na2,  and  also  the  univalent  group  MgF,  in 
order  to  account  for  fluorine,  water,  and  alumina.  All  of  the  amphi- 
boles are  then  formulated  as  polymetasilicates. 

All  of  these  interpretations  of  the  amphibole  group  need  careful 
reconsideration  in  the  light  of  evidence  obtained  by  E.  T.  Allen  and 
J.  K.  Clement.6  These  chemists  find  that  water  is  an  almost  invaria- 
ble constituent  of  these  minerals,  running  up  in  tremolite  to  as  high 
as  2.5  per  cent.  This  water  is  gradually  lost  on  heating,  without  any 
loss  of  homogeneity  and  with  very  slight  change  in  the  optical  prop- 
erties. It  is  therefore  not  constitutional  but  occluded  water,  or 
water  in  “ solid  solution,”  as  the  authors  express  it.  W.  T.  Schaller, 
however,  finds  that  the  water  of  tremolite  is  essential  to  the  meta- 
silicate ratio,  and  is  therefore  more  probably  constitutional. 

Glauco'phane. — Monoclinic.  Normally  NaAlSi206.(FeMg)Si03,  but 
variable  amounts  of  the  calcium  metasilicate  may  be  present  also. 
Color,  blue,  bluish  black,  or  grayish.  Specific  gravity,  3 to  3.1. 
Hardness,  6 to  6.5. 

1 Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  85,  pt.  1,1882,  p.  153.  SeealsoH.  Haefcke,  Doct.  Diss.,  Gottingen, 
1890. 

2 Am.  Geologist,  vol.  21, 1898,  p.  370. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  1, 1896,  p.  210.  “Hastingsite.” 

* According  to  C.  Doelter  and  E.  Dittler  (Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  121,  Abth.  1,  1912, 
p.  897),  the  compound  MgALSiOe  is  unstable  in  fusion.  A compound  K2Al2Si06  has  been  prepared  by  Z. 
Weyberg,  Centralbl.  Min.,  Geol.  u.  Pal.,  1911,  p.  326. 

* Am.  Jour.  Sci. , 4th  ser.,  vol.  23, 1907,  p.  23.  Other  discussions  of  the  constitution  of  the  amphiboles  are 
by  S.  Kreutz,  Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  117,  Abth.  1, 1908,  p.  877,  and  G.  Murgoci,  Bull.  Dept. 
Geology  TJniv.  California,  vol.  4, 1906,  p.  359. 

6 Am.  Join*.  Sci.,  4th  ser.,  vol.  26,  p.  101,  1908,  Schaller’s  criticism  is  as  yet  unpublished. 


388 


THE  DATA  OF  GEOCHEMISTRY. 


Riebeckite. — Monoclinic.  Composition,  2NaFeSi206.FeSi03.  Color, 
black. 

Crocidolite. — Composition,  NaFeSi206.FeSi03.  Resembles  riebeck- 
ite.  Molecular  weight,  364.1.  Specific  gravity,  3.2  to  3.3.  Molecu- 
lar volume,  112.  Asbestiform.  Color,  dark  blue,  sometimes  greenish 
or  nearly  black.  Hardness,  4. 

Several  other  amphiboles  related  to  the  three  species  described 
above  have  been  given  independent  names.  Rhodusite,  described  by 
H.  B.  Foullon,1  is  an  asbestiform  variety  of  glaucophane  in  which 
aluminum  has  been  replaced  by  ferric  iron.  Crossite,  from  Cali- 
fornia, according  to  C.  Palache,2  is  intermediate  between  riebeckite 
and  glaucophane.  Holmquistite  is  a glaucophane  from  Sweden  con- 
taining over  2 per  cent  of  lithia,  described  by  A.  Osann.3 

Arfvedsonite. — Monoclinic.  The  composition  is  approximately 
4Na2Si03+  13FeSi03  + 3CaSi03  + Fe//Al2Si06,  but  probably  variable. 
Specific  gravity,  3.45.  Color,  black,  Hardness,  6. 

Barkevikite. — Intermediate  between  arfvedsonite  and  hornblende.4 
Color,  black.  Specific  gravity,  3.43. 

AEnigmatite. — Triclinic.  Essentially  a metasilicate  of  sodium  and 
ferrous  iron,  but  with  titanium  replacing  a part  of  the  silicon,  and  a 
small  admixture  of  the  basic  salt  RFe"'2Si06.5  Specific  gravity,  3.80. 
Color,  black. 

Among  these  alkali  amphiboles,  glaucophane  and  riebeckite  are  the 
most  important.  They  are  partly,  although  not  absolutely,  the  equiv- 
alent of  jadeite  and  acmite  among  the  pyroxenes,  but  differ  from  them 
chemically  in  containing  the  molecules  FeSi03  and  MgSi03  in  addi- 
tion to  the  aluminous  compounds.  None  of  them  has  been  prepared 
synthetically,  and,  like  the  other  amphiboles,  they  yield  pyroxenes 
upon  fusion.6 

Glaucophane  occurs  chiefly  in  a series  of  glaucophane  schists  and  in 
eclogite.7  It  has  also  befen  observed  in  some  eruptive  rocks.  It  alters 
into  chlorite,  feldspar,  and  hematite.8  Riebeckite  is  found  in  gran- 
ites and  syenites;  crocidolite  also  occurs  in  granite  and  in  quartz 


1 Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  100,  Abth.  1, 1891,  p.  176. 

2 Bull.  Dept.  Geology  Univ.  California,  vol.  1, 1894,  p.  181. 

2 Sitzungsb.  Heidelberg  Akad.,  1913,  Abhandl.  23. 

* For  a discussion  of  the  composition  of  barkevikite,  see  W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16, 

1890,  p.  412.  For  constitution  of  these  amphiboles  see  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588, 
pp.  102,  103. 

6 See  Brogger,  op.  cit.,  pp.  428-429.  See  also  J.  Soellner,  Neues  Jahrb.,  Beil.  Band  24,  1907,  p.  475,  who 
has  described  a new  mineral,  rhoenite,  allied  to  aenigmatite. 

« See  Brogger,  op.  cit.,  p.  410,  with  reference  to  arfvedsonite.  C.  Doelter  (Min.  pet.  Mitt.,  vol.  10, 1888, 
p.  70)  fused  glaucophane  with  sodium  fluoride  and  magnesium  fluoride  and  obtained  a product  resembling 
acmite. 

7 See  K.  Oebbeke,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  38, 1886,  p.  634,  for  a summary  of  occurrences  and 
bibliography.  Also  H.  S.  Washington,  Am.  Jour.  Sci.,  4th  ser.,  vol.  11,  1901,  p.  35;  G.  F.  Becker,  Mon. 
U.  S.  Geol.  Survey,  vol.  13, 1888,  p.  102;  and  H.  Rosenbusch,  Sitzungsb.  K.  Akad.  Wiss.  Berlin,  1898,  p.  706. 
Washington’s  memoir  is  very  full.  On  the  glaucophane  rocks  of  California,  see  J.  P.  Smith,  Proc.  Am. 
Philos.  Soc.,  vol.  45,  1907,  p.  183. 

8 L.  Colomba,  Zeitschr.  Kryst.  Min.,  vol.  26, 1896,  p.  215. 


ROCK-FORMING  MINERALS. 


389 


schist.  By  oxidation  of  the  iron  and  infiltration  of  silica,  crocidolite 
alters  into  the  beautiful  ornamental  stone  known  as  “ tiger-eye.” 
Riebeckite  is  reported  as  altering  to  epidote.1 

Arfvedsonite  and  barkevikite  occur  chiefly  in  augite  and  elseolite 
syenites,  also  in  a granite.  iEnigmatite  is  known  chiefly  from  the 
sodalite  syenite  of  Greenland;  but  cossyrite,  which  is  probably  the 
same  mineral,  was  found  in  a rhyolite  lava.  Arfvedsonite  alters  into 
acmite  and  lepidomelane,2  and  so  also  does  barkevikite.3 

Kaersutite  from  Greenland  and  linosite  from  the  island  of  Linosa, 
east  of  Tunis,  are  aluminous  amphiboles  rich  in  titanium.  In  lin- 
osite H.  S.  Washington 4 found  over  10  per  cent  of  Ti02. 

THE  O El  VINE  GROUP. 

Forsterite. — Orthorhombic.  Composition,  Mg2Si04.  Molecular 

weight,  141.4.  Specific  gravity,  3.2.  Molecular  volume,  44.2.  Color, 
white,  often  tinted  yellowish,  greenish,  or  gray.  Hardness,  6 to  7. 
Melting  point,  1,890°,  Bowen. 

Fayalite. — Orthorhombic.  Composition,  Fe2Si04.  Molecular 

weight,  204.4.  Specific  gravity,  4 to  4.14.  Molecular  volume,  49.8. 
Color,  yellow  to  brown  and  black.  Hardness,  6.5. 

Forsterite  and  fayalite  are  two  minerals  which,  rare  by  themselves, 
are  very  common  in  isomorphous  mixture.  The  usual  mixture,  in 
which  the  magnesium  salt  predominates,  is  known  as  olivine,  chryso- 
lite, or  peridot.  A variety  containing  a large  amount  of  iron  is  called 
hyalosiderite.  Hortonolite  is  another  member  of  the  group,  contain- 
ing much  iron,  less  magnesia,  and  about  4.5  per  cent  of  manganese 
oxide.  The  compound  Mn2Si04  occurs  as  tephroite,  and  roepperite  is 
a variety  containing  zinc.  Knebelite  is  intermediate  between  fayalite 
and  tephroite.  All  of  these  minerals  are  represented  by  the  general 
orthosilicate  formula  R2Si04.  Titanic  oxide,  up  to  5 per  cent  or 
more,  may  replace  a part  of  the  silica  in  olivine,  forming  a variety  to 
which  the  name  titanolivine  has  been  given.5 

Monticellite. — Orthorhombic.  Composition,  MgCaSi04.  Molecu- 
lar weight,  188.9.  Specific  gravity,  3 to  3.25.  Molecular  volume,  61. 
Colorless  to  yellowish,  greenish,  or  gray.  Hardness,  5 to  5.5.  The 
very  rare  glaucochroite,  CaMnSi04,  is  analogous  to  monticellite  in 
composition. 


1 On  riebeckite  rocks,  see  G.  T.  Prior,  Mineralog.  Mag.,  vol.  12, 1889,  p.  92;  P.  Termier,  Bull.  Soc.  min., 
vol.  27,  1904,  p.  265;  G.  M.  Murgoci,  Am.  Jour.  Sci.,  4th  ser.,  vol.  20, 1905,  p.  133.  According  to  Murgoci, 
riebeckite  forms  only  from  persilicic  magmas.  Riebeckite  rocks  from  Oklahoma  are  described  by  A.  F. 
Rogers  in  Jour.  Geology,  vol.  15, 1907,  p.  283. 

* W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16, 1900,  pp.  407-410;  also  N.  V.  Ussing,  idem,  vol.  26,  1896, 
p.  104. 

3 Brogger,  op.  cit.,  pp.  418-422. 

4 Am.  Jour.  Sci.,  4th  ser.,  vol.  26, 1909,  p.  187. 

6 See  A.  Damour,  Bull.  Soc.  min.,  vol.  2,  1879,  p.  15;  and  L.  Brugnatelli, Zeitschr.  Kryst.  Min.,  vol.39, 
1904,  p.  209. 


390 


THE  DATA  OF  GEOCHEMISTRY. 


The  members  of  the  olivine  group  are  easily  prepared  by  artificial 
means,  and  are  of  common  occurrence  in  slags.1 

The  first  intentional  synthesis  of  olivine  was  effected  by  Berthier,2 
by  simply  fusing  its  constituent  oxides  together.  Fouque  and  Levy 3 
also  obtained  it  by  fusing  silica  and  magnesia  with  ferrous  ammo- 
nium sulphate.  In  their  synthesis  of  basalt 4 they  observed  olivine 
among  the  earliest  crystallizations  from  the  magma.  J.  J.  Ebelmen 5 
prepared  forsterite  by  fusing  a mixture  of  boric  oxide,  silica,  and 
magnesia.  In  this  case  the  boric  oxide  simply  serves  as  a solvent  of 
relatively  low  melting  point,  from  which  the  synthetic  mineral  crys- 
tallizes just  as  ordinary  salts  crystallize  from  solution  in  water.  A. 
Daubree  6 obtained  olivine  by  recrystallization  from  fused  meteorites, 
magnesian  eruptive  rocks,  and  serpentine.  He  also  7 prepared  mix- 
tures of  olivine  and  metallic  iron,  resembling  certain  meteorites,  by 
partial  oxidation  of  an  iron  silicide  and  subsequent  fusion  of  the 
product.  G.  Lechartier8  fused  silica  and  magnesia  with  calcium 
chloride,  and  P.  Hautef euille 9 operated  with  the  same  oxides  and 
magnesium  chloride.  Olivine  was  produced  in  both  cases  when  the 
oxides  were  in  the  proper  proportions.  By  varying  the  proportions 
enstatite  or  enstatite  and  olivine  together  were  formed.  S.  Meunier,10 
by  heating  magnesium  vapor  to  redness  in  a mixture  of  water  vapor 
and  silicon  chloride,  obtained  both  olivine  and  enstatite.  Fayalite 
was  prepared  by  A.  Gorgeu,11  who  heated  ferrous  chloride  with  silica 
to  redness  in  a stream  of  moist  hydrogen.  Olivine  is  also  formed,  ac- 
cording to  C.  Doelter,12  when  hornblende  is  fused  with  calcium  and 
magnesium  chlorides,  and  is  among  the  products  of  fusion  of  biotite, 
vesuvianite,  tourmaline,  clinochlore,  and  some  garnets.  Forsterite 
was  obtained  by  E.  T.  Allen,  F.  E.  Wright,  and  J.  K.  Clement13 
incidentally  to  their  preparation  of  magnesian  pyroxenes. 

Olivine  is  an  essential  pyrogenic  constituent  of  many  eruptive 
rocks,  such  as  peridotite,  norite,  basalt,  diabase,  and  gabbro.  Dunite 
is  a rock  consisting  of  olivine  alone,  or  at  most  accompanied  by 

1 See  Fouqu6  and  L6vy,  Synthase  des  min^raux  et  des  roches,  p.  96;  L.  Bourgeois,  Reproduction  artificielle 
des  min6raux,  pp.  108-110;  Vogt,  Mineralbildung  in  Schmelzmassen,  p.  8.  A.  Stelzner  and  H.  Schulze 
(Neues  Jahrb.,  1882,  pt.  1,  p.  170)  have  described  a slag  containing  a zinc-bearing  fayalite;  and  H.  Laspeyres 
(Zeitschr.  Kryst.  Min.,  vol.  7,  1883,  p.  494)  has  reported  another  furnace  product  having  the  composition 
MnFe3Si20s. 

2 Cited  by  Fouqu4  and  L6vy,  op.  cit.,  p.  97. 

2 Bull.  Soc.  min.,  vol.  4, 1881,  p.  279. 

* Compt.  Rend.,  vol.  92,  1881,  p.  367. 

5 Annales  chim.  phys.,  3d  ser.,  vol.  33, 1851,  p.  56. 

6 Compt.  Rend.,  vol.  62, 1866,  pp.  200, 369, 660. 

7 Etudes  synthfitiques  de  gSologie  exp<5rimentale,  p.  524. 

8 Compt.  Rend.,  vol.  67,  1868,  p.  41. 

9 Annales  chim.  phys.,  4th  ser.,  vol.  4,  1865,  p.  129. 

10  Compt.  Rend.,  vol.  93, 1881,  p .737. 

11  Idem,  vol.  98, 1884,  p.  920. 

i*  Min.  pet.  Mitt.,  vol.  10, 1888,  p.  67;  and  Neues  Jahrb.,  1897,  Band  1,  p.  1. 

is  Am.  Jour.  Sci.,  4th  ser.,  vol.  22, 1906,  p.  385.  See  also  N.  L.  Bowen  and  O.  Andorsen,  Am.  Jour.  6ci., 
4th  ser.,  vol.  37,  p.  487, 1914. 


ROCK-FORMING  MINERALS. 


391 


trivial  amounts  of  accessories.  Since  olivine,  fused  with  silica,  yields 
enstatite,  it  can  occur  normally  only  in  rocks  low  in  silica.  As  the 
latter  increases  in  amount,  pyroxenes  take  its  place.  Olivine,  how- 
ever, sometimes  appears  abnormally,  as  a minor  accessory,  in  highly 
siliceous  rocks  like  trachyte  and  andesite.  Fayalite,  for  instance,  was 
found  by  J.  P.  Iddings,1  associated  with  tridymite  in  lithophyses  of 
rhyolite  and  obsidian,  in  the  Yellowstone  Park.  A similar  occur- 
rence in  the  Lipari  Islands  is  reported  by  Iddings  and  S.  L.  Pen- 
field.2  At  Rockport,  Massachusetts,  fayalite  has  been  found  in 
granite.3  Olivine  is  also  a common  constituent  of  meteorites  and  is 
often  conspicuously  associated  with  metallic  iron.  As  products  of 
thermal  metamorphism  olivine  and  forsterite  are  found  in  limestones 
and  dolomites,  frequently  accompanied  by  spinel.4  The  boltonite  of 
Bolton,  Massachusetts,  is  an  occurrence  of  this  kind. 

The  members  of  the  olivine  group  all  undergo  alteration  with 
extreme  facility.  The  typical  alteration  of  peridotite  rocks  is  into 
serpentine.  By  further  changes,  magnetite,  magnesite,  hvdromag- 
nesite,  brucite,  calcite,  opal,  and  quartz  may  be  formed.  By  oxidation 
of  the  iron  silicate,  limonite  is  produced.  P.  von  Jeremeef 5 has 
described  pseudomorphs  of  talc,  serpentine,  and  epidote  after  olivine. 
The  olivine  was  first  transformed  to  serpentine,  that  into  epidote,  and 
that  finally  into  talc  and  clay.  Pseudomorphs  of  hornblende  after 
olivine  are  recorded  by  F.  Becke  6 and  B.  Kolenko.7  By  a reaction 
between  olivine  and  feldspar,  according  to  R.  Brauns,8  a pyroxene 
can  be  formed.  Monticellite  alters  into  serpentine  and  pyroxene; 
and  C.  H.  Warren  9 found  a ferrous  anthophyllite,  FeSiOs,  derived 
from  the  fayalite  of  Rockport. 

THE  MICAS. 

Muscovite . — Mono  clinic.  Composition  normally  Al3KH2Si3012. 

Molecular  weight,  399.6.  Specific  gravity,  2.85.  Molecular  volume, 
140.  Colorless  when  pure,  but  usually  tinted  slightly  by  impurities. 
Hardness,  2 to  2.5. 

Some  varieties  of  muscovite  differ  from  the  normal  compound  in 
containing  a higher  proportion  of  silica.  These  all  represent  admix- 
tures of  the  isomorphous  trisilicate  Al3KH2Si9024.  Fuchsite  is  a 
muscovite  containing  small  amounts  of  chromium,  replacing  alumi- 
num. Baddeckite  10  appears  to  be  a muscovite  containing  much  ferric 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  30, 1885,  p.  58. 

2 Idem,  vol.  40, 1890,  p.  75. 

3 See  S.  L.  Penfield  and  E.  H.  Forbes,  Am.  Jour.  Sci.,  4th  ser.,  vol.  1,  1896,  p.  129- 

4 See  C.  T.  Clough  and  W.  Pollard,  Quart.  Jour.  Geol.  Soc.  vol.  55, 1899,  p.  372 

8  Zeitschr.  Kryst.  Min.,  vol.  32, 1900,  p.  430. 

® Min.  pet.  Mitt.,  vol.  4,  1882,  p.  450. 

7 Neues  Jahrb.,  1885,  Band  2,  p.  90. 

8 Idem,  1898,  Band  2,  p.  79. 

9 Am.  Jour.  Sci.,  4th  ser.,  vol.  16, 1903,  p.  337. 

10  G.  C.  Hoffmann,  Ann.  Rept.  Geol.  Survey  Canada,  vol.  9, 1896,  p.  11  R. 


392 


THE  DATA  OF  GEOCHEMISTRY. 

iron,  due  to  admixtures  of  the  compound  Fe3KH2Si3012.  F.  W. 
Clarke  and  N.  H.  Darton  1 have  described  an  altered  mica  which 
seems  to  be  derived  in  part  from  the  same  ferric  salt.  Roscoelite  is 
similar,  but  with  nearly  two-thirds  of  the  aluminum  replaced  by 
vanadium.2  Sericite,  margarodite,  damourite,  gilbertite,  etc.,  are 
muscovites  of  secondary  origin. 

P aragonite. — Monoclinic.  A sodium  mica,  Al3NaH2Si3012,  corre- 
sponding to  muscovite.  Molecular  weight,  383.5.  Specific  gravity, 
2.9.  Molecular  volume,  132.2.  Color,  like  muscovite.  Hardness, 
2.5  to  3. 

Lepidolite. — Monoclinic.  A lithia-bearing  mica  of  variable  com- 
position. In  most  cases  a mixture  of  a fluoriferous  trisilicate, 
AlF2.Si308.R/3,  in  which  R'=  (Li,K),  with  molecules  of  the  muscovite 
type.  Color  commonly  rose-red  or  lilac,  but  also  white,  gray,  or  brown. 
Specific  gravity,  2.8  to  2.9.  Cookeite,3  Al3LiH  (Si04)2(0H)3.H20,  is 
probably  a derivative,  by  hydration,  of  lepidolite;  but  it  may  be 
an  alteration  of  tourmaline.  Polylithionite  is  another  lithia  mica 
in  which  the  ratio  Si:0  is  entirely  trisilicate.  The  separate  exist- 
ence of  such  a compound  among  the  micas  sheds  much  light  upon 
their  constitution;  but  of  that,  more  later.  Zinnwaldite  and  cryo- 
phyllite  are  other  lithia  micas  containing  iron  and  intermediate  in 
composition  between  lepidolite  and  the  ferruginous  biotites.  Lepido- 
lite is  found  chiefly,  if  not  exclusively,  in  albitic  pegmatite  veins  and 
has  little  significance  as  a rock-forming  mineral. 

Biotite. — Monoclinic.  Normal  composition,  Al2Mg2KHSi3012,  but 
with  admixtures  of  the  corresponding  ferric  and  ferrous  salts  in 
variable  proportions.  Molecular  weight  of  the  normal  biotite,  420.3. 
Specific  gravity,  2.7.  Molecular  volume,  155.6.  The  specific  gravity 
of  the  iron  biotites  may  reach  3.1.  That  is  the  density  of  siderophyl- 
lite,  which  is  very  near  to  the  normal  ferrous  biotite  in  composition 
and  has  a molecular  volume  of  155.9.  There  are  also  biotites  con- 
taining small  amounts  of  chromium,  barium,  manganese,  etc.  Color, 
in  biotite  generally,  green  to  black,  rarely  white,  sometimes  yellow 
to  brown.  Hardness,  2.5  to  3. 

Phlogopite. — Monoclinic.  Composition  variable;  typical  phlogo- 
pite  approximates  to  AIMg3KH2Si3012.  Usually  contains  a low  pro- 
portion of  water  and  some  fluorine;  also  iron  in  small  quantities. 
Normal  molecular  weight,  418.6.  Specific  gravity,  2.75.  Molecular 
volume,  152.2.  Color,  brown,  yellowish,  reddish,  greenish,  some- 
times white.  Hardness,  2.5  to  3.  Between  phlogopite  and  biotite 
there  are  many  intermediate  mixtures;  and  the  varieties  contain- 


i Bull.  U.  S.  Geol.  Survey  No.  167,  1900,  p.  154. 

* F.  W.  Clarke,  idem,  p.  73. 

3 See  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588,  1914,  p.  57. 


BOCK-FORMING  MINERALS. 


393 


ing  much  ferric  iron  are  known  as  lepidomelane.  The  ratios  of  the 
latter  are  commonly  near  those  of  biotite. 

CJiloritoid. — Monoclinic.1  Composition,  Al2Fe"H2Si07;  being  a 
very  basic  orthosilicate.  Some  magnesia  or  manganese  may  replace 
a part  of  the  iron.  Molecular  weight,  252.5.  Specific  gravity,  3.45. 
Molecular  volume,  73.2.  Color,  gray,  greenish  gray,  and  grayish  or 
greenish  black.  Hardness,  6.5.  Ottrelite,  which  is  an  important 
constituent  of  some  schists,  is  probably  the  trisilicate  corresponding 
to  chloritoid,  ALjFeHjSigOn.  These  minerals,  together  with  mar- 
garite,  seybertite,  and  xanthophyllite,  form  the  clintonite  group,  or 
so-called  brittle  micas.  They  are  all  foliated,  micaceous  minerals, 
extremely  basic,  and  free  from  alkalies.  The  true  ferromagnesian 
micas  often  contain  admixtures  of  these  basic  molecules. 

Although  muscovite  is  very  simple  in  its  constitution,  the  other 
micas,  including  the  clintonite  series,  are  quite  complex.  Just  as  in 
the  pyroxene  and  amphibole  groups,  we  have  to  deal  with  isomorphous 
mixtures  of  different  salts,  which  vary  not  only  to  some  extent  in  type, 
but  also  in  their  “ replacements”  of  aluminum  by  iron  or  chromium, 
potassium  and  hydrogen  by  sodium  or  lithium,  and  magnesium  by 
iron  or  manganese.  In  some  of  the  brittle  micas  calcium  also  appears, 
and  in  lepidolite  and  phlogopite  the  equivalency  of  hydroxyl  and 
fluorine  has  to  be  taken  into  account.  Furthermore,  the  ferromag- 
nesian micas  are  highly  alterable  by  hydration;  and  it  is  not  always 
possible  to  be  certain  whether  a change  of  that  order  may  not  have 
begun.  In  spite  of  all  difficulties,  however,  the  normal  micas  can  be 
expressed  by  a smaller  number  of  generalized  formulae,  which  are  all 
derivable  from  one  general  type,  as  follows : 

Muscovite,  R///3R/3(Si04)3  and  R///3R/3(Si308)3. 

Biotite,  R///2R//2R/2(Si04)3  and  R///2R//2R/2(Si308)3. 

Phlogopite,  R///1R//3R/3(Si04)3  and  R///1R//3R/3(Si308)3. 

According  to  J.  Uhlig,2  the  rare  mineral  kryptotile,  an  alteration 
product  of  prismatine,  is  an  end  member  of  the  muscovite  series, 
with  formula  Al3H3(Si04)3.  Possibly  the  claylike  mineral  leverrierite 
may  be  akin  to  kryptotile.  To  these  normal  micas  must  be  added 
two  basic  types,  E,/"F2.Si308K,,3  in  lepidolite,  zinnwaldite,  and  some 
phlogopites,  and  the  clintonite  molecule  R",02K".Si308.R,3,  with 
its  orthosilicate  equivalent  R,/,02R*>Si04.R,3.  To  each  of  these 
forms  a known  mica  corresponds,  so  that  the  expressions  involve  no 
assumptions  of  hypothetical  molecules.  In  G.  Tschermak’s  theory 
of  the  mica  group,3  hypothetical  compounds  are  invoked  with  which 
no  actual  micas  agree. 

1 Triclinic  according  to  H.  F.  Keller  and  A.  C.  Lane,  Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  499. 

2 Zeitschr.  Kryst.  Min.,  vol.  47, 1910,  p.  215.  See  also  A.  Sauer,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  38, 
1886,  p.  705. 

3 Zeitschr.  Kryst.  Min.,  vol.  2,  1878,  p.  14;  vol.  3,  1879,  p.  122. 


394 


THE  DATA  OF  GEOCHEMISTRY. 


Several  syntheses  of  mica  have  been  reported,  but  they  are  not  alto- 
gether satisfactory,  for  the  reason  that  the  products  obtained  were 
not,  except  in  one  instance,  verified  by  analysis.  Unfortunately,  a 
large  proportion  of  the  work  so  far  done  in  synthetic  mineralogy  has 
been  purely  qualitative,  and  therefore  incomplete.  A substance  may 
be  micaceous  and  yet  a different  thing  from  any  natural  member  of 
the  mica  group.  The  true  micas,  as  a rule,  are  hydrous  minerals; 
water  is  one  of  their  essential  constituents;  syntheses  by  igneous 
methods,  at  ordinary  pressures,  are  therefore  to  be  regarded  with  sus- 
picion. Some  phlogopites  are  nearly  anhydrous,  however,  and  it 
would  be  unwise  to  condemn  the  reported  syntheses  without  further 
investigation.  The  magnesian  mica,  described  and  partly  analyzed 
by  Jo  H.  L.  Vogt,* 1  from  the  slags  of  the  Kafveltorp  copper  works  in 
Sweden,  may  have  been  a phlogopite  of  the  type  just  indicated,  with 
its  hydroxyl  replaced  by  some  other  monad  radicle.  To  Fouque 
and  Levy’s2  synthesis  of  a mica  trachyte,  the  objections  just  cited  do 
not  apply.  They  heated  a powdered  granitic  glass  with  a little  water, 
under  pressure,  and  for  a long  time,  to  redness,  and  obtained  an  arti- 
ficial rock  in  which  scales  of  mica  were  visible.  In  this  synthesis 
water  played  a distinct  part. 

By  the  prolonged  heating  of  andalusite  with  a solution  of  potassium 
carbonate  and  potassium  fluoride  at  250°,  C.  Doelter  3 obtained  scales 
of  white  mica.  This  transformation  is  instructive,  for  andalusite 
alters  into  muscovite  quite  readily.  P.  Hautefeuille  and  L.  P.  de 
Saint-Gilles  4 fused  the  constituents  of  an  iron  mica  with  potassium 
silicofluoride  and  found  crystals  resembling  mica  in  their  product. 
K.  ChrustschofFs 5 work  was  more  definite.  He  fused  a mixture 
equivalent  to  a mica  basalt  with  the  fluorides  of  sodium,  aluminum^ 
and  magnesium,  and  also  with  potassium  silicofluoride.  After  very 
slow  cooling,  the  mass  contained  a micaceous  mineral,  which  was 
separated  and  analyzed.  It  was  essentially  an  anhydrous  biotite. 
J.  Morozewicz  6 added  about  1 per  cent  of  tungstic  acid  to  a mixture 
having  the  composition  of  rhyolite,  and  obtained,  after  prolonged 
fusion  and  slow  cooling,  tables  of  biotite. 

C.  Doelter,7  in  a series  of  memoirs,  reports  the  formation  of  micas 
by  the  fusion  of  various  natural  silicates  with  fluorides.  Hornblende, 
augite,  pyrope,  almandite,  and  grossularite,  fused  with  sodium  fluor- 
ide and  magnesium  fluoride,  yielded,  among  other  products,  biotite. 
It  must,  however,  have  been  a sodium  biotite,  for  the  materials  used 
seem  to  have  contained  no  potassium.  Glaucophane  treated  in  the 


1 Berg-  u.  Hiittenm.  Zeitung,  vol.  47,  p.  197. 
a Compt.  Rend.,  vol.  113, 1891,  p.  283. 

1 Allgemeine  chemische  Mineralogie,  p.  207. 

* Compt.  Rend.,  vol.  104,  1887,  p.  508. 

* Min.  pet.  Mitt.,  vol.  9, 1887,  p.  55. 

« Neues  Jahrb.,  1893,  Band  2,  p.  48. 

1 1dem,  1888,  Band  2,  p.  178;  1897,  Band  1,  p.  1.  Also  Min.  pet.  Mitt.,  vol.  10,  1888,  p.  67. 


ROCK-FORMING  MINERALS. 


395 


same  way  gave  a phlogopite.  Leucite,  with  sodium  or  potassium 
fluoride,  was  converted  into  an  alkali  mica  and  with  magnesium 
fluoride  yielded  biotite.  Andalusite,  heated  to  redness  with  potas- 
sium silicofluoride  and  aluminum  fluoride,  gave  muscovite,  and  when 
lithium  carbonate  was  added  to  the  mixture  a lithia  mica  was 
obtained.  An  artificial  mixture  corresponding  to  KAlSi04  + Mg2Si04, 
fused  with  sodium  and  magnesium  fluoride,  also  formed  biotite. 
From  other  mixtures  he  produced  muscovite,  phlogopite,  and  an  iron 
mica.  None  of  these  products  seems  to  have  been  analyzed,  and  as 
their  generation  is  ascribed  to  presumably  anhydrous  materials,  it  is 
probable  that  they  were  analogous  to  rather  than  identical  with  the 
natural  micas.  Possibly  they  were  micas  containing  fluorine  in  place 
of  hydroxyl.  In  nearly  all  the  reported  syntheses  of  mica  fluorides 
have  played  an  important  part,  but  their  exact  function  is  unknown. 

Primary  muscovite  is  essentially  a mineral  of  the  deep-seated 
rocks,  especially  of  the  granites  and  quartz  porphyries.  It  is  never 
found  in  recent  eruptives.  From  its  water  content  we  may  infer 
that  it  was  formed  under  pressure.  Muscovite  is  also  abundant  in 
mica  schist,  and  paragonite  is  similarly  found  in  a paragonite  schist. 
As  an  alteration  product  of  other  minerals  muscovite  is  very  common. 
Feldspar,  topaz,  andalusite,  kyanite,  nephelite,  spodumene,  the  scapo- 
lites,  and  various  other  silicates  alter  readily  into  mica.  Pinite  and 
several  other  pseudomorphous  minerals  of  like  character  consist  of 
muscovite  more  or  less  impure.  Lepidolite  is  probably  in  many  oases 
secondary  after  muscovite,  for  it  often  forms  margins  upon  plates  of 
the  latter  mineral.  Cryophyflite  forms  similar  margins  upon  lepi- 
domelane. 

Biotite  is  an  important  constituent  of  many  massive  igneous  rocks, 
such  as  granite,  syenite,  diorite,  trachyte,  andesite,  mica  basalt,  etc. 
It  forms  among  the  earliest  secretions,  immediately  following  the 
ores,  apatite  and  zircon.  It  is  sometimes  altered  by  magmatic  corro- 
sion to  a mixture  of  augite  and  magnetite.1  Pressure  seems  to  con- 
dition its  formation.  Phlogopite  occurs  chiefly  in  granular  Archean 
limestones  and  in  serpentine ; but  W.  Cross  2 has  described  it  as  a 
constituent  of  a peculiar  igneous  rock,  wyomingite.  Chloritoid 
and  ottrelite  are  found  only  in  phyllitic  schists,3  and  are  of  minor 
importance. 

Muscovite,  under  ordinary  conditions,  is  one  of  the  least  alterable 
of  minerals.  The  feldspar  of  a granite  may  be  completely  kaolin- 
ized,  while  the  embedded  plates  of  mica  retain  their  brilliancy  almost 
unchanged.  By  treatment  with  aqueous  reagents  at  500°,  however, 

1 For  a discussion  of  this  alteration,  see  H.  S.  Washington,  Jour.  Geology,  vol.  4,  1896,  p.  257. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  4, 1897,  p.  115. 

* See  A.  Cathrein,  Min.  pet.  Mitt.,  vol.  8, 1887,  p.  331;  and  L.  van  Werveke,  Neues  Jahrb.,  1885,  Band 

1,  p.  227. 


396 


THE  DATA  OF  GEOCHEMISTRY. 


C.  and  G.  Friedel 1 transformed  muscovite  into  nephelite,  sodalite, 
leucite,  orthoclase,  and  anorthite.  Upon  fusion,  according  to  C. 
Doelter,2  muscovite  breaks  up  into  leucite  glass,  and  a substance 
resembling  nephelite.  Lepidolite  and  zinnwaldite  behave  in  a similar 
manner.  W.  Vernadsky  3 observed  corundum  and  sillimanite  among 
the  fusion  products  of  mica.  From  the  composition  of  muscovite  a 
splitting  up  into  water,  leucite,  and  sillimanite  may  be  inferred, 
according  to  the  equation — 

Al3KH2Si3012=AlKSi206  + Al2Si05  + H20 ; 
and  with  this  the  reported  derivation  of  muscovite  from  leucite  can 
be  correlated.4  Biotite,  according  to  Doelter,  yields  no  leucite  upon 
fusion,  but  breaks  up  into  olivine  and  spinel,  with  other  less  com- 
pletely identified  substances.  On  the  other  hand,  H.  Backstrom5 
fused  biotite  and  found  olivine,  leucite,  a little  spinel,  and  glass  to 
be  the  substances  formed  by  its  decomposition. 

Unlike  muscovite,  biotite  and  phlogopite  alter  easily,  and  pass  into 
a series  of  apparently  indefinite  substances  known  as  “vermiculites.” 
The  change,  however,  is  very  simple,  and  consists  merely  in  the 
replacement  of  the  alkaline  metals  by  hydrogen,  with  assumption  of 
additional,  loosely  combined  water.  From  the  typical  ferromag- 
nesian  micas  the  following  derivatives  are  thus  formed: 

From  Al2Mg2KHSi3012 Al2Mg2H2Si3012.3H20 . 

From  AlMg2KH2Si3012 AlMg3H3Si3012.3H20 . 

From  any  mixture  of  biotite  and  phlogopite  molecules  the  cor- 
responding hydrated  mixture  may  be  generated.  These  compounds, 
so  simply  related  to  the  parent  substances,  form  a series  intermediate 
between  the  micas  and  the  chlorites  and  mark  a transition  into  the 
latter  group  of  minerals,  which  will  be  considered  next  in  order.6 

THE  CHLORITES. 

Under  this  general  name  a considerable  number  of  minerals  are 
embraced  which  are  closely  related  to  the  micas.  They  are,  how- 
ever, much  more  basic,  highly  hydrated,  and  free  from  alkalies. 
They  are  silicates  of  aluminum  or  ferric  iron,  with  magnesium  or 
ferrous  iron,  and  resemble  the  micas  crystallographically  as  well  as  in 
the  scaly  or  foliated  habit  which  they  commonly  assume.  The  fol- 

1 Compt.  Rend.,  vol.  110, 1890,  p.  1170. 

2 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

3 Cited  by  Morozewicz,  Min.  pet.  Mitt.,  vol.  18, 1898,  p.  26. 

4 See  Doelter’s  experiment,  cited  above. 

6 Geol.  Foren.  Forhandl.,  vol.  18,  1896,  p.  162. 

6 On  the  alteration  products  of  the  magnesian  micas,  see  E.  Zschimmer,  Jenaische  Zeitschr.,  vol.  32, 1898, 
p.  551.  On  the  action  of  water  upon  micas,  A.  Johnstone,  Quart.  Jour.  Geol.  Soc.,  vol.  45, 1889,  p.  363.  For 
analyses  of  vermiculites,  see  E.  S.  Dana,  System  of  mineralogy,  6th  ed.,  pp.  664-668;  also  F.  W.  Clarke  and 
E.  A.  Schneider,  Bull.  U.  S.  Geol.  Survey  No.  78, 1891;  Bull.  No.  90, 1892.  The  earlier  papers  of  J.  P.  Cooke 
and  F.  A.  Genth  are  also  important. 


ROCK-FORMING  MINERALS. 


397 


lowing  species  are  recognized  by  Dana,1  who  assigns  to  them  the 
annexed  empirical  formulae : 


Clinochlore 1 

Penninite }H8(Mg,Fe)5Al2Si3018. 

Prochlorite II«l(Fe,Mg).!3Al14Si130110. 

Corundophilite H2o(Fe,Mg)11Al8Si6045. 

Daphnite H56F 627-^-l29Sii80  42i  • 

Cronstedtite H6(FeJMg)3Fe///2Si2013. 

Thuringite H18Fe8(Al,Fe)8Si6041 . 

Stilpnomelane 

Strigovite H4(Fe,Mn)2(Fe,  Al)2Si2On . 

Diabantite H^Mg^FehaAfiSigO^. 

Aphrosiderite H10(Fe,Mg)6Al4Si4O25. 

Delessite II10  (Mg,  Fe)4Al4Si4022 . 

Rumpfite H28Mg7Al16Si10O65. 


To  these  may  be  added  the  more  or  less  uncertain  minerals  amesite, 
metachlorite,  klementite,  chamosite,  epichlorite,  etc. 

None  of  the  formulae  given  above  is  fixed  and  definite,  for  each  of 
the  many  “chlorites”  is  variable  in  composition.  The  minerals,  like 
the  ferromagnesian  micas,  are  mixtures  of  compounds,  and  several 
attempts  to  disentangle  their  components  have  been  made.2  The 
simplest  and  most  natural  interpretation  of  the  chlorites  represents 
them  as  formed  from  a series  of  compounds  parallel  with  those  iden- 
tified in  the  micas  and  vermiculites,  according  to  the  following 
scheme: 


Normal  micas. 

Al3KH2(Sid4)3 . 
Al2Mg2KH(Si04)3. 
AlMg3KH2(Si04)3. 
A102Mg.Si04.R/3. 


Vermiculites. 


Al2Mg2H2(Si04)3.3H20. 
AlMg3H3  (Si04)3 . 3H20 . 
A102Mg.  SiC^R^  .3H20 . 


Normal  chlorites. 


Al2(Mg0H)4H2(S104)3. 

Al(Mg0H)6H3(Si04)3. 

A102Mg.Si04.R/3. 


On  this  basis  the  relations  between  the  several  series  are  clear  and 
in  accord  with  the  natural  occurrences  of  the  minerals.  In  penninite 
and  clinochlore  we  have  varying  mixtures  of  the  first  and  second 
chloritic  types,  just  as  among  the  micas  we  find  examples  interme- 
diate between  biotite  and  phlogopite.  Prochlorite  appears  to  be  a 
derivative  of  the  last  molecule,  having  the  formula — 

A102R'.Si04o  (R"OH)H2, 
in  which  R"  is  partly  Fe  and  partly  Mg.3 

It  is  obvious,  from  their  hydrous  character,  that  the  chlorites  can 
not  form  as  pyrogenic  minerals.  They  are  always  of  secondary 
origin;  and  when  they  appear  in  volcanic  rocks  it  is  as  the  result  of 


1 System  of  mineralogy,  6th  ed.,  p.  643. 

2 See  G.  Tschermak,  Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  99,  Abth.  1,  1890,  p.  174;  vol.  100,  Ajth.  1, 
p.  29.  R.  Brauns, Neues  Jahrb.,Band  l,1894,p.  205,  and  Chemische  Mineralogie,p.  221.  F.  W.  Clarke, 
Bull.  U.  S.  Geol.  Survey  No.  588,  1914,  pp.  59-65.  An  earlier  discussion  by  Clarke,  on  different  lines,  is 
given  in  Bull.  U.  S.  Geol.  Survey  No.  113,  1893,  p.  11. 

8 For  the  other  chloritic  minerals  see  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588, 1914,  pp.  59-65. 


398 


THE  DATA  OF  GEOCHEMISTRY. 


hydrothermal  alteration.  Almost  any  aluminous  ferromagnesian 
mineral  may  yield  a chlorite  in  this  way.  Augite,  hornblende,  bio- 
tite,  vesuvianite,  epidote,  tourmaline,  or  garnet  may  be  the  parent 
mineral.1  Chlorites  have  been  produced  artificially  by  G.  Friedel 
and  F.  Grandjean,2  by  the  action  of  alkaline  solutions  on  pyroxenes. 

When  a magnesian  chlorite,  such  as  clinochlore,  is  strongly  ignited, 
it  breaks  down  into  a soluble  and  an  insoluble  portion,  and  the  latter 
has  the  composition  of  spinel.3  This  fact  is  strong  evidence  against 
Tschermak’s  theory  of  the  chlorite  group,  in  which  the  normal  series 
is  regarded  as  formed  by  mixtures  of  serpentine,  H4Mg3Si209,  with 
amesite,  H4Mg2Al2Si09.  For  serpentine,  on  ignition,  splits  up  into 
water,  olivine,  and  enstatite,  and  the  last-named  mineral  does  not 
appear  among  the  decomposition  products  of  clinochlore.  The  latter, 
therefore,  contains  no  serpentine,  and  the  theory  which  assumes  its 
presence  falls  to  the  ground.  C.  Doelter4  reports  spinel,  olivine, 
and  augite  as  formed  by  the  fusion  of  clinochlore;  but  the  experi- 
ments conducted  in  the  laboratory  of  this  Survey  exclude  the  insolu- 
ble augite  from  the  list  of  probabilities. 

Chlorites  are  abundant  among  the  metamorphic  schists,  chlorite 
schist  being  the  commonest  occurrence.  An  interesting  metamorpho- 
sis of  such  a rock,  a phyllite  containing  approximately  75  per  cent  of 
muscovite  with  25  of  chlorite,  is  reported  by  K.  Dalmer.5  With 
almost  no  change  of  composition,  other  than  loss  of  water,  it  was 
transformed  into  a mixture  of  andalusite  and  biotite. 

THE  MELILITE  GROUP. 

Melitite. — Tetragonal.  A silicate  of  aluminum  and  calcium  of 
variable  composition,  with  Fe'"  replacing  some  Al,  and  Mg  or  Na 
replacing  a part  of  the  Ca.  Specific  gravity,  2.9  to  3.1.  Hardness,  5. 
Color,  white,  yellow,  greenish  yellow,  brown. 

Gehlenite . — Tetragonal.  Composition  variable,  as  with  melilite. 
The  formula  commonly  assigned  to  gehlenite,  Al2Ca3Si2O10,  is  not 
sustained  by  the  best  evidence.  Specific  gravity,  3.  Hardness, 
5.5  to  6.  Color,  grayish  green  to  brown. 

Akermanite. — Tetragonal.  Composition,  Ca4Si3O10,  with  about  one- 
third  of  the  calcium  replaced  by  magnesium.  According  to  A.  L. 
Day  and  E.  S.  Shepherd  6 a calcium  silicate  of  this  formula  can  not 
be  deposited  from  lime-silica  fusions.  The  magnesia  is  essential  to 
its  formation.  Ordinarily  found  only  in  slags,  but  the  natural  min- 

1 For  a complete  discussion  of  pseud omorphous  chlorite  after  pyrope,  see  J.  Lemberg,  Zeitschr.  Deutsch. 
geol.  Gesell.,  vol.  27, 1875,  p.  531. 

2 Bull.  Soc.  min.,  vol.  32, 1909,  p.  150. 

8 F.  W.  Clarke  and  E.  A.  Schneider,  Bull.  U.  S.  Geol.  Survey  No.  113, 1893, pp.  27-33. 

* Neues  Jahrb.,  1897,  Band  1,  p.  1. 

6 Idem,  1897,  Band  2,  p.  156. 

8 Am.  Jour.  Sci.,  4th  ser.,  vol.  22, 1906,  p.  265. 


ROCK-FORMING  MINERALS. 


399 


eral  is  reported  by  F.  Zambonini  1 as  occurring  in  calcareous  blocks 
at  Monte  Somma. 

These  three  isomorphous  silicates  are  closely  related  to  one  another. 
J.  H.  L.  Vogt 2 regards  gehlenite  and  akermanite  as  the  two  inde- 
pendent species,  which,  isomorphously  commingled,  form  the  vari- 
able melilite.  This  view  is  plausible,  but  not  universally  accepted. 
Furthermore,  although  melilite  is  a pyrogenic  mineral  characteristic 
of  certain  eruptive  rocks,  natural  gehlenite  has  been  found  only  as  a 
product  of  contact  metamorphism  in  limestones.  If  gehlenite  were 
a constituent  of  melilite,  we  should  expect  to  find  igneous  rocks  in 
which  it  appeared  as  an  essential  component,  or  at  least  as  a con- 
spicuous accessory.  A more  probable  interpretation  of  melilite  and 
gehlenite  treats  them  as  intermediate  mixtures  of  silicates  analogous 
to  the  plagioclase  feldspars.  One  of  these  silicates,  Al2Ca2Si07,  has 
been  prepared  synthetically  by  E.  S.  Shepherd  and  G.  A.  Rankin  in 
the  Geophysical  Laboratory  of  the  Carnegie  Institution.  It  is 
easily  formed  by  direct  fusion  of  a mixture  of  its  component  oxides. 
The  other  silicate,  Al2Ca9(Si04)6  is  not  known  by  itself,  but  is  approxi- 
mated by  some  artificial  gehlenites.  It  is  nearly  related  in  structure 
to  minerals  of  the  garnet  and  scapolite  groups.3 

Both  melilite  and  gehlenite  are  common  minerals  hi  slags,4  and  both 
have  been  prepared  synthetically.  An  artificial  melilite  basalt  was 
prepared  by  J.  Morozewicz,5  and  the  mineral  was  also  found  by 
Fouque  and  Levy 6 among  the  constituents  of  some  of  their  synthetic 
rocks.  In  Morozewicz ’s  preparation  the  melilite  was  accompanied 
by  augite,  plagioclase,  olivine,  corundum,  and  spinel.  Melilite  and 
feldspar  were  the  last  silicates  to  crystallize  from  the  magma.  F. 
Fouque7  has  shown  that  melilite  is  formed  when  an  augite  andesite 
or  a basalt  is  fused  with  lime,  and  he  gives  analyses  of  two  products 
thus  obtained.  G.  Bodlander8  found  melilite  in  a sample  of  Portland 
cement;  but  according  to  Vogt9  the  mineral  was  not  pure.  L.  Bour- 
geois10 prepared  melilite  by  direct  fusion  of  silica,  lime,  alumina,  and 
certain  other  oxides  commingled  in  proper  proportions,  but  could 
not  obtain  the  calcium  alumosilicate  alone.  The  presence  of  iron, 

1 Mineralogia  Vesuviana,  p.  255. 

* MineralbMung  in  Schmelzmassen,  1892,  pp.  96-176.  See  also  G.  Bodlander,  Neues  Jahrb.,  Band  1, 1893, 
p.  15;  and  F.  Fouqu6,  Bull.  Soc.  min.,  vol.  23,  1900,  p.  10.  Also  a more  recent  discussion  by  Vogt,  Die 
Sflikatschmelzlosungen,  pt.  1,  1903,  p.  49.  F.  Zambonini  (Zeitschr.  Kryst.  Min.,  vol.  41,  1906,  p.  226) 
has  advanced  strong  arguments  against  Vogt’s  hypothesis. 

3 See  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588, 1914,  pp.  31-34. 

* See  L.  Bourgeois,  Reproduction  artificielie  des  mineraux,  p.  123.  J.  H.  L.  Vogt,  Mineralbildung  in 
Schmelzmassen,  1892.  F.  Fouque,  Bull.  Soc.  min.,  vol.  9,  1886,  p.  287.  P.  Heberdey,  Zeitschr.  Kryst. 
Min.,  vol.  26, 1896,  p.  19.  J.  S.  Biller,  Am.  Jour.  Sci.,  3d  ser.,  vol.  37, 1889,  p.  220. 

5 Min.  pet.  Mitt.,  vol.  18,  1898,  p.  191. 

6 Bull.  Soc.  min.,  vol.  2, 1879,  p.  105. 

7 Idem,  vol.  23, 1900,  p.  10. 

8 Neues  Jahrb.,  Band  1, 1892,  p.  53. 

8 Idem,  Band  2,  1892,  p.  73. 

* Annales  chim.  phys.,  5th  ser.,  vol.  29, 1883,  p.  450. 


400 


THE  DATA  OF  GEOCHEMISTRY. 


magnesia,  or  manganese  was  essential  to  a successful  synthesis.  Soda 
also  is  probably  essential;  at  all  events,  melilite  forms  more  readily 
when  soda  is  present.  All  natural  melilite  contains  soda.  C.  Doelter 
and  E.  Hussak 1 found  melilite  among  the  fusion  products  of  garnet 
and  vesuvianite,  and  Doelter 2 reports  it  also  as  formed  when  tourma- 
line is  fused  with  calcium  chloride  and  sodium  fluoride.  The  synthesis 
of  gehlenite  was  effected  by  L.  Bourgeois,3  who  simply  fused  the  con- 
stituent oxides  together  in  the  proportions  indicated  by  the  formula 
of  the  species. 

Melilite  is  a mineral  found  only  in  the  younger  eruptives;  never 
in  the  plu tonic  rocks  or  crystalline  schists.  It  is  frequently  associated 
with  nephelite  or  leucite,  and  sometimes  takes  the  place  of  feldspar. 
Perofskite  is  one  of  its  most  constant  companions.  Its  origin  is 
always  pyrogenic.4  Its  most  remarkable  occurrence  is  in  the  Uncom- 
pahgre  quadrangle,  Colorado,  where  it  forms  about  two-thirds  of  a 
rock  which  contains  also  pyroxene,  magnetite,  perofskite,  and  apatite, 
with  other  minor  accessories.  The  melilite  is  enormously  developed, 
and  cleavages  a foot  across  are  not  rare.5 

Alterations  of  melilite  seem  to  have  been  little  studied.  A.  Cath- 
rein6  has  described  pseudomorphs  of  pyroxene  (fassaite)  and  gros- 
sularite  after  gehlenite.  By  heating  gehlenite  with  a solution  of 
potassium  carbonate  to  200°,  J.  Lemberg7  obtained  calcium  carbonate 
and  an  amorphous  product  having  the  composition  of  a potassium 
mica.  A fibrous,  zeolitic  alteration  of  the  Uncompahgre  melilite, 
cevollite,  has  been  described  by  E.  S.  Larsen  and  W.  T.  Schaller.8 

THE  GARNETS. 

Grossularite. — Isometric.  Composition,  Ca3Al2Si3012.  Molecular 
weight,  451.7.  Specific  gravity,  3.5.  Molecular  volufne,  129.  Color, 
white,  yellow,  brown,  and  sometimes  pale  green  or  rose-red.  The  col- 
oration is  due  to  impurities. 

Pyrope. — Isometric.  Composition,  Mg3Al2Si3012.  Molecular  weight, 
404.6.  Specific  gravity,  3.7.  Molecular  volume,  109.4.  Color,  deep 
red  to  nearly  black. 

Almandite. — Isometric.  Composition,  Fe3Al2Si3012.  Molecular 

weight,  499.1.  Specific  gravity,  3.9  to  4.2.  Molecular  volume,  118. 
Color,  red  to  brown  and  black.  Pyrope  and  almandite  shade  one  into 

1 Neues  Jahrb.,  1884,  Band  1,  p.  159. 

2 Idem,  1897,  Band  l,p.l. 

8 Annales  chim.  phys.,  5th  ser.,  vol.  29, 1883,  p.  448. 

4 For  data  upon  melilite  rocks  see  A.  E.  Tomebohm,  Geol.  Foren.  Forhandb,  vol.  6, 1882,  p.  240.  A. 
Stelzner,  Neues  Jahrb.,  Beil.  Band  2, 1883,  p.  369.  F.  D.  Adams,  Am.  Join:.  Sci.,  3d  ser.,  vol.  43, 1892,  p. 
269.  C.  H.  Smyth,  idem,  vol.  46, 1893,  p.  104.  The  last  two  references  deal  with  American  occurrences. 

5 See  E.  S.  Larsen  and  J.  F.  Hunter,  Jour.  Washington  Acad.  Sci,  voL  4, 1914,  p.  473. 

6 Min.  pet.  Mitt.,  vol.  8, 1887,  p.  400. 

7 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  44, 1892,  p.  237. 

8 Jour.  Washington  Acad.  Sci.,  vol.  4, 1914,  p.  480. 


ROCK-FORMING  MINERALS. 


401 


the  other  through  varying  mixtures  of  the  iron  and  magnesium  com- 
pounds. 

Spessartite. — Isometric.  Composition,  Mn3Al2Si3012.  Molecular 

weight,  496.4.  Specific  gravity,  4.2.  Molecular  volume,  118.  Color, 
red  to  brown. 

Andradite,  melanite,  or  common  garnet. — Isometric.  Composition, 
Ca3Fe"'2Si3012.  Molecular  weight,  509.3.  Specific  gravity,  3.85. 
Molecular  volume,  158.2.  Color,  green,  yellow,  brown,  or  black. 

Uvarovite. — Isometric.  Composition,  Ca3Cr2Si3012.  Molecular 

weight,  501.7.  Specific  gravity,  3.5.  Molecular  volume,  143.  Color, 
emerald-green. 

The  foregoing  six  species,  with  their  many  isomorphous  mixtures, 
form  the  important  garnet  group.  With  them  may  be  included  the 
rare  mineral  schorlomite,  which  contains  titanium  partly  replacing 
silicon  and  ferric  iron.  Its  formula  is  Ca3(Fe,Ti///)2(SiTiiv)3012.1 
The  sodium  garnet  lagoriolite,  Na6Al2Si3012,  which  was  obtained  by 
J.  Morozewicz 2 from  some  of  his  artificial  magmas,  also  belongs  here. 
Its  existence  accounts  for  the  small  amounts  of  alkalies  which  appear 
in  some  analyses  of  grossularite,  although  they  may  be  due  in  part  to 
inclusions.  Garnets  are  peculiarly  prone  to  carry  other  species  as 
inclosures  within  their  crystals.  Some  garnets  are  hardly  more  than 
shells  enveloping  other  species.3 

Although  garnet  is  undoubtedly  a pyrogenic  mineral,  its  synthesis 
is  attended  by  considerable  difficulties.  When  fused  by  itself  garnet 
breaks  up  into  other  compounds.  C.  Doelter  and  E.  Hussak,4  upon 
fusing  garnets  alone,  obtained  meionite,  melilite,  anorthite,  lime 
olivine,  a calcium  nephelite  (?),  hematite,  and  spinel,  the  products 
varying  with  the  composition  of  the  original  mineral.  By  fusing 
grossularite  with  sodium  and  magnesium  fluorides,  Doelter 5 obtained 
biotite,  anorthite,  meionite,  olivine,  and  magnetite.  L.  Bourgeois,6 
from  the  fusion  of  a mixture  equivalent  to  grossularite,  obtained 
anorthite  and  monticellite;  and  J.  H.  L.  Vogt7  reports  anorthite  as 
formed  under  similar  conditions.  When  magnesia,  oxide  of  manga- 
nese, or  iron  oxide  was  added  to  Vogt’s  mixture,  melilite  was  also 
produced.  The  syntheses  of  garnet  reported  by  several  early  inves- 
tigators8 are  of  doubtful  authenticity. 


1 R.  Soltmann  (Zeitschr.  Kryst.  Min.,  vol.  18,  1891,  p.  628)  has  described  a melanite  garnet  containing 
11.01  per  cent  of  Ti02,  which  should  probably  be  partly  reduced  to  T^Os- 

2 Min.  pet.  Mitt.,  vol.  18,  1898,  p.  147. 

3 For  systematic  papers  on  the  garnet  group  see  W.  C-.  Brogger  and  H.  Backstrom,  Zeitschr.  Kryst.  Min., 
vol.  18,  1891,  p.  209;  E.  Weinschenk,  idem,  vol.  25,  1896,  p.  365;  H.  E.  Boeke,  idem,  vol.  53,  1913,  p.  149; 
and  J.  Uhlig,  Verhandl.  Naturhist.  Verein  preuss.  Rhcinlande  u.  Westfalens,  vol.  67, 1911,  p.  307.  Uhlig 
gives  many  analyses. 

4 Neues  Jahrb.,  1884,  Band  1,  p.  158. 

& Idem,  1897,  Band  1,  p.  1. 

6 Annales  chim.  phys.,  5th  ser.,  vol.  29,  1883,  p.  458. 

2 Mineralbildung  in  Schmelzmassen,  1892,  p.  187. 

8 See  Fouqu6  and  Ldvy,  Synthase  des  mineraux  et  des  roches,  p.  122. 

97270°— Bull.  616—16 26 


402 


THE  DATA  OF  GEOCHEMISTRY. 


Bourgeois,  however,  in  the  research  just  cited,  prepared  spessartite 
by  fusing  together  its  constituent  oxides  in  the  proper  proportions. 
A.  Gorgeu 1 also  obtained  spessartite  when  pipe  clay  was  fused  with 
an  excess  of  manganese  chloride.  A similar  fusion  with  calcium 
chloride  gave,  with  other  products,  crystals  which  were  possibly 
grossularite.  Fouque  and  Levy  2 report  melanite  as  formed  when 
nephelite  and  pyroxene  are  fused  together.  L.  Michel3  produced 
melanite  and  sphene  by  heating  a mixture  of  ilmenite,  silica,  and  cal- 
cium sulphide  to  1,200°.  In  this  case  the  artificial  melanite  was  ver- 
ified by  analysis.  E.  S.  Shepherd  and  G.  A.  Kankin 4 mention,  but 
without  details,  the  formation  of  grossularite  by  the  action  of  alu- 
minum chloride  upon  calcium  orthosilicate  under  pressure. 

Apparently  pyrogenic  garnet  can  be  produced  only  during  a limited 
range  of  temperatures,  and  the  success  of  an  attempted  synthesis 
depends  upon  securing  the  exact  conditions.  Pressure,  also,  may 
exert  some  influence  upon  the  process.5 

Garnet,  especially  andradite,  is  an  exceedingly  common  mineral, 
and  is  found  as  an  accessory  in  a great  variety  of  rocks.  Grossular- 
ite is  found  principally  in  crystalline  limestones,  where  it  has  been 
developed  by  contact  metamorphism.  Almandite  and  andradite  are 
common  in  granitic  rocks,  gneisses,  etc.  Andradite  also  occurs  as  an 
accessory  mineral  in  subsilicio  eruptives,  especially  in  leuoite  and 
nephelite  rocks.  It  is  also  found  in  serpentines,  in  iron  ore  beds,  and 
as  a product  of  contact  action,  associated  with  wollastonite  and 
pyroxene,  in  certain  volcanic  rocks.  Pyrope  is  often  found  in  perido- 
tites  and  the  serpentines  derived  from  them.  Spessartite  occurs  in 
granite,  quartzite,  and  some  schists.  W.  Cross 6 has  reported  it  from 
lithophyses  in  rhyolite.  Garnets  are  also  abundant  in  many  crystal- 
fine  schists,  such  as  garnet  rock,  garnet  amphibolite,  garnet  hornfels, 
garnet-mica  schist,  etc.  Eclogite  is  a rock  in  which  garnet  and  a 
green  pyroxene  are  the  principal  minerals. 

Alterations  of  garnet  are  exceedingly  common.  A.  Cathrein,7 
describing  the  rocks  of  a single  region,  reports  pseudomorphs  after 
garnet  of  scapofite,  epidote,  ofigoclase,  hornblende,  saussurite,  and 
chlorite.  Chloritic  pseudomorphs  are  perhaps  the  most  frequent.8 
The  pyrope  found  in  peridotite  rocks  is  often  surrounded  by  a zone 
or  shell  of  altered  material,  to  which  A.  Schrauf 9 has  given  the 

1 Annales  chim.  phys.,  6th  ser.,  vol.  4,  1885,  pp.  536,  553. 

2 Compt.  Bend.,  vol.  87, 1878,  p.  962. 

3 Idem,  vol.  115,  1892,  p.  830. 

* Am.  Jour.  Sci.,  4th  ser.,  vol.  28, 1909,  p.  305. 

6 See  L.  L.  Fermor  (Rec.  Geol.  Survey  India,  vol.  43,  pt.  1, 1913,  p.  41,  and  Jour.  Asiatic  Soc.  Bengal, 
vol.  8, 1912,  p.  315)  on  the  probable  formation  of  garnet  at  great  depths. 

e Am.  Jour.  Sci.,  3d  ser.,  vol.  31,  1886,  p.  432. 

7 Zeitschr.  Kryst.  Min.,  vol.  10,  1885,  p.  433. 

8 See  for  example  J.  Lemberg,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  27,  1875,  p.  531,  and  S.  L.  Penfield 
and  F.  L.  Sperry,  Am.  Jour.  Sci.,  3d  ser.,  vol.  32,  1886,  p.  307. 

9 Zeitschr.  Kryst.  Min.,  vol.  6,  1882,  p.  358. 


BOCK-FORMING  MINERALS. 


403 


name  kelyphite.  It  is,  however,  not  a substance  of  uniform  com- 
position. The  kelyphite  studied  by  A.  von  Lasaulx  1 was  mainly 
a mixture  of  pyroxenes  and  amphiboles.  J.  Mrha2  described  a 
kelyphite  consisting  of  bronzite,  monoclinic  pyroxene,  picotite,  and 
hornblende.  The  pyrope  from  the  peridotite  dikes  of  Elliott 
County,  Kentucky,  described  by  J.  S.  Diller,3  was  surrounded  by 
a similar  shell  made  up  of  biotite  and  magnetite,  with  a little  pico- 
tite. Biotite  is  not  an  uncommon  derivative  of  the  magnesian  gar- 
nets. Garnet  itself  appears  occasionally  as  an  alteration  product 
of  other  minerals.  P.  Jeremeef4  has  recorded  pseudomorphs  of 
grossularite  after  vesuvianite;  and  grossularite  after  gehlenite  was 
observed  by  A.  Cathrein.5 

VESUVIANITE. 

Tetragonal.  Composition  variable,  and  best  represented  by  the 
general  formula  Al2Ca7Si6024B/4 ; in  which  K'4  may  be  Ca2,  (A10H)2, 
(A102H)4,  or  H4.  Some  replacements  of  magnesium  and  iron  are 
usually  present;  a little  fluorine  may  be  substituted  for  hydroxyl,  and 
in  the  variety  wiluite  there  is  a small  amount  of  boric  oxide.6  Specific 
gravity,  3.35  to  3.45.  Hardness,  6.5.  Color,  brown  or  green,  some- 
times yellow  or  pale  blue.  A massive  variety  of  vesuvianite  resem- 
bling jade  has  been  called  calif ornite. 

Vesuvianite  has  not  yet  been  prepared  synthetically.  It  is  known 
chiefly  as  a product  of  contact  metamorphism  in  limestones,  asso- 
ciated with  pyroxene,  scapolite,  garnet,  wollastonite,  and  epidote. 
It  is  also  found  in  some  serpentines,  chlorite  schist,  gneiss,  etc. 
Pseudomorphs  of  grossularite  after  vesuvianite  have  been  reported 
by  P.  Jeremeef.7  When  vesuvianite  is  fused,  it  breaks  up  into 
meionite,  melilite,  anorthite,  and  possibly  a lime  olivine.8 

THE  SCAPOLITES. 

Meionite.  — Tetragonal.  Composition,  Ca4Al6Si6025.  Molecular 

weight,  893.4.  Specific  gravity,  2.72.  Molecular  volume,  328.4. 

Colorless  or  white.  Hardness,  5.5  to  6. 

Marialite. — Tetragonal.  Composition,  Na4Al3Si9024Cl.  Molecular 
weight,  848.4.  Specific  gravity,  2.57.  Molecular  volume,  330.1. 

Colorless  or  white.  Hardness,  5.5  to  6. 

1 Verhandl.  Naturhist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  vol.  39,  pt.  2,  1882,  p.  114. 

2 Min.  pet.  Mitt.,  vol.  19,  1899,  p.  111. 

3 Bull.  U.  S.  Geol.  Survey  No.  38,  1887. 

* Zeitschr.  Kryst.  Min.,  vol.  31,  1899,  p.  505. 

6  Min.  pet.  Mitt.,  vol.  8,  1887,  p.  400. 

6 See  F.  W.  Clarke  and  G.  Steiger,  Bull.  U.  S.  Geol.  Survey  No.  262,  1905.  For  other  interpretations  of 
vesuvianite  see  P.  Jannasch  and  P.  Weingarten,  Zeitschr.  anorg.  Chemie,  vol.  8,  1895,  p.  356;  M.  Weibull, 
Zeitschr.  Kryst.  Min.,  vol.  25, 1895,  p.  1;  A.  Kenngott,  Neues  Jahrb.,  Band  1, 1891,  p.  200;  H.  Sjogren,  Geol. 
Foren.  Forhandl.,  vol.  17,  1895,  p.  267. 

7 Zeitschr.  Kryst.  Min.,  vol.  31,  1899,  p.  505. 

8 C,  Doelter  and  E.  Hussak,  Neues  Jahrb.,  1884,  Band  1,  p.  158. 


404 


THE  DATA  OF  GEOCHEMISTRY. 


These  two  species,  with  their  isomorphous  mixtures,  form  the 
scapolite  group  as  interpreted  by  G.  Tschermak.1  Intermediate 
between  them,  and  analogous  to  the  plagioclase  feldspars  lying 
between  anorthite  and  albite,  are  the  following  scapolites,  which  have 
received  independent  names: 

Wernerite MegM^  to  Me^a^ 

Mizzonite  or  dipyre M^Maa  to  Me^ag 

The  reported  syntheses  of  scapolite  are  not  altogether  conclusive. 
L.  Bourgeois2  attempted  to  prepare  meionite  by  fusing  together  its 
constituent  oxides,  and  obtained  principally  anorthite.  By  adding 
fragments  of  marble  to  a molten  basaltic  glass,  however,  he  observed 
in  one  case  the  formation  of  crystals  which  were  probably  meionite. 
By  fusing  a leucitite  with  the  fluorides  of  sodium  and  calcium,  K.  B. 
Schmutz 3 obtained  an  artificial  rock  containing  scapolite;  and  a 
similar  experiment  with  eclogite  also  yielded  the  mineral.  The  same 
procedure  with  epidote  and  fluorides  gave  C.  Doelter  4 a product  in 
which  meionite  was  recognized.  Doelter  also  reports  the  synthesis 
of  meionite  by  fusion  of  the  mixed  oxides,  lime,  silica,  and  alumina; 
and  by  fusion  of  a silicate,  CaAl2Si208,  with  sodium  chloride.  His 
attempts  to  prepare  marialite  failed.  E.  S.  Shepherd  and  G.  A. 
Rankin5  obtained  meionite  by  heating  a glass  of  that  composition 
with  a solution  of  sodium  chloride  in  a bomb.  They  give  no  details, 
however. 

The  scapolites  occur  principally  in  the  crystalline  schists,  gneisses, 
amphibolites,  and  metamorphosed  limestones.  They  are  commonly 
products  of  metamorphic  contact  action  and  appear  to  be,  as  their 
composition  would  indicate,  derived  from  plagioclase  feldspar.  They 
have  been  found  as  secondary  minerals  in  various  eruptive  rocks.6 
In  Norway  scapolite  rocks  are  associated  with  masses  of  apatite 
especially  at  Oedegaarden.  In  this  instance  J.  W.  Judd  7 has  traced 
the  development  of  the  scapolite  from  plagioclase,  and  has  ascribed 
the  transformation  partly  to  the  action  of  sodium  chloride  solutions 
contained  in  cavities  of  the  rock,  and  partly  to  powerful  mechanical 
stresses.  A.  Lacroix,8  however,  regards  the  change  as  due  to  contact 

1 Min.  pet.  Mitt.,  vol.  7,  p.  400,  1886;  Monatsh.  Chemie,  vol.  4,  1883,  p.  851.  Compare  F.  W.  Clarke’s 
constitutional  formulae  in  Bull.  U.  S.  Geol.  Survey  No.  588,  1914,  p.  36;  and  A.  Himmelbauer,  Sitzungsb. 
K.  Akad.  Wiss.  Wien,  1910,  Abth.  1,  p.  119.  A scapolite  containing  the  sulphate  radicle  S04  has  recently 
been  described  by  R.  Brauns,  Neues  Jahrb.,  Beil.  Band  39,  1914,  p.  121.  It  is  named  silvialite.  Also 
scapolite  containing  carbonate  groups  by  L.  H.  Borgstrom,  Zeitschr.  Kryst.  Min.,  vol.  54, 1914,  p.  238. 

2 Annales  chim.  phys.,  5th  ser.,  vol.  29, 1883,  pp.  446,  472. 

3 Neues  Jahrb.,  1897,  vol.  2,  pp.  133,  149. 

* Idem,  vol.  1,  p.  1. 

6 Am.  Jour.  Sci.,  4th  ser.,  vol.  28,  p.  305,  1909. 

e See  F.  Zirkel,  Lehrbuch  der  Petrographie,  vol.  1,  1893,  p.  382.  W.  Salomon,  Min.  pet.  Mitt.,  vol.  15, 
1895,  p.  159,  gives  a good  bibliography  relative  to  dipyre. 

7 Mineralog.  Mag.,  vol.  8,  1889,  p.  186. 

8 Bull.  Soc.  min.,  vol.  14, 1891,  p.  16.  In  vol.  12,  1889,  p.  83,  Lacroix  has  an  elaborate  monograph  upon 
scapolite  rocks. 


BOCK-FORMING  MINERALS. 


405 


action  between  the  rock  and  the  apatite,  although  in  other  localities 
solutions  of  chlorides  appear  to  be  operative.  Mechanical  agencies 
are  considered  by  Lacroix  to  be  unimportant.  At  the  Oedegaarden 
locality,  which  has  been  studied  by  several  authorities,  a granitic 
mixture  of  pyroxene  and  feldspar  has  been  transformed  into  an 
aggregate  of  hornblende  and  scapolite.  By  fusion  Fouque  and  Levy  1 
transformed  it  back  again  into  pyroxene  and  labradorite.  A Canadian 
scapolite  diorite  has  been  described  by  F.  D.  Adams  and  A.  C.  Lawson,2 
and  H.  Lenk 3 has  studied  an  augite-scapolite  rock  from  Mexico. 

The  scapolites  are  exceedingly  alterable,  and  most  so  toward  the 
sodium  or  marialite  end  of  the  series.  Many  of  the  alteration  prod- 
ucts have  been  regarded  as  distinct  species  and  have  received  inde- 
pendent names.  Pseudomorphs  of  mica,  often  in  the  form  of  ‘ ‘ pinite,” 
after  scapolite  are  very  common.  Alterations  into  epidote,  steatite, 
kaolin,  and  free  silica  are  also  recorded.  A.  Cathrein 4 has  reported 
pseudomorphs  of  scapolite  after  garnet. 

IOLITE. 

Iolite  or  cordierite. — Orthorhombic.  F ormula,5  II2  (Mg,F e)4Al8Si10O37. 
Molecular  weight  and  volume  variable  on  account  of  variations  be- 
tween Mg  and  Fe.  Specific  gravity,  2.60  to  2.66.  Color,  blue, 
often  smoky  or  grayish.  Hardness,  7 to  7.5. 

A possible  synthesis  of  iolite  was  reported  by  L.  Bourgeois,6  who 
fused  silica,  magnesia,  and  alumina  together  in  proper  proportions. 
J.  Morozewicz  7 also  obtained  it  in  his  experiments  upon  artificial 
magmas,  supersaturated  with  alumina,  of  the  general  formula 
R0.mAl203.7iSi02.  When  magnesia  and  iron  were  present  and  n 
was  greater  than  6,  iolite  was  formed.  In  short,  he  produced  an  arti- 
ficial cordierite-vitrophyrite,  resembling  the  African  rock  described 
by  G.  A.  F.  Molengraaf.8  These  syntheses,  however,  were  made  with 
anhydrous  materials;  and  the  product  could  not  have  been  identical 
with  the  iolite  of  natural  occurrences.  All  the  trustworthy  analyses 
of  the  mineral  show  that  water  is  one  of  its  essential  constituents. 

Iolite  is  found  in  nature  in  a great  variety  of  rocks,  including  both 
metamorphic  rocks  and  eruptives.  It  has  been  reported  in  granite, 
quartz  porphyry,  basalt,  quartz  trachyte,  biotite  dacite,  and  andesite; 

1 Bull.  Soc.  min.,  vol.  2,  1879,  p.  112. 

a Canadian  Rec.  Sci.,  vol.  3,  1888,  p.  186. 

8 Neues  Jahrb.,  1899,  Band  1,  ref.  73. 

4 Zeitschr.  Kryst.  Min.,  vol.  9, 1884,  p.  378;  vol.  10, 1885,  p.  434. 

6 Formula  based  upon  O.  C.  Farrington’s  analysis,  Am.  Jour.  Sci.,  3d  ser.,  vol.  43, 1892,  p.  13.  M.  Weibull 
(Geol.  Foren.  Forhandl.,  vol.  22,  1900,  p.  33)  regards  the  mineral  as  anhydrous,  and  writes  the  formula 
Mg2Al2(A10)2Si50i6. 

c Annales  chim.  phys.,  5th  ser.,  vol.  29,  1883,  p.  462. 

7 Min.  pet.  Mitt.,  vol.  18, 1898,  pp.  68, 167.  See  ante,  p.  338,  under  “Corundum.” 

8 Neues  Jahrb.,  Band  1, 1894,  p.  79. 


406 


THE  DATA  OF  GEOCHEMISTEY. 


and  seems  to  be  a primary  separation  from  the  magmas.1  In  order 
of  deposition  it  follows  biotite,  but  precedes  the  feldspars.  In  cor- 
dierite  gneiss  and  cordierite  hornfels  iolite  is  a characteristic  con- 
stituent. The  gneiss  from  Connecticut  described  by  E.  O.  Hovey2 
consisted  mainly  of  biotite,  quartz,  and  iolite,  with  some  plagioclase. 
Iolite  is  also  well  known  as  a product  of  contact  metamorphism.  For 
example,  Bucking 3 found  it  in  sandstones  which  had  been  vitrified 
by  contact  with  basalt;  and  Kikuchi 4 has  described  a Japanese 
locality  where  iolite  occurs  in  slate  at  contact  with  granite. 

Iolite  alters  with  great  ease,  taking  up  water  and  alkalies.  The 
product  is  usually  an  impure  mica,  and  many  pseudomorphs  of  this 
character  have  received  distinctive  names.  Chlorophyllite,  praseolite, 
aspasiolite,  gigantolite,  fahlunite,  pinite,  etc.,  are  merely  altered 
iolite.5 

THE  ZOISITE  GROUP. 

Zoisite. — Orthorhombic.6  Composition,  HCa2Al3Si3013.  Molecular 
weight,  455.9.  Specific  gravity,  3.25  to  3.37.  Molecular  volume,  138. 
Color,  white,  gray,  greenish,  yellowish,  reddish.  Hardness,  6 to  6.5. 

Epidote. — Monoclinic.  Composition  like  zoisite,  but  with  varying 
replacements  of  A1  by  Fe.  The  variety  with  little  or  no  iron  has 
been  called  clinozoisite.  Specific  gravity,  3.25  to  3.5.  Color,  com- 
monly green,  yellowish  or  brownish  green,  to  black,  sometimes  red, 
yellow,  or  gray;  rarely  colorless.  Hardness,  6 to  7. 

Piedmontite. — Monoclinic.  Composition  like  epidote,  but  with  Mn 
replacing  some  A1  and  Fe.  Specific  gravity,  3.4.  Color,  reddish 
brown  to  black.  Hardness,  6.5. 

Allanite  or  orthite. — Monoclinic.  Composition  like  epidote,  but 
with  cerium  earths  partly  replacing  alumina  and  iron.  Specific  grav- 
ity, 3.5  to  4.2.  Color,  brown  to  black.  Hardness,  5.5  to  6. 

The  reported  syntheses  of  zoisite  and  epidote  are  questionable,  for 
the  products  seem  to  have  contained  no  water.  A.  Brun  7 claimed  to 
have  produced  zoisite  by  fusing  40  parts  of  silica  with  37  of  lime 
and  23  of  alumina.  C.  Doelter,8  upon  fusing  epidote  powder  with 
the  fluorides  of  sodium  and  calcium,  obtained  indications  of  some 
recrystallization  of  the  epidote,  together  with  garnet,  meionite,  anor- 

1 See  H.  Bucking,  Ber.  Senckenbergischen  naturforsch.  Gesell.,  Abhandl.,  1900,  p.  3;  J.  Szab<5,  Neues 
Jahrb.,  Beil.  Band  1, 1881,  p.  308;  E.  Hussak,  Sitzungsb.  K.  Akad.  Wiss.  Wien, vol.  87,  Abth.  1, 1883,  p.  332; 
Neues  Jahrb.,  1885,  Band  2,  p.  81;  A.  Harker,  Geol.  Mag.,  1906,  p.  176. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  36, 1888,  p.  57. 

3 Loc.  cit. 

4 Jour.  Coll.  Sci.  Japan,  vol.  3,  1890,  p.  313.  Kikuchi  also  describes  an  alteration  of  the  iolite  into  pinite. 

5 For  a summary  of  these  alterations  see  A.  Wichmann,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  26, 1874, 
p.  675.  For  the  mechanism  of  the  change  from  iolite  to  chlorophyllite  see  F.  W.  Clarke,  Bull.  U.  S.  Geol. 
Survey  No.  588, 1914,  p.  79. 

6 Foroptical  variations  in  zoisite,  see  P.  Termier,  Bull.  Soc.  min.,  vol.  21, 1898,  p.  148;  vol.  23,  1900,  p.  50. 
Termier  regards  the  silicate  HCa2R,,,3Si30i3  as  trimorphous. 

7 Arch.  sci.  phys.  nat.,  3d  ser.,  vol.  25, 1891,  p.  239. 

8 Neues  Jahrb.,  1897,  Band  1,  p.  1. 


ROCK-FORMING  MINERALS. 


407 


thite,  olivine,  and  magnetite.  Epidote  fused  alone  gave  anorthite 
and  a lime  augite.  Satisfactory  syntheses  of  the  minerals  forming 
this  group  are  yet  to  be  made. 

Zoisite  is  essentially  a mineral  of  the  crystalline  schists,  such  as 
amphibolite,  glaucophane  schist,  eclogite,  etc.  It  is  also  found  in 
some  granites  and  in  beds  of  sulphide  ores.  A secondary  zoisite, 
derived  from  plagioclase  and  commonly  containing  both  minerals 
commingled,  is  known  as  saussurite  and  is  common  in  gabbros.1  It 
is  not  at  all  uniform  in  composition. 

Epidote,  like  zoisite,  is  a mineral  of  the  crystalline  schists,  although 
C.  R.  Keyes2  has  cited  evidence  to  show  that  it  is  a primary  mineral 
in  certain  granites  of  Maryland.  It  is  there  intergrown  with  allanite 
and  was  also  observed  inclosed  in  primary  sphene.  A.  Michel-Levy 3 
also  regards  the  epidote  of  certain  Pyrenean  ophites  as  primary. 
It  is  also  found,  according  to  B.  S.  Butler,4  in  dikes  cutting  soda 
granite  porphyry  in  Shasta  County,  California.  There  are  many 
other  examples  on  record. 

Epidote  is  common  in  gneisses,  garnet  rock,  amphibolite,  parag- 
onite  and  glaucophane  schists,  and  the  phyllites,  and  as  a contact 
mineral  in  limestones.  It  is  also  common  as  a secondary  mineral, 
derived  from  feldspars,  pyroxene,  amphibole,  biotite,  scapolite,  and 
garnet,  and  is  frequently  associated  with  chlorite.  When  lime-bear- 
ing ferromagnesian  minerals  chloritize  their  lime  goes  to  the  produc- 
tion of  epidote.  An  epidote-quartz  rock  derived  from  diabase  has 
been  called  epidosyte.5 

Piedmontite  is  much  less  abundant  than  zoisite  or  epidote  and  is 
mainly  confined  to  the  crystalline  schists.  It  also  occurs  with  iron  ores 
and  as  a secondary  mineral  in  eruptives.  G.  H.  Williams  6 has  re- 
ported piedmontite  in  a rhyolite  from  Pennsylvania  and  N.  Yamasaki7 
has  described  a similar  occurrence  in  Japan.  Piedmontite  is  quite  com- 
mon in  the  crystalline  schists  of  Japan,8  forming  a piedmontite  schist, 
and  also  associated  with  rocks  containing  chlorite  or  glaucophane. 

Allanite  is  widely  diffused  as  a primary  accessory  in  many  igneous 
rocks.  J.  P.  Iddings  and  W.  Cross,9  who  have  pointed  out  its 
importance,  cite  occurrences  of  allanite  in  gneiss,  granite,  quartz 

1 Also  in  the  greenstones  of  the  Lake  Superior  region.  See  G.  H.  Williams,  Bull.  U.  S.  Geol.  Survey  No. 
62, 1890,  where  the  process  of  saussuritization  is  discussed.  Williams  cites  abundant  references  to  the 
literature  of  the  subject. 

2 Bull.  Geol.  Soc.  America,  vol.  4, 1893,  p.  305. 

3 Bull.  Soc.  g§ol.  France,  3d  ser.,  vol.  6,  p 161. 

4 Am.  Jour.  Sci.,  4th  ser.,  vol.  28,  1909,  p.  27.  Butler  gives  many  references  to  literature. 

s For  a discussion  of  this  alteration,  with  references  to  literature,  see  A.  Schenck,  Doct.  Diss.,  Bonn, 
1884.  Williams,  in  Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  also  discusses  the  process  of  epidotization  some- 
what fully. 

6 Am.  Jour  Sci.,  3d  ser.,  vol.  46,  1893,  p.  50.  This  paper  contains  many  references  to  literature. 

7 Jour.  Coll.  Sci.  Japan,  vol.  9, 1897,  p.  117. 

8 See  B.  Koto,  idem,  vol.  1, 1887,  p.  303. 

8 Am.  Jour.  Sci.,  3d  ser.,  vol.  30, 1885,  p.  108. 


408 


THE  DATA  OF  GEOCHEMISTRY. 

porphyry,  diorite,  andesite,  dacite,  rhyolite,  etc.  W.  H.  Hobbs,1  study- 
ing the  granite  of  Ilchester,  Maryland,  in  which  allanite  and  epidote 
are  intergrown,  has  especially  discussed  the  paragenesis  of  the  two 
species.  The  same  association  of  minerals  has  been  reported  by 
F.  D.  Adams,2  A.  Lacroix,3  G.  H.  Williams,4  and  others.  In  the 
granite  of  Pont  Paul,  France,  allanite  is  sometimes  enveloped  by 
biotite.5  W.  Mackie  6 has  reported  several  occurrences  of  allanite 
in  Scottish  granites.  Allanite  is  often  much  altered,  yielding  car- 
bonates of  the  cerium  group,  together  with  earthy  products  of  uncer- 
tain character. 

TOPAZ. 

Orthorhombic.  Simplest  empirical  formula,  Al2Si04F2,  but  with 
part  of  the  fluorine  commonly  replaced  by  hydroxyl.7  Molecular 
weight,  184.6.  Specific  gravity,  3.56.  Molecular  volume,  51.9 
Color,  white,  yellow,  greenish,  bluish,  and  reddish.  Hardness,  8. 
The  true  formula  is  probably  three  times  that  given  above,  with  the 
molecular  weight  and  volume  correspondingly  tripled.8 

The  synthesis  of  a product  allied  to  topaz  was  early  reported  by 
A.  Daubree,9  who  heated  alumina  in  a current  of  silicon  fluoride.  It 
contained,  however,  too  little  fluorine,  and  varied  in  other  respects 
from  topaz.  H.  Sainte-Claire  Deville,10  repeating  the  experiment, 
obtained  no  fluoriferous  silicate.  C.  Friedel  and  E.  Sarasin 11  claim  to 
have  prepared  topaz  by  heating  alumina,  silica,  water,  and  hydrofluo- 
silicic  acid  together  at  500°,  but  give  no  details  nor  analyses.  A. 
Keich  12  subjected  a mixture  of  silica  and  aluminum  fluoride  to  a 
strong  red  heat,  and  afterwards  ignited  the  mixture  thus  obtained  in  a 
current  of  silicon  fluoride.  By  this  process  topaz  was  formed,  which 
was  identified  both  crystallographically  and  by  analysis.  This  is 
the  only  satisfactory  synthesis  of  topaz  so  far  recorded. 

Topaz  commonly  occurs  in  gneiss  or  granite,  and  especially  in  tin- 
bearing  pegmatites.  The  rock  from  the  tin  mine  at  Mount  Bischoff, 
Tasmania,  has  been  described  by  A.  von  Groddeok  13  as  a porphyritic 
topazfels.  The  Brazilian  topazes  are  found  in  decomposed  material, 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  30,  1885,  p.  108;  vol.  38,  1889,  p.  223. 

2 Canadian  Rec.  Sci.,  vol.  4, 1891,  p.  344.  * 

3 Bull.  Soc.  min.,  vol.  12,  1889,  pp.  138,  157,  210. 

4 Bull.  U.  S.  Geol.  Survey  No.  62,  1890. 

6 A.  Michel-Levy  and  A.  Lacroix,  Bull.  Soc.  min.,  vol.  11, 1888,  p.  65. 

e Trans.  Edinburgh  Geol.  Soc.,  vol.  9,  1909,  p.  216.  A Canadian  “granite,"  containing  56  per  cent  of 
allanite,  is  reported  by  G.  C.  Hoffmann  in  Ann.  Kept.  Geol.  Survey  Canada,  vol.  7,  1894,  p.  12R. 

7 S.  L.  Penfield  and  J.  C.  Minor,  Am.  Jour.  Sci.,  3d  ser.,  vol.  47,  1894,  p.  387. 

8 See  F.  W.  Clarke  and  J.  S.  Diller,  Bull.  U.  S.  Geol.  Survey  No.  27, 1886,  and  also  Clarke,  Bull.  No.  588, 
1914% 

9 Etudes  synthetiques  de  gfiologie  experimental,  p.  57. 

10  Compt.  Rend.,  vol.  52,  1861,  p.  780. 

11  Bull.  Soc.  min.,  vol.  10,  1887,  p.  169. 

12  Monatsh.  Chemie,  vol.  17,  1896,  p.  149. 

13  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  36,  1884,  p.  642.  On  the  topaz-bearing  rocks  of  Gunong  Bakau, 
Malay  States,  seo  J.  B.  Scrivenor,  Quart.  Jour.  Geol.  Soc.,  vol.  70, 1914,  p.  363. 


ROCK-FORMING  MINERALS. 


409 


which,  according  to  O.  A.  Derby,1  was  probably  a mica  schist  derived 
from  an  antecedent  augite  or  nepheline  syenite.  In  Colorado  and 
Utah  topaz  occurs  in  litbophyses  of  rhyolite.2  Gaseous  emanations 
containing  fluorine  probably  play  an  important  part  in  its  develop- 
ment. Topaz  alters  easily,  by  hydration  and  by  the  action  of  perco- 
lating alkaline  solutions,  and  is  transformed  into  compact  muscovite.3 
The  reported  alterations  to  steatite  and  serpentine  are  probably 
based  upon  erroneous  diagnoses.  By  heating  topaz  with  a solution 
of  sodium  silicate  174  hours  at  200°  to  210°,  J.  Lemberg4  converted 
it  into  an  alkaline  alumo-silicate  of  presumably  zeolitic  character. 
At  a white  heat  topaz  loses  fluorine  and  becomes  transformed  into 
sillimanite.5 

THE  AND ALU SITE  GROUP. 

Andalusite. — Orthorhombic.  Simplest  empirical  formula,  Al2Si05; 
true  formula  probably  three  times  as  great.  Corresponding  molecular 
weight,  162.6.  Specific  gravity,  3.18.  Molecular  volume,  51.1. 
Color,  white,  reddish,  violet,  brown,  olive-green.  Hardness,  7.5. 

Sillimanite  or  fibrolite. — Orthorhombic.  Composition  and  lowest 
molecular  weight  the  same  as  for  andalusite.  Specific  gravity,  3.2. 
Molecular  volume,  50.8.  Color,  grayish  white,  grayish  brown,  pale 
green,  brown.  Hardness,  6 to  7. 

Kyanite  or  cyanite. — Triclinic.  Composition,  etc.,  as  with  anda- 
lusite and  sillimanite.  Specific  gravity,  3.6.  Molecular  volume,  45.2. 
Color,  commonly  blue,  sometimes  white,  gray,  or  green.  Hardness,  7. 

These  three  minerals  are  of  peculiar  interest  because  of  their  iden- 
tity in  chemical  composition.  They  undoubtedly  differ  in  chemical 
structure,  and  kyanite  possibly  differs  from  the  other  two  in  molecu- 
lar weight,  but  upon  the  latter  point  the  evidence  is  not  conclusive. 
Andalusite  and  sillimanite  are  commonly  regarded  as  basic  ortho- 
silicates, and  kyanite,  on  account  of  its  greater  resistance  to  the 
action  of  acids,  has  been  interpreted  by  P.  Groth  as  a metasilicate, 
(A10)2Si03.6  In  an  interesting  investigation  by  W.  Vernadsky 7 
it  is  shown  that  both  andalusite  and  kyanite  are  transformed  into 
sillimanite  by  simply  heating  to  a temperature  between  1,320°  and 
1,380°.  Sillimanite,  therefore,  is  the  most  stable  of  the  three  species, 
at  least  under  pyrogenic  conditions.  Vernadsky  has  identified  it  as 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  11, 1901,  p.  25. 

2 See  W.  Cross,  idem,  3d  ser.,  voi.  31,  1886,  p.  432. 

3 For  a complete  study  of  this  alteration,  see  F.  W.  Clarke  and  J.  S.  Diller,  Bull.  U.  S.  Geol.  Survey 
No.  27, 1886.  See  also  A.  Atterberg,  Geol.  Foren.  Forhandl.,  vol.  2,  1874-75,  p.  402. 

4Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  40,  1888,  pp.  651  et  seq. 

5 W.  Vernadsky,  Bull.  Soc.  min.,  vol.  13, 1890,  pp.  259-260. 

6 A different  but  not  very  plausible  interpretation  of  these  species  has  been  offered  by  K.  Zulkowski, 
Monatsh.  Chemie,  vol.  21,  1900,  p.  1086. 

7 Bull.  Soc.  min.,  vol,  13, 1890,  p.  256;  Compt.  Rend.,  vol.  110, 1890,  p.  1377.  For  earlier  syntheses  of  these 
minerals,  by  Daubrde,  Deville  and  Caron,  Fremy  and  Feil,  Meunier,  and  Hautefeuille  and  Margottet,  see 
L.  Bourgeois,  Reproduction  artificielle  des  mindraux,  pp.  119, 120.  The  processes,  except  the  last,  involved 
the  use  of  aluminum  fluoride,  silicon  fluoride,  or  silicon  chloride,  and  were  therefore  indirect. 


410 


THE  DATA  OF  GEOCHEMISTBY. 


an  essential  constituent  of  hard  porcelain.  He  also  obtained  silli- 
manite  by  fusing  silica  and  alumina  together.  This  synthesis  has 
also  been  effected  by  E.  S.  Shepherd  and  G.  A.  Rankin,1  who  find  that 
sillimanite  is  the  only  one  of  the  three  silicates  which  is  stable  in  the 
pure  melt.  They  also  confirm  the  statement  that  kyanite  and 
andalusite  pass  into  sillimanite  when  strongly  heated.  Their  arti- 
ficial sillimanite  melted  at  1,811°.  A.  Reich,2  by  heating  aluminum 
fluoride  with  silica  to  strong  redness,  obtained  a mixture  of  silli- 
manite and  corundum.  The  conditions  under  which  sillimanite  can 
form  magmatically  have  also  been  determined  by  J.  Morozewicz.3 
In  the  magmatic  mixture  R0.mAl203./?iSi02,  if  magnesia  and  iron 
are  absent,  m = 1,  and  n is  greater  than  6,  sillimanite  is  developed. 
K.  Dalmer  4 has  reported  the  alteration  of  a chlorite-mica  phyllite 
into  a mixture  of  andalusite  and  biotit e. 

Andalusite  is  a mineral  of  the  metamorphic  schists,  and  is  espe- 
cially common  in  the  contact  zones  of  clay  slate  near  dikes  of  granite 
or  diorite.  It  is  also  found  in  Archean  gneiss  and  mica  schist,  and 
sometimes  as  an  accessory  in  graifite. 

Sillimanite  is  common  in  the  crystalline  schists,  particularly  in 
feldspathic  gneiss,  and  in  cordierite  gneiss.  It  is  often  found  inter- 
grown  with  quartz. 

Kyanite  also  occurs  in  crystalline  schists,  such  as  gneiss,  mica 
schist,  paragonite  schist,  and  eclogite.  It  is  often  embedded  in 
quartz,  and  has  been  reported  in  limestone.5 

Andalusite  alters  to  muscovite,6  and  sometimes  also  to  chlorite  and 
kaolin.7  J.  Lemberg,8  by  heating  andalusite  or  kyanite  with  alkaline 
silicates  or  carbonates  under  pressure,  converted  them  into  zeolitic 
substances.  C.  Doelter,9  upon  heating  andalusite  with  potassium 
carbonate  and  fluoride  during  several  weeks  at  250°,  observed  the 
formation  of  scales  of  mica. 

It  has  already  been  stated  that  the  empirical  formulae  for  topaz 
and  andalusite  should  probably  be  tripled,  a suggestion  which  is 
based  partly  upon  their  alterability  into  muscovite.  On  this  basis 
the  three  species  compare  as  follows: 


Andalusite Al3(Si04)3(A10)3. 

Topaz Al3(Si04)3(AlF2)3. 

Muscovite Al3(Si04)3KH2. 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  28,  1900,  p.  293.  See  also  W.  Eitel,  Zeitschr.  anorg.  Chem.,  vol.  88,  1914, 
p. 173. 

2 Monatsh.  Chemie,  vol.  17, 1896,  p.  190. 

3 Min.  pet.  Mitt.,  vol.  18,  1898,  p.  72. 

* Neues  Jahrb.,  1897,  Band  2,  p.  156. 

5 J.  Kovaf,  Zeitschr.  Kryst.  Min.,  vol.  34,  1901,  p.  704. 

« A.  Gramann,  Neues  Jahrb.,  Bd.  2, 1901,  p.  193. 

7 P.  E.  Haefele,  Zeitschr.  Kryst.  Min.,  vol.  23,  1894,  p.  551. 

8 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  40,  1888,  p.  651. 

9 Allgemeine  chemische  Mineralogie,  p.  207.  •> 


ROCK-FORMING  MINERALS. 


411 


STAUROLITE. 

Orthorhombic.  Composition,  HFeAl5Si2013,1  with  a little  mag- 
nesia or  sometimes  manganese  oxide  replacing  a part  of  the  iron. 
Molecular  weight,  457.2.  Specific  gravity,  3.7.  Molecular  volume, 
123.  Color,  brown  to  black.  Hardness,  7 to  7.5. 

No  authentic  synthesis  of  staurolite  has  yet  been  recorded.  The 
substance  obtained  by  H.  Sainte-Claire  Deville  and  H.  Caron,2  by 
the  action  of  silicon  fluoride  upon  a heated  mixture  of  alumina  and 
quartz,  and  called  staurolite  by  them,  had  nearly  the  composition 
of  sillimanite.3  P.  Hautefeuille  and  J.  Margottet,4  in  their  memoir 
upon  the  synthesis  of  certain  phosphates,  also  mention  the  produc- 
tion of  a mineral  resembling  staurolite  hut  give  no  further  details. 

Staurolite  is  a mineral  of  the  metamorphic  schists,  especially  of 
muscovite  or  paragonite  schist,  and  some  gneisses  or  slates.  It  is 
often  associated  with  kyanite.  Staurolite  alters  into  muscovite.5 
The  reported  alteration  into  steatite  is  very  questionable. 

LAWSONITE. 

Orthorhombic.  Composition,  H4CaAl2Si2O10.  Molecular  weight, 
315.1.  Specific  gravity,  3.09.  Molecular  volume,  102.  Color,  pale 
blue  to  grayish  blue.  Hardness,  8.25. 

Lawsonite  was  discovered  by  F.  L.  Ransome 6 in  1895,  in  a glauco- 
phane-bearing  schist  from  Tiburon  Peninsula,  California.  It  has 
since  been  found  by  S.  Franchi  and  A.  Stella 7 in  the  metamorphic 
schists  of  the  Alps;  by  C.  Viola8  in  the  saussuritized  gabbros  of 
southern  Italy;  and  by  A.  Lacroix 9 in  similar  rocks  and  glauco- 
phane  schists  from  Corsica  and  New  Caledonia.  J.  P.  Smith 10  has 
recently  described  lawsonite  rocks  from  several  localities  in  Cali- 
fornia, especially  a lawsonite-glaucophane  schist  and  a lawsonite- 
glaucophane  gneiss.  The  latter  rock  carried  about  25  per  cent  of 
lawsonite.  The  mineral  is  evidently  of  widespread  occurrence.  Its 
formula  suggests  a derivation  from  anorthite,  by  assumption  of  two 
molecules  of  water.  Upon  fusion,  lawsonite  would  undoubtedly  yield 
anorthite. 

1 Established  by  S.  L.  Penfield  and  J.  H.  Pratt,  Am.  Jour.  Sci.,  3d  ser.,  vol.  47,  1894,  p.  81. 

2 Compt.  Rend.,  vol.  46,  1858,  p.  764. 

a H.  Sainte-Claire  Deville,  idem,  vol.  52,  1861,  p.  780. 

* Idem,  vol.  96,  1883,  p.  1052. 

e See  analysis  in  Bull.  U.  S.  Geol.  Survey  No.  220,  1903,  p.  54. 

® Bull.  Dept.  Geology  Univ.  California,  vol.  1,1895,  p.  301.  See  also  F.  L.  Ransome  and  C.  Palache, 
Zeitschr.  Kryst.  Min.,  vol.  25,  1896,  p.  531;  and  W.  T.  Schaller  and  W.  F.  Hillebrand,  Bull.  U.  S.  Geol. 
Survey  No.  262, 1905,  p.  58. 

7 Cited  by  P.  Termier,  Bull.  Soc.  min.,  vol.  20, 1897,  p.  5.  See  also  Termier,  idem,  vol.  27,  1904,  p.  265. 

s Zeitschr.  Kryst.  Min.,  vol.  28, 1897,  p.  553. 

9 Bull.  Soc.  min.,  vol.  20, 1897,  p.  309. 

10  Proc.  Am.  Philos.  Soc.,  vol.  45, 1907,  p.  183.  See  also  A.  S.  Eakle,  Bull.  Dept.  Geology  Univ.  Cali- 
fornia, vol.  5, 1907,  p.  82. 


412 


THE  DATA  OF  GEOCHEMISTRY. 


According  to  F.  Cornu/  the  compound  H4CaAl2Si209  is  dimor- 
phous. Lawsonite  is  one  modification;  the  other,  isometric,  he  has 
named  hibschite.  It  was  found  enveloping  garnet  as  an  inclusion 
in  the  phonolite  of  Aussig,  Bohemia. 

DUM  ORTIERITE. 

Orthorhombic.  Composition,  Al8HBSi3O20.1 2  Molecular  weight, 
634.  Specific  gravity,  3.3.  Molecular  volume,  192.  Color,  blue, 
bluish  green,  lavender,  or  black.  Hardness,  7. 

Dumortierite  was  originally  discovered  in  a pegmatite  gneiss  near 
Lyons,  in  France.  It  has  since  been  found  in  Germany,  Austria, 
Norway,  Argentina,  and  at  several  localities  in  the  United  States.3 
It  has  been  observed  in  pegmatite,  in  cordierite  gneiss,4  in  granite, 
and  in  certain  quartz  rocks  associated  with  kyanite  (Arizona),  sil- 
limanite  (California),  and  andalusite  (Washington).  Muscovite  is 
also  one  of  its  companions,  and  Schaller  has  observed  its  alteration 
into  muscovite.  It  is  an  inconspicuous  mineral,  except  for  its  usual 
bright-blue  color,  and  is  probably  not  at  all  rare.  Its  close  relation- 
ship to  andalusite,  sillimanite,  and  kyanite  is  obvious.  According 
to  W.  Vernadsky,5  dumortierite,  at  a white  heat,  is  converted  into 
sillimanite.  What  other  product  is  formed  at  the  same  time  is  not 
stated.6 

TOURMALINE. 

Rhombohedral.  Composition,  a complex  borosilicate  of  aluminum 
and  other  bases.  Color,  white,  yellow,  brown,  green,  red,  blue,  and 
black.  Specific  gravity,  2.98  to  3.20.  Hardness,  7 to  7.5. 

Tourmaline  really  represents  a group  of  isomorphous  species,  whose 
chemical  relations  are  not  yet  completely  understood.  There  are, 
however,  three  distinct  types,  as  follows: 

Alkali  tourmaline:  Contains  lithium  or  sodium,  sometimes  potas- 
sium in  less  amount.  Found  in  pegmatites,  with  muscovite  and 
lepidolite. 

Magnesium  tourmaline:  Chief  base,  after  aluminum,  magnesium. 
Often  found  in  limestone  or  dolomite,  with  phlogopite  as  the  accom- 
panying mica. 

Iron  tourmaline:  The  common  black  variety,  which  alone  is  signifi- 
cant as  a rock-making  mineral.  Contains  iron  in  place  of  magne- 
sium. Associated  commonly  with  muscovite  or  biotite. 

1 Min.  pet.  Mitt.,  vol.  25, 1906,  p.  249. 

2 As  determined  by  W.  T.  Schaller,  Bull.  U.  S.  Geol.  Survey  No.  262, 1905,  pp.  91-120.  See  also  W.  E. 
Ford,  Am.  Jour.  Sci.,  4th  ser.,  vol.  4, 1902,  p.  426.  Ford’s  formula  differs  slightly  from  Schaller’s. 

3 See  Schaller’s  memoir,  cited  above,  for  a full  summary  of  the  known  localities  and  a bibliography  of  the 
species. 

4 See  A.  Lacroix,  Bull.  Soc.  min.,  vol.  12, 1889,  p.  211. 

6 Idem,  vol.  13, 1890,  p.  256. 

6 Q.  I.  Finlay  (Jour.  Geology,  vol.  15, 1907,  p.  479)  reports  dumortierite  and  corundum  as  original  pyro- 
genic constituents  of  a pegmatite  dike  near  Canon  City.  Colorado. 


ROCK-FORMING  MINERALS. 


413 


Between  these  distinct  types  there  are  various  intermediate  mix- 
tures, and  also  rare  examples  in  which  a little  chromium  appears, 
partly  replacing  aluminum. 

Over  the  chemical  formula  of  tourmaline  there  has  been  much  dis- 
cussion, and  no  set  of  expressions  can  be  assumed  as  final.1  The 
following  formulae  seem  to  be  best  sustained  by  evidence:2 

(1)  AlgR/gSisBgOgx. 

(2)  AfiR^SigBgOgx. 

(3)  AfiR/^SieBgOgj. 

In  No.  3 the  B/  is  largely  replaced  by  R",  which  may  he  Fe  or  Mg. 
Hydrogen  is  important  among  the  components  of  R'.  Fluorine  is 
also  commonly  present  in  small  amounts.  The  general  formula 
Al3R9(B0H)2Si4019,  proposed  by  S.  L.  Penfield  and  H.  W.  Foote,3 
is  preferred  by  some  authorities. 

Tourmaline  has  not  as  yet  been  produced  synthetically.  The  rock- 
forming iron-hearing  variety  is  commonly  found  in  the  older  and  more 
highly  siliceous  igneous  and  granular  rocks,  such  as  granite,  syenite, 
and  diorite.  It  is  also  abundant  in  mica  schists,  clay  slates,  and 
other  similar  matrices.  It  forms  in  some  cases  at  the  contact  between 
schists  and  granite,  and  may  be  abundant  enough  to  characterize  an 
occurrence  as  a tourmaline  hornstone.  In  igneous  rocks  it  seems  to 
have  been  produced  by  fumarole  action,  and  not  as  a direct  separation 
from  the  magma.  H.  B.  Patton  4 regards  the  tourmaline  of  certain 
schists  in  Colorado  as  having  been  formed  at  the  expense  of  the  bio- 
tite  contained  in  the  pegmatites  adjoining  the  contact  zone. 

Tourmaline  alters  to  mica,  chlorite,  and  cookeite.  Upon  fusion, 
according  to  C.  Doelter,5  tourmaline  yields  olivine  and  spinel. 

BERYL. 

Hexagonal.  Normal  composition,  Al2Gl3Si6018.  Molecular  weight, 
539.9.  Specific  gravity,  2.7.  Molecular  volume,  200.  Colorless, 
white,  more  commonly  green,  sometimes  yellow,  blue,  or  rose.  Hard- 
ness, 7.5  to  8. 

Although  normal  beryl  has  the  composition  given  above,  the  min- 
eral generally  varies  from  it.  S.  L.  Penfield  6 has  shown  that  many 
beryls  contain  alkalies,  replacing  glucina,  and  also  some  combined 

1 See  C.  Rammelsberg,  Neues  Jahrb.,  1890,  Band  2,  p.  149.  A.  Kenngott,  idem,  1892,  Band  2,  p.  44. 
G.  Tschermak,  Min.  pet.  Mitt.,  vol.  19, 1899,  p.  155;  Zeitschr.  Kryst.  Min.,  vol.  35, 1899, p.  206.  V.  Gold- 
schmidt, Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  pp.  52,  61.  R.  Scharizer,  idem,  vol.  15,  1889,  p.  337.  P. 
Jannasch  and  G.  Calb,  Ber.  Deutsch.  chem.  Gesell.,  vol.  22,  1889,  p.  216.  H.  Rheineck,  Zeitschr.  Kryst. 
Min.,  vol.  17, 1890,  p.  604;  vol.  22, 1894,  p.  52.  E.  A.  Wiilfing,  Min.  pet.  Mitt.,  vol.  10, 1888,  p.  161;  Reiner, 
Inaug.  Diss.  Heidelberg,  1913;  W.  T.  Schaller,  Zeitschr.  Kryst.  Min.,  vol.  51,  p.  321, 1913. 

2 Bull.  U.  S.  Geol.  Survey  No.  167, 1900,  p.  26;  Am.  Jour.  Sci.,  4th  ser.,  vol.  8, 1899,  p.  111.  Also  in  Bull. 

U.  S.  Geol.  Survey  No.  588, 1914. 

s Am.  Jour.  Sci.,  4th  ser.,  vol.  7, 1899,  p.  97;  vol.  10, 1900,  p.  19. 

* Bull.  Geol.  Soc.  America,  vol.  10,  1898,  p.  21. 

6 Neues  Jahrb.,  1897,  Band  1,  p.  1. 

6 Am.  Jour.  Sci.,  3d  ser.,  vol.  28,  1884,  p.  25;  vol.  36,  1888,  p.  317. 


414 


THE  DATA  OF  GEOCHEMISTRY. 


water,  up  to  nearly  3 per  cent.  A beryl  from  Hebron,  Maine,  con- 
tained 3.60  per  cent  of  Cs20.  A beryl  analyzed  by  J.  S.  De  Benne- 
ville1  carried  2.76  per  cent  of  K20;  and  F.  C.  Robinson,2  in  another 
example,  found  2.76  per  cent  of  P205. 

J.  J.  Ebelmen3  succeeded  in  recrystallizing  beryl  by  fusion  with 
boric  oxide.  P.  Hautefeuille  and  A.  Perrey  4 obtained  it  in  crystals 
by  fusing  a mixture  of  alumina,  glucina,  and  silica  with  the  same 
flux.  H.  Traube 5 precipitated  a solution  containing  aluminum  sul- 
phate and  glucinum  sulphate  with  sodium  metasilicate,  and  crystal- 
lized the  product  from  fused  boric  oxide  in  the  same  way.  In  both 
of  the  cases  just  cited,  the  beryl  obtained  was  identified  crystallo- 
graphically  and  by  analysis. 

Beryl  is  a common  accessory  in  pegmatite  veins.  It  is  also  found 
in  clay  slate  and  mica  schist.  It  alters  into  mica  and  kaolin,  when 
the  removed  glucina  generally  appears  as  a constituent  of  other 
secondary  minerals,  such  as  bertrandite,  herderite,  or  beryllonite. 
Although  beryl  is  not  commonly  included  by  petrographers  in  their 
lists  of  rock-forming  minerals,  it  seems  entitled  to  recognition  in  a 
chapter  of  this  kind. 

SERPENTINE,  TALC,  AND  KAOLINITE. 

Serpentine. — Optically  monoclinic,  but  not  known  in  true  crystals. 
Composition,  H4Mg3Si209.  Molecular  weight,  278.  Specific  grav- 
ity, 2.5  to  2.6.  Molecular  volume.  109.  Color  commonly  green, 
often  yellowish. 

Hydrous  magnesian  silicates  are  easily  prepared  by  various  wet 
reactions,  but  these  syntheses  have  little  or  no  significance  in  the 
interpretation  of  serpentine.6  The  mineral  occurs  in  nature  only  as 
a secondary  product,  derived  by  hydrous  alteration  from  olivine, 
hornblende,  actinolite,  enstatite,  diopside,  chondrodite,  and  other 
magnesian  minerals.  Large  rock  masses  are  frequently  found  which 
have  become  transformed  into  impure  serpentine.  Gabbro,7  perido- 
tite,8  and  amphibolite  9 may  undergo  this  change.10  The  alterative 
process,  however,  does  not  end  here.  Serpentine  itself  may  undergo 
further  alteration,  yielding  brucite,  magnesite,  hydromagnesite,  etc. 
R.  Brauns  11  has  described  a derivative  of  serpentine,  which  he  calls 

» Jour.  Am.  Chem.  Soc.,  vol.  16,  1894,  p.  65. 

2 Jour.  Anal,  and  Appl.  Chem.,  vol.  6,  1892,  p.  510. 

3 Annales  chim.  phys.,  3d  ser.,  vol.  22,  1848,  p.  237. 

* Compt.  Rend.,  vol.  106,  1888,  p.  1800. 

6 Neues  Jahrb.,  1894,  Band  1,  p.  275. 

6 See,  for  example,  A.  Gages,  Rept.  Brit.  Assoc.,  1863,  p.  203.  Gage’s  product  resembled  deweylite. 

2 See  L.  Finckh,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  50, 1898,  p.  108. 

8 See  G.  H.  Williams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  34,  1887,  p.  137. 

9 See  J.  B.  Jaquet,  Rec.  Geol.  Survey  New  South  Wales,  vol.  5,  1905,  p.  18. 

10  For  general  discussion  over  the  origin  of  serpentine,  see  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13, 
1888,  pp.  108  et  seq.;  and  J.  J.  H.  Teall,  British  petrography.  The  literature  is  very  abundant. 

11  Neues  Jahrb.,  Beil.  Band  5, 1887,  p.  318.  Brauns  discusses  the  different  varieties  of  serpentine  fully  and 
cites  much  literature. 


BOCK-FORMING  MINERALS. 


415 


webskyite,  H6Mg4Si3013.6H20;  and  F.  W.  Clarke1  has  reported  an 
apparent  serpentine  which  proved  upon  analysis  to  be  nearly  60  per 
cent  brucite.  By  solfataric  action  serpentine  may  lose  its  magnesia 
in  the  forms  of  sulphate  or  carbonate  and  become  transformed  into  a 
mass  of  quartz  and  opal.2  When  serpentine  is  fused  it  yields  a mix- 
ture of  olivine  and  enstatite.3 

Talc. — Monoclinic.  Composition,  H2Mg3Si4C12.  Molecular  weight, 
380.8.  Specific  gravity,  2.7  to  2.8.  Molecular  volume,  138.  Color, 
white  to  green.  The  name  talc  is  commonly  applied  to  the  foliated 
varieties;  the  massive  mineral  is  called  steatite. 

Talc  is  common  as  a pseudomorphous  mineral,  derived  from  other 
magnesian  species,  often  from  tremolite  or  enstatite.4  Assuming  the 
change  to  be  brought  about  by  carbonated  water,  the  reactions  may 
be  simply  written  as  follows : 

. CaMg3Si4012  + H20  + C02  = H2Mg3Si4012  + CaC03. 

Mg4Si4012  + H20  + C02  = H2Mg3Si4012  + MgC03. 

The  talc  thus  produced  is  not  infrequently  associated  with  marble 
or  dolomite.  The  most  important  occurrence  of  talc,  however,  from 
a geological  point  of  view,  is  in  the  form  of  talcose  schist. 

According  to  F.  A.  Genth,  talc  may  alter  into  anthophyllite.5 
When  talc  is  ignited,  it  loses  water,  and  one-fourth  of  the  silica  is 
split  off  in  the  free  state.6  The  residue  after  removing  the  liberated 
silica,  has  the  composition  MgSi03. 

A number  of  other  hydrous  magnesian  silicates  occur  as  secondary 
minerals,  such  as  deweylite,  saponite,  etc.;  but  they  are  geologically 
unimportant. 

Kaolinite. — Monoclinic.  Composition,  H4Al2Si209.  Molecular 

weight,  259.  Specific  gravity,  2.6.  Molecular  volume,  99.6.  Color, 
white,  often  tinted  by  impurities. 

Known  only  as  a secondary  mineral,  the  product  of  hydrous  alter- 
ation of  other  species.  Derived  chiefly  from  feldspars. 

Halloysite,  cimolite,  newtonite,  montmorillonite,  pyrophyllite,  and 
allophane  are  other  hydrous  silicates  of  aluminum.  They  need  no 
consideration  here. 


1 Bull.  U.  S.  Geol.  Survey  No.  262,  1905,  p.  69. 

2 See  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888, pp.  108 etseq.;  also  A.  Lacroix,  Compt.  Bend, 
vol.  124,  1897,  p.  513. 

3 Daubr6e;  see  ante,  p.  376,  under  enstatite. 

4 See  C.  H.  Smyth,  School  of  Mines  Quart.,  vol.  17,  1896,  p.  333,  and  J.  H.  Pratt,  North  Carolina  Geol. 

Survey,  Economic  Paper  No.  3. 

6 Proc.  Am.  Philos.  Soc.,  vol.  20,  1882,  p.  381. 

6 F.  W.  Clarke  and  E.  A.  Schneider,  Bull.  U.  S.  Geol.  Survey  No.  78,  1891,  p.  13. 


416 


THE  DATA  OF  GEOCHEMISTRY. 


THE  ZEOEXTES. 


Under  the  general  term  zeolites  are  included  a number  of  impor- 
tant minerals,  which,  however,  do  not  strictly  belong  to  the  rock- 
making class.  They  occur  in  eruptive  rocks  only  as  secondary  prod- 
ucts, except  in  the  noteworthy  case  of  analcite,  which  has  already 
been  described.  The  more  important  zeolites  are  the  following: 


Heulandite 

Stilbite 

Laumontite 

Chabazite 

Thomsonite 

Scolecite 

Natrolite 

Hydronephelite. 


CaAbSi^O  16 . 5H20 . 
CaAl2Si<jO  16 . 6H20 . 

. CaAl2Si4012.4H20 . 
CaAl2Si40 12 . 6H20 . 
CaAl2Si208 . 2 JH20 . 
CaAl2Si30 10 . 3H20 . 

. N a2  Al2Si30 10 . 2H20 . 

. HN  a2  Al3Si30 12 . 3H20 


To  these  may  be  added  ptilolite,  mordenite,  brewsterite,  epistilbite, 
pliiHipsite,  gismondite,  laubanite,  gmelinite,  levynite,  faujasite, 
edingtonite,  mesolite,  erionite,  wellsite,  and  perhaps  other  species.  As 
a rule,  in  the  lime-bearing  zeolites  a part  of  the  lime  may  be  replaced 
by  other  bases,  generally  by  soda.  Potassium,  however,  is  found  in 
notable  quantities  in  phillipsite,  harmotome,  edingtonite,  and  wells- 
ite, and  strontium  in  brewsterite  and  wellsite.  The  formulae  given 
above  are  general  and  empirical,  nothing  more;  but  they  suggest 
some  paragenetic  relations.  Stilbite  and  heulandite  seem,  for  exam- 
ple, to  be  derivatives  of  an  unknown  calcium-albite;  and  in  general 
the  zeolites  appear  to  have  been  formed  from  feldspars  or  feldspa- 
thoids.  Anorthite  and  nephelite  are  common  parents  of  zeolitic 
minerals.  Pectolite,  okenite,  gyrolite,  and  apophyllite 1 are  other 
secondary  minerals  whose  mode  of  occurrence  is  like  that  of  the  true 
zeolites,  and  possibly  the  species  prehnite  and  datolite  should  on 
genetic  grounds  be  grouped  with  them.  Mineralogically  these  min- 
erals are  classed  elsewhere ; it  is  only  as  regards  their  mode  of  forma- 
tion that  they  are  mentioned  now. 

Many  syntheses  of  zeolites  and  zeolitic  compounds  are  recorded, 
and  several  species  have  been  recrystallized  from  solution  in  super- 
heated waters.  The  syntheses  were  necessarily  effected  by  hydro- 
chemical reactions,  either  operating  upon  such  minerals  as  anorthite 
or  nephelite,  or  by  double  decomposition  between  aqueous  solutions.  . 
H.  Sainte-Claire  Deville,2  for  example,  produced  phillipsite,  levyn- 
ite, and  gmelinite  by  heating  solutions  of  potassium  silicate  with 
sodium  or  potassium  aluminate  to  170°.  C.  Doelter 3 prepared  apoph- 
yllite, okenite,  chabazite,  heulandite,  stilbite,  laumontite,  thomsonite, 


* On  apophyllite  as  a rock-forming  mineral,  see  F.  Cornu,  Centralbl.  Min.,  Geol.  u.  Pal.,  1907,  p.  239. 

2 Compt.  Rend.,  vol.  54,  1862,  p.  324. 

s Neues  Jahrb.,  1890,  Band  1,  p.  118 


ROCK-FORMING  MINERALS. 


417 


natrolite,  and  scolecite  by  various  processes;  and  J.  Lemberg1  has 
shown  that  zeolites  can  be  generated  from  one  another  by  the  action 
at  moderately  high  temperatures  of  suitable  reagents,  such  as  the 
alkaline  carbonates  and  silicates.  The  syntheses  of  analcite  by  De 
Schulten  and  Friedel  and  Sarasin  have  already  been  described.2  At 
the  hot  springs  of  Plombieres  A.  Daubree  3 found  zeolites  which  had 
been  produced  by  the  action  of  the  percolating  waters  upon  the 
cement  and  brick  work  of  the  old  Roman  baths.  Chabazite,  phillips- 
ite,  apophyllite,  and  gismondite  were  identified,  and  similar  develop- 
ments were  afterward  discovered  at  other  hot  springs  in  France  and 
Algeria.4 

High  temperatures,  however,  are  not  essential  to  the  formation  of 
zeolites.  Phillipsite  has  been  found  abundantly  in  volcanic  mud 
dredged  up  from  the  bottom  of  the  Pacific  Ocean;5  and  A. Lacroix 6 
discovered  several  of  the  species  under  conditions  which  showed  a 
recent  origin  from  cold  percolating  waters.7 

THE  CARBONATES. 

Calcite. — Rhombohedral.  Composition,  CaC03.  Molecular  weight 
100.1.  Specific  gravity,  2.72.  Molecular  volume,  36.8.  Hardness, 
3.  Normally  colorless,  but  often  variously  colored  by  impurities. 

Aragonite. — Orthorhombic.  Composition,  CaC03,  like  calcite. 

Specific  gravity,  2.94.  Molecular  volume,  34.  Hardness,  3.5  to  4. 
Color,  white,  but  often  tinted  by  impurities. 

Dolomite. — Rhombohedral.  Composition,  CaMgC206.  Molecular 
weight,  184.5.  Specific  gravity,  2.83.  Molecular  volume,  65.2. 
Hardness,  3.5  to  4.  Normally  colorless  but  often  tinted  pink  or 
brown. 

Magnesite. — Rhombohedral.  Composition,  MgC03.  Molecular 

weight,  84.4.  Specific  gravity,  3.0.  Molecular  volume,  28.1.  Hard- 
ness, 3.5  to  4.5.  Color,  white  to  brown. 

Siderite. — Rhombohedral.  Composition,  FeC03.  Molecular  weight, 
115.9.  Specific  gravity,  3.88.  Molecular  volume,  29.9.  Hardness, 
3.5  to  4.  Color,  gray  to  brown,  sometimes  white.  Breunnerite  and 
mesitite  are  carbonates  intermediate  in  composition  between  siderite 
and  magnesite. 

1 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  28,  1876,  p.  519.  On  artificial  zeolites  see  also  F.  Singer,  Diss., 
Tech.  Hochschule,  Berlin,  1910. 

2 See  ante,  p.  369. 

s Etudes  synth6tiques  de  g4ologie  exp^rimentale,  p.  179. 

4 Idem,  p.  199. 

B Rept.  Challenger  Exped.,  Narrative,  vol.  1,  pt.  2,  1885,  pp.  774,  815. 

6 Compt.  Rend.,  vol.  123,  1896,  p.  761.  The  localities  described  are  in  the  Pyrenees.  Plagioclase  and 
scapolite  were  the  parent  minerals. 

7 For  a discussion  of  the  constitution  of  the  zeolites  see  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588, 

1914,  pp.  40-50. 


97270°— Bull.  616—10 27 


418 


THE  DATA  OF  GEOCHEMISTRY. 


All  these  carbonates  occur  in  igneous  rocks  as  secondary  or  altera- 
tion products.  Calcite  is  sometimes  apparently  of  primary  origin, 
but  not  certainly  so.  When  heated  under  ordinary  conditions,  cal- 
cite dissociates  into  CaO  + C02 ; but  under  great  pressures  it  may  be 
fused  without  decomposition.  It  is  not  impossible,  therefore,  that  it 
may  have  formed  in  some  cases  during  the  solidification  of  a magma 
at  great  depth.1 

Calcite  alone,  as  a rock,  is  represented  by  marble,  limestone,  chalk, 
etc.,  and  is  therefore  a most  important  mineral.  Dolomite  also  forms 
extensive  rock  masses.  Both  species  will  be  more  fully  considered 
later  in  the  study  of  sedimentary  rocks. 

1 For  examples  of  primary  calcite  in  igneous  rocks  see  F.  D.  Adams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  48,  1894, 
p.  14;  T.  L.  Walker,  Quart.  Jour.  GeoL  Soc.,  vol.  53,  1897,  p.  55;  T.  H.  Holland,  Mem.  Geol.  Survey  India, 
vol.30,  1901,  p.  197;  O.  Stutzer,  Centralbl.  Min.,  Geol.  u.  Pal.,  1910,  p.  433;  Rachel  Workman,  Geol.  Mag., 
1911,  p.  193.  Many  other  examples  are  on  record.  The  occurrences  are  principally  in  granite  or  nepheline 
syenite. 


CHAPTER  XL 
IGNEOUS  ROCKS. 

PRELIMINARY  CONSIDERATIONS. 

When  a magma  solidifies  to  form  a rock,  it  may  become  either  that 
indeterminate  substance  known  as  glass  or  a mixture  of  definite  min- 
eral species.  Between  these  two  stages  of  development  any  interme- 
diate phase  may  be  produced,  from  a glass  containing  a few  individ- 
ualized crystals  or  microlites  to  a mass  of  crystalline  matter  with 
some  vitreous  remainder.  The  character  of  the  product  will  depend 
upon  a variety  of  conditions,  such  as  the  composition  of  the  molten 
material,  the  rate  of  cooling,  and  the  circumstances  under  which  it 
cools.  If  solidification  takes  place  at  the  surface  of  the  earth,  as  in 
an  ordinary  volcanic  outflow,  one  set  of  consequences  will  follow;  if 
it  is  effected  under  pressure — that  is,  at  great  depth — the  gaseous 
contents  of  the  magma,  being  unable  to  escape,  will  play  a part  in  the 
process,  and  determine  the  formation  of  compounds  which  could  not 
otherwise  be  generated.  In  either  case  a relatively  small  number  of 
these  will  form  in  preponderating  quantities.  If  we  consider  the 
igneous  rocks  statistically,  we  shall  find  that  in  the  average  they 


contain  the  following  minerals: 

Feldspars 59.5 

Hornblende  and  pyroxene 16.8 

Quartz 12.0 

Biotite 3.8 

Titanium  minerals 1.5 

Apatite 6 


94.2 


The  less  abundant  rock-forming  minerals  will  make  up  the  remain- 
ing 5.8  per  cent.1  The  computation  is  by  no  means  exact,  but  it 
serves  to  illustrate  the  relative  importance  of  the  several  groups  or 
species.  Feldspars  predominate,  the  ferromagnesian  minerals  come 
next  in  abundance,  then  quartz,  and  after  that  all  other  species  as 
minor  accessories.  This  statement,  it  must  be  borne  in  mind,  deals 
with  averages  only.  Individual  rocks  may  contain  some  of  the  less 
frequent  minerals  as  principal  constituents,  such  as  olivine  in  the 
peridotites,  nepheline  or  leucite  in  certain  syenites  or  basalts,  and  so 
on.  The  moment  we  begin  to  study  rocks  separately  we  shall  see 
that  they  vary  widely  from  the  mean. 

1 A somewhat  different  estimate  is  given  by  H.  S.  Washington  in  Prof.  Paper  17.  S.  Geol.  Survey  No.  14, 
1903,  p.  155.  Its  general  purport  is,  however,  much  the  same  as  mine. 


419 


420 


THE  DATA  OF  GEOCHEMISTRY. 


Being  mixtures,  the  igneous  rocks  represent  an  almost  infinite 
range  of  composition.  The  minerals  which  are  capable  of  simul- 
taneous generation  from  a magma  may  be  commingled  in  various 
proportions.  Locks,  therefore,  are  not  sharply  classifiable  upon  the 
basis  of  their  composition,  for  they  shade  into  one  another  through 
all  possible  gradations,  and  are  separable  by  no  precise  dividing  lines. 
A mineral  is  a distinct  stoichiometric  compound;  a rock,  except  when 
it  happens  to  consist  of  one  mineral  alone,  is  not.  Miner alogic ally 
a rock  may  be  quartz,  or  olivine,  or  hornblende,  or  pyroxene,  with 
very  little  impurity;  but  these  are  the  exceptional  cases.  Mixtures 
of  two  or  more  components,  in  variable  proportions,  form  the  rule. 

Certain  mixtures,  however,  are  much  more  common  than  others 
and  are  represented  by  widely  diffused  and  abundant  rock  types. 
Granite,  for  example,  is  a mixture  of  quartz  and  feldspar,  with  sub- 
ordinate ferromagnesian  minerals,  and  samples  from  different  parts 
of  the  world  are  surprisingly  similar.* 1  Absolute  identity  is,  of  course, 
out  of  the  question;  but  the  approximation  to  it  is  close  enough  to 
mark  out  what  we  may  regard  as  a good  rock  species.  Upon  uni- 
formities of  this  kind  the  prevalent  classifications  of  the  igneous 
rocks  are  based.  The  more  frequent  mixtures  form  the  familiar 
types,  and  under  them  there  appear  an  indefinite  number  of  varieties, 
representing  minor  differences  of  composition,  intermediate  forms, 
modes  of  occurrence,  textures,  genetic  relationships,  or  even  geologic 
age.  With  some  of  these  criteria  we  have  no  present  concern;  only 
the  chemical  aspects  of  rock  classification  fall  within  the  scope  of  this 
work.  Other  considerations  have  much  weight,  of  course,  but  it  is 
not  the  province  of  the  chemist  to  discuss  them. 

CLASSIFICATION. 

From  a chemical  point  of  view  the  igneous  rocks  may  be  classified 
in  three  different  ways.  First,  on  the  basis  of  their  ultimate  compo- 
sition. Second,  by  their  proximate  units,  the  minerals  which  they 
contain.  The  latter  procedure  is  at  present  most  in  vogue,  but  the 
first  method  has  strong  advocates  and  may  possibly  prevail.  In  the 
third  place  we  can  start  from  the  conception  of  a magma  as  a solu- 
tion and  regard  the  eutectic  mixtures  as  the  definite  types  with  which 
the  igneous  rocks  shall  be  compared.  Let  us  consider  the  three 
propositions  separately. 

At  first  sight  the  mineralogical  classification,  a classification  by  the 
compounds  which  a rock  actually  contains,  would  seem  to  be  the 
simplest  and  most  reasonable.  In  practice,  however,  it  is  beset  with 

i In  R.  A.  Daly’s  paper  on  the  average  composition  of  igneous  rock  types,  Proc.  Am.  Acad.,  vol.  45, 1910, 
p . 2 11 , the  clustering  of  analyses  around  “ center-points  ” is  strongly  emphasized.  F or  the  average  specific 
gravity  of  rocks,  considered  group  hy  group,  see  F.  Becke,  Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  120,  Abth. 

1,  p.  265, 1911.  The  average  specific  gravity  of  958  igneous  rocks,  computed  by  F.  W.  Clarke,  is  2.737. 


IGNEOUS  ROCKS. 


421 


difficulties.  A perfectly  fresh,  unaltered,  entirely  crystalline  rock  is 
easy  to  describe  on  this  basis;  but  all  rocks  do  not  fulfill  these  con- 
ditions. In  some  rocks  the  mineralogical  development  is  obscure,  so 
that  essential  constituents  can  not  be  clearly  defined.  In  others  the 
development  is  incomplete,  a certain  amount  of  undifferentiated  glass 
remaining  to  complicate  the  problem.  We  can  infer  in  such  cases 
what  minerals  should  form  if  the  devitrifying  process  were  ended; 
but  our  inferences  may  not  be  conclusive.  In  some  instances  sup- 
posed glass  has  proved  to  be  analcite,  and  misapprehensions  of  that 
order  are  not  easily  avoided.  This  objection,  of  course,  carries  little 
weight,  for  any  classification  is  liable  to  be  influenced  by  errors  of 
diagnosis.  Only,  other  things  being  equal,  that  classification  is  best 
in  which  the  liabilities  to  error  are  fewest.  The  fundamental  diffi- 
culty of  all  is  inherent  in  the  nature  of  our  problem;  for  in  dealing 
with  mixtures  it  is  not  easy  to  establish  dividing  lines,  and  to  decide 
on  which  side  of  an  imaginary  boundary  a given  rock  should  be 
placed.  This  difficulty,  which  chiefly  affects  our  judgment  in  dealing 
with  intermediate  forms,  exists  in  all  rock  classifications.  It  can  only 
be  overcome  by  conventional  devices,  which  must  be  more  or  less 
arbitrary. 

Some  of  the  difficulties  which  obstruct  a mineralogical  classification 
are  avoided  by  the  purely  chemical  system.  The  latter  rests  upon 
supposedly  good  analyses  of  rocks,  and  the  molecular  ratios  deduced 
from  the  analytical  data  are  the  ultimate  criteria.  Good  analyses  are 
easily  obtained;  their  discussion  involves  no  questionable  hypotheses, 
and  their  classification  is  comparatively  simple.1  But  is  a classifica- 
tion of  analyses  a classification  of  rocks  ? That  question  needs  to 
be  considered  very  carefully. 

In  the  first  place  a rock  mass  may  be  a perfectly  definite  petro- 
graphic unit  and  yet  not  be  homogeneous.  In  fact,  the  presence  of 
separately  distinguishable  minerals  in  it  is  evidence  of  heterogeneity. 
Suppose,  now,  that  two  analysts,  equally  competent,  receive  samples 
of  a given  rock  taken  from  the  same  quarry  by  two  different  col- 
lectors. In  one  sample  the  phenocrysts  of  a certain  mineral  are  a 
little  more  numerous  or  a little  larger  than  in  the  other.  The  two 
analyses  will  therefore  diverge,  and  the  same  rock,  because  of  their 
dissimilarities,  may  be  classified  under  two  distinct  headings.  Evi- 
dently, in  such  a case,  something  more  than  analysis  is  needed  in 
order  to  define  the  nature  of  the  substance  under  examination. 
Chemically  at  least  the  nature  of  the  substance  is  the  essential  thing 
to  be  determined;  and  therefore  both  chemical  and  mineralogical  evi- 
dence must  be  taken  into  account  together.  According  to  its  nature 
the  substance  is  to  be  classified. 


1 Such  a classification  has  been  proposed  by  H.  Warth,  Geol.  Mag.,  1906,  p.  131,  and  elaborated  in 
Proc.  Roy.  Soc.  Edinburgh,  vol.  28,  1907,  p.  85. 


422 


THE  DATA  OF  GEOCHEMISTRY. 


The  interdependence  of  the  two  schemes  of  classification  can  be 
brought  out  in  still  another  way.  It  is  a commonplace  of  chemistry 
that  two  or  even  many  substances  may  have  absolutely  the  same 
percentage  composition  and  yet  be  very  different  in  their  molecular 
structure  and  physical  properties.  Methyl  oxide,  for  instance,  is  a 
gas;  ethyl  alcohol  is  a liquid;  and  yet  both  compounds  are  accu- 
rately represented  by  the  same  empirical  formula,  C2H60.  Nor  is 
this  an  exceptional  case,  for  organic  chemistry  takes  cognizance  of 
similar  examples  by  the  thousand.  The  differences  are  ascribed  to 
different  arrangements  of  the  atoms  within  the  molecule,  and  the 
substances  which  exhibit  tins  empirical  identity  are  said  to  be 
isomeric. 

Similar  instances,  although  not  so  sharply  defined,  and  by  no 
means  so  clearly  interpreted,  are  found  in  mineralogy.  The  pyroxenes 
and  amphiboles,  for  example,  have  in  general  the  same  molecular 
ratios,  while  enstatite  and  anthophyllite  are  alike  in  ultimate  com- 
position. Amphiboles,  by  fusion  alone,  are  transformable  into  pyrox- 
enes, and  the  reverse  change  takes  place  when  pyroxene  is  altered  into 
uralite.  Two  rocks,  then,  alike  in  composition  as  shown  by  analysis, 
and  magma tically  identical,  may  be  quite  different  miner alogically, 
the  one  containing  amphibole  and  the  other  pyroxene.1  Analytical 
data  will  lead  us  to  class  them  together;  mineralogical  considerations 
place  them  apart.  This  is  a simple  case,  but  as  rocks  become  more 
complex,  the  chances  of  pseudoidentity  increase,  and  mixtures  that 
are  very  unlike  may,  as  interpreted  by  analysis  alone,  appear  to  be 
the  same.  Even  when  the  analyses  show  empirical  differences,  the 
molecular  ratios  may  become  identical,  and  therefore  deceptive. 
Mere  analysis,  then,  does  not  furnish  a complete  basis  for  rock  classi- 
fication. It  takes  us  one  step  toward  the  goal,  but  other  steps  must 
follow.  The  chemical  constitution  of  a rock,  as  indicated  by  its 
proximate  ingredients,  is  fully  as  important  a factor  in  its  classi- 
fication as  its  ultimate  composition. 

Two  suggestions,  intended  to  be  helpful  in  at  least  a partial  classi- 
fication of  igneous  rocks,  may  be  noticed  briefly  here.  A.  N.  Win- 
chell2  proposes  to  divide  the  rocks  into  three  classes,  peralkaline, 
alkaline,  and  alkalcic.  The  first  class  includes  such  rocks  as  the 
nepheline  syenites,  which  contain  a high  proportion  of  alkalies.  The 
second  class  comprises  those  wdiich  are  characterized  by  feldspathic 
minerals.  In  the  third  class  are  placed  the  rocks  which  are  deficient 
in  alkalies.  The  other  suggestion,  by  S.  J.  Shand,3  provides  for  two 

1 For  example,  H.  Andesner  (Neues  Jahrb.,  Beil.  Band,vol.  30, 1910,  p.  467)  fused  a homblendite con- 
taining principally  hornblende,  and  some  zoisite,  quartz,  rutile,  and  apatite.  The  product  had  the 
character  of  a basalt,  with  microscopic  crystals  of  magnetite,  augite,  and  plagioclase. 

2 Jour.  Geology,  vol.  21,  p.  208, 1913. 

3 Geol.  Mag.,  1913,  p.  508.  A criticism  by  A.  Scott  is  in  the  same  journal  for  1914,  p.  319,  followed  by  a 
reply  from  Shand,  p.  485. 


IGNEOUS  ROCKS. 


423 


main  classes,  which  he  calls  saturated  and  unsaturated  rocks.  Un- 
saturated minerals,  which  characterize  the  latter  class,  are  those 
which,  like  nephelite  and  olivine,  are  capable  of  taking  up  more 
silica,  forming  feldspar  and  pyroxene.  Rocks  in  which  such  minerals 
are  conspicuous  are  called  unsaturated.  The  saturated  minerals  and 
rocks,  obviously,  are  those  in  which  no  more  silica  can  be  assimilated 
by  the  silicates;  and -also  those  in  which  free  silica  appears.  These 
classifications,  of  course,  do  not  claim  completeness,  but  are  offered 
as  starting  points  from  which  the  details  may  be  developed. 

The  classification  of  igneous  rocks  on  the  basis  of  eutectic  mixtures, 
advocated  by  G.  F.  Becker,1  is  of  a different  order  from  either  of  the 
other  systems.  Rocks,  considered  in  the  mass,  are  variable  commin- 
glings of  minerals;  but  the  eutectics,  being  definite  mixtures,  may  be 
taken  as  the  standard  types.  From  this  point  of  view,  the  ground- 
mass  of  a rock  becomes  its  most  characteristic  feature,  and  the  pheno- 
crysts  are  only  the  accidental  excesses  of  one  constituent  or  another 
over  the  eutectic  ratio.  The  importance  of  this  principle  has  been 
already  discussed  in  a previous  chapter,2  and  its  application  to  petrog- 
raphy is  foreshadowed  in  the  writings  of  Guthrie,  Lagorio,  Teall, 
Lane,  and  Vogt.3  That  magmas  and  the  products  of  their  solidifica- 
tion must  be  studied  on  physicochemical  lines  is  generally  admitted, 
and  a eutectic  classification  would  seem  to  follow  naturally  from  that 
kind  of  investigation.  At  present,  however,  such  a classification  is 
only  a matter  of  theory,  and  its  effectiveness  can  not  be  tested  until  a 
reasonable  number  of  eutectics  have  been  identified  and  described. 
Teall,  Lane,  and  Vogt  all  agree  in  thinking  that  micropegmatite  is  a 
eutectic  mixture  of  quartz  and  feldspar,  and  Vogt  has  gone  still 
further  in  the  development  of  probabilities.  In  a recent  memoir  4 he 
has  sought  to  show  that  a large  number  of  eruptive  rocks  fall  into  two 
classes,  which  he  terms  “ anchi-eutektische”  and  “ anchi-monomine- 
ralische”;  that  is,  nearly  eutectic  and  nearly  composed  of  one  mineral 
alone.  Under  the  latter  heading  fall  those  anorthosites,  pyroxenites, 
peridotites,  etc.,  which  happen  to  consist  of  single  minerals  to  the 


1 Twenty-first  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3, 1901,  p.  519.  Science,  1st  ser.,  vol.  20, 1904,  p.  550. 
Pub.  Carnegie  Inst.  Washington  No.  31. 

2 See  ante,  Chapter  IX,  p.  301. 

2 F.  Guthrie,  Philos.  Mag.,  4th  ser.,  vol.  49, 1875,  p.  20.  A.  Lagorio,  Min.  pet.  Mitt.,  vol.  8,  1887,  p.  421. 
Teall,  British  petrography,  1888,  pp.  392-402.  A.  C.  Lane,  Jour.  Geology,  vol.  12, 1904,  p.  83.  J.  H.  L.  Vogt, 
Die  Silikatschmelzlosungen,  pt.  1,  1903,  pp.  101-107;  pt.  2,  1904,  pp.  113-128;  and  Min.  pet.  Mitt.,  vol.  25, 
1900,  p.  361.  Later  discussions  of  the  subject  are  by  H.  E.  Johannson,  Geol.  Foren.  Forhandl.,  vol.  27, 1905, 
p.  119;  S.  Zemduzny  and  F.  Loewinson-Lessing,  Geol.  Centralbl.,  vol.  8, 1906,  p.  393;  and  A.  Bygd&i,  Bull. 
Geol.  Inst.  Upsala,  vol.  7,  1906,  p.  1.  Some  difficulties  in  the  way  of  an  eutectic  classification  have  been 
clearly  pointed  out  by  W.  Cross  in  Quart.  Jour.  Geol.  Soc.,  vol.  66, 1910,  pp.  485-488. 

* Norsk  Geol.  Tidsskr.,  vol.  1,  No.  2,  1905;  and  Vidensk.  Selskabets  Skrifter,  Math.-nat.  Klasse,  1908, 
No.  10.  Vogt’s  nomenclatufe  suggests  that  the  igneous  rocks  might  be  briefly  described  by  the  adjectives 
unicomponent,  bicomponent,  tricomponent,  and  possibly  multicomponent,  with  reference,  obviously,  to 
their  principal  constituents  and  regarding  small  amounts  of  accessory  minerals  as  impurities.  In  such  a 
classification  it  would  be  necessary  to  regard  isomorphous  mixtures,  like  the  plagioclases,  as  single  com- 
ponents. 


424 


THE  DATA  OF  GEOCHEMISTRY. 


extent  of  90  per  cent  or  more.  The  nearly  eutectics  he  illustrates 
chiefly  by  the  micropegmatites.  The  suggested  eutectics,  however, 
are  not  yet  fully  established;  and  the  proposed  classification  can  not 
be  attempted  until  much  more  experimental  work  has  been  done. 
Its  difficulties  will  be  chiefly  manifest  in  dealing  with  multicomponent 
systems;  and  to  anything  beyond  a three-component  group  of  min- 
erals its  application  may  be  impracticable.  Its  units,  it  must  be 
observed,  are  those  of  the  mineralogical  system,  with  which  it  is  much 
more  nearly  allied  than  with  the  classification  by  radicles  or  oxides. 
The  classification  by  analyses  deals  with  the  latter,  the  mineralogical 
method  with  the  compounds  which  actually  appear  to  the  eye.  To 
a considerable  extent  the  three  systems  lead  to  the  same  grouping  of 
rocks,  and  it  remains  to  be  seen  whether  the  study  of  the  eutectics 
may  not  bring  both  physical  and  chemical  data  still  more  into  har- 
mony. In  a complete  classification  the  systems  should  converge,  each 
one  to  the  reinforcement  of  the  others.  The  prevalence  of  a few 
clearly  marked  rock  types  may  perhaps  be  explained  when  the 
eutectic  mixtures  are  known. 

Now,  recognizing  the  fact  that  all  classifications  of  the  igneous 
rocks  are  at  present  more  or  less  arbitrary,  let  us  consider  the  two 
available  systems  together.  We  may  also  take  into  account  a very 
rough,  provisional  classification  of  the  rocks,  which  serves  a certain 
descriptive  purpose  in  helping  us  to  avoid  verbiage.  I refer  to  the 
division  of  rocks  into  two  classes,  namely,  the  “basic”  and  the  “ acid,” 
to  which,  if  it  were  valid,  a third  “ neutral”  group  should  be  added. 
These  terms,  as  used  by  petrographers,  have  little  more  than  collo- 
quial significance,  and  serve  to  indicate  whether  a rock  contains  much 
or  little  silica.  They  are,  however,  objectionable  and  possibly  mis- 
leading, for  the  two  terms  as  used  in  chemistry  have  a more  precise 
and  quite  different  significance.  Their  fallaciousness  can  be  illus- 
trated by  considering  the  composition  of  the  two  fundamental  olivines, 
forsterite  and  fayalite,  Mg2Si04  and  Fe2Si04. 


Composition  of forsterite  and  fayalite. 


Forsterite. 

Fayalite. 

Si02 

42.8 

29.5 

MgO 

57.2 

FeO 

70.5 

100.0 

100.0 

Here  are  two  definite  orthosilicates  of  the  same  simple  type  which 
replace  each  other  isomorphously.  Chemically  they  are  both  neutral 
salts,  and  yet  one  contains  13.3  per  cent  more  silica  than  the  other. 


IGNEOUS  ROCKS. 


425 


The  terms  acid  and  basic  are  here  obviously  inapplicable,  and  the 
case  cited  is  but  one  of  many.  It  is  desirable,  then,  that  the  two 
terms  should  be,  generally  speaking,  dropped  from  petrographic 
usage  and  replaced  by  others  which  do  not  conflict  with  good  chemical 
nomenclature.  Acidic  and  basylic  might  be  better;  but  a closer  sub- 
division would  be  effective  by  using  the  self-explanatory  expressions 
'persilicic,  mediosilicic,  and  subsilicic.  Conventionally  these  terms 
might  represent  silica  percentages  of  more  than  60,  between  50  and  60, 
and  below  50.  A more  precise  definition  is  undesirable.  Another 
alternative  is  offered  by  the  words  salic,  sdlfemic,  and  femic,  which 
appear  in  a classification  of  rocks  to  be  considered  presently.  A few 
rocks,  consisting  mainly  of  corundum  or  magnetite — that  is,  of  basic 
oxides — may  be  properly  termed  basic.  These  are  the  only  important 
exceptions  to  the  rule  here  laid  down.  A quartz  rock,  obviously, 
would  be  in  the  highest  degree  persilicic. 

In  the  volume  upon  the  “ Quantitative  classification  of  igneous 
rocks/’1  by  W.  Cross,  J.  P.  Iddings,  L.  V.  Pirsson,  and  H.  S.  Wash- 
ington, the  first-named  author  has  given  a very  full,  critical  summary 
of  the  different  systems  of  rock  classification  which  had  been  seriously 
proposed.  To  discuss  all  of  these  systems,  with  their  nonchemical 
features,  would  be  impracticable  in  a work  on  geochemistry,  and  also 
superfluous,  for  the  details  are  easily  found  elsewhere.2  It  will  be 
enough  for  present  purposes  to  examine  the  scheme  of  arrangement 
offered  by  the  authors  of  the  book  just  cited  and  to  see  how  nearly  it 
corresponds  with  the  evidence  offered  by  mineralogy.  It  is  the 
most  complete  scheme  of  its  kind  that  has  as  yet  been  suggested  and 
the  one  most  thoroughly  worked  out;  it  therefore  deserves  a very 
careful  consideration. 

The  quantitative  classification  starts  from  the  chemical  analysis  of 
a rock,  and  begins  with  a division  of  the  magmas  into  two  groups, 
the  salic  and  the  femic.  The  rock-forming  minerals  are  similarly 
divided  into  two  principal  classes;  the  one,  as  its  name  indicates, 
being  characterized  by  compounds  of  silica  and  aZumina,  and  the 
others  by  /erro-magnesian  substances.  Between  the  two  groups  of 
minerals  there  is  an  intermediate  alferric  group,  which  is  given 
subordinate  value  in  the  classification.  The  salic  minerals,  including 


1 Chicago,  University  of  Chicago  Press,  1903. 

2 Among  the  modern  classifications  the  following  are  especially  important:  H.  Rosenbusch,  Elemente 
der  Gesteinslehre,  1898,  p.  66.  J.  J.  H.  Teall,  British  petrography,  1888,  pp.  70-77.  F.  Loewinson-Lessing, 
Compt.  rend.  VII  Cong.  g£ol.  internat.,  1897,  p.  193.  A.  Osann,  Min.  pet.  Mitt.,  vol.  19,  1900,  p.  351;  vol. 
20, 1901,  p.  399;  vol.  21,  1902,  p.  365;  vol.  22,  1903,  pp.  322, 403.  Osann’s  system  is  distinctly  chemical;  the 
others  are  mineralogical.  See  also  the  '‘Kern-theorie”  of  Rosenbusch  (Min.  pet.  Mitt.,  vol.  11, 1900,  p.  144) 
which  is  a chemical  classification  of  magmas,  and  the  discussion  of  it  by  W.  C.  Brogger,  Die  Eruptivgesteine 
des  Kristianiagebietes,  pt.  3, 1898,  p.  302.  A paper  by  E.  Sommerfeldt  (Centralbl.  Min.,  Geol.  u.  Pal.,  1907, 
p.  2)  relates  to  a part  of  the  Rosenbusch  theory.  Recent  papers  on  classification  are  by  F.  H.  Hatch,  Sci. 
Progress,  Oct.,  1908;  A.  Schwantke,  Centralbl.  Min.,  Geol.  u.  Pal.,  1910,  p.  169;  W.  Cross, Quart.  Jour.  Geol. 
Soc.,  vol.  66, 1910,  p.  470;  and  Am.  Jour.  Sci.,  4th  ser.,  vol.  39, 1915,  p.  657. 


426 


THE  DATA  OF  GEOCHEMISTRY. 


zircon  as  an  accessory,  are  as  follows  (the  symbols  used  for  pur- 
poses of  notation  accompany  the  names  of  the  species): 


Quartz,  Si02 

Zircon,  Zr02.Si02 

Corundum,  A1203 

Orthoclase,  K20.Al203.6Si02 

Albite,  Na20.Al203.6Si02 

Anorthite,  Ca0.Al203.2Si02 

Leu  cite,  K20.Al203.4Si02 

Nephelite,  Na20.Al203.2Si02 

Kaliophilite,  K20.Al203.2Si02 

Sodalite,  3(Na20.Al203.2Si02).2NaCl. . 
N oselite,  2(N a20 . A1203 .2Si02) . N a2S04 . 


Q. 

z. 

c. 


or. 

ab. 

an. 

lc. 

ne. 

kp. 

so. 

no. 


F. 

Feldspars. 


Lenads,1  or  feldspathoids. 


Mineralogically,  muscovite,  analcite,  hauynite,  and  cancrinite 
should  appear  in  this  list;  but  they  are  omitted  in  order  to  simplify 
calculations.  Muscovite,  for  instance,  in  computing  the  mineral  com- 
position of  a rock,  is  conventionally  regarded  as  if  it  were  a mixture 
of  orthoclase  and  corundum.  Analcite  is  treated  in  a similar  man- 
ner and  represented  by  a mixture  of  albite,  nephelite,  and  water. 
One  consequence  of  this  procedure  is  that  the  normative  composition 
of  a rock,  as  calculated  from  the  minerals  given  in  the  list,  often 
varies  from  its  actual  or  modal  composition.  A rock  containing 
quartz,  orthoclase,  and  muscovite  would  be  represented  by  a norm  of 
quartz,  orthoclase,  and  corundum,  with  the  water  of  the  muscovite 
left  entirely  out  of  consideration.  The  conventional  composition  of  a 
rock,  its  norm , may  be  quite  unlike  its  actual  composition  or,  in  the 
nomenclature  of  the  new  system,  its  mode.  This  method  of  computa- 
tion, then,  does  not  profess  to  represent  mineral  compositions  exactly; 
and  there  is  therefore  danger  that  in  certain  cases  it  may  be  mislead- 
ing— that  is,  if  its  avowed  limitations  are  not  kept  constantly  in 
mind.  In  rocks  like  the  mixture  cited  above  corundum  does  not 
normally  occur,  as  may  be  seen  from  the  experiments  by  Morozewicz 
described  in  the  preceding  chapter.  The  intentional  variation  from 
reality  is  simply  an  evasion  of  the  difficulties  which  often  arise  in  cal- 
culating from  the  analysis  of  a rock  its  mineral  composition.  As  a 
mathematical  device  it  is  perhaps  legitimate,  but  it  must  not  be  mis- 
interpreted. 

The  group  of  femic  minerals,  as  its  name  indicates,  is  dominantly 
ferromagnesian,  but  not  exclusively  so.  The  species  recognized  in 
the  classification  as  standard  are  as  follows: 


Acmite,  Na20.Fe203.4Si02 ac. 

Sodium  metasilicate,  Na20.Si02 ns. 

Potassium  metasilicate,  K20.Si02 ks. 

Diopside,  Ca0.(MgFe)0.2Si02 di. 

Wollastonite,  CaO.Si02 wo. 

Hypersthene,  (MgFe)0.Si02 hy. 


P. 


1 From  leucite  and  nephelite. 


IGNEOUS  ROCKS. 


427 


Olivine,  2(MgFe)0.Si02 ol. 

Akermanite,  4Ca0.3Si02 am. 

Magnetite,  Fe0.Fe203 mt. 

Chromite,  Fe0.Cr203 cm. 

Hematite,  Fe203 hm. 

Ilmenite,  FeO.TiOo il. 

Titanite,  Ca0.Ti02.Si02 tn. 

Perofskite,  CaO.Ti02 pf. 

Futile,  Ti02 ru. 

Apatite,  3(3Ca0.P205).CaF2 ap. 

Fluorite,  CaF2 fr. 

Calcite,  CaO.C02 cc. 

Pyrite,  FeS2 pr. 

Native  metals  and  other  metallic  oxides  and  sulphides. 


.0. 


II. 


T. 


M. 


Here,  as  with  the  salic  minerals,  certain  conventions  have  been 
adopted.  The  two  metasilicates  of  sodium  and  potassium  do  not  exist 
as  independent  mineral  species,  but  appear  as  possible  components  of 
certain  pyroxenes  and  amphiboles.  The  two  last-named  groups, 
moreover,  are  not  separately  identified  in  the  table,  but  are  repre- 
sented by  the  minerals  embraced  under  the  general  symbol  P.  The 
aluminous  ferromagnesian  and  salic  minerals,  the  alferric  compounds 
biotite,  garnet,  tourmaline,  melilite,  spinel,  and  the  aluminous 
pyroxenes  and  amphiboles  are  not  taken  into  account  as  normative  or 
standard  species.  In  computing  the  norm  of  a rock  they  are  treated 
as  mixtures  of  other  molecules  by  devices  like  those  adopted  in  the 
salic  division.  From  the  norm  the  mode  can  be  approximately  cal- 
culated by  methods  which  are  fully  discussed  in  the  “ Quantitative 
classification.”  An  example  of  the  differences  which  thus  appear 
may  be  cited  from  the  discussion  of  Butte  granite,  on  pages  223-225  of 
that  work.  Under  norm  is  given  the  composition  in  standard  or  con- 
ventional minerals  and  under  mode  the  percentages  of  the  species 
actually  present  in  the  rock. 


Composition  of  Butte  granite. 


Norm. 


Quartz 

19.38 

Orthoclase 

25.02] 

Albite 

23.58 

Anorthite 

18.  07J 

Diopside 

67] 

Hypersthene 

6.  78] 

Magnetite 

3. 01] 

Ilmenite 

1.22] 

Pyrite 

24] 

Apatite 

31] 

Etc 

99 

Mode. 

Quartz 

Orthoclase 

Albite 

Anorthite 

Biotite 

Hornblende 

Magnetite 

Ilmenite 

Pyrite 

Apatite. 

Etc 


22.  86 
18. 35] 

23.  06>  58.  09 
16.  68J 
10.  92] 

3.  56] 

1.  86] 

. 46] 

.24] 

• 31] 

.85 


14.  48 


2.  32 


.55 


99.  27 


99. 15 


428 


THE  DATA  OF  GEOCHEMISTRY. 


The  divergence  between  convention  and  reality  is  evident  at  a 
glance.  In  many  cases,  however,  the  norm  and  mode  of  a rock  are 
practically  identical,  and  then  the  standard  computation  is  more 
satisfactory.  The  normative  and  actual  minerals  may  or  may  not 
be  the  same.  Some  discrepancies,  however,  exist,  to  which  much 
weight  can  not  be  given.  In  calculating  the  percentage  of  a mineral 
from  the  proportions  of  oxides  shown  by  analysis  there  is  a strong 
tendency  toward  the  multiplication  of  errors.  Alumina,  for  instance, 
is  often  uncertain,  at  least  in  ordinary  analyses  of  fair  average  quality, 
by  as  much  as  one-half  of  1 per  cent.  This  amount  corresponds  to  an 
error  in  orthoclase,  if  all  the  alumina  goes  to  that  mineral,  of  2.7  per 
cent,  and  the  variation  entrains  others,  especially  in  the  estimation 
of  the  residual  quartz.  The  computed  mineral  composition  of  a rock 
is  incorrect  by  multiples  of  the  errors  existing  in  the  analysis,  and 
these  may  be,  in  fact  are,  sometimes  large. 

The  normative  or  standard  minerals,  then,  so  far  as  the  make-up  of 
a rock  is  concerned,  are  partly  real  and  partly  conventional.  They 
are,  however,  quantitative  in  application  and  give  uniformity  to  the 
discussion  of  rocks.  Upon  them  the  quantitative  classification  is 
founded. 

First,  all  igneous  rocks  are  divided  into  five  classes , which  are 
fixed  within  certain  arbitrary  limits  by  the  ratios  between  the  salic 
and  femic  minerals.  These  classes  are  as  follows: 

I.  Persalane:  Extremely  salic 

II.  Dosalane:  Dominantly  salic 

III.  Salfemane:  Equally  salic  and  femic 

IV.  Dofemane:  Dominantly  femic 

V.  Perfemane:  Extremely  femic 

That  is,  the  field  between  an  entirely  salic  rock  and  one  entirely 
femic  is  divided  into  five  parts,  each  representing  a definite  range  of 
variation.  A rock  containing  more  than  seven-eighths  of  salic  min- 
erals to  one-eighth  femic  is  in  the  class  persalane ; one  with  less  than 
seven-eighths  salic  to  more  than  three-eighths  femic  falls  under 
dosalane,  and  so  on.  A granite,  for  example,  containing  over  87.5 
per  cent  of  quartz  and  feldspar  is  placed  in  Class  I;  a peridotite 
with  over  87.5  per  cent  of  femic  minerals  belongs  in  Class  V.  Many 
basalts,  gabbros,  diorites,  etc.,  contain  salic  and  femic  compounds  in 
nearly  equal  proportions,  and  are  therefore  in  Class  III.  From  the 
norm  of  a rock  its  class  can  be  determined  at  once,  and  in  many  cases 
a mere  inspection  of  the  analysis  is  sufficient.  The  two  extreme 


sal  ..  7 

fem  ^ 1 
sal  .7^5 
fem  ^ 1 > 3 
sal  ^.5^3 
fem  <_3_>T 
sal  3.1 
fem  ^ 5 ^ 7 
sal  ^ 1 
fem  ^ 7 


IGNEOUS  ROCKS. 


429 


classes  occupy  each  one-eighth  of  the  field;  the  other  classes  divide 
the  remaining  six-eighths  between  them. 

The  division  of  classes  into  subclasses  is  based  upon  a previous 
division  among  the  standard  minerals  themselves.  Thus  the  salic 
minerals  are  grouped  as  quartz,  Q;  feldspar,  F;  lenads,  or  feld- 
spathoids,  L;  corundum,  C;  and  zircon,  Z.  Q,  F,  and  L are  placed 
together  as  one  subclass;  C and  Z as  another.  In  the  femic  series 
we  have,  first,  pyroxenes,  P;  olivine  and  akermanite,  O;  with  the 
group  of  iron  ores  and  titanium  minerals,  M;  and,  second,  the  acces- 
sories apatite,  fluorite,  pyrite,  etc.,  represented  by  A.  In  Classes  I 
to  III  the  subdivision  is  effected  through  the  ratio  QFL  to  CZ  by  the 
same  fivefold  process,  one-eighth,  two-eighths,  and  so  on,  as  in  the 
formation  of  classes  themselves.  In  Classes  IV  and  V,  the  dofemic 
and  perfemic,  the  ratio  POM  to  A is  used  in  precisely  the  same  way. 
There  are  therefore  twenty-five  subclasses,  but  the  vast  majority  of 
igneous  rocks  belong  to  the  first  subclass  in  each  class.  These  are 
indicated  by  the  expressions — 


QFL  7 , 

~CZ >Iand 


POM  7 
A >1 


the  minerals  thus  given  prominence  being  those  which  make  up  the 
greater  part  of  the  lithosphere.  Pocks  in  which  C,  Z,  or  A abound 
are  not  common,  and  their  distribution  or  volume  is  extremely 
limited. 

After  the  subclasses  come  the  orders , which  are  formed  according 
to  the  proportions,  in  the  rocks,  of  the  preponderating  minerals.  In 
Classes  I to  III  the  salic  minerals  are  used  as  a basis  for  subdivision, 
and  the  ratios  connecting  Q,  F,  and  L are  alone  considered.  Quartz 
and  the  lenads,  however,  are  chemically  antithetic,  and  do  not  occur 
together;  and  this  leads  to  a doubling  of  the  ordinary  fivefold  divi- 
sion of  a class,  with  one  term  dropped  out.  That  is,  each  class  is 
divided  into  nine  orders;  if  there  were  ten,  the  fifth  and  sixth  would 
practically,  although  not  absolutely,  repeat  each  other.  These  orders 
are  as  follows : 


1.  Perquaric:  Quartz  extreme 

2.  Doquaric:  Quartz  dominant 

3.  Quarfelic:  Equal  quartz  and  feldspar. 

4.  Quardofelic:  Feldspar  dominant 


5.  Perfelic:  Feldspar  extreme. 


F 


430 


THE  DATA  OF  GEOCHEMISTEY. 


6.  Lendofelic:  Feldspar  dominant 

7.  Lenfelic:  Equal  feldspar  and  lenad 

8.  Dolenic:  Lenad  dominant 

9.  Perlenic:  Lenad  extreme 


F 1 

In  Classes  IV  and  V the  f emic  ratio  P + O : M is  used  to  designate 
the  orders.  They  are: 

P+O  7 

1.  Perpolic:  Silicate  extreme >— 

M 1 

P +0  7 5 

2.  Lopolic:  Silicate  dominant < — > — 

M 13 

P +0  5 3 

3.  Polmitic:  Silicate  and  nonsilicate  equal < — >— 

M 3 5 

P+O  3 1 

4.  Domitic:  Nonsilicate  dominant < — > 

M 5 7 

P+O  1 

5.  Permitic:  Nonsilicate  extreme < — 

M 7 


In  orders  1 to  3 there  is  also  a precisely  similar  fivefold  division 
into  sections,  which  indicate  the  proportions  between  pyroxenes  and 
the  olivine  subgroup.  In  orders  4 and  5 a like  subdivision  into  sub- 
orders is  based  upon  the  ratio  H : T,  hematite  plus  magnetite  on  the 
one  hand  and  the  titanium  minerals  ilmenite,  titanite,  perofskite, 
and  rutile  on  the  other.  It  is  not  necessary  for  present  purposes  to 
carry  these  subdivisions  out  in  detail,  for  the  ratios  are  expressed  by 
precisely  the  same  fractions  as  appear  in  the  classes  and  orders. 

Up  to  this  point  the  quantitative  classification  has  been  mineral- 
ogical,  and  expressed  in  terms  of  the  standard  or  normative  minerals. 
The  division  of  orders  into  rangs , however,  proceeds  on  chemical 
lines,  but  is  still  fivefold  as  before.  In  Classes  I to  III,  which  are 
characterized  by  feldspars  and  lenads,  the  molecular  ratio  of  salic 
K20  + Na20  to  salio  CaO  is  the  determining  factor.  In  Classes  IV 
and  V the  molecular  ratio  of  f emic  CaO  + (MgFe)  O to  femio  alkalies  is 
considered.  By  salio  CaO  is  meant  the  lime  in  salio  minerals,  such 
as  anorthite;  femic  lime  is  that  in  diopside,  wollastonite,  etc.  Salio 
alkalies  are  found  in  feldspars  and  lenads;  femio  alkalies  occur  in 
acmite  and  certain  other  pyroxenes  and  amphiboles.  In  the  par- 
tition of  actual  minerals,  such  as  the  micas,  between  the  two  norma- 
tive groups,  the  potash  of  muscovite  will  go  to  the  salic  side,  while 
that  of  biotite  is  regarded  as  femic.  Now,  uniting  K20  and  Na20 


IGNEOUS  ROCKS. 


431 


under  the  general  symbol  of  R20,  the  rangs  under  the  orders  of 
Classes  I to  III  develop  thus: 


R20  7 

1.  Peralkalic . > 

CaO  1 

R20  7 5 

2.  Domalkalic < > 

CaO  1 3 

R20  5 3 

3.  Alkalicalcic < > 

CaO  3 5 

R20  3 1 

4.  Docalcic < — > — 

CaO  5 7 

R20  1 

5.  Percalcic < 

CaO  7 


The  nomenclature  here  would  seem  to  be  self-explanatory,  but  in 
Classes  IV  and  V a less  obvious  device  is  proposed,  namely,  to  indi- 
cate magnesium,  iron,  and  Zime  the  word  mirlic  is  suggested.  Unit- 
ing MgO,  FeO,  and  CaO  under  the  symbol  RO  we  now  have  in  the 
distinctively  f emic  classes  these  rangs : 

RO  7 

1.  Permirlic > 

R20  1 

RO  7 5 

2.  Domirlic < — > 

R20  1 3 

RO  5 3 

3.  Alkalimirlic < — > — 

R20  3 5 

RO  3 1 

4.  Domalkalic < — > 

R20  5 7 

RO  1 

5.  Peralkalic.... < 

R20  7 

The  femio  rangs  are  again  subjected  to  a fivefold  subdivision  into 
sections,  depending  upon  the  ratio  (MgFe)  O to  CaO;  and  they  are  also 
divided  into  subrang s which  indicate  the  ratio  between  magnesia 
and  ferrous  oxide.  So  also,  in  Classes  I to  III  there  are  subrangs 
based  upon  the  alkalies  alone,  and  these  are  called,  respectively,  per- 
potassic,  dopotassic,  sodipotassic,  dosodic,  and  persodic.  These  sub- 
rangs are  still  further  divisible  in  such  manner  as  to  show  the  ratios 
between  the  lenad  minerals  leucite  and  ncphelite,  and  sodalite  and 
noselite,  and  either  of  these  pairs  may  be  subdivided  in  the  same  way. 
In  some  of  these  cases  a threefold  division  is  employed  instead  of  the 
usual  method.  In  Classes  II,  III,  and  IV  the  rangs  are  again 
divided  into  grads , which  serve  to  classify  the  subordinate  minerals. 
In  Classes  II  and  III  the  subordinate  femic  group  is  divided  accord- 
ing to  the  ratio  P + O to  M,  just  as  in  forming  the  orders  of  Classes 


432 


THE  DATA  OF  GEOCHEMISTRY. 


IV  and  V.  In  Class  IV  the  subordinate  salic  minerals  serve  to 
designate  five  grads,  depending  upon  the  relations  between  quartz, 
feldspars,  and  lenads.  In  Class  III  there  is  also  a threefold  discrim- 
ination between  pyroxene  and  olivine,  forming  the  sections  prepyric, 
pyrolic,  and  preolic.  Furthermore,  precisely  as  rangs  are  formed 
within  orders,  so  subgrads  are  formed  within  grads.  That  is,  the 
ratios  RO  to  R20;  R20  to  CaO;  (MgFe)  O to  CaO;  and  MgO  to  FeO 
are  used  to  express  between  subordinate  minerals  the  same  relations 
that  hold  in  forming  the  larger  divisions  of  the  classification. 

The  quantitative  classification,  then,  takes  pairs  of  factors,  and 
divides  each  pair,  with  a few  limitations  only,  into  five  terms, 
expressive  of  different  ratios.  This  process,  obviously,  can  be  car- 
ried out  to  any  desired  degree  of  minuteness;  but  for  most  practical 
purposes  four  subdivisions  are  generally  enough.  These  may  be 
stated  as  classes,  orders,  rangs,  and  subrangs;  the  subclasses,  sub- 
orders, grads,  etc.,  being  less  useful  in  actual  work.  In  order  to 
express  the  composition  of  a rook,  or,  more  precisely,  of  a magma, 
a simple  notation  has  been  devised,  which  makes  use  of  numerals  to 
indicate  the  several  subdivisions.  Thus  the  symbol  II. 5. 2.3  indicates 
that  the  magma  which  it  represents  belongs  in  Class  II,  dosalane; 
order  5,  perfelio;  rang  2,  domalkalic;  and  subrang  3,  sodipotassic.1 
That  such  a system  is  convenient  we  can  see  at  a glance;  but  its 
limitations,  due  to  the  distinction  between  normative  and  actual 
minerals,  must  never  be  overlooked.  Analyses  are  readily  classified 
and  summarized  by  the  system;  as  regards  minerals  it  is  confessedly 
incomplete.  The  important  alferric  minerals  muscovite,  biotite, 
augite,  and  hornblende  fall  outside  of  the  classification,  and  have  to 
be  expressed  by  means  of  a recalculation  from  a norm  into  a mode. 
It  is  an  artificial  classification  of  great  provisional  value;  but  its 
ultimate  standing  is  yet  to  be  determined  by  the  severe  tests  of 
experience.  Even  if  it  should  be  finally  adopted  by  all  petrologists, 
some  form  of  classification  like  that  now  in  vogue  would  have  to  be 
retained  with  it.  Good  analyses  can  not  be  obtained  for  every  rock 
which  the  geologist  is  called  upon  to  determine,  and  in  many  cases 
he  must  be  content  with  the  results  of  a microscopic  examination.  He 
can  then  say  at  once  that  a certain  rock  consists  of  alkali  feldspar, 
quartz,  and  subordinate  femic  minerals,  and  so  define  it  as  a granite 
or  rhyolite.  To  accurately  name  its  subrang  is  a more  troublesome 
matter,  and  impracticable  without  analytical  data.2  In  short,  the 
quantitative  system  can  only  be  applied  to  the  classification  of  rocks 
which  have  been  quantitatively  studied,  but  then  it  yields  results  of 
unquestionable  utility.  It  brings  to  light  magmatic  analogies  which 

1 For  the  detailed  development  of  this  notation,  which  can  be  extended  to  grads  and  subgrads,  see  H.  S. 
Washington,  Prof.  Paper  U.  S.  Geol.  Survey  No.  28, 1904,  pp.  13-15.  On  the  calculation  of  norms,  see  G.  I. 
Finlay,  Jour.  Geology,  vol.  18, 1910,  p.  58. 

2 The  need  of  rock  names  for  field  use  is  fully  recognized  by  the  authors  of  the  quantitative  system. 


IGNEOUS  ROCKS. 


433 


might  not  be  recognized  without  its  aid,  and  so  assists  in  the  com- 
parison of  magmas  and  in  the  study  of  their  differentiation.  From 
the  application  of  the  classification  to  the  study  of  rocks,  one  highly 
beneficent  result  has  already  followed.  The  two  memoirs  of  H.  S. 
Washington,1  in  which  he  has  collected  and  classified  all  the  trust- 
worthy rock  analyses  which  had  been  recorded  between  1869  and  1900, 
are  of  the  highest  value  and  go  far  to  justify  the  system. 

COMPOSITION  OF  ROCKS. 

Now,  passing  on  from  the  general  statements  relative  to  classifica- 
tions, we  may  consider  the  actual  composition  of  rocks  as  revealed 
by  chemical  analysis.  In  order  to  do  this  most  advantageously,  and 
to  compare  classifications,  the  ordinary  miner alogical  grouping  will 
be  followed,  but  the  rocks  within  each  group  will  be  arranged  in  the 
order  of  the  quantitative  system,  and  the  brief  description  of  each  one 
will  precede  the  analyses.  To  the  descriptions  the  magmatic  symbols 
and  magmatic  names  are  appended,  and  after  each  table  the  compo- 
sition of  the  norms , as  found  in  Washington’s  tables,  will  be  given. 
We  shall  thus  be  able  to  see  how  nearly  the  two  classifications  coin- 
cide, and  so  be  better  fitted  to  judge  of  their  comparative  merits.  As 
a rule,  the  analyses  are  those  which  have  been  made  in  the  laboratory 
of  the  United  States  Geological  Survey,  and  are  cited  from  the  col- 
lection published  in  Bulletin  No.  591.  Only  those  are  selected  which 
have  been  characterized  by  Washington  as  excellent.  In  a few  cases 
analyses  from  other  sources  must  be  used,  but  due  credit  will  be 
given.  Since  rocks  are  aggregates  of  minerals,  all  sorts  of  interme- 
diate variations  are  possible,  but  in  a work  of  this  general  character 
such  minor  details  of  classification  must  be  ignored.  Only  the  larger 
features  of  the  subject  can  be  taken  into  account. 

THE  RHYOLITE -GRANITE  GROUP. 

In  Class  I of  the  quantitative  classification,  order  1,  perquaric,  is 
represented  by  rocks  which  consist  mainly  of  quartz,  such  as  quartz 
veins  and  segregations  of  igneous  origin.  In  order  2,  doquaric,  Wash- 
ington places  a few  rocks  which  contain  from  53  to  69  per  cent  of 
quartz,  but  none  of  them  is  particularly  important.  It  is  in  order  3, 
quarfelic,  that  the  noteworthy  rocks  begin  to  appear,  and  a large 
number  of  them  belong  in  the  familiar  group  of  rhyolites  and  gran- 
ites. With  this  group  it  is  convenient  to  begin. 

1 Prof.  Papers  U.  S.  Geol.  Survey  Nos.  14  and  28.  For  analyses  made  in  the  laboratories  of  the  Survey, 
see  also  Bull.  No.  591.  For  an  extended  application  of  the  quantitative  classification,  see  Washington’s 
Roman  comagmatic  region,  Pub.  No.  51  of  the  Carnegie  Institution,  1906.  For  reviews  and  criticisms  of 
the  new  system,  see  A.  Michel-L6vy,  Bull.  Carte  g6ol.  France,  No.  92,  1903;  A.  H[arker],  Geol.  Mag.,  1903, 
p.  173;  J.  W.  Evans,  Science  Progress,  vol.  1,  1906,  p.  259;  E.  B.  Mathews,  Am.  Geologist,  vol.  31,  1903, 
p.  399;  L.  Milch,  Centralbl.  Min.,  Geol.  u.  Pal.,  1903,  p.  677;  and  G.  W.  Tyrrell,  Sci.  Progress,  vol.  9,  p.  61, 
1914. 

97270°— Bull.  616—16 28 


434 


THE  DATA  OF  GEOCHEMISTRY. 


In  the  broadest  sense,  granite  may  be  defined  as  a holocrystalline, 
plutonic  rock,  consisting  chiefly  of  quartz  and  an  alkali  feldspar,  the 
latter  being  commonly  orthoclase  or  microcline.  A soda  granite  is 
one  containing  a soda  feldspar,  preferably  anorthoclase.  With  these 
dominant  minerals  there  may  be,  and  usually  are,  subordinate  species, 
such  as  muscovite,  biotite,  hornblende,  etc.  Hence  the  varieties 
muscovite  granite,  biotite  granite  or  granitite,  hornblende  granite, 
tourmaline  granite,  and  the  like.  When  only  quartz  and  feldspar  are 
present  the  rock  is  called  aplite,  although  it  must  be  observed  that 
this  term  is  often  used  in  other  senses.1  Rhyolite  is  the  eruptive 
equivalent  of  granite  and  has  the  same  chemical  composition.  The 
minerals  which  develop  individually  in  it  are  also  broadly  the  same, 
quartz  and  alkali  feldspar  largely  predominating.  Rhyolite,  how- 
ever, very  commonly  contains  more  or  less  undifferentiated  glass,  and 
obsidian  is  a wholly  vitreous  variety.  The  quartz  porphyries,  which 
are  intermediate  between  granites  and  rhyolites,  are  old,  devitrified 
forms  of  the  latter.  Nevadite,  liparite,  and  quartz  trachyte  are 
synonyms  for  rhyolite.  The  differences  between  granite  and  rhyolite 
are  structural  and  genetic;  chemically  and  magmatically  they  are  the 
same.  This  essential  identity  of  composition  appears  in  the  subjoined 
tables  of  analyses.  First  in  order  come  the  rhyolites. 

1 On  account  of  this  ambiguity  in  the  use  of  the  word  aplite,  J.  E.  Spurr  has  proposed  the  name  “alaskite” 
for  rocks  of  this  character.  For  the  corresponding  eruptive  or  fine-grained  porphyritic  rocks  tho  term 
“tordrillite”  is  offered.  Am.  Geologist,  vol.  25, 1900,  p.  229.  On  the  formation  of  granite  see  H.  Le  Chate- 
lier,  Annales  des  mines,  8th  ser.,  vol.  13, 1888,  p.  232.  On  the  origin  of  pegmatite  see  J.  B.  Hastings,  Trans* 
Am.  Inst.  Min.  Eng.,  vol.  39,  1909,  p.  104;  E.  S.  Bastin,  Jour.  Geology,  vol.  18, 1910,  p.  297;  and  A.  Harker, 
Natural  history  of  igneous  rocks,  p.  293.  On  the  origin  of  granite  see  A..  Brun,  Eclog.  Geol.  Helvet.,  vol.  12, 
1912,  p.  172. 


IGNEOUS  ROCKS. 


435 


Analyses  of  rhyolites. 

A.  From  Buena  Vista  Peak,  Amador  County,  California.  Analysis  by  W.  F.  Hillebrand.  Described 
by  H.  W.  Turner  as  containing  sanidine,  quartz,  and  biotite  in  a glassy  groundmass.  Magmatic  symbol, 

1.3.1.2.  Magdeburgose. 

B.  From  near  Willow  Lake,  Plumas  County,  California.  Analysis  by  Hillebrand.  Described  by  J.  S. 
Diller  as  containing  phenocrysts  of  quartz  and  feldspar,  in  a groundmass  of  the  same  materials.  Symbol, 

1.3.1.3.  Alaskose. 

C.  Obsidian,  Obsidian  Cliff,  Yellowstone  National  Park.  Analysis  by  J.  E.  Whitfield.  Described  by 
Arnold  Hague  and  J.  P.  Iddings.  A glass  containing  microlites  of  augite  and  ferric  oxide,  with  traces  of 
quartz  and  feldspar.  Symbol,  1.3.1. 3.  Alashose. 

D.  From  Madison  Plateau,  Yellowstone  National  Park.  Analysis  by  Whitfield.  Not  described.  Sym- 
bol, 1.3.1. 4. 

E . From  the  Hyde  Park  dike,  Butte  distr  ict,  Montana.  Analysis  by  H.  N.  Stokes.  Contains,  according 
to  W.  H.  W eed,  sanidine,  quartz,  plagioclase,  and  biotite,  in  a groundmass  of  quartz  and  feldspar.  Symbol, 

1.3.2.3.  Tehamose. 

F.  From  “Elephant’s  Back,”  Yellowstone  National  Park.  Analysis  by  Whitfield.  Reported  by  J.  P. 
Iddings  to  contain  quartz  and  sanidine,  with  a little  augite  and  magnetite,  in  a glassy  groundmass.  Symbol 

1.3.2.3.  Tehamose. 

G.  From  Haystack  Mountain,  Aroostook  County,  Maine.  Analysis  by  Hillebrand.  Described  by  H.  E . 
Gregory.  Contains  quartz,  albite,  and  orthoclase,  with  titanite  and  accessory  chlorite  and  kaolin.  Symbol 

1.4.1.3.  Liparose. 

H.  From  Crater  Lake,  Oregon.  Analysis  by  Stokes.  Described  by  H.  B.  Patton.  Contains  plagioclase, 
hornblende,  hypersthene,  and  magnetite,  in  a glassy  groundmass  crowded  with  microlites  of  feldspar  and 
augite.  Symbol,  1. 4.2.4.  Lassenose. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02 

73.  23 

74.  24 

75.  52 

75. 19 

74.  34 

75.  34 

75.  98 

71.  87 

ai2o3 

12.  73 

14.  50 

14. 11 

13.  77 

12.  97 

12.  51 

12.  34 

14.  53 

Fe203 

.99 

1.  27 

1.  74 

.61 

.75 

.42 

.85 

1.  28 

FeO 

.16 

. 67 

.08 

1.  37 

.54 

1.  55 

.93 

1.  02 

MgO 

.22 

.25 

. 10 

.09 

.86 

.32 

.15 

.48 

CaO 

.61 

.11 

.78 

. 68 

.85 

1.  07 

.13 

1.  59 

Na20 

1.  91 

3.  00 

3.  92 

3.  83 

2.  49 

3.  31 

4.  02 

5.  08 

K20 

5. 17 

3.  66 

3.  63 

3.  33 

4.  72 

4. 17 

4.  44 

2.  84 

H20- 

. 53 

'l 

1 OK 

1.  03 

'l 

. 24 

. 06 

h2o+ 

4.  51 

2.  04 

^ . 39 

1. 11 

> . 86 

.64 

.22 

Ti02 

.09 

.20 

None. 

None. 

. 18 

None. 

.17 

.41 

Zr02 

. 05 

.03 

. 04 

P205 

.02 

. 07 

None. 

. 07 

None. 

. 03 

. 10 

MnO 

Trace. 

.06 

None. 

Trace. 

Trace. 

. 07 

Trace? 

BaO 

. 02 

. 18 

. 07 

. 07 

. 08 

SrO 

None. 

Trace. 

Trace. 

Trace? 

. 03 

Li20 

Trace. 

None. 

.02 

Trace. 

Trace. 

Trace. 

SO, 

.03 

. 29 

. 03 

. 42 

FeS2 

. 11 

None. 

Cl 

Trace. 

100. 19 

100.  28 

100.  38 

99.  83 

100.  06 

100.  04 

100.  02 

99.  63 

Norms. 


A 

B 

c 

D 

E 

F 

G 

H 

Q 

40.  7 

42.0 

36.7 

38.2 

38.  7 

36.1 

35.1 

27.4 

or 

31.1 

21.  7 

21.7 

19.5 

27.8 

25.0 

26.1 

16.7 

ab 

15.  7 

25.2 

33.0 

32.0 

21.0 

27.8 

33.5 

43.0 

an 

2.8 

.6 

3.9 

3.3 

4.2 

5.6 

.6 

8.1 

C 

3.  0 

5.  4 

2.  2 

2.  8 

2.  2 

4 

. 8 

Fy 

. 6 

.6 

.3 

2.2 

2.4 

3.3 

1.4 

1.2 

mt 

.5 

1.9 

.2 

.9 

1.2 

.7 

1.2 

1.4 

hm 

1. 1 

1.  6 

il 

.8 

436 


THE  DATA  OP  GEOCHEMISTRY. 


The  following  analyses  represent  quartz  porphyry: 

Analyses  of  quartz  porphyry. 

A.  From  near  Blowing  Rock,  Watauga  County,  North  Carolina.  Analysis  by  W.  F.  Hillebrand.  Re- 
ported by  A.  Keith  to  contain  quartz  and  orthoclase,  with  subordinate  sericite,  chlorite,  and  biotite.  Mag- 
matic symbol,  I.3.I.2.  Magdeburgose. 

B.  From  the  Modoc  mine,  Butte  district,  Montana.  Analysis  by  Hillebrand.  Contains,  according  to 
W.  H.  Weed,  quartz,  orthoclase,  and  plagioclase  in  a groundmass  of  quartz  and  feldspar.  Symbol,  I.4.2.3. 
Toscanose. 

C.  From  Prospect  Mountain,  Leadville  district,  Colorado.  Analysis  by  L.  G.  Eakins.  Described  by 
W.  Cross.  Contains  orthoclase,  plagioclase,  quartz,  biotite,  apatite,  magnetite,  and  zircon.  Symbol, 
I.4.2.3.  Toscanose. 

D.  From  the  Swansea  mine,  Tintic  district,  Utah.  Analysis  by  H.  N.  Stokes.  Described  by  G.  W. 
Tower  and  G.  O.  Smith.  Contains  feldspar,  quartz,  magnetite,  apatite,  secondary  pyrite,  and  a little 
chlorite  and  biotite.  Symbol,  I.4.2.3.  Toscanose. 

E.  From  Grizzly  Mountains,  Plumas  County,  California.  Analysis  by  Hillebrand.  Contains,  accord- 
ing to  H.  W.  Turner,  quartz,  feldspar,  and  pyrite,  in  a fine  groundmass.  Symbol,  I.4.2.3.  Toscanose. 


A 

B 

c 

D 

E 

Si02 

79.  75 

69.  95 

73.  50 

71.  56 

73.  25 

ai2o3 

10.  47 

15. 14 

14.  87 

14.  27 

13.  25 

Fet,Og 

. 64 

.38 

. 95 

1 .89 

FeO 

. 92 

. 83 

.42 

1.  74 

MgO 

. 13 

. 56 

.29 

. 42 

.28 

CaO 

. 15 

1.  45 

2.  14 

1. 18 

2.  23 

Na20 

1.  36 

2.  70 

3.  46 

3.  00 

2.  69 

k2o 

6.  01 

6.  36 

3.  56 

} .90 

J 

4.  37 

3.  79 

h2o- 

. 08 

. 40 

. 36 

.07 

h2o+ 

. 60 

. 91 

. 79 

1.  03 

Ti02 

. 15 

.24 

.38 

Trace. 

Zr02 

.05 

. 02 

co2  

. 37 

None. 

1.  05 

P205 

Trace. 

. 10 

None. 

. 13 

Trace. 

MnO 

Trace. 

.08 

.03 

Trace. 

Trace. 

BaO 

. 06 

. 13 

. 28 

Trace. 

SrO 

Trace. 

. 02 

Trace. 

Trace. 

Trace? 

Li20 

Trace. 

Trace. 

None. 

Trace. 

Cr203 

Trace. 

VoO,-.. 

. 01 

ci..! 

.06 

Cu 

. 03 

FcS 

.39 

2.  29 

.58 

~ ^ 

100.  37 

100.  06 

100. 12 

99.  99 

99.  96 

Norms. 

A 

B 

c 

D 

E 

Q 

47.  8 

25.  5 

34.  7 

34.  2 

30. 1 

or 

35.  6 

37.  8 

21. 1 

26. 1 

33.  9 

ab 

11.  5 

22.  5 

29.  3 

25.  2 

22.  5 

an 

. 8 

7.  2 

10.  6 

5.  8 

7.  2 

C 

1.  4 

1.1 

1.4 

2.5 

di 

3.  2 

hy 

1.  4 

2.  7 

. 7 

1. 1 

2.3 

mt 

.8 

1. 1 

1.4 

. 9 

il 

. 5 

pr 

2.3 

.6 

IGNEOUS  ROCKS. 


437 


The  subjoined  analyses  of  granites  are  all  by  W.  F.  Hillebrand: 1 

Analyses  of  granites. 

A.  From  Currant  Creek  Canyon,  near  Pikes  Peak,  Colorado.  Described  by  E.  B.  Mathews.  Contains 
microcline,  quartz,  muscovite,  and  sericitic  aggregates  replacing  plagioclase  and  a part  of  the  microcline. 
Magmatic  symbol,  I.3.I.2.  Magdeburgose. 

B.  Biotite  granite,  Sentinel  Point,  Pikes  Peak,  Colorado.  Described  by  Mathews.  Contains  micro- 
cline, microcline-perthite,  quartz,  biotite,  a little  oligoclase,  and  accessory  fluorite,  apatite,  zircon,  sphene, 
allanite,  and  magnetite.  Symbol,  I.3.I.3.  Alaskose. 

C.  From  Currant  Creek  Canyon,  Pikes  Peak,  Colorado.  Described  by  Mathews.  Contains  perthitic 
microcline,  quartz,  biotite,  muscovite,  altered  plagioclase,  and  flakes  of  limonite.  Symbol,  I.4.I.2. 
Omeose. 

D.  Biotite  granite,  Mount  Ascutney,  Vermont.  Described  by  R.  S.  Daly.  Contains  quartz,  orthoclase, 
plagioclase,  biotite,  magnetite,  sphene,  apatite,  and  zircon.  Symbol,  I.4.I.3.  Liparose. 

E.  Soda  granite,  Pigeon  Point,  Minnesota.  Described  by  W.  S.  Bayley.  Contains  feldspar,  quartz, 
chlorite,  some  muscovite,  rutile,  leucoxene,  hematite,  and  apatite,  and  sometimes  secondary  calcite. 
Symbol,  I.4.I.3.  Liparose. 

F.  Granitite,  near  Florissant,  Colorado.  Described  by  Mathews.  Contains  microcline,  albite,  quartz, 
and  biotite.  Symbol,  1.4. 1.4.  Kallerudose. 

G.  Granite,  Big  Timber  Creek,  Crazy  Mountains,  Montana.  Reported  by  J.  E.  Wolff  as  containing 
quartz,  orthoclase,  oligoclase,  and  biotite.  Symbol,  I.4.2.3.  Toscanose. 

H.  Aplite,  Yuba  Gap,  Sierra  County,  California.  Described  by  H.  W.  Turner.  Contains  orthoclase, 
quartz,  plagioclase,  a little  microcline,  brown  mica,  and  iron  ore.  Symbol,  I.4.2.3.  Toscanose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

74.  40 

77.  03 

73.  90 

71.  90 

72.  42 

75.  92 

74.  37 

76.  03 

A1203 

14.  43 

12.  00 

13.  65 

14. 12 

13.  04 

12.  96 

13. 12 

13.  39 

Fe203 

.89 

.76 

.28 

1.  20 

.68 

.33 

.73 

.48 

FeO.. 

.22 

.86 

.42 

.86 

2.  49 

1.  40 

.87 

.31 

MgO 

.07 

.04 

.14 

.33 

.58 

Trace. 

.35 

.05 

CaO 

.58 

.80 

.23 

1. 13 

.66 

.15 

1.  26 

1.  28 

Na20 

1.  76 

3.  21 

2.  53 

4.  52 

3.  44 

4.60 

2.  57 

2.  98 

K20 

6.  56 

4.  92 

7.  99 

4.  81 

4.  97 

4. 15 

6.  09 

5. 18 

h20- 

.15 

.14 

.16 

.18 

l 1 91 

.16 

.05 

.15 

h2o+ 

.92 

.30 

.33 

.42 

> 1.  Z± 

.32 

.25 

.34 

Ti02 

.12 

.13 

.07 

.35 

.40 

.05 

.29 

.07 

Zr02 

.04 

co2 

.21 

. 03 

p2o5 

.22 

Trace. 

.05 

.11 

.20 

Trace. 

.06 

.03 

MnO 

Trace. 

Trace. 

Trace. 

.05 

.09 

.04 

Trace. 

Trace. 

BaO 

Trace. 

Trace. 

Trace. 

.04 

.15 

Trace. 

.10 

.04 

SrO 

None. 

None. 

None. 

Trace? 

None. 

Trace. 

Trace. 

Li20 

Trace. 

Trace. 

Trace. 

Trace? 

Trace. 

Trace. 

None. 

F 

.04 

. 36 

None. 

.06 

. 12 

Cl 

. 02 

Trace. 

FeS2 

Trace. 

100.  36 

100.  55 

99.  75 

100.  35 

100.  33 

100.  23 

100. 11 

100.  33 

Norms. 


JA.  Gautier  (Compt.  Rend.,  vol.  32,  1901,  p.  932)  found  traces  of  nitrogen,  argon,  arsenic,  and  iodine  in 
granite. 


438 


THE  DATA  OF  GEOCHEMISTRY. 


All  of  the  rocks  here  cited  belong  in  the  first  subclass  of  Class  I 
and  lie  between  the  limits  indicated  by  the  symbols  1. 3. 1.2  and 

I.  4. 2. 4.  Some  granites  appear  in  Washington’s  tables  under  Class 

II,  but  they  are  few  in  number  and  represent,  probably,  intermediate 
gradations  toward  the  syenites.  So  far  as  the  foregoing  analyses  are 
concerned,  they  show  that  up  to  this  point  the  quantitative  and 
miner alogical  classification  coincide  fairly  well  and  that  the  norms 
can  not  vary  very  much  from  the  modes.  The  normative  corundum 1 
probably  represents  the  micas,  either  muscovite  or  biotite,  or  both,  so 
that  the  actual  orthoclase  of  these  rocks  must  be  lower  than  is  shown 
in  the  norms.  The  latter  show  with  sufficient  emphasis  that  quartz 
and  alkali  feldspars  are  the  most  important  minerals  in  the  granite- 
rhyolite  group  and  that  the  rocks  differ  chiefly  in  the  varying  pro- 
portions of  quartz,  orthoclase  or  microcline,  and  albite  or  anorthoclase. 
The  presence  of  much  muscovite  in  a granite,  however,  would  increase 
the  divergence  between  norm  and  mode,  and  even  throw  the  rock 
into  some  other  order  than  those  shown  by  the  limiting  symbols  just 
given. 

THE  TRACHYTE-SYENITE  GROUP. 

The  trachyte-syenite  series  of  rocks  differs  from  the  rhyolite-granite 
series  in  being  free,  or  nearly  so,  from  quartz.  The  trachytes,  like 
the  rhyolites,  are  eruptive  rocks;  the  syenites  resemble  granite  in  their 
plutonic  origin.  Between  trachyte  and  syenite  there  are  intermediate 
forms,  analogous  to  the  quartz  porphyries.  All  of  these  rocks  contain 
principally  alkali  feldspars,  with  subordinate  femic  minerals,  and 
often  alferric  species  such  as  hornblende  or  mica.  These  minor  con- 
stituents are  recognized  in  nomenclature  by  such  terms  as  biotite 
trachyte,  mica  syenite,  hornblende  syenite,  etc.  There  are  also  many 
varietal  names,  which  are  based  on  minor  distinctions.  The  nephe- 
line  syenites  will  be  considered  separately.  The  following  analyses 
represent  typical  examples  within  the  series  as  defined  here : 


i Or  undistributed  alumina. 


IGNEOUS  ROCKS. 


439 


Analyses  of  trachyte-syenite  rocks. 

A.  Nordmarkite,  Mount  Ascutney,  Vermont.  Analysis  by  W.  F.  Hillebrand;  description  by  R.  S. 
Daly.  Contains  orthoclase,  plagioclase,  quartz,  hornblende,  magnetite,  apatite,  and  zircon,  with  very 
little  biotite,  titanite,  diopside,  and  allanite.  Magmatic  symbol,  I.5.I.3.  Phlegrose. 

B.  Quartz  syenite  porphyry,  Gray  Butte,  Bearpaw  Mountains,  Montana.  Analysis  by  H.  N.  Stokes. 
Described  by  W.  H.  Weed  and  L.  V.  Pirsson.  Contains  anorthoclase,  microlites  of  plagioclase,  aegirite, 
augite,  quartz,  and  apatite,  with  an  occasional  zircon  and  traces  of  biotite.  Symbol,  I.5.I.4.  Nordmarkose. 

C.  Biotite  trachyte.  Dike  Mountain,  Yellowstone  National  Park.  Analysis  by  Hillebrand.  Reported 
by  Arnold  Hague  and  T.  A.  Jaggar  as  containing  plagioclase,  orthoclase,  biotite,  magnetite,  and  chlorite. 
Symbol,  I.5.I.4.  Nordmarkose. 

D.  Soda  syenite  porphyry,  Moccasin  Creek,  Tuolumne  County,  California.  Analysis  by  Stokes. 
Described  by  H.  W.  Turner.  Consists  mainly  of  albite,  with  possibly  segirite.  Symbol,  I.5.I.5.  Tuo- 
lumnose. 

E.  Soda  syenite,  Douglas  Island,  Alaska.  Analysis  by  Hillebrand.  Described  by  G.  F.  Becker.  Con- 
tains mostly  albite,  with  secondary  quartz,  calcite,  and  pyrite.  Symbol,  I.5.I.5.  Tuolumnose. 

F.  Biotite  trachyte,  Dike  Mountain,  Yellowstone  National  Park.  Analysis  by  Hillebrand.  Reported 
by  Hague  and  Jaggar  to  contain  orthoclase,  plagioclase,  biotite,  and  chlorite.  Symbol,  I.5.2.3.  Pulaskose. 


A 

B 

C 

D 

E 

F 

Si02 

65.  43 

66.  22 

63.  24 

67.  53 

63.  01 

57.  73 

A1203 

16. 11 

16.  22 

17.  98 

18.  57 

18.  47 

18.  93 

Fe203 

1. 15 

1.  98 

2.  67 

1. 13 

.06 

1.  97 

FeO 

2.  85 

.16 

.85 

.08 

.32 

1.  92 

MgO 

.40 

.77 

.63 

.24 

.06 

.91 

CaO 

1.  49 

1.  32 

.93 

.55 

2.  66 

2.  78 

Na20 

5.  00 

6.  49 

6.  27 

11.  50 

10.  01 

5.  52 

K20 

5.  97 

5.  76 

5.  47 

.10 

.39 

6. 11 

H20- 

.19 

.08 

.37 

.15 

.05 

.22 

h2o+ 

.39 

.24 

.80 

.31 

.27 

2.  93 

Ti02 

.50 

.22 

.38 

.07 

.13 

.33 

Zr02 

. 11 

Trace. 

Trace. 

C02 

None. 

2.  01 

. 26 

PA 

. 13 

.10 

.22 

. 11 

.06 

.25 

so3 

.02 

Trace. 

Cl 

. 05 

. 04 

F 

.08 

Trace. 

Trace. 

MnO 

.23 

Trace. 

.04 

Trace. 

.06 

.06 

BaO 

. 03 

. 29 

. 25 

.02 

. 16 

SrO 

.06 

. 03 

Trace. 

Trace. 

. 09 

V203 

. 01 

. 01 

. 01 

Li20 

Trace. 

Trace. 

None. 

Trace. 

FeSo 

.07 

Trace. 

2. 10 

. 02 

100. 18 

99.  97 

100. 14 

100.  34 

99.  69 

100.  20 

440 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  trachyte-syenite  rocks — Continued. 

G.  Augite  syenite  porphyry,  Copper  Creek  basin,  Yellowstone  National  Park.  Analysis  by  Hillebrand. 
Contains,  according  to  Hague  and  Jaggar,  augite,  biotite,  orthoclase,  a little  hornblende,  and  quartz.  Sym- 
bol, I.5.2.4.  Laurvikose. 

H.  Augite  syenite.  Turnback  Creek,  Tuolumne  County,  California.  Analysis  by  Stokes.  Reported  by 
Turner  to  contain  orthoclase  and  augite,  with  less  plagioclase  and  quartz.  Symbol,  H.5.1.2.  Highwoodose. 

I.  Syenite,  Yogo  Peak,  Little  Belt  Mountains,  Montana.  Analysis  by  Hillebrand.  Described  by  Weed 
and  Pirsson.  Contains  orthoclase,  oligoclase,  quartz,  apatite,  titanite,  iron  ores,  pyroxene,  hornblende 
and  biotite,  with  traces  of  decomposition  products.  Symbol,  II.5.2.3.  Monzonose. 

J.  Syenite,  La  Plata  Mountains,  Colorado.  Analysis  by  Stokes.  Reported  by  W.  Cross  to  contain  much 
alkalifeldspar,  some  oligoclase,  augite,  biotite,  and  hornblende,  with  a little  titanite,  magnetite,  and  apatite. 
Symbol,  II.5.2.3.  Monzonose. 

K.  Syenite,  Crazy  Mountains,  Montana.  Analysis  by  Hillebrand.  Reported  by  J.  E.  Wolff  to  contain 
anorthoclase,  hornblende,  augite,  sphene,  apatite,  and  magnetite.  Symbol,  II.5.2.4.  Aherose. 


G 

H 

I 

J 

K 

Si09 

64.  40 

61.  28 

61.  65 

59.  79 

58.  28 

ALO- 

16.  90 

14.  71 

15.  07 

17.  25 

17.  89 

Fe203 

1.  86 

1.  21 

2.  03 

3.  60 

3.  20 

FeO " 

1.  37 

2.  85 

2.  25 

1.  59 

1.  73 

MgO 

1. 13 

1.  69 

3.  67 

1.  24 

1.  51 

CaO 

2.  60 

5.  61 

4.  61 

3.  77 

3.  69 

Na.,0 

5.  79 

2.  99 

4.  35 

5.  04 

5.  89 

KoO 

4.  56 

7.  70 

4.  50 

5.  05 

5.  34 

H20  — 

. 16 

.28 

.26 

. 19 

. 17 

h2o+ 

. 39 

.43 

.41 

. 39 

. 98 

Ti02. 

. 23 

.41 

.56 

.67 

.64 

Zr02 

. 02 

co2 

None. 

. 72 

p205 

.21 

.16 

.33 

.35 

.26 

so, 

.08 

.04 

Cl 

F 

MnO 

.07 

Trace. 

.09 

.20 

.06 

BaO 

. 27 

. 72 

.27 

. 14 

.36 

SrO 

. 14 

.04 

. 10 

. 11 

.05 

T/LO 

Trace. 

Trace. 

Trace. 

Trace. 

100. 10 

100. 16 

100. 15 

100. 14 

100.05 

Norms. 

A 

B 

c 

D 

E 

F 

Q 

8.  8 

5.  3 

2.  8 

or 

35.  6 

33.  9 

32.  8 

0.  6 

2.  2 

36. 1 

ab 

42.4 

51.9 

52.  9 

95.4 

83.3 

37.7 

an 

3.6 

4.4 

4.4 

8.6 

ne 

. 6 

4.8 

ac 

2.  8 

1.4 

di 

3.4 

1.4 

1.  3 

L 2 

4.5 

wo 

1.6 

.5 

3.1 

hv 

2.4 

1.6 

of. 

1.0 

mt 

2.1 

1.6 

.2 

3.0 

hm 

1.  0 

1.  6 

. 5 

il 

. 9 

.3 

.8 

.3 

.6 

2.1 

IGNEOUS  ROCKS. 


441 


Analyses  of  trachyte-syenite  roclcs — Continued. 


G 

H 

I 

J 

K 

Q 

7. 1 

3.4 

6.  2 

3. 1 

or 

27.  2 

45.  6 

26.  7 

30.  6 

31.  7 

ab 

48.  7 

25.  2 

36.  7 

42.  4 

41.  9 

an 

6.  7 

3.9 

8.3 

9.5 

6.4 

ne 

4.3 

ac 

di 

5.2 

16.  0 

11.9 

6.7 

8.0 

wo 

1.9 

hv 

.8 

5.0 

oL 

mt 

2.8 

1.6 

3.3 

3.  2 

4.6 

hm 

1.  4 

il 

5 

.8 

1. 1 

1.  2 

1.  2 

ap 

.8 

. 7 

The  rocks  of  this  group,  being  deficient  in  quartz,  tend  to  run 
lower  in  silica  than  the  granites  and  rhyolites.  Their  magmatic 
range  is  between  1. 5. 1.3  and  II. 5. 2.4;  so  that,  despite  their  miner- 
alogical  similarities,  they  are  divided  between  two  classes,  but  fall 
within  each  class  into  the  same  order,  the  perfelic.  With  decrease 
of  quartz,  at  one  end  of  the  series,  they  shade  into  rocks  in  which 
the  femic  minerals  are  no  longer  subordinate.  Among  these  femic 
rocks  are  found  varieties  which  have  been  named  minette,  kersantite, 
lamprophyre,  and  shonkinite.  Some  of  these  terms  are  vaguely  used, 
and  are  very  often  applied  to  rocks  of  a transitional  character  which 
contain  considerable  amounts  of  soda-lime  feldspars.  The  subjoined 
analyses  represent  some  of  these  femic  syenites. 


442 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  offemic  syenites. 

A.  Soda  minette,  Brathagen,  Laugendal,  Norway.  Analysis  by  V.  Schmelck.  Described  by  W.  C. 
Brogger  (Die  Eruptivgesteine  des  Kristianiagebietes,  vol.  3,  1898,  p.  130).  Contains,  in  approximate 
percentages,  54  soda  feldspar,  29  lepidomelane,  13  aegirine-augite,  2\  apatite,  and  1 sphene.  Magmatic 
symbol,  II.5.2.4.  Akerose. 

B.  Soda  minette,  Hao,  Langesund  Fjord,  Norway.  Analysis  by  Schmelck,  description  by  Brogger 
(Die  Eruptivgesteine  des  Kristianiagebietes,  vol.  3,  1898,  p.  139).  Contains  about  51§  per  cent  soda  feld- 
spar, 26.5  lepidomelane,  16|  diopside,  2\  each  of  apatite  and  sphene.  Symbol,  II.6.1.4.  Laurdalose. 

C.  Syenitic  lamprophyre,  Two  Buttes,  Prowers  County,  Colorado.  Analysis  by  W.  F.  Hillebrand. 
Contains,  according  to  W.  Cross,  alkali  feldspar,  diopside,  biotite,  magnetite,  and  olivine.  Symbol, 
III.5.2.2.  Prowersose. 

D.  Shonkinite,  Beaver  Creek,  Bearpaw  Mountains,  Montana.  Analysis  by  H.  N.  Stokes.  Described 
by  W.  H.  Weed  and  L.  V.  Pirsson.  Contains  anorthoclase,  diopside,  biotite,  iron  ores,  and  apatite,  with 
a very  little  olivine  and  nephelite.  Symbol,  HI.5.1.3. 

E.  Shonkinite,  Yogo  Peak,  Little  Belt  Mountains,  Montana.  Analysis  by  Hillebrand.  Described  by 
Weed  and  Pirsson.  Contains  augite  and  orthoclase,  with  biotite,  iron  ore,  andesine,  apatite,  olivine,  and 
a trace  of  kaolin.  Symbol,  III.6.2.3.  Shonkinose. 


A 

B 

C 

D 

E 

Si02 

51.  22 

51.  95 

50.  41 

50.  00 

48.  98 
12.  29 
2.  88 

A1203 

17.  56 

14.  95 

12.  27 

9.  87 

FeXC 

3.  51 

4.  09 

5.  71 

3.  46 

FeO 

4.  34 

5.  70 

3.  06 

5.  01 

5.  77 

MgO 

3.  22 

3.  54 

8.  69 

11.  92 

9. 19 

CaO 

4.  52 

6. 10 
5.  43 

7.  08 

8.  31 

9.  65 

Na20 

5.  72 

. 97 

2.  41 

2.  22 

K20 

4.  37 

4. 45 

7.  53 

5.  02 

4.  96 

h2o- 

H20+ 

1}  1.93 

} 1.10 

.46 
1.  80 

.17 
1. 16 

.26 

.56 

Ti02 

1.  70 

1.  95 

1.  47 

. 73 

1.44 

co2 

.60 

.31 

PoO- 

1.  08 

1. 15 

. 46 

.81 

co 

00 

A 2v-/5* 

so, 

None. 

.02 

Cl 

Trace. 

.08 

F 

Trace? 

.16 

.22 

v,o, 

.03 

Cr203 

. 11 

Trace. 

MnO 

.20 

.30 

. 15 

Trace. 

.08 

NiO 

. 04 

. 07 

BaO 

. 23 

.32 

.43 

SrO 

.06 

. 07 

.08 

Li20 

Trace. 

Trace. 

Trace. 

99.  97 

100.  71 

100.  42 

100.  01 

99.  99 

Norms. 

1 

A 

B 

C 

D 

E 

or 

25.  6 

26. 1 

44.5 

29.5 

29.5 

ab 

32.  0 

28.3 

4.2 

8.9 

5.3 

an 

9.  5 

3.  3 

6.  7 

1. 1 

8.6 

ne 

8.8 

9.  7 

2.3 

6.2 

6.8 

di 

5.3 

16.8 

20.4 

28.9 

26.5 

ol 

5.6 

3.2 

8.6 

14.8 

11.7 

mt 

5. 1 

6.0 

5.8 

5.1 

4.2 

il 

3.2 

3.  7 

2.8 

1.4 

2.6 

an 

2.5 

2.  7 

1.0 

1.7 

2.2 

hm 

1.6 

IGNEOUS  ROCKS. 


443 


A comparison  of  the  norms  under  A and  B with  the  modes  as 
given  by  Brogger  will  show  how  widely  the  two  diverge.  These  two 
rocks  are  in  Class  II;  the  others,  on  account  of  their  higher  propor- 
tion of  femic  minerals,  fall  in  Class  III.  All  five  of  the  rocks  contain 
micas,  which  accounts  for  some  of  the  differences  between  the  mag- 
matic and  the  mineralogical  composition.  In  A and  B,  also,  sphene 
is  reported,  while  in  the  norms  the  titanium  is  reckoned  entirely  as 
ilmenite. 

NEPHELITE  ROCKS. 

In  the  norms  of  the  foregoing  rocks  small  quantities  of  nephelite 
appear.  These  mark  a transition  from  the  syenites  and  trachytes 
proper  to  the  phonolites  and  nepheline  syenites,  in  which  the  lenad 
minerals  replace  the  alkali  feldspars  to  a greater  or  less  extent. 
Taking  the  nephelite  rocks  first  in  order,  we  find  an  eruptive  and  a 
deep-seated  group,  just  as  with  the  trachyte-syenite  series.  Quartz 
is  excluded  from  these  rocks,  for  if  it  were  introduced  in  excess  into 
the  magma  it  would  convert  the  lenads  into  feldspars,  nephelite  into 
albite,  and  leucite  into  orthoclase.  In  phonolite  we  have  commonly 
orthoclase,  nephelite,  and  pyroxene;  tinguaite  is  a varietal  name. 
Some  rocks  richer  in  femic  minerals  than  the  phonolites  have  been 
classed  with  the  basaltic  basanites,  but  they  contain  so  little  soda- 
lime  feldspar  that  it  is  well  to  include  them  in  the  following  table, 
as  allied  to  phonolite  chemically.  The  subjoined  data  relate  to 
members  of  the  eruptive  series. 


444 


THE  DATA  OF  GEOCHEMISTRY. 


v 


Analyses  of  eruptive  nephelite  rocks. 

A.  Phonolite,  Southboro,  Massachusetts.  Analysis  by  H.  N.  Stokes.  Collected  by  B.  K.  Emerson 
but  not  described.  Magmatic  symbol,  1.6. 1.4.  Miaskose. 

B.  Phonolite,  Black  Hills,  South  Dakota.  Analysis  by  W.  F.  Hillebrand.  Described  by  W.  Cross. 
Contains  orthoclase,  nephelite,  aegirite,  noselite,  sodalite,  sphene,  apatite,  and  zircon;  also  secondary 
zeolites  and  calcite,  but  no  magnetite.  Symbol,  1.6. 1.4.  Miaskose. 

C.  Phonolite,  Cripple  Creek,  Colorado.  Analysis  by  Hillebrand.  Described  by  Cross.  Contains  ortho- 
clase, nephelite,  sodalite,  noselite,  aegirite,  etc.  Symbol,  1.6. 1.4.  Miaskose. 

D.  Phonolite,  Pleasant  Valley,  Colfax  County,  New  Mexico.  Analysis  by  Hillebrand.  Reported  by 
Cross  to  contain  nephelite,  alkali  feldspar,  aegirite,  traces  of  magnetite,  and  a little  noselite  or  sodalite. 
Symbol,  I.6.I.4.  Miaskose. 

E.  Tinguaite,  Bear  Creek,  Bearpaw  Mountains,  Montana.  Analysis  by  Stokes.  Described  by  W.  H. 
Weed  and  L.  V.  Pirsson.  Contains  orthoclase,  nephelite,  cancrinite,  augite,  aegirite,  apatite,  a little  soda- 
lite, and  a doubtful  hornblende.  Symbol,  H.6.1.3.  Judithose. 

F.  Phonolite,  Uvalde  County,  Texas.  Analysis  by  Hillebrand.  Reported  by  Cross  to  contain  orthoclase, 
nephelite,  and  aegirite,  with  a very  little  hornblende,  augite,  and  magnetite.  Symbol,  II.6.1.4.  Laurdalose. 

G.  Basanite,  near  Big  Mountain,  Uvalde  County,  Texas.  Analysis  by  Hillebrand;  description  by  Cross. 
Contains  alkali  feldspar,  augite,  magnetite,  olivine,  nephelite,  aegirite,  biotite,  and  zeolitic  minerals. 
Symbol,  H.6.2.4.  Essexose. 

H.  Basanite,  Mount  Inge,  Uvalde  County,  Texas.  Analysis  by  Hillebrand;  description  by  Cross. 
Contains  orthoclase,  nephelite,  hornblende,  augite,  aegirine-augite,  olivine,  magnetite,  apatite,  and  a 
trace  of  pyrite.  Symbol,  H.7.1.4.  Lujavrose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

54.  22 

57.  86 

58.  98 

56.  24 

57.46 

54.  42 

48.  23 

48. 13 

A1203 

20.  20 

20.  26 

20.  54 

21.  43 

15.  40 

20.  76 

17.  43 

18.44 

Fe203 

2.  35 

2.  35 

1.  65 

2.  01 

4.  87 

2.64 

2.  77 

3.  41 

FeO 

1.  02 

.39 

.48 

. 55 

.87 

1.  33 

5.  92 

4.  30 

MgO 

.29 

.04 

.11 

.15 

1.  37 

.22 

2.  99 

3.  06 

CaO 

.70 

.89 

.67 

1.  38 

2.  59 

1.34 

6.  38 

5.  89 

Na20 

9.44 

9.  47 

9.  95 

10.  53 

5.  48 

10.41 

6.  87 

8.00 

K20 

4.85 

5.19 

5.  31 

5.  74 

9.44 

4.89 

2.  78 

3.  80 

H20- 

.42 

.21 

.19 

. 12 

.09 

.22 

. 54 

.18 

H20+ — 

5.57 

2.  40 

.97 

.86 

.82 

2.  50 

2.84 

1.  59 

Ti02 

.38 

.22 

.24 

.26 

.60 

.40 

2.00 

1.  74 

ZrOo 

. 15 

.20 

.09 

. 15 

.04 

.05 

CO,. 

. 13 

p2o5 

. 11 

.03 

.04 

.06 

.21 

.11 

.69 

.49 

so3! 

None. 

.06 

.20 

. 10 

. 13 

s 

.03 

.03 

.01 

.08 

.09 

Cl 1 

.08 

.28 

. 12 

.20 

.23 

.03 

.29 

F 1 

(?) 

Trace. 

Trace. 

None. 

.06 

v9o, 

.04 

MnO 

.19 

.21 

.26 

.08 

Trace. 

.15 

.18 

.19 

NiO 

None. 

None. 

Trace. 

. 02 

BaO 

Trace. 

.09 

None. 

.08 

.60 

.04 

.08 

.10 

SrO 

.04 

None. 

.03 

. 16 

Trace. 

.08 

.10 

Li20 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

99.  74 

99.  97 

100.  07 

99.  86 

100. 42 

99.  82 

99.  97 

99.  93 

Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

or 

28.9 

30.6 

31.1 

33.9 

55.6 

29.5 

16.7 

22.2 

ab 

33.5 

39.3 

38.3 

22.0 

5.8 

23.6 

23.6 

14. 1 

an 

8.3 

3. 1 

ne 

23.3 

19.0 

17.2 

32.7 

9.9 

30.4 

18.7 

29.0 

so 

3.  9 

2.  9 

ac 

2.  8 

4.  2 

4.  6 

.6 

13.  8 

7.4 

di 

1. 5 

2.6 

2.9 

8.0 

4.9 

15.9 

18.6 

ol 

3.7 

.8 

WO 

1.  9 

1.5 

1.0 

.6 

mt 

. o 

o 1 

1.2 

3.9 

4.9 

il  . 

Z.  1 

Q 

1.2 

.8 

3.7 

3.4 

ap 

. o 

1.7 

1.1 

IGNEOUS  ROCKS. 


445 


The  following  table  contains  analyses  of  deep-seated  rocks  of  the 
nephelite  series : 

Analyses  of  deep-seated  nephelite  rocks. 

A.  Elseolite  syenite,  or  litchfieldite,  Litchfield,  Maine.  Analysis  by  L.  G.  Eakins.  Described  by  W.  S. 
Bayley.  Contains  elseolite,  two  feldspars,  and  lepidomelane,  with  accessory  sodalite,  cancrinite,  and 
zircon.  Magmatic  symbol,  1.5. 1.4.  Nordmarkose. 

B.  Elseolite  syenite,  Beemersville,  New  Jersey.  Analysis  by  Eakins.  Described  by  J.  P.  Iddings. 
Contains  nephelite,  orthoclase,  segirite,  and  biotite,  with  less  melanite,  titanite,  apatite,  magnetite,  and 
zircon.  Symbol,  1.5. 6.3.  Beemerose. 

C.  Nephelite  syenite,  Brookville,  New  Jersey.  Analysis  by  G.  Steiger.  Described  by  F.  L.  Ransome. 
Contains  alkali  feldspars,  altered  nephelite,  amphibole,  biotite,  cancrinite,  plagioclase,  muscovite,  segirine- 
augite,  apatite,  fluorite,  and  traces  of  magnetite,  with  secondary  analcite,  sericite,  and  natrolite  ( ?).  Symbol, 
I.6.2.4.  Viezzenose. 

D.  Elseolite  syenite.  Red  Hill,  Moultonboro,  New  Hampshire.  Analysis  by  W.  F.  Hillebrand;  descrip- 
tion by  Bayley.  Contains  elseolite,  hornblende,  augite,  biotite,  sodalite,  albite,  and  orthoclase,  with 
accessory  apatite,  sphene,  magnetite,  and  an  occasional  zircon.  Symbol,  II.5.1.4.  Umptekose. 

E.  Nephelite  syenite,  Cripple  Creek,  Colorado.  Analysis  by  Hillebrand.  Described  by  W.  Cross. 
Contains  alkali  feldspars,  nephelite,  sodalite,  augite,  some  segirine,  hornblende,  biotite,  sphene,  apatite, 
and  magnetite.  Symbol,  II.5.2.4.  Akerose. 

F.  Urtite,  Kola  Peninsula,  Finland.  Analysis  by  N.  Sahlbom.  Described  by  W.  Ramsay,  Geol. 
Foren.  Forhandl.,  vol.  18,  p.  463, 1896.  Contains,  in  percentages,  nephelite,  85.7;  pyroxene,  mostly  segirite, 
12.0;  and  apatite,  2.0.  Symbol,  II.9.1.4.  Urtose. 

G.  Ijolite,  Iivaara,  Finland.  Analysis  by  A.  Zilliacus.  Described  by  W.  Hackman,  Bull.  Comm.  geol. 
Finland,  No.  11.  1900.  Contains,  in  average  percentages,  nephelite,  51.6;  pyroxene,  39.2;  apatite,  4.3; 
titanite,  2.1;  and  ivaarite,  0.7.  Symbol,  II.9. 1.4.  Urtose. 

H.  Theralite,  Crazy  Mountains,  Montana.  Analysis  by  Hillebrand.  Contains,  according  to  J.E.  Wolff, 
augite,  segirite,  biotite,  sodalite,  nephelite,  feldspar,  apatite,  magnetite,  and  titanite.  Symbol,  III.7.1.4. 
Malignose. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02 

60.  39 

53.  56 

54.  68 

59.  01 

54.  34 

45.  28 

43.  02 

44.  65 

A1203 

22.  57 

24.  43 

21.  63 

18. 18 

19.  21 

27.  37 

24.  63 

13.  87 

Fe203 

.42 

2. 19 

2.  22 

1.  63 

3. 19 

3.  53 

3.  59 

6.  06 

FeO 

2.  26 

1.  22 

2.00 

3.  65 

2. 11 

.49 

2. 17 

2.  94 

MgO 

.13 

.31 

1.  25 

1.  05 

1.  28 

.33 

1.  96 

5.15 

CaO 

.32 

1.24 

2.  86 

2.  40 

4.  53 

1.  22 

5.  47 

9.  57 

Na20 

8.  44 

6.  48 

7.  03 

7.  03 

6.  38 

17.  29 

14.  81 

5.  67 

K20 

4.  77 

9.  50 

4.  58 

5.  34 

5. 14 

3.  51 

2.  99 

4.  49 

h2o  - 

} .57 

} .93 

. 27 

. 15 

. 14 

} .40 
) 

. 96 

h2o+ 

1.  88 

. 50 

1. 17 

2. 10 

Ti02  

. 79 

.81 

1.  09 

. 63 

. 95 

Zr02  

.07 

co2  

None. 

. 12 

None. 

. 11 

PoO, 

. 28 

Trace. 

. 27 

. 70 

1.  50 

2U5  • 

so,  

. 07 

.07 

. 61 

F 

.22 

Cl  

.28 

Trace. 

MnO  

.08 

.10 

Trace. 

.03 

.08 

. 19 

. 17 

BaO  

.05 

.08 

.24 

. 76 

SrO  

Trace. 

. 16 

. 37 

v,o, 

.02 

Li20 

Trace. 

Trace. 

Trace. 

99.  95 

99.  96 

99.  81 

99.  98 

99.  77 

99.  61 

99.  97 

99.  93 

446 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  deep-seated  nephelite  rocks — Continued. 


Norms. 


A comparison  of  these  norms  with  the  modes  indicated  in  the  de- 
scriptions of  the  rocks  shows  great  divergencies.  The  normative  and 
actual  minerals  are  only  in  part  the  same.  All  of  the  rocks,  however, 
consist  dominantly  of  alkali  feldspar  and  nephelite,  with  varying 
accessories.  In  the  Brookville  syenite  the  normative  anorthite  shows 
a gradation  toward  the  plagioclase  rocks.  The  urtite  and  ijolite  rep- 
resent the  highest  proportions  of  nephelite;  and  in  the  theralite  we 
have  the  femic  minerals  forming  nearly  one-half  of  the  rock.  Taken 
all  together,  the  nephelite  rocks,  eruptive  and  plutonic,  range  from 
1. 5. 1.4  to  III. 7. 1.4.  The  miner alogical  variations  are  great  enough 
to  justify  a much  more  minute  subdivision  in  classification  than  they 
are  given  here.  The  many  varietal  names  that  have  been  given  the 
nepheline  syenites  follow  from  a recognition  of  their  differences. 
Ditroite,  foyaite,  laurdalite,  litchfieldite,  urtite,  and  ijolite  are  exam- 
ples of  this  varied  nomenclature.1 


1 A very  full  description  of  the  Norwegian  nepheline  syenites  is  given  by  W.  C.  Brogger  in  his  work  Die 
Eruptivgesteine  des  Kristianiagebietes,  especially  in  part  3 (1898).  Laurdalite,  heumite,  nepheline  por- 
phyry, foyaite,  and  hedrumite  are  the  nephelite  rocks  described  in  this  memoir.  A remarkable  rock 
found  in  Dungannon  Township,  Ontario,  has  been  described  by  F.  D.  Adams,  Am.  Jour.  Sci.,  4th  ser., 
vol.  17,  1904,  p.  269.  It  contains  72.2  per  cent  of  nephelite,  with  15.09  of  hornblende  and  5.14 
of  cancrinite.  Some  minor  constituents  are  also  present.  This  rock  Adams  has  named  monmouthite,  and 
its  norm  differs  widely  from  its  mode.  On  the  origin  of  “alkaline”  rocks  see  H.  I.  Jensen,  Proc.  Linn. 
Soc.  New  South  Wales,  vol.  33, 1908,  p.  491;  R.  A.  Daly,  Bull.  Geol.  Soc.  America,  vol.  21, 1910,  p.  87;  and 
C.  H.  Smyth,  jr.,  Am.  Jour.  Sci.,  4th  ser.,  vol.  36, 1913,  p.  33. 


IGNEOUS  ROCKS. 


447 


LETJCITE  ROCKS. 

The  leucite-bearing  rocks  are  much  less  common  than  those  carry- 
ing nephelite,  and,  like  the  latter,  have  been  designated  by  various 
names.  The  following  examples  among  those  containing  little  or  no 
soda-lime  feldspar  will  suffice  to  show  their  composition: 

Analyses  of  leucite  rocks. 

A.  Pseudoleucite-sodalite  tinguaite,  Bearpaw  Mountains,  Montana.  Analysis  by  H.  1ST.  Stokes.  De- 
scribed by  W.  H.  Weed  and  L.  V.  Pirsson.  Contains  orthoclase,  nephelite,  sodalite,  noselite,  segirite, 
diopside,  and  fluorite.  Magmatic  symbol,  II.7.1.3.  Janeirose.  Although  leucite  is  not  reported  here,  it 
appears  abundantly  in  the  norm. 

B.  Arkite,  or  leucite  syenite,  Magnet  Cove,  Arkansas.  Described  and  analyzed  by  H.  S.  Washington, 
Jour.  Geology,  vol.  9, 1901,  p.  616.  Contains,  in  percentages,  orthoclase,  3.9;  leucite,  36.9;  nephelite,  25.5; 
aegirite,  8.4;  diopside,  10.8;  garnet,  14.5.  Symbol,  II.9.1.3.  Arkansose. 

C.  Wyomingite,  Boar’s  Tusk,  Leucite  Hills,  Wyoming.  Analysis  by  W.  F.  Hillebrand.  Described 
by  W.  Cross.  Contains  phlogopite,  leucite,  diopside,  and  apatite.  Symbol,  III.6.1.1.  Wyomingose. 

D.  Leucitite,  Bearpaw  Mountains,  Montana.  Analysis  by  Stokes.  Described  by  Weed  and  Pirsson 
as  an  olivine-free  leucite  basalt.  Contains  leuc’te,  augite,  iron  oxides,  rarely  biotite,  and  a little  glassy 
base.  Symbol,  III.8.1. 2.  Chotose. 

E.  Leucitite,  Alban  Hills,  Italy.  Described  and  analyzed  by  Washington,  Am.  Jour.  Sci.,  4th  ser., 
vol.  9, 1900,  p.  53.  Contains  leucite,  nephelite,  melilite,  diopside,  magnetite,  a trace  of  biotite,  and  scarcely 
any  apatite.  Symbol,  III.8.2. 2.  Albanose. 

F.  Madupite,  Leucite  Hills,  Wyoming.  Analysis  by  Hillebrand.  Described  by  Cross.  Contains 
diopside  and  phlogopite,  with  perofskite  and  magnetite,  in  a glassy  base  of  nearly  the  composition  of  leucite. 
Symbol,  III.9.1.2.  Madupose. 

G.  Missourite,  Highwood  Mountains,  Montana.  Analyzed  by  E.  B.  Hurlbut.  Described  by  Weed 
and  Pirsson  in  Bull.  U.  S.  Geol.  Survey  No.  237,  1905.  Contains  leucite,  augite,  biotite,  olivine,  apatite, 
iron  ore,  some  zeolites,  and  analcite.  Symbol,  IV. 1.1.2.  In  this  rock',  as  the  symbol  indicates,  femic 
minerals  are  dominant. 


A 

B 

C 

D 

E 

F 

G 

Si02 

51.  93 

44.  40 

50.  23 

46.  51 

45.  99 

42.  65 

46.  06 

ai2o3 

20.  29 

19.  95 

11.  22 

11.86 

17. 12 

9. 14 

10.  01 

Fe203 

3.  59 

5. 15 

3.  34 

7.  59 

4. 17 

5. 13 

3. 17 

FeO 

1.  20 

2.  77 

1.  84 

4.  39 

5.  38 

1.07 

5.  61 

MgO 

.22 

1.  75 

7.  09 

4.  73 

5.  30 

10.  89 

14.  74 

CaO 

1.  65 

8.  49 

5.  99 

7.  41 

10.  47 

12.  36 

10.  55 

Na20 

8.  49 

6.  50 

1.37 

2.  39 

2. 18 

.90 

1.  31 

k2o 

9.  81 

8. 14 

9.  81 

8.  71 

8.  97 

7.  99 

5. 14 

H20- 

. 10 

.24 

. 93 

1. 10 

2.  04 

h2o+ 

.99 

1. 17 

1.  72 

2.  45 

.45 

2. 18 

1 1.44 

Ti02 

.20 

1.  53 

2.  27 

.83 

.37 

1.  64 

^7 

CO 

Zr02 

.03 

C02 

.25 

. 12 

None. 

P206 

.06 

. 37 

1.  89 

. 80 

1.  52 

. 21 

S03 

. 67 

.06 

. 74 

. 05 

. 58 

.05 

Cl 

. 70 

.03 

. 04 

. 03 

.03 

F 

. 27 

. 50 

Trace. 

. 47 

Cr90, 

. 10 

None. 

. 07 

Di203 

.03 

. 11 

MnO 

Trace. 

.08 

.05 

.02 

Trace. 

.12 

Trace. 

NiO 

.04 

BaO 

.09 

.01 

1.23 

.50 

.45 

.89 

.32 

SrO 

. 07 

. 24 

. 16 

None. 

. 33 

.20 

Li20 

Trace. 

Trace. 

Trace. 

Trace. 

100.  58 

100.  76 

100.  62 

99.  78 

100.  65 

100. 11 

99.  57 

448 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  leudte  rocks — Continued. 
Norms. 


It  is  worthy  of  note  that  there  are  many  rocks  specifically  desig- 
nated as  leucite-bearing  which,  as  interpreted  by  Washington,  reveal 
no  leucite  in  the  norms.1  It  is  also  to  be  observed  that  the  leucite 
rocks  are  all  effusive  and  never  deep  seated;  at  least  no  plutonic 
member  of  the  group  is  known.  In  an  abyssal  rock,  which  has  con- 
solidated under  pressure,  water  is  retained;  and  in  such  cases,  when 
magnesium  and  potassium  available  for  the  formation  of  olivine  and 
leucite  are  present,  biotite  is  produced  instead.  Under  ordinary  cir- 
cumstances the  fusion  of  biotite  yields  olivine,  leucite,  some  glass, 
and  a little  spinel.2  By  fusing  biotite  and  microcline  together, 
Fouque  and  L6vy  3 obtained  a mixture  of  leucite,  olivine,  and  mag- 
netite, together  with  a mineral  resembling  melilite,  which,  however, 
could  not  be  that  species.  A magma,  then,  which  would  form 
biotite  under  pressure,  will  lose  water  if  it  solidifies  at  the  surface 
of  the  earth,  and  may  generate  olivine  and  leucite. 

The  other  lenad  minerals,  sodalite,  noselite,  and  haiiynite,  are  also 
noteworthy  constituents  of  certain  rare  rocks,  which  we  need  not 
consider  in  detail.  Sodalite  syenite,  haiiynophyre,  and  nosean  sani- 
dinite  are  names  of  rocks  in  which  these  minerals  are  conspicuous.4 

One  sodalite  syenite,  however,  is  included  in  the  next  table  of 
analyses,  for  the  reason  that  it  also  contains  analcite,  a rock-making 
mineral  whose  significance  has  been  realized  only  within  recent  years. 


1 On  the  formation  of  leucite  in  igneous  rocks,  see  H.  S.  Washington,  Jour.  Geology,  vol.  15, 1907,  pp.  257, 
357.  Also  in  his  Roman  comagmatic  region,  Pub.  No.  51  Carnegie  Inst.,  Washington,  19C6. 

2 See  H.  Backstrom,  Geol.  Foren.  Forhandl.,  vol.  18, 1896,  p.  155. 

3 Synthase  des  min^raux  et  des  roches,  p.  77. 

* For  analyses  see  Washington’s  Tables,  Prof.  Paper  U.  S.  Geol.  Survey  No.  14,  1903,  pp.  201,  215,  303, 
305, 349,  351. 


IGNEOUS  ROCKS. 


449 


ANALCITE  ROCKS. 

The  occurrence  of  analcite  as  a primary  mineral  was  first  recog- 
nized by  W.  Lindgren,1  who  described  certain  rocks  from  Montana 
as  analcite  basalts.  In  them  the  analcite  played  a part  like  that 
usually  taken  by  the  feldspars.  Since  then  the  mineral  has  been 
identified  in  a considerable  number  of  other  rocks,2  and  W.  Cross  3 
has  found  it  to  be  commonly  present  in  the  phonolites  of  Cripple 
Creek.  According  to  L.  V.  Pirsson,4  the  supposed  “ glass  base”  of 
monchiquite  is  really  analcite.  This  rock  was  originally  described 
by  M.  Hunter  and  H.  Rosenbusch  5 as  consisting  of  olivine,  with 
either  amphibole,  pyroxene,  or  biotite,  or  all  three,  in  a glassy  ground- 
mass;  but  the  composition  of  the  latter  is  that  of  analcite,  and  like 
analcite  it  gelatinizes  with  weak  acids.  In  a magma  having  the 
general  composition  of  a nepheline  rock,  the  presence  or  absence 
of  water  is  an  important  factor.  If  water  is  retained,  analcite  is 
likely  to  be  formed;  if  lost,  then  nepheline  is  generated.  Analcite, 
however,  is  more  nearly  akin,  structurally,  to  leucite  than  to  nephe- 
lite,  and  between  the  leucite  and  analcite  rocks  there  are  strong 
resemblances.  The  following  analyses  represent  the  last-named  rock 
family:  6 

1 Proc.  California  Acad.  Sci.  2d  ser.,  vol.  3, 1891,  p.  51. 

2 See  citations  under  analcite  in  Chapter  X,  ante,  p.  370. 

2 Sixteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2, 1896,  p.  32. 

« Jour.  Geology,  vol.  4, 1896,  p.  679. 

* Min.  pet.  Mitt.,  vol.  11, 1890,  p.  454. 

0 On  the  analcite  rocks  of  Sardinia,  see  H.  S.  Washington,  Jour.  Geology,  vol.  22, 1914,  p.  742.  A remarka- 
ble rock,  blairmorite,  containing  71  per  cent  of  analcite,  found  near  Crowsnest  Pass,  Alberta,  is  described 
by  J.  D.  MacKenzie,  Dept.  Mines, Canada,  Museum  Bull.  No.  4, 1914.  Analysis  by  M.  F.  Conner  on  p.  23. 

97270°— Bull.  616—16 29 


450 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  analdte  rocks. 

A.  Sodalite  syenite,  Square  Butte,  Highwood  Mountains,  Montana.  Analysis  by  W.  H.  Melville. 
Described  by  W.  Lindgren,  Am.  Jour.  Sci.,  3d  ser.,  vol.  45,  1893,  p.  286.  Contains,  in  percentages,  ortho- 
clase,  50;  albite,  16;  hornblende,  23;  sodalite,  8;  analcite,  3.  Magmatic  symbol  I.5.2.3.  Pulaskose. 

B.  Analcite  tinguaite,  Manchester,  Massachusetts.  Analyzed  and  described  by  H.  S.  Washington,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  6, 1898,  p.  182.  Contains,  in  percentages,  analcite,  37.4;  albite,  20.9;  nephelite,  10.9; 
orthoclase,  17.3;  segirite,  10.2;  pyroxene,  3.3.  Symbol  I.6.I.4.  Miaskose. 

C.  Heronite,  Heron  Bay,  Lake  Superior.  Analysis  by  H.  W.  Charlton.  Described  by  A.  P.  Coleman, 
Join:.  Geology,  vol.  7,  1899,  p.  431.  Contains,  in  percentages,  analcite,  47.0;  orthoclase,  28.24;  labradorite, 
13.0;  segirite,  4.04;  limonite,  3.59;  calcite,  1.96.  Symbol,  I.6.I.4.  Miaskose. 

D.  Monchiquite,  Little  Belt  Mountains,  Montana.  Analysis  by  H.  N.  Stokes.  Described  by  W.  H. 
Weed  and  L.  V.  Pirsson.  Contains  olivine,  augite,  biotite,  analcite,  and  apatite,  with  traces  of  serpentine 
and  chlorite.  Symbol,  III.6.1.4.  No  subrang  name  assigned.  Called  analcite  basalt  in  Washington’s 
tables. 

E.  Monchiquite,  Cabo  Frio,  Brazil.  Described  by  Hunter  and  Rosenbusch,  Min.  pet.  Mitt.,  vol.  11. 
1890,  p.  445.  Analysis  by  M.  Hunter.  The  type  of  monchiquite,  as  described  above.  Symbol,  III.6.2.4. 
Monchiquose. 

F.  Monchiquite,  Big  Baldy,  Little  Belt  Mountains,  Montana.  Analysis  by  W.  F.  Hillebrand.  De- 
scribed by  Weed  and  Pirsson.  Contains  pyroxene,  a few  serpentinized  olivines,  iron  ore,  and  apatite,  in  a 
base  of  analcite.  Symbol,  III.6.2.4.  Monchiquose . 

G.  Monchiquite,  Highwood  Mountains,  Montana.  Analysis  by  H.  W.  Foote.  Described  by  Weed  and 
Pirsson.  Contains  augite,  olivine,  biotite,  iron  ore,  apatite,  and  analcite,  with  some  serpentine  and  a little 
kaolin.  Symbol,  III.6.2.4.  Monchiquose. 

H.  Analcite  basalt,  near  Cripple  Creek,  Colorado.  Analysis  by  Hillebrand.  Described  by  W.  Cross. 
Contains  augite,  olivine,  analcite,  alkali  feldspars,  biotite,  and  apatite.  Symbol,  III.6.2.4.  Monchiquose. 


A 

B 

c 

D 

E 

F 

G 

H 

SiO, 

56.  45 

56.  75 

52.  73 

48.  39 

46.  48 

48.  35 

47.  82 

45.  59 

A1203 

20.  08 

20.  69 

20.  05 

11.  64 

16. 16 

13.  27 

13.  56 

12.  98 

Fe203 

1.  31 

3.  52 

3.  43 

4.  09 

6. 17 

4.  38 

4.  73 

4.  97 

FeO 

4.  39 

.59 

.99 

3.  57 

6.  09 

3.23 

4.  54 

4.  70 

MgO : 

.63 

.11 

. 17 

12.  55 

4.  02 

8.  36 

7.  49 

8.  36 

CaO 

2. 14 

.37 

3.  35 

7.  64 

7.  35 

9.  94 

8.  91 

11.  09 

Na20 

5.  61 

11.  45 

7.  94 

4. 14 

5.  85 

3.  35 

4.  37 

4.  53 

K20 

7. 13 

2.  90 

4.  77 

3.24 

3.  08 

3.  01 

3.  23 

1.04 

h2o- 

.26 

.04 

.69 

.28 

l A 9*7 

.90 

l Q 9*7 

.51 

h2o+ 

1.  51 

3. 18 

4.  85 

2.  56 

> *k.  Z/ 

2.89 

>0.0/ 

3.  40 

Ti02 

.29 

.30 

. 73 

.99 

.52 

. 67 

1.  32 

Zr02  

.03 

co2 

.93 

.45 

.30 

P9(X  

. 13 

Trace. 

.45 

.40 

1. 10 

. 91 

SO,  

Trace. 

. 08 

Trace. 

Cl 

.43 

. 28 

Trace. 

.04 

.05 

F 

. 25 

Cr203 

.07 

Trace. 

MnO 

. 09 

Trace. 

Trace. 

. 19 

Trace. 

. 14 

NiO 

Trace. 

. 04 

BaO 

None. 

. 11 

.32 

. 54 

. 16 

.13 

SrO... 

. 15 

. 09 

. 21 

.12 

Li20 

Trace. 

Trace. 

100.  45 

100. 18 

100.  01 

99.  90 

100.  91 

100.  01 

100.  20 

99.  87 

IGNEOUS  ROCKS. 


451 


Analyses  of  analcite  rochs — Continued. 
Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

or 

41.  7 

17.  2 

28.  4 

18.  9 

18.3 

17.  8 

18.  9 

6. 1 

ab 

28.  3 

46.6 

30.  9 

14.  7 

14. 1 

14.  7 

17.  8 

18.  9 

an 

10.  6 

5.  0 

3.  6 

8.  6 

12.  2 

7.  8 

12.  2 

ne 

3.4 

23.6 

19.6 

11. 1 

19.0 

7.4 

10.5 

10.2 

so 

5.9 

ac 

6.  0 

di 

.5 

1.0 

24.4 

22.3 

27.2 

23.9 

30.0 

wo 

.5 

ol 

6. 1 

4.  4 

15.  2 

2.  9 

6.  7 

7.4 

6.  5 

mt 

1.9 

2.0 

3.  2 

5.8 

9.0 

7.2 

8.0 

7.2 

hm 

1.1 

il 

.6 

1.  4 

1.8 

.9 

1.  2 

2.  5 

ap 

1.1 

1.0 

2.5 

1.9 

wr 

In  these  norms  analcite  is  represented  by  normative  nephelite;  and 
biotite,  in  part,  by  olivine.  The  anorthite  in  some  of  them  indicates 
a shading  toward  the  plagioclase  rocks. 

THE  MONZONITE  GROUP. 

The  rhyolite-granite  series  of  rooks,  and  the  trachyte-syenite  series 
also,  are  defined  by  the  predominance  in  them  of  alkali  feldspars,  and 
commonly  of  orthoclase.  The  andesite-diorite  series,  on  the  other 
hand,  is  characterized  by  plagioclase  feldspars;  but  between  these 
rocks  and  those  already  described  there  are  all  sorts  of  gradations. 
Between  the  orthoclase  and  plagioclase  rocks,  therefore,  considera- 
tions of  convenience  have  led  to  the  formation  of  an  intermediate 
group,  whose  granitoid  members  are  known  as  monzonites.  Quartz 
monzonite  corresponds  to  granite,  monzonite  to  syenite,  and  so  on. 
The  effusive  equivalents,  intermediate  between  trachyte  and  andesite, 
have  been  named  latites.  All  of  these  rocks  carry  orthoclase  or 
anorthoclase  with  plagioclase  in  approximately  equal  amounts,  with 
or  without  quartz,  and  with  smaller  amounts  of  the  ferromagnesian 
silicates.  The  next  table  of  analyses  represents  members  of  this 
intermediate  group. 


452 


THE  DATA  OF  GEOCHEMISTRY, 


Analyses  of  monzonites  and  latites. 

A.  Quartz  monzonite,  Hailey,  Idaho.  Analysis  by  W.  F.  Hillebrand.  Described  by  W.  Lindgren. 
Contains  quartz,  orthoclase,  microcline,  oligoclase,  biotite,  apatite,  titanite,  and  magnetite.  Magmatic 
symbol,  1.4.2. 3.  Toscanose. 

B.  Quartz  monzonite,  Telluride  quadrangle,  Colorado.  Analysis  by  H.  N.  Stokes.  Described  by  W- 
Cross.  Contains  orthoclase  and  plagioclase  in  nearly  equal  amounts,  quartz,  augite,  hornblende,  biotite, 
magnetite,  and  apatite.  Symbol,  1.4.2. 3.  Toscanose. 

C.  Biotite-augite  latite,  near  Clover  Meadow,  Tuolumne  County,  California.  Analysis  by  Hillebrand. 
Described  byF.  L.  Ransome.  Co  ntains  plagioclase,  biotite,  augite,  magnetite,  apatite,  and  glass.  Symbol 
1.4.2. 3.  Toscanose. 

D.  Monzonite,  Tintic  district,  Utah.  Analysis  by  Stokes.  Described  by  G.  W.  Tower  and  G.  O.  Smith- 
Contains  orthoclase,  plagioclase,  quartz,  hornblende,  biotite,  magnetite,  apatite,  zircon,  and  titanite,  with 
a little  chlorite  and  epidote.  Symbol,  II.4.3.3.  Harzose. 

E.  Monzonite  (yogoite),  Yogo  Peak,  Little  Belt  Mountains,  Montana.  Analysis  by  Hillebrand.  De- 
scribed by  W.  H.  Weed  and  L.  V.  Pirsson.  Contains  orthoclase,  oligoclase,  pyroxene,  hornblende,  biotite, 
apatite,  titanite,  iron  ore,  and  a little  kaolin.  Symbol,  II. 5. 2. 3.  Monzonose. 

F.  Augite  latite,  Dardanelle  flow,  Tuolumne  County,  California.  Analysis  by  Stokes.  Described  by 
Ransome.  Contains  plagioclase,  augite,  iron  ore,  some  olivine,  apatite,  and  brown  glass.  Symbol,  n.5.2.3- 
Monzonose. 

G.  Augite  latite.  Table  Mountain , Tuolumne  County,  California.  Analysis  by  Hillebrand.  Described 
by  Ransome.  Contains  labradorite,  olivine,  augite,  and  magnetite.  Symbol,  II.5.3.3.  Shoshonose. 

H.  Monzonite,  La  Plata  Mountains,  Colorado.  Analysis  by  Stokes.  Described  by  Cross.  Contains 
orthoclase  and  plagioclase  in  nearly  equal  amounts,  augite,  hornblende,  quartz,  titanite,  magnetite,  and 
apatite.  Symbol,  II. 5.3.4.  Andose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

68.  42 

65.  70 

62.  33 

59.  76 

54.  42 

59.  43 

56. 19 

57.  42 

A1203 

15.  01 

15.  31 

17.  30 

15.  77 

14.  28 

16.  68 

16.  76 

18. 48 

Fe90o 

.97 

2.  54 

3.  00 

3.  77 

3.  32 

2.  54 

3.  05 

3.  74 

FeO 

1.  93 

1.  62 

1.  63 

3.  30 

4. 13 

3.  48 

4. 18 

2. 10 

MrO 

1.  21 

1.  62 

1.  05 

2. 16 

6. 12 

1.  84 

3.  79 

1.  71 

CaO  

2.  60 

2.  56 

3.  23 

3.  88 

7.  72 

4.  09 

6.  53 

6.  84 

Na20 

3.  23 

3.  62 

4.21 

3.  01 

3.  44 

3.  72 

2.  53 

4.  52 

k2o 

4.  25 

4.  62 

4.  46 

4.  40 

4.  22 

5.  04 

4.  46 

3.  71 

h2o- 

.54 

. 17 

.44 

.31 

.22 

.27 

.34 

.08 

h2o+ 

.73 

.42 

.75 

1. 11 

.38 

. 72 

.66 

.28 

Ti02 

.50 

.72 

1.  05 

.87 

.80 

1.  38 

.69 

.86 

Zr02 

.04 

.08 

co2 

.20 

None. 

. 78 

None. 

P90. 

. 13 

.33 

.29 

.42 

.59 

.58 

.55 

.36 

s? 

.02 

None. 

so3 

. 12 

None. 

None. 

Cl 

.03 

.04 

.05 

.03 

VoOo 

. 01 

.02 

MnO 

.06 

Trace. 

.08 

. 12 

. 10 

Trace. 

. 10 

.09 

BaO 

. 12 

. 12 

.24 

.09 

.32 

. 14 

. 19 

. 15 

SrO 

.03 

.03 

.05 

Trace. 

. 13 

Trace. 

Trace. 

.08 

Li20 

Trace. 

Trace. 

Trace. 

Trace. 

None. 

Trace. 

Trace. 

FeS2 

.06 

C 

.11 

99.  95 

99.  53 

100.  33 

99.  81 

100. 19 

100.04 

100. 02 

100. 45 

Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

Q 

25. 1 

19. 1 

12.4 

14.  6 

8.4 

5.9 

4.0 

or 

25.  6 

27.2 

26.  7 

26. 1 

25.0 

29.0 

26.  7 

21.  7 

ab 

26.  7 

30.4 

35.  6 

24. 1 

28.  8 

30.  9 

21.  5 

37.  7 

an 

13. 1 

12. 1 

15.0 

16.7 

11.1 

13.9 

20.9 

20.0 

C 

.3 

.4 

di 

.8 

2.4 

19. 1 

2.3 

6.8 

8.7 

hy 

5.0 

4. 1 

2.3 

5.8 

9.  9 

5.8 

10. 1 

mt 

1.4 

3.5 

2. 1 

5.6 

2.6 

3.5 

4.6 

5.3 

hm 

1.  6 

il 

.9 

1.4 

2.0 

1.7 

1.5 

2.6 

1.2 

1.5 

ap 

1.3 

1.4 

1.2 

1.0 

IGNEOUS  ROCKS. 


453 


THE  ANDESITE-DIORITE  SERIES. 

From  the  monzonite  group  to  the  dacites  and  quartz  diorites  the 
gradation  is  very  slight.  These  rocks,  which  mark  the  persilicic  end 
of  the  andesite-diorite  series,  are  characterized  by  quartz,  with 
plagioclase  as  the  prevailing  feldspar,  and  with  subordinate  amounts 
of  femic  minerals.  The  dacites  are  eruptive  rocks;  the  quartz 
diorites  are  their  granitoid  or  plutonic  equivalents.  They  correspond 
to  rhyolite  and  granite  in  the  orthoclase  series,  and  between  dacite 
and  quartz  diorite  there  are  porphyritic  forms  analogous  to  the 
quartz  porphyries.  For  dacites  and  quartz  diorites  a single  group  of 
analyses  must  suffice,  as  follows: 


Analyses  of  dacites  and  quartz  diorites. 

A.  Dacite,  Bear  Creek  Falls,  Shasta  County,  California.  Analysis  by  R.  B.  Riggs.  Described  by  J.  S. 
Diller.  Contains  plagioclase,  with  a little  sanidine,  hornblende,  quartz,  magnetite,  some  pyroxene  inclu- 
sions, and  glass.  Magmatic  symbol,  I.4.2.4.  Lassenose. 

B.  Quartz  diorite,  near  Enterprise,  Butte  County , California.  Analysis  by  W.  F.  Hillebrand.  Reported 
by  H.  W.  Turner  to  contain  plagioclase,  potash  feldspar,  quartz,  hornblende,  mica,  and  accessories.  Sym- 
bol, I.4.2.4.  Lassenose. 

C.  Dacite,  Sepulcher  Mountain,  Yellowstone  National  Park.  Analysis  by  J.  E.  Whitfield.  Described 
by  J.  P.  Iddings.  Contains  plagioclase,  quartz,  biotite,  and  hornblende.  Symbol,  I.4.3.4.  Yellowstonose. 

D.  Quartz  diorite,  Pigeon  Point,  Minnesota.  Analysis  by  Hillebrand.  Described  by  W.  S.  Bayley. 
Contains  feldspar,  quartz,  hornblende,  chlorite,  magnetite,  apatite,  and  rutile.  Symbol,  II.4.2.3. 
Adamellose. 

E.  Quartz-mica  diorite,  near  Milton,  Sierra  County,  California.  Analysis  by  Hillebrand.  Described 
by  Tinner.  Contains  plagioclase,  quartz,  hornblende,  brown  mica,  iron  ore,  and  apatite.  Harzose. 

F.  Quartz-mica  diorite,  Electric  Peak,  Yellowstone  National  Park.  Analysis  by  Whitfield.  Described 
by  Iddings.  Contains  plagioclase,  orthoclase,  quartz,  biotite,  hornblende,  augite,  and  hypersthene. 
gyrnbol,  II.4.3.4.  Tonalose. 

G.  Quartz-mica  diorite,  Yaqui  Creek,  Mariposa  County,  California.  Analysis  by  G.  Steiger.  Described 
by  Turner.  Contains  plagioclase,  quartz,  biotite,  hornblende,  a little  pyroxene,  iron  ore,  and  apatite. 
Symbol,  II.4.3.4.  Tonalose. 

H.  Quartz-mica-hornblende  diorite,  Stone  Run,  Cecil  County,  Maryland.  Analysis  by  Hillebrand. 
Described  by  A.  G.  Leonard.  Contains  hornblende,  biotite,  quartz,  plagioclase,  a little  orthoclase,  zircon, 
apatite,  titanite,  and  magnetite,  with  secondary  chlorite  and  epidote.  Symbol,  II.4.4.3.  Bandose. 


Si02. . 
A1203 . 
Fe203. 
FeO... 
MgO. . 
CaO... 
Na20.. 
K20... 

h2o-. 

h20+. 

Ti02. . 
Zr02. . 
C02... 

£A-- 
so3 — 

Cl 

VA- 

MnO.. 
BaO. . 
SrO... 
Li20 . . 
C 


68. 10 

15.  50 

3.  20 
None. 

.10 
3. 02 

4.  20 
3. 13 


2.  72 
.15 


.03 


Trace. 

.06 

Trace. 

None. 


B 

70.  36 
15.  47 
.98 

1. 17 
.87 

3. 18 
4.  91 

1.  71 

.06 

1.  00 

.20 


11 


Trace. 

.06 

Trace. 

Trace. 


100.21  100.08  100.27 


65.  66 
15.  61 

2. 10 

2.  07 

2.  46 

3.  64 

3.  65 
2.  03 

\ 1.07 
1.37 


Trace. 

.13 

.12 


None. 


.36 


57.  98 
13.  58 

3. 11 
8.  68 

2.  87 
2.  01 

3.  56 
3.  44 

\ 2.47 

1.  75 


.29 


Trace. 


.13 

.04 

Trace. 

Trace. 


99.  91 


57.  26 
6.  51 
3.  27 

5. 19 
3.  41 
6.  69 

2.  65 
2.  93 
.20 
.95 
.53 


.30 


.18 

.10 

.06 

Trace. 


100.  23 


65. 11 

16.  21 
1.  06 

3. 19 

2.  57 

3.  97 

4.  00 
2.  51 

\ .94 
.71 


.02 

Trace. 

None. 


None. 


.04 


100.  33 


G 

58.  09 

17.  46 
1. 12 

5.  08 

4.  06 

6.  24 
2.  94 
2.  02 

.29 
1. 45 
.95 


.21 

.17 

.05 

.02 


None. 

.07 

.04 

None. 

.11 


58.  57 
16. 10 
2.  89 
6. 12 
2.  33 

7.  39 
2. 11 
1.  01 
.21 
1.  27 
1.41 
.09 
None. 
.37 


.02 

.18 

Trace. 

Trace. 

Trace. 


100.  37 


100.  07 


454 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  dacites  and  quartz  diorites — Continued. 
Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

Q 

25.4 

27. 1 

25.0 

11.  1 

10.  3 

18.  5 

11.  2 

21.  3 

or 

18.  3 

10.  0 

12.2 

20.  0 

17.  2 

15.  0 

12.2 

6. 1 

ab 

35.  6 

41.4 

30.  9 

29.  9 

22.  5 

33.  5 

24.  6 

17.  8 

an 

14.2 

15.3 

18. 1 

10.0 

24.5 

18.9 

28.4 

31.4 

C 

. 7 

.5 

di 

7.  3 

.8 

2. 1 

4.5 

hv 

.7 

3.1 

6.2 

17.7 

10.9 

9.  7 

16.0 

10.0 

mt, 

1.6 

2.8 

8.0 

4.6 

1.6 

1.6 

4.2 

hm 

3.2 

il 

.5 

2.6 

3.4 

1.1 

1.4 

1.8 

2.8 

tn 

.4 

With  these  rocks  it  must  be  borne  in  mind  that  normative  ortho- 
clase  in  part  represents  biotite.  The  actual  orthoclase,  therefore,  will 
be  less  in  amount  than  appears  in  the  norms. 

Dacite  is  a quartz  andesite;  and  the  andesites  which  are  poor  or 
lacking  in  quartz  form  a group  of  rocks  parallel  with  the  trachytes. 
They  contain  plagioclase  as  a principal  constituent,  with  subordinate 
biotite,  hornblende,  or  pyroxene.  Six  analyses  of  andesites  are  given 
in  the  next  table. 


IGNEOUS  ROCKS. 


455 


Analyses  of  andesites. 

A.  From  Pikes  Peak,  Colorado.  Analysis  by  W.  F.  Hillebrand.  According  to  W.  Cross,  it  contains 
plagioclase,  orthoclase  (?),  augite,  iddingsite,  hypersthene,  flakes  of  limonite,  and  a little  tridymite. 
Magmatic  symbol,  I.5.2.3.  Pulaskose. 

B.  From  Silver  Cliff,  Colorado.  Analysis  by  L.  G.  Eakins.  Described  by  Cross.  Contains  plagioclase, 
orthoclase,  augite,  biotite,  hornblende,  quartz,  magnetite,  and  apatite.  Symbol,  II.5.2.4.  Akerose. 

C.  Augite  andesite,  Dike  Mountain,  Yellowstone  National  Park.  Analysis  by  Hillebrand.  According 
to  Arnold  Hague  and  T.  A.  Jaggar  it  contains  plagioclase,  augite,  apatite,  magnetite,  and  serpentinized 
olivine.  Symbol,  II.5.3.3.  Shoshonose. 

D.  Augite-bronzite  andesite,  Unga  Island  Alaska.  Analysis  by  Hillebrand.  Described  by  G.  F. 
Becker.  Contains  plagioclase,  augite,  bronzite,  a little  glass,  and  some  indeterminate  material.  Symbol, 
II.5.3.4.  Andose. 

E.  Hypersthene  andesite,  Franklin  Hill,  Plumas  County,  California.  Analysis  by  Hillebrand. 
Reported  by  H.  W.  Turner  to  contain  plagioclase,  rhombic  pyroxene,  augite,  and  magnetite.  Symbol, 
II.5.4.3.  Hessose. 

F.  Augite  andesite,  near  Electric  Peak,  Yellowstone  National  Park.  Analysis  by  Hillebrand. 
Described  by  J.  P.  Iddings.  Contains  plagioclase,  malacolite,  actinolite,  and  magnetite.  Symbol, 
HI.5.3.3.  Kentallenose. 


A 

B 

C 

D 

E 

F 

Si02 

62.  64 

57.  01 

51. 17 

56.  63 

56.  88 

50.  59 



17.  82 

18.  41 

16. 14 

16.  85 

18. 25 

11.49 

Fe203 

3.  91 

3.  69 

4. 11 

3.  62 

2.  35 

1.  83 

FeO 

.31 

2.  36 

4.  48 

3.  44 

4. 45 

7.  64 

MgO 

.47 

2.  34 

4.  82 

4.  23 

4.  07 

11.  27 

CaO 

3.  22 

4.  29 

7.  72 

7.  53 

7.  53 

8.  79 

4. 47 

4.  95 

2.  99 

3.  08 

3.  29 

2.  27 

k26 

4.  99 

3.  72 

3.  54 

2.  24 

1.42 

2.  33 

h2o- 

.58 

l 9 9Q 

.63 

.80 

.24 

.21 

h2o+ 

.65 

2.  24 

.51 

.50 

1.  76 

Ti02 

.59 

.27 

1.  01 

.67 

.45 

.80 

Zr02 

.08 

None. 

PA 

.25 

.42 

.48 

.16 

.30 

.48 

.04 

.04 

.04 

MnO 

.04 

.21 

.21 

.23 

.18 

.17 

NiO  

.01 

Trace? 

.06 

BaO 

.28 

.20 

.09 

.11 

.10 

SrO 

.07 

. 10 

Trace. 

.04 

.03 

T,i„0 

Trace. 

Trace. 

Trace. 

Trace. 

FeS2 

.05 

.06 

100.  37 

99.  96 

99.  94 

100. 18 

100.  06 

99.  86 

Norms. 


A 

B 

c 

D 

E 

F 

Q 

10.2 

2.2 

9.1 

9. 1 

30.0 

22.2 

20.6 

13.3 

8.3 

13.8 

ab 

37.7 

41.9 

25.2 

26.2 

27.8 

19.4 

an 

13.6 

16.7 

20.3 

25.3 

30.9 

13.9 

di 

1.8 

1.7 

12.4 

9.1 

5.3 

22.4 

hy 

.4 

5.9 

8.5 

8.4 

13.2 

8.7 

ol 

.6 

14. 1 

mt 

5.3 

5.  8 

5.3 

3.  5 

2.6 

hm 

3.9 

il 

.6 

.5 

1.8 

1.2 

.8 

1.5 

an 

1.0 

1. 1 

1.0 

Diorite  is  the  plutonic  equivalent  of  andesite.  It  is  commonly 
defined  as  a granitoid  rock  consisting  chiefly  of  plagioclase,  with 


456 


THE  DATA  OF  GEOCHEMISTRY. 


either  biotite  or  hornblende,  or  both;  but  many  diorites  carry  pyrox- 
ene also,  and  shade  into  the  gabbros.  In  fact,  as  the  femic  minerals 
become  more  prominent  in  rocks  the  problems  of  classification 
become  more  complex,  and  the  results  are  less  satisfactory  than  with 
the  similar  mixtures  of  feldspar  and  quartz.  A variety  of  diorite  is 
called  “camptonite.”  Tonalite  and  kersantite  are  other  varieties. 
The  following  analyses  represent  the  diorite  group: 

Analyses  of  diorites. 


A.  Diorite,  Mount  Ascutney,  Vermont.  Analysis  by  W.  F.  Hillebrand.  Described  by  R.  A.  Daly. 
Contains  hornblende,  augite,  biotite,  plagioclase,  titaniferous  magnetite,  titanite,  zircon,  and  quartz. 
Magmatic  symbol,  II.5.2.3.  Monzonose. 

B . Diorite  porphyry,  La  Plata  Mountains,  Colorado.  Analysis  by  Hillebrand.  Described  by  W.  Cross. 
Contains  hornblende,  plagioclase,  orthoclase,  quartz,  titanite,  apatite,  and  magnetite,  with  secondary 
epidote,  chlorite,  and  calcite.  Symbol,  II.5.2.4.  Akerose. 

C.  Diorite,  Crazy  Mountains,  Montana.  Analysis  by  Hillebrand.  According  to  J.  E.  Wolff  it  contains 
biotite,  labradorite,  augite,  orthoclase,  quartz,  magnetite,  apatite,  and  hornblende.  Symbol,  II.5.3.3. 
Shoshonose. 

D.  Tonalite,  South  Leverett,  Massachusetts.  Analysis  by  L.  G.  Eakins.  Described  by  B.  K.  Emerson. 
Contains  feldspar,  hornblende,  and  epidotic  quartz  veins.  Symbol,  II.5.3.4.  Andose. 

E.  Diorite,  South  Honcut  Creek,  Butte  County,  California.  Analysis  by  Hillebrand.  Reported  by 
H.  W.  Turner  to  contain  feldspar,  hornblende,  and  a little  chlorite.  Symbol,  II.5.3.5.  Beerbachose. 

F.  Camptonite,  La  Plata  Mountains,  Colorado.  Analysis  by  Hillebrand.  Reported  by  Cross  to  contain 
hornblende,  augite,  plagioclase,  orthoclase,  magnetite,  apatite,  and  some  secondary  calcite.  Symbol, 
III.5.3.3.  Kentallenose. 

G.  Camptonite,  Mount  Ascutney,  Vermont.  Analysis  by  Hillebrand.  Described  by  Daly.  Contains 
plagioclase,  hornblende,  a little  augite,  olivine,  magnetite,  and  apatite.  Symbol,  III.5.3.4.  Camptonose. 

H.  Diorite,  Hump  Mountain,  Mitchell  County,  North  Carolina.  Analysis  by  Hillebrand.  Reported 
by  A.  Keith  to  contain  plagioclase,  orthoclase,  hornblende,  quartz,  biotite,  magnetite,  andgarnet.  Sym- 
bol, III.5.4.3.  Auvergnose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

57.  97 

60.44 

57.  97 

55.  51 

57.  87 

47.  25 

48.  22 

46.  91 

ai2o3 

17.  28 

16.  65 

15.  65 

16.  51 

16.  30 

15. 14 

14.  27 

15.  85 

Fe203 

2.  23 

2.  31 

.73 

1.  68 

1.  71 

5.  05 

2. 46 

2.  86 

FeO. 

3.  75 

3.  09 

2.  80 

4.  57 

3.  86 

4.  95 

9.  00 

9.  95 

MgO 

2.  20 

2. 18 

4.  96 

6.  73 

5.  50 

6.  87 

6.  24 

7.  01 

CaO 

4.  33 

4.  22 

10.  93 

6.  73 

5.  53 

9.  98 

8.  45 

9.  62 

Na20 

4.  31 

5. 18 

3.03 

3. 19 

5.  01 

2.  39 

2.  90 

2.  65 

K20 

4. 12 

2.  71 

3. 16 

2.  46 

.75 

2.60 

1.  93 

.69 

h2o- 

.18 

.36 

.22 

1 1 KQ 

.26 

.40 

.28 

.24 

h2o+ 

.57 

1.  07 

.38 

> 1.  Do 

2. 40 

2. 12 

1.  66 

1.  62 

Ti02 

1 1 KA 

.60 

.60 

.91 

.53 

1.  22 

2.  79 

2.  03 

Zr02 

> 1.  0*± 

.03 

None. 

C02 

.05 

.48 

1.  87 

.15 

PA 

.64 

.29 

.15 

.17 

.27 

.25 

.64 

.26 

Cl 

.10 

F 

.04 

Trace. 

.05 

VoO,. 

.02 

.05 

.03 

▼ 2vy3 • 

Cr203 

.01 

MnO 

.15 

.13 

Trace. 

.11 

o 

00 

.17 

.20 

.22 

(NiCo)O 

Trace. 

None. 

.02 

.03 

.03 

BaO 

.07? 

.12 

.09 

.02 

.05 

.08 

.04 

Trace? 

SrO 

. 11 

.02 

Trace. 

.05 

Trace? 

Li20 

Trace. 

Trace. 

Trace. 

Trace. 

Trace. 

FeS2- . . 

.32 

None. 

.36 

99.  75 

99.  96 

100.  69 

100. 12 

100. 12 

100.  46 

99.  80 

99.  98 

IGNEOUS  ROCKS. 


457 


Analyses  of  diorites — Continued. 

Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

0 

4.  9 

7.  7 

3.1 

2.3 

5.0 



or 

24.5 

16.1 

18.9 

14.5 

4.4 

15.0 

11.1 

3.9 

ab 

37.2 

44.0 

25.7 

26.7 

41.9 

17.8 

24.6 

22.5 

an 

15.0 

13.9 

19.5 

23.4 

20.3 

22.8 

20.3 

29.2 

ne 

1.4 

di 

2.5 

5.7 

27.8 

8.1 

5.9 

21.4 

15.1 

15.1 

hy 

6.  9 

5.5 

2.  7 

18.4 

16.5 

9.2 

8.1 

ol. 

7.2 

6.4 

10.7 

mt. 

3.2 

3.2 

1.2 

2.6 

2.3 

7.4 

3.5 

4.2 

il 

2.9 

1.2 

1.1 

1.7 

1.1 

2.3 

5.4 

3.8 

1.  3 

1.3 



! 

THE  BASALTS. 

The  basalts  form  an  ill-defined  group  of  lavas  which  vary  from  the 
andesites  in  containing  a larger  proportion  of  the  femic  minerals. 
Plagioclase,  pyroxene,  often  olivine,  and  magnetite  are  the  principal 
minerals  of  basalt,  but  many  variations  of  it  are  known.  Some 
basalts  are  free  from  olivine,  other  examples  contain  such  minerals  as 
leucite,  nephelite,  melilite,  etc.  Hornblende  basalts  are  known,  but 
they  are  rare.  In  a few  basalts  quartz  has  been  identified,  but  its 
presence  is  anomalous  and  not  well  explained.1  The  following 
analyses  relate  to  basalt,  as  the  unqualified  term  is  commonly  used. 


1 See  J.  S.  Diller,  Bull.  U.  S.  Geol.  Survey  No.  79,  1891. 


458 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  basalts. 

A.  Basalt,  early  flow,  Table  Mountain,  Colorado.  Analysis  by  L.  G.  Eakins.  Described  by  W.  Cross. 
Contains  augite,  olivine,  plagioclase,  probably  ortboclase,  magnetite,  apatite,  and  a little  biotite.  Mag- 
matic symbol,  II.5.3.3.  Shoshonose. 

B.  Basalt,  Saddle  Mountain,  Pikes  Peak,  Colorado.  Analysis  by  W.  F.  Hillebrand.  Described  by 
Cross.  Contains  augite,  olivine,  plagioclase,  orthoclase,  magnetite,  biotite,  and  apatite.  Symbol,  II.5.3.4. 
Andose. 

C.  Quartz  basalt,  Cinder  Cone,  near  Lassen  Peak,  California.  Analysis  by  Hillebrand.  Described  by 
J.  S.  Diller.  Contains  plagioclase,  pyroxene  (mostly  hypersthene),  olivine,  quartz,  magnetite,  augite 
sparingly,  and  much  unindividualized  base.  Symbol,  II.5.3.4.  Andose. 

D.  Basalt,  San  Joaquin  River,  Madera  County,  California.  Analysis  by  Hillebrand.  Reported  by 
H.  W.  Turner  to  contain  pyroxene,  partly  augite,  plagioclase,  olivine,  and  iron  ore.  Symbol,  II.5.3.4. 
Andose. 

E.  Basalt,  McCloud  River,  near  Mount  Shasta,  California.  Analysis  by  H.  N.  Stokes.  Not  described. 
Symbol,  II.5.4.3.  Hessose. 

F.  Basalt,  San  Rafael  flow,  Colfax  County,  New  Mexico.  Analysis  by  Hillebrand.  According  to 
Cross  it  contains  plagioclase,  augite,  olivine,  much  iddingsite,  magnetite,  and  apatite.  Symbol,  III.5.3.4. 
Camptonose. 

G.  Basalt,  Pine  Hill,  South  Britain,  Connecticut.  Analysis  by  Hillebrand.  Described  by  W.  H. 
Hobbs.  Contains  plagioclase,  augite,  olivine,  and  magnetite.  Symbol,  III.5.4.3.  Auvergnose. 


A 

B 

C 

D 

E 

F 

G 

Si02 

49.  69 

48.  76 

57.  25 

51.  89 

47.  94 

48.  35 

52. 40 

ai2o3 

18.  06 

15.  89 

16. 45 

15.  28 

18.  90 

15.  47 

13.  55 

Fe203 

2.  64 

6.  04 

1.  67 

3. 10 

2.  21 

4.  80 

2.  73 

FeO 

. 6.19 

4.  56 

4.  72 

3.  60 

8.  59 

7.  58 

9.  79 

MgO 

5.  73 

5.  98 

6.  74 

8.  68 

8.  21 

8. 15 

5.  53 

CaO 

8.  24 

8. 15 

7.  65 

7.  38 

9.  86 

8.  81 

10.  01 

Na20 

2.  99 

3.  43 

3.  00 

3.  27 

2.  81 

3.  09 

2.  32 

K20 

3.  90 

2.  93 

1.  57 

2.  57 

.29 

.95 

.40 

H20- 

\ qn 

.40 

l AC\ 

1. 17 

.39 

.28 

.62 

H20+ •-  - - 

/ -91 

1.  48 

1.  37 

.74 

.73 

1.  05 

Ti02 

.85 

1.  65 

.60 

.91 

.57 

1.  33 

1.  08 

p206 

.81 

.60 

.20 

.61 

.15 

.33 

.12 

SOo 

. 07 

ci3 ;; 

. 13 

MnO 

.13 

.13 

.10 

.12 

Trace. 

.21 

.26 

NiO 

.02 

.02 

Trace. 

BaO 

.17 

.03 

.15 

None. 

.06 

Trace. 

SrO 

.06 

Trace. 

. 09 

None. 

.03 

None. 

Li20 

None. 

Trace. 

Trace. 

Trace. 

None. 

FeS2 

. 13 

4 

100.  27 

100.  23 

100.  38 

100.  21 

100.  66 

100.  26 

99.  99 

Norms. 


A 

B 

c 

D 

E 

F 

G 

Q 

6.  9 

6.7 

or 

22.  8 

17.  2 

9.  5 

15.0 

1.  7 

5.  6 

2.2 

ab 

19.4 

26.  7 

25.  2 

27.  8 

23.  6 

26.  2 

19.4 

an 

24.5 

19.  2 

26.7 

22.2 

38.1 

25.6 

25.6 

ne 

3. 1 

1.1 

di 

9.4 

14.1 

9.0 

9.0 

8.  9 

14.  7 

19.7 

hy 

18.9 

7.9 

5.9 

6.  7 

18.1 

ol 

12.  8 

6.  5 

7.  2 

17.  0 

10.  5 

mt 

3.  7 

8.  6 

2.3 

4.  6 

3.  2 

7.  0 

3.9 

il 

1.7 

3. 1 

1.1 

1.7 

1.1 

2.5 

2.2 

ap 

1.9 

1.3 

1.2 



IGNEOUS  ROCKS. 


459 


The  following  table  contains  analyses  of  a number  of  exceptional 
rocks,  which  are  classed  with  the  basalts,  but  vary  from  them  in 
having  the  feldspar  more  or  less  replaced  by  leucite,  nephelite, 
or  melilite.  The  unique  venanzite  is  placed  here,  as  being  more 
nearly  akin  to  this  group  of  rocks  than  to  any  other.  The  analcite 
basalts  given  in  a previous  table  properly  belong  here  also,  and  so 
perhaps  do  some  of  the  rocks  described  in  connection  with  the  tables 
on  pages  444-450. 


Analyses  of  basaltic  rocks. 

A.  Kulaite,  Kula,  Lydia,  Asia  Minor.  Described  and  analyzed  by  H.  S.  Washington,  Jour.  Geology, 
vol.  8, 1900,  p.  613.  Contains,  in  percentages,  anorthite,  17.9;  albite,  8.4;  orthoclase,  23.4;  nephelite,  20.4; 
diopside,  12.8;  olivine,  10.7;  magnetite,  3.8;  apatite,  1.8.  The  diopside  is  derived  from  hornblende. 
Magmatic  symbol,  II.6.2.4.  Essexose. 

B.  Leucite  kulaite,  Kula.  Described  and  analyzed  by  Washington,  loc.  cit.  Contains,  in  percentages, 
anorthite,  17.9;  albite,  23.6;  leucite,  17.4;  nephelite,  12.8;  diopside,  13.8;  olivine,  9.5;  magnetite,  3.7. 
Symbol,  II.6.2.4.  Essexose. 

C.  Basalt,  Pinto  Mountain,  Uvalde  County,  Texas.  Analysis  by  W.  F.  Hillebrand.  Described  by 
W.  Cross.  Contains  olivine,  augite,  plagioclase,  magnetite,  apatite,  and  a very  little  alkali  feldspar. 
Symbol,  III.6.3.4.  Limburgose. 

D.  Leucite  basalt,  Highwood  Mountains,  Montana.  Analysis  by  H.  W.  Foote.  Described  by  W.  H. 
Weed  and  L.  V.  Pirsson.  Contains  augite,  olivine,  biotite,  some  leucite,  analcite,  iron  ore,  and  apatite. 
Symbol,  III.7.2.3.  No  subrang  name  given. 

E.  Venanzite  or  euctolite,  San  Venanzo,  Umbria,  Italy.  Described  by  H.  Rosenbusch,  Sitzungsb.  Akad. 
Berlin,  1899,  pt.  1,  p.  111.  Contains  olivine,  melilite, leucite,  biotite,  magnetite,  some  zeolites,  and  a trace 
of  nephelite.  Symbol,  IV  l5. 1.2.  Venanzose . 

F.  Nephelite  basalt,  Tom  Munn’s  Hill,  Uvalde  County,  Texas.  Analysis  by  Hillebrand.  Described  by 
Cross.  Contains  olivine,  augite,  nephelite,  magnetite,  and  apatite.  Symbol,  IV.22.1.2.  TJvaldose. 

G.  Nephelite  basalt,  Black  Mountain,  Uvalde  County,  Texas.  Analysis  by  Hillebrand.  Described  by 
Cross.  Contains  olivine,  augite,  nephelite,  magnetite,  and  apatite.  Symbol,  IV.22.1.2.  TJvaldose. 

H.  Nephelite-melilite  basalt,  near  Uvalde,  Texas.  Analysis  by  Hillebrand.  Described  by  Cross. 
Contains  nephelite,  melilite,  olivine,  augite,  apatite,  and  magnetite.  Symbol,  IV.23.1.2.  Casselose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

48.  35 

49.  90 

45. 11 

46.  04 

41.  43 

40.  32 

39.  92 

37.  96 

A1203 

19.  94 

19.  89 

12.44 

12.  23 

9.  80 

9.46 

8.  60 

10. 14 

Fe203 

2.  48 

2.  55 

2.  67 

3.  86 

3.  28 

4.  75 

4.  40 

3.  69 

FeO 

5.  25 

4.  78 

9.  36 

4.  60 

5. 15 

7.  48 

8.  00 

7.  59 

MgO 

5. 15 

5.  05 

11.  56 

10.  38 

13. 40 

18. 12 

10. 17 

14.  69 

CaO 

7.  98 

7.  21 

10.  61 

8.  97 

16.  62 

10.  55 

10.  68 

16.  28 

Na20 

5. 47 

5.  60 

3.  05 

2.42 

1.  64 

2.  62 

1.  91 

2. 18 

K20 

3.  99 

3.  74 

1.  01 

5.77 

4 7.40 

1. 10 

1.  03 

.69 

H20- 

.16 

.13 

.16 

1 9 07 

.57 

.43 

.39 

h2o+ 

.22 

.19 

.78 

> Zi.Oi 

iLii 

1.  25 

1.  45 

1.  82 

Ti02 

.12 

.93 

2.  34 

.64 

.29 

2.  66 

2.  70 

2.  93 

PA 

.84 

Trace. 

.51 

1. 14 

None. 

.68 

.51 

1. 13 

s.... 

.01 

.01 

Trace. 

.04 

so, 

Trace. 

Trace. 

.03 

Cl 

.11 

.11 

.05 

Trace . 

Trace. 

F 

Undet. 

.04 

.07 

.07 

YA- 

.04 

.04 

.95 

Cr203 

.14 

.08 

MnO 

Trace. 

Trace. 

.22 

Trace. 

.25 

.24 

.22 

NIO 

.04 

.06 

.06 

.04 

BaO 

Trace. 

.48 

.06 

.06 

.06 

SrO 

Trace. 

.25 

.03 

.04 

.05 

Li20 

None. 

Trace. 

Trace. 

Trace. 

99.  95 

99.  97 

100. 02 

99.  76 

100. 12 

100.  09 

100. 45 

100. 13 

460 


THE  DATA  OF  GEOCHEMISTEY. 


Analyses  of  basaltic  rocks — Continued. 

Norms. 


A 

B 

c 

D 

E 

F 

G 

H 

or 

23.4 

22.  4 

6. 1 

22.2 

3.3 

ab 

8.  9 

13.  6 

13. 1 

an 

18. 1 

18. 1 

17.  2 

5.3 

11.1 

12.0 

18.  6 

ne 

20.1 

18.2 

6.8 

11.1 

4.  8 

11.9 

8.5 

9.9 

kp 

25.0 

lc. 

9,6 

2.6 

4.9 

3.1 

ac 

4.2 

di 

13.  4 

14.  2 

26.  4 

26.  3 

29.  3 

24.  6 

13.  5 

ol 

10.1 

7.  6 

19.8 

12.3 

32.  3 

26.2 

32. 1 

26. 1 

am 

29.  8 

2.  4 

13.  8 

mt 

3.8 

3.  7 

3.  9 

5.  6 

2.  8 

7.  0 

6.  3 

5.3 

il. 

1.7 

4.  3 

1.  2 

.6 

5. 1 

5. 1 

4.4 

ap 

1.8 

1.1 

2.6 

1.6 

1.2 

2.6 

Jr 

The  appearance  of  normative  kaliophilite  in  analysis  E is  very 
striking.  The  absence  of  normative  leucite  from  the  “ leucite  kulaite  ” 
is  also  noticeable. 

DIABASE. 


Intermediate  in  texture  between  basalt  and  the  granitoid  gabbros 
are  the  diabases,  which,  like  basalt,  are  principally  composed  of  pla- 
gioclase,  augite,  magnetite,  and  sometimes  olivine.  Their  range  of 
composition  is  fairly  well  shown  in  the  next  table. 


IGNEOUS  ROCKS. 


461 


Analyses  of  diabase. 

A.  Turnpike  Creek,  Kittitas  County,  Washington.  Analysis  by  W.  F.  Hillebrand.  Reported  by  G.  O 
Smith  to  contain  plagioclase,  augite,  olivine,  magnetite,  and  apatite.  Magmatic  symbol,  II.4.3.4.  Tonalose. 

B.  Grass  Valley,  Nevada  County,  California.  Analysis  by  H.  N.  Stokes.  Described  by  W.  Lindgren. 
Contains  feldspar,  pyroxene,  hornblende,  ilmenite,  pyrrhotite,  pyrite,  and  chlorite,  with  probably  a little 
quartz.  Symbol,  II.4.4.3.  Bandose. 

C.  Shoshone  Canyon,  Yellowstone  National  Park.  Analysis  by  Hillebrand.  Contains,  according  to 
Arnold  Hague  and  T.  A.  Jaggar,  plagioclase,  augite,  and  chlorite.  Symbol,  II.5.3.4.  Andose. 

D.  Aroostook  Falls,  Maine.  Analysis  by  Hillebrand.  Description  by  H.  E.  Gregory.  Contains  pla- 
gioclase, pyroxene,  pyrite,  apatite,  chlorite,  and  a little  calcite.  Symbol,  II.5.3.5.  Beerbachose. 

E.  Diabase  porphyry,  near  Milton,  Sierra  County,  California.  Analysis  by  Hillebrand.  Described  by 
H.  W.  Turner.  Contains  plagioclase,  augite,  and  hornblende.  Symbol,  III.5.3.4.  Camptonose. 

F.  Mount  Ascutney,  Vermont.  Analysis  by  Hillebrand.  Described  by  R.  A.  Daly.  Contains  plagio- 
clase, augite,  and  magnetite.  Symbol,  III.5.4.3.  Auvergnose. 


A 

B 

C 

D 

E 

F 

Si02 

57.  21 

53. 19 

52. 18 

49.  64 

51.  27 

49.  63 

A1203 

12.  99 

17. 12 

18. 19 

15.  07 

12. 14 

14.  40 

Fe203 

3.  28 

4.  35 

3.  31 

1.  66 

2.  51 

2.  85 

FeO 

10. 18 

5. 16 

4.  36 

8.  82 

6.  71 

8.  06 

MgO 

1.  59 

3.  98 

4.  69 

5.  43 

10.  86 

7.  25 

CaO 

5.  97 

9.  39 

' 6.51 

7.  23 

10.  32 

9.28 

Na20 

3.  07 

2.  79 

4.  58 

4. 19 

2.  00 

2.  47 

K20 

1.  61 

.28 

1.  88 

.89 

1.  63 

.70 

H20- 

.68 

.17 

.75 

.45 

. 17 

.27 

h20+ 

1.03 

1.  21 

2.  00 

2.  81 

1. 16 

1.  47 

Ti02....: 

1.  72 

1.  34 

.99 

2.  32 

.60 

1.  68 

co2 

None. 

.32 

1.  36 

p2o5 

.44 

.13 

.29 

.29 

.21 

.25 

Cl 

Trace. 

. 07 

v2o3 

None. 

.04 

MnO 

.24 

Trace. 

.14 

.25 

.21 

.17 

NiO 

Trace. 

Trace. 

Trace. 

. 04 

. 04 

BaO 

.06 

Trace. 

.11 

.02 

.07 

Trace? 

SrO 

Trace. 

. 06 

.05 

Trace? 

Li20 

Trace. 

Trace. 

Trace. 

FeS2 

. 13 

. 94 

. 79 

. 22 

100.  20 

100.  05 

100.  04 

100.  27 

99.  92 

100. 17 

Norms. 


A 

B 

C 

D 

E 

F 

Q 

15.4 

10.  4 

1.5 

or 

9.  5 

1.  7 

11. 1 

5.0 

9.5 

4.4 

ab 

26.  2 

23.  6 

38.  8 

35.  6 

16.  8 

21.0 

an 

16.  7 

33.  4 

23.  4 

19.  7 

19.  5 

25.  9 

di 

8.  9 

10.  6 

7.  2 

13.  9 

25.  4 

16.  6 

hy 

12.5 

9.5 

3.  8 

6.  0 

16.  5 

19.  8 

ol 

5.8 

9.  0 

5.  7 

mt 

4.  9 

6.  3 

4.  9 

2.3 

3.  5 

4.  2 

il 

3.2 

2.  5 

1.8 

_ 4.3 

1.2 

3.2 

pr 

. 9 

ap 

1.  0 

462 


THE  DATA  OF  GEOCHEMISTRY. 


THE  GABBROS. 

The  gabbros,  which  are  the  granitoid  equivalents  of  the  basalts 
and  diabases,  consist  mainly  of  plagioclase  and  pyroxene,  with  vari- 
ous admixtures  of  other  minerals.  At  one  end  of  the  series  we  have 
anorthosite,  or  labradorite  rock,  which  is  almost  entirely  composed 
of  feldspar;  at  the  other  end  the  plagioclase  diminishes  in  amount, 
and  the  rocks  approach  the  pyroxenites.  Normal  gabbro  contains 
monoclinic  pyroxene;  in  norite,  rhombic  pyroxene,  usually  hyper- 
sthene,  appears.  The  gabbro  family  is  a large  one,  with  many  varie- 
ties of  rock,  and  only  a few  examples  of  it  are  covered  by  the  subjoined 
table. 

Analyses  of  gabbros. 

A.  Anorthosite,  Monhegan  Island,  Maine.  Analyzed  and  described  by  E.  C.  E.  Lord,  Am.  Geologist, 
vol.  26, 1900,  p.  340.  Nearly  pure  plagioclase.  Magmatic  symbol,  1.5.5.  Canadase. 

B.  Gabbro,  near  Emigrant  Gap,  Placer  County,  California.  Analysis  by  W.  F.  Hillebrand.  Described 
by  W.  Lindgren.  Contains  biotite,  hypersthene,  diallage,  plagioclase,  and  orthoclase.  Symbol,  II.5.3.4. 
Andose. 

C.  Gabbro,  Emigrant  Gap,  California.  Analysis  by  Hillebrand.  Described  by  Lindgren.  Contains 
hypersthene,  diallage,  plagioclase,  and  orthoclase.  Symbol,  III.4.3.4.  Vaalose. 

D.  Norite,  Elizabethtown,  Essex  County,  New  York.  Analysis  by  Hillebrand.  Described  by  J.  F. 
Kemp.  Contains  labradorite,  hypersthene,  garnets,  augite,  hornblende,  biotite,  magnetite,  and  apatite. 
Symbol,  III.5.3.4.  Camptonose. 

E.  Bronzite  norite,  Crystal  Falls,  Michigan.  Analysis  by  G.  Steiger.  Described  by  J.  M.  Clements 
and  H.  L.  Smyth.  Contains  bronzite,  hornblende,  and  labradorite.  Symbol,  HI.5.4.3.  Auvergnose. 

F.  Olivine  gabbro,  Birch  Lake,  Minnesota.  Analysis  by  H.  N.  Stokes.  Contains  a large  proportion 
of  diallage  and  olivine.  Symbol,  III.5.4.3.  Auvergnose. 

G.  Hypersthene  gabbro,  Wetheredville,  Maryland.  Analysis  by  Hillebrand.  Described  by  G.  H. 
Williams.  Contains  hypersthene,  diallage,  plagioclase,  magnetite,  and  apatite.  Symbol,  HI.5.5.  Keda. 
bekase. 

H.  Hypersthene  gabbro,  Gunflint  Lake,  Minnestota.  Analysis  by  St  okes.  Described  by  W.  S.  Bayley 
Contains  hypersthene,  biotite,  diallage,  magnetite,  and  plagioclase.  Symbol,  IV.1.1.2.  Cookose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

45.  78 

55. 40 

55.  87 

47. 16 

48.  23 

45.  66 

44.  76 

46.  96 

A1203 

30.  39 

15. 32 

13.  52 

14.  45 

18.  26 

16.44 

18.  82 

14. 13 

Fe203 

1.33 

2.  70 

2.  70 

1.  61 

1.  26 

.66 

2. 19 

.76 

FeO 

| 1.22 

5.  49 

5.  89 

13.  81 

6. 10 

13.  90 

4.  73 

14.  95 

MgO 

1 2.14 

5.  75 

6.  51 

5.  24 

10.  84 

11.57 

11.  32 

15.  97 

CaO 

16.66 

9.  90 

8.  87 

8. 13 

9.  39 

7.  23 

14.  58 

2.  32 

Na20 

1.66 

2.  89 

2. 42 

3.  09 

1.  34 

2. 13 

.89 

.35 

K20 

.10 

1.  52 

1.  72 

1.  20 

.73 

.41 

.11 

1.  68 

h2o- 

1 51 

.03 

.09 

.12 

.26 

.07 

.17 

.07 

h2o+ 

/ *51 

.38 

1.  56 

.48 

2.  00 

.83 

2.  36 

1.  26 

Ti02 

.60 

.56 

3.  37 

1.  00 

.92 

.13 

.62 

co2 

.35 

.43 

P9CL 

.22 

.25 

.57 

.07 

.05 

None. 

.03 

s 

. 14 

VoO, 

(?) 

*2X3 

CToO-5 

Trace. 

.08 

TVace. 

VA2v/3  

MnO 

.11 

. 10 

.24 

Trace. 

.15 

.93 

NiO 

.02 

. 16 

.06 

BaO 

.07 

.02 

Trace. 

SrO 

None. 

None. 

LiaO 

Trace. 

Trace. 

Trace. 

99.  79 

100.  38 

100.  08 

99.  98 

99.  91 

100. 03 

100.  29 

100. 09 

IGNEOUS  ROCKS. 


463 


Analyses  of  gabbros — Continued. 
Norms. 


A 

B 

C 

D 

E 

F 

G 

H 

0 

5. 1 

8.0 

or 

0.  6 

8.  9 

10.0 

7.2 

3.  9 

2.2 

0.  6 

10.0 

ab 

12. 1 

24.  6 

20.4 

26.2 

11.0 

17.  8 

7.3 

3.1 

an 

75. 1 

.24.2 

20.9 

22.0 

42.0 

34.2 

47.0 

11.4 

ne 

1.1 

C 

7.5 

di 

6.1 

20.  5 

19.  0 

12.  5 

3.  9 

1.4 

20. 1 

hy 

11.4 

14.6 

8. 1 

29.9 

10. 1 

3. 1 

57.5 

ol 

2.5 

12.8 

2.9 

30.3 

16.0 

6.0 

mt. 

1.9 

3.  9 

3.9 

2.3 

1.9 

.9 

3.2 

1.2 

il 

LI 

1.1 

6.4 

1.8 

2.6 

1.1 

an 

1.3 

wr 

These  figures,  with  a range  from  persalane  to  dofemane,  from 
1.5.5  to  IV.  1.1. 2,  are  enough  to  show  the  vagueness  of  the  terms 
gabbro  and  norite.  Although  it  is  difficult  to  see  why  B and  C 
should  be  separated,  being  placed  in  different  classes,  orders,  and 
rangs,  the  quantitative  system  brings  out  the  general  diversity  of 
character  better  than  the  ordinary  mineralogical  classification.  It 
separates  things  which,  with  the  exception  above  noted,  are  essen- 
tially distinct. 

FEMIC  ROCKS. 

From  the  feldspathic  gabbros  rocks  pass  by  insensible  gradations 
into  varieties  which  are  wholly  femic,  or  nearly  so,  the  pyroxenites, 
hornblendites,  and  peridotites.  These  rocks  may  contain  pyroxene 
alone,  hornblende  alone,  or  olivine  alone,  or  may  be  mixtures  of  such 
minerals.  Small  quantities  of  plagioclase  may  remain  as  minor 
impurities;  but  they  count  for  little  in  classification.  Dunite  is 
nearly  pure  olivine;  saxonite  contains  enstatite  and  olivine;  picrite 
is  a mixture  of  augite  and  olivine.  In  cortlandtite  we  have  horn- 
blende and  olivine;  in  wehrlite,  diallage  and  olivine;  in  Iherzolite, 
diopside,  a rhombic  pyroxene,  and  olivine.  Websterite  contains 
bronzite  and  diopside,  and  so  forms  the  pyroxenite  end  of  the  series. 
The  nomenclature  is  varied,  and  the  terms  are  not  rigorously  used. 
Hornblendite  is  a femic  rock  in  which  hornblende  is  the  prevailing 
mineral.1  The  following  table  deals  with  the  rocks  in  which  pyrox- 
enes predominate : 

i Two  analyses  of  hornblendites  are  given  in  Washington’s  tables,  Prof.  Paper  U.  S.  Geol.  Survey  No. 
14, 1903,  pp.  345,  359. 


464 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  pyroxenites. 

A.  Cortlandtite,  Belcher  town,  Massachusetts.  Analysis  by  L.  G.  Eakins.  Described  by  B.  K.  Emer- 
son. Contains  hornblende,  pyroxene,  biotite,  olivine,  and  magnetite.  Magmatic  symbol,  IV.P.l.l. 
Belcherose. 

B.  Wehrlite,  near  Bed  Bluff,  Montana.  Analysis  by  Eakins.  Described  by  G.  P.  Merrill.  Contains 
olivine,  diallage,  brown  mica,  rarely  plagioclase,  and  secondary  iron  oxides.  Symbol,  IV.13.1.2.  Wehrlose. 

C.  Hornblende  picrite,  North  Meadow  Creek,  Montana.  Analysis  by  Eakins.  Described  by  Merrill. 
Contains  hornblende,  olivine,  pleonaste,  iron  oxides,  and  occasionally  hypersthene.  Symbol,  IV.13.1.2. 
Wehrlose. 

D.  Pyroxenite,  Baltimore  County,  Maryland.  Analysis  by.J.  E.  Whitfield.  Described  by  G.  H. 
Williams.  Contains  hypersthene  and  diallage.  Symbol,  V.D.1.1.  Maricose. 

E.  Websterite,  Webster,  North  Carolina.  Analysis  by  E.  A.  Schneider.  Described  by  Williams. 
Consists  of  diopside  and  bronzite.  Symbol,  V. 11.2.1.  Websterose. 

F.  Websterite,  Oakwood,  Maryland.  Analysis  by  W.  F.  Hillebrand.  Described  by  A.  G.  Leonard. 
Contains  hypersthene  and  diallage.  Symbol,  V. 11.1.2.  Cecilose. 

G.  Lherzolite,  Baltimore  County,  Maryland.  Analysis  by  T.  M.  Chatard.  Described  by  Williams. 
Contains  olivine,  bronzite,  and  diallage;  the  olivine  partly  serpentinized.  Symbol,  V.l*.l.l.  Baltimoriase. 

H.  Pyroxenite,  Baltimore  County,  Maryland.  Analysis  by  Whitfield.  Described  by  Williams.  Con- 
tains hypersthene  and  diallage.  Symbol,  V.l2. 1.2.  Baltimorose. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

48.  63 

48.  95 

46. 13 

51.  94 

55. 14 

53.  21 

43. 87 

50.  80 

ALOo 

5.  32 

5.  69 

4.  69 

2.  53 

.66 

1.  94 

1.  64 

3.  40 

Fe9Oo 

2.  91 

1.  20 

.73 

2.  88 

3. 48 

1.  44 

8.  94 

1.  39 

FeO." 

3.  90 

12. 11 

16.  87 

9.  38 

4.  73 

7.  92 

2.  60 

8. 11 

MgO 

21.  79 

23.  49 

25. 17 

25.  97 

26.  66 

20.  78 

27.  32 

22.  77 

CaO 

13.  04 

5.  33 

4. 41 

3.  60 

8.  39 

13. 12 

6.  29 

12.  31 

]-Trace. 

J 

Na20 

.'34 

1.  58 

.08 

None. 

.30 

.11 

| .50 

K20.  

.23 

} 2.81 

.79 

} .18 

Trace. 
} 1.38 

None. 
| 2.82 

.07 

HoO- 

} .38 

. 14 

J 1.08 

| .52 

h2o+ 

.87 

7.  64 

Ti02 

.47 

.81 

.73 

None. 

Trace. 

.26 

.12 

None. 

P20s. 

.21 

.12 

.07 

None. 

.23 

Trace. 

Trace. 

Trace. 

C02 

Trace. 

.10 

s 

.24 

so, 

.19 

Trace. 

Cl 

. 16 

.24 

v2o, 

.03 

Cr20, 

.36 

.05 

.04 

. 60 

.25 

.20 

.44 

.32 

MnO 

.12 

.08 

Trace. 

Trace. 

.03 

.22 

. 19 

.17 

(Ni,Co)0 

.16 

.09 

.11 

.03 

Trace: 

FeS2 

.03 

100. 13 

100.  54 

100.  63 

100.  07 

100.  36 

100.  47 

100.  63 

100.  03 

Norms. 

A 

B 

C 

D 

E 

F 

G 

H 

Q 

0.6 

1.7 

or 

1.  1 

5.0 

0.  6 

ab 

2.  6 

13.6 

.5 

2.6 

1.0 

4.2 

an 

12.  5 

5.6 

12.  5 

6.  7 

3.2 

2.2 

9.2 

di 

41.  7 

16.  5 

7.  6 

8.  9 

32.7 

48.  9 

22.  6 

41.4 

hy 

21.  9 

18.  5 

44.8 

76.4 

57.1 

41.4 

34.  3 

33.8 

of. 

11.7 

37.6 

30.4 

16.  3 

12.2 

mt 

5.1 

1.6 

.9 

2.8 

5.1 

2.1 

8.4 

2.1 

hm 

3.0 

il 

1.5 

1.2 

.5 

IGNEOUS  ROCKS, 


465 


The  general  presence  of  chromium  and  nickel  in  these  rocks  is 
noteworthy.  The  wehrlite  (analysis  B)  is  almost  on  the  line  between 
pyroxenites  and  peridotites.  The  formation  of  actual  diallage  from 
the  normative  diopside  in  it  would  give  the  pyroxenes  a slight  pre- 
dominance over  the  olivine.  The  following  analyses  represent 
peridotites : 

Analyses  of  'peridotites. 

A.  Cortlandtite,  Ilchester,  Maryland.  Analysis  by  W.  F.  Hillebrand.  Described  by  G.  H.  Williams. 
Contains  olivine,  pyroxene,  and  hornblende  partly  altered  to  talc.  Magmatic  symbol,  IV. I4. 1.1.  Cort- 
landtose. 

B.  Peridotite,  near  Silver  Cliff,  Colorado.  Analysis  by  L.  G.  Eakins.  Described  by  W.  Cross.  Contains 
hornblende,  biotite,  hypersthene,  olivine,  a little  plagioclase,  apatite,  pyrrhotite,  and  sillimanite.  Symbol, 
IV.  I4. 1.2.  Custer  ose. 

C.  Peridotite,  near  Opin  Lake,  Michigan.  Analysis  by  Hillebrand.  Described  by  C.  It.  Van  Hise 
and  W.  S.  Bayley.  Contains  diallage,  olivine,  magnetite,  and  plagioclase.  Symbol,  IV. 23. 1.2. 

D.  Mica  peridotite,  Crittenden  County , Kentucky.  Analysis  by  Hillebrand.  Described  by  J.  S.  Differ. 
Contains  biotite,  serpentine,  and  perofskite,  with  less  apatite,  muscovite,  magnetite,  calcite,  chlorite,  and 
other  secondary  products.  Symbol,  IV.24.1.2.  Subrang  of  Casseliase. 

E.  Saxonite,  Douglas  County,  Oregon.  Analysis  by  F.  W.  Clarke.  Described  by  J.  S.  Differ  and  F.  W. 
Clarke.  Contains  olivine  and  enstatite,  with  a little  magnetite  and  chromite.  Symbol,  V.l4.l.l. 

F.  Dunite,  Corundum  Hill,  North  Carolina.  Analysis  and  description  by  T.  M.  Chatard.  Contains 
olivine,  with  a little  chromite.  Symbol,  V.1M.1.  Dunose. 

G.  Peridotite,  Tulameen  River,  British  Columbia.  Analysis  by  Hillebrand.  Described  by  J.  F.  Kemp. 
Contains  olivine  and  serpentine,  with  magnetite,  magnesite,  and  calcite.  Symbol,  V.D.l.l.  Dunose. 


A 

B 

C 

D 

E 

F 

G 

Si02 

39.  20 

46.  03 

39.  37 

33.  84 

41. 43 

40. 11 

38.  40 

A1203 

4.  60 

9.27 

4.  47 

5.  88 

.04 

.88 

.29 

Fe203 

3.  45 

2.  72 

4.  96 

7.04 

2.  52 

1.  20 

3.42 

FeO 

6. 15 

9.  94 

9. 13 

5. 16 

6.  25 

6.09 

6.  69 

MgO 

31.  65 

25.  04 

26.  53 

22.  96 

43.  74 

48.  58 

45.  23 

CaO 

3.23 

3.  53 

3.  70 

9.46 

.55 

.35 

Na20 

.42 

1.48 

.50 

.33 

K20 

.14 

.87 

.26 

2.  04 

} .08 

h2o  - 

. 50 

1 

.87 

.24 

h2o+ 

9.  38 

> . 64 

7.  08 

| 7. 50 

4. 41 

2.74 

4. 11 

Ti02 

.52 

. 66 

3.  78 

None. 

002 

1.  23 

.43 

1. 10 

P.,0, 

Trace. 

. 17 

.17 

.89 

Trace. 

s!.. 

.06 

Cl 

.05 

Cr203 

.41 

. 68 

. 18 

. 76 

.18 

.07 

MnO 

.20 

.40 

. 12 

. 16 

None. 

.24 

NiO 

.30 

.21 

. 10 

. 10 

.10 

BaO 

Trace. 

.06 

None. 

Chromite 

.56 

100. 15 

100.  09 

99.  94 

99.  86 

99.  80 

100.  34 

100.  38 

97270°— Bull.  616—16 30 


466 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  peridotites — Continued. 

Norms. 


In  the  peridotites  a certain  amount  of  serpentinization  is  almost 
always  observed.  This  is  shown  in  the  analyses  by  the  unusually 
large  percentages  of  water.  The  latter  is  neglected  in  calculating  the 
norms,  and  so  normative  hypersthene  appears,  which  an  absolutely 
unaltered  rock  would  not  show.  That  is,  serpentine,  instead  of  rep- 
resenting the  parent  olivine,  is  equivalent  to  hypersthene  plus  olivine, 
and  the  norms  become  misleading.  A rock  consisting  originally  of 
pure  olivine  might  find  its  place  in  any  one  of  several  different  rangs 
or  subrangs,  according  to  the  amount  of  alteration  which  it  has 
undergone.  Two  samples  from  the  same  rock  mass  might  vary  in 
this  manner.  Theoretically,  no  doubt,  the  quantitative  classification 
applies  only  to  fresh  material;  practically  it  is  applied  to  altered 
peridotites,  like  those  cited  above,  which  all  appear  in  Washington’s 
tables.  A very  remarkable  peridotite  from  East  Union,  Maine, 
described  by  E.  S.  Bastin,1  contains  22.5  per  cent  of  sulphides, 
mainly  pyrrhotite.  Magmatic  name,  lermondose. 

BASIC  ROCKS. 

A few  igneous  rocks  exist  which  seem  to  form  an  exceptional  group 
by  themselves.  They  consist  largely,  or  even  mainly,  of  free  basic 
oxides,  such  as  corundum  or  magnetite;  and  many  transitional  mix- 
tures lie  between  them  and  the  ordinary  silicate  rocks.  With  these 
oxides  it  is  convenient  to  group  certain  titaniferous  rocks,  which 
otherwise  might  form  a class  by  themselves.  The  following  analyses 
represent  a few  rocks  of  this  truly  basic  character,  with  examples  of 
the  transitional  forms. 


1 Jour.  Geology,  vol.  16, 1908,  p.  124. 


IGNEOUS  BOCKS, 


467 


Analyses  of  basic  and  titaniferous  rocks. 

A.  Corundum  pegmatite,  Ural  Mountains,  Siberia.  Described  and  analyzed  by  J.  Morozewicz,  Min. 
pet.  Mitt.,  vol.  18,  1898,  p.  219.  Contains  corundum  and  ortboclase,  with  accessory  rutile,  apatite,  and 
zircon.  Magmatic  symbol,  P.5.1.3.  Uralose. 

B.  Kyschtymite,  Borsowka,  Ural  Mountains.  Described  and  analyzed  by  Morozewicz,  op.  cit.,  p.  212. 
Contains  corundum,  with  a little  spinel,  anorthite,  biotite,  and  zircon.  Symbol,  I1. 5.5.  Kyschtymase. 

C.  Umenite  norite,  Soggendal,  Norway.  Described  and  analyzed  by  C.  F.  Kolderup,  Bergens  Museums 
Aarbog,  1896,  p.  165.  Contains,  in  approximate  percentages,  ilmenite,  37.5;  hypersthene,  40.1;  anorthite, 
11;  albite,  8.7;  orthoclase,  0.9.  Symbol,  IV.31.1.3.  Bergenose. 

D.  Titaniferous  iron  ore,  Lincoln  Pond,  Essex  County,  New  York.  Analysis  by  W.  F.  Hillebrand. 
Described  by  J.  F.  Kemp.  Symbol,  IV.  42.1.4.  Adirondackiase. 

E.  Titaniferous  iron  ore,  Elizabethtown,  New  York.  Analysis  by  Hillebrand.  Described  by  Kemp. 
Symbol,  IV.4U.4.  Champlainiase. 

F.  Magnetite  spinellite,  Routivaara,  Finland.  Analyzed  and  described  by  W.  Petersson,  Geol.  Foren. 
Forhandl.,  vol.  15,  p.  49, 1893.  Symbol,  Y.5J.1.4.  No  magmatic  name  assigned. 


A 

B 

C 

D 

E 

F 

SiO 

40.  06 

16.  80 

31.  59 

11.73 

13.  35 

4.  08 

A1203 

13.  65 

13.  89 

8.  54 

6.46 

8.  75 

6.  40 

Fe203 

.35 

. 76 

24.  52 

30.  68 

20.  35 

33.  43 

FeO 

2.  36 

27.  92 

28.  82 

34.  58 

MgO 

. 15 

. 61 

10.  70 

3.  35 

6.  63 

3.  89 

CaO 

. 30 

7.  26 

2.  25 

3.  95 

2. 15 

. 65 

Na20 

3.  71 

. 38 

1.  03 

. 50 

. 29 

K20 

5.  20 

. 13 

. 15 

. 26 

. 15 

H20 

.46 

. 76  , 

. 64 

1.  68 

1.  32 

Ti02 

18.  49 

12.  31 

16.  45 

14.  25 

co2 

. 32 

. 17 

.02 

. 82 

.02 

.02 

s.  

. 04 

.09 

Cl 

. 12 

Trace. 

y„o3 

.04 

. 61 

Cr203 

.55 

. 20 

MnO 

.45 

Organic  matter 

.05 

Trace. 

Corundum 

35.  40 

« 59.  51 

99.  28 

100.  10 

99.  65 

99. 19 

99.  62 

99.  71 

a Including  a little  spinel. 

Norms. 


468 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  basic  and  titaniferous  rocks — Continued. 

G.  Magnetite  basalt,  arapahite,  North  Park,  Colorado.  Described  by  H.  S.  Washington  and  E.  S.  Lar- 
sen, Jour.  Washington  Acad.  Sci.,  vol.  3, 1913,  p.  449.  Contains  magnetite,  bytownite,  pyroxene,  and  a 
little  apatite.  Magmatic  symbol  IV.4(5).1.1.  Arapahose. 

H.  Cumberlandite,  Cumberland,  Rhode  Island.  Described  by  B.  L.  Johnson  and  C.  H.  Warren,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  25, 1906,  p.  1.  Contains  magnetite,  ilmenite,  plagioclase,  olivine,  and  minor  acces- 
sories. Magmatic  symbol  V. 3. 1.2.  Rhodose. 

I.  Gabbro-nelsonite,  Nelson  County,  Virginia.  Contains  ilmenite,  apatite,  hypersthene,  plagioclase, 
some  orthoclase,  with  grains  of  quartz  and  pyrite.  Magmatic  symbol  IV.3. 1.2.3.  Roselandose. 

J.  Ilmenite-nelsonite,  Nelson  County,  Virginia.  Contains  ilmenite,  apatite,  minor  hornblende,  biotite, 
leucoxene,  etc.  Magmatic  symbol  V.5.5.3.5.  Nelsonose. 

K.  Rutile-nelsonite,  Nelson  County,  Virginia.  Contains  rutile  and  apatite,  with  accessory  feldspar, 
ilmenite,  and  quartz.  Magmatic  symbol  V.5.5.4.5.  Virginose.  Analyses  I,  J,  K,  by  W.  M.  Thornton,  jr. 
Rocks  described,  with  others  of  similar  character,  by  T.  L.  Watson  in  Geol.  Survey  Virginia,  Bull.  Ill,  A, 
1913. 

L.  Perofskite-apatite-magnetite  rock,  Uncompahgre  quadrangle,  Colorado.  Collected  by  E.  S.  Larsen, 
analyzed  by  G.  Steiger.  Not  yet  fully  described.  Magmatic  symbol  Vn.53.3.3. 


Si02.. 

A1203. 


FeO. 

MgO, 

CaO. 


H20+. 
Ti02. . 
Zr02. . 
C02. . . 


S 

F 

Cl 

v2o3.... 

Cr203. .. 
MnO. . . 
NiO...., 
(Ni,  Co). 
BaO  — 
SrO.... 

Zn 

Cu 

Pb 


19.  74 
9.  72 
39.  70 
15.  60 
3.  70 
6.  64 
.46 
' .66 
.32 
.04 
.58 


None. 
1.  67 


.44 

None. 

.38 

None. 


99.  65 


22.  35 
5.  26 
14.  05 
28.  84 
16. 10 
1. 17 
.44 
.10 
.42 


10. 11 


.02 

.02 

.38 


.18 

Trace. 

.43 


.08 


.71 

.08 

Trace. 


100.  74 
.19 


100.  55 


33.  83 
5. 19 
11.  38 
15.  08 
8.  57 
8.  22 
1.  28 
.50 
.45 
.75 
10.00 


Trace. 
4.  84 
.25 
.55 
.04 


.26 


101. 19 
.30 


100.  89 


0.70 


11. 12 
27.  93 
.72 
8.  34 


.15 
.58 
42.  84 


Trace. 
6.  89 


21 

01 


.18 


99.  67 
.08 


99.  59 


0.  67 


2.  87 
5.04 
.15 
12. 16 


.09 
.11 
69.  67 


9.  41 
.34 
. 70 
Trace. 


101.  21 
.39 


100.  82 


8.  43 
.74 
19. 16 
13.  68 
5.  06 
19.  98 
.35 
.59 
.35 
.65 
24.  74 
.01 
None. 
5.  58 
.04 
.19 
None. 
.20 
None. 
.26 
.05 


.05 

.12 


100.  23 
.08 


100. 15 


Less  O. 


IGNEOUS  ROCKS. 


469 


Analyses  of  basic  and  titaniferous  rocks — Continued. 
Norms. 


1 G 

1 

H 

I 

J 

K 

L 

Q 

7.  38 

0.  42 

or 

3.  89 

0.  56 

2.  78 

3.  34 

ab 

3.  67 

3.  67 

11.  00 

.52 

an 

22.  24 

5.  56 

6.  95 

ns 

.61 

C. . 

.10 

di. . 

1.  51 

hy 

7.  70 

22.  55 

1. 10 

.40 

7.  20 

ol 

1. 12 

45.  70 

3.  85 

mt 

49.  88 

20.  65 

16.  47 

27.  84 

hm . . . 

5.  28 

11.  04 

2.  88 

il 

1.  06 

19.  00 

19. 15 

58.  98 

9.  73 

11.  25 

ru 

11.  76 

64.  56 

. 72 

4.  03 

11.  42 

16. 13 

22. 18 

13. 10 

p?.;;.:::: 

30.  74 

pr . . . 

.42 

.62 

Spinel 

3.  55 

Sulphides 

1. 15 

The  foregoing  table  might  be  much  extended,  but  it  is  not  neces- 
sary to  do  so.  Other  similar  rocks  are  a magnetite  syenite  porphyry 
Qcirunose),  described  by  P.  Geijer,1  which  contains  predominating 
albite  with  38.7  per  cent  of  magnetite  and  minor  accessories.  Kra- 
gerite,  from  Krageroe,  Norway,  described  by  T.  L.  Watson,2  con- 
sists largely  of  plagioclase  feldspars  with  25  per  cent  of  rutile.  The 
Canadian  urbainite  3 is  essentially  a mixture  of  ilmenite,  hematite, 
and  rutile,  with  only  a few  per  cent  of  other  minerals.  The  New 
York  (Adirondack)  ores,4  of  which  analyses  are  given  above,  are 
found  in  close  association  with  norites  or  gabbros.  Rocks  of  this 
class  could  hardly  be  associated  with  persilicic  masses,  such  as  gran- 
ites or  syenites.  They  represent  a marked  deficiency  of  silica  in  the 
magmas  from  which  they  came. 

LIMITING  CONDITIONS. 

Although  the  igneous  rocks,  as  the  analyses  and  descriptions  show, 
represent  a great  variety  of  mineral  mixtures,  their  proximate  con- 
stitution is  subject  to  distinct  limitations.  In  the  preceding  chapter 
upon  rock-forming  minerals  some  of  these  limitations  were  indicated, 
and  it  was  shown  that  certain  species  can  appear  only  under  certain 


1 Geol.  Kiruna  district,  Stockholm,  1910,  p.  60. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  34, 1912,  p.  509. 

8 See  C.  H.  Warren,  Am.  Jour.  Sci.,  4th  ser.,  vol.  33, 1912,  p.  263. 

* Recent  memoirs  on  the  Adirondack  ores  are  by  J.  F.  Kemp,  Nineteenth  Aim.  Rept.  U.  S.  Geol.  Sur- 
vey, pt.  3, 1899,  p.  383;  and  Bulls.  New  York  State  Museum  No.  119, 1908;  No.  138, 1910.  Also  D.  H.  New- 
land,  Econ.  Geology,  vol.  2,  p.  763.  An  important  paper  on  the  Scandinavian  ores,  by  H.  Sjogren,  is  in 
Trans.  Am.  Inst.  Min.  Eng.,  vol.  37,  1907,  p.  809.  On  the  titaniferous  iron  ores  of  the  United  States,  see 
J.  T.  Singerwald,  Bull.  U.  S.  Bureau  of  Mines  No.  64, 1913. 


470 


THE  DATA  OF  GEOCHEMISTRY. 


definite  conditions.  The  experiments  of  Morozewicz  upon  the  sepa- 
ration of  corundum,  iolite,  etc.,  from  magmas  are  cases  in  point. 
It  may  be  well,  however,  to  reiterate  some  of  the  observations  which 
have  already  been  made  or  suggested  in  order  to-  properly  emphasize 
these  important  considerations.  For  this  purpose  we  need  only  take 
into  account  the  more  conspicuous  magmatic  minerals,  and  neglect 
the  rarer  species. 

Since  nearly  all  igneous  rocks  are  formed  chiefly  of  silicates,  a 
partial  table  of  rock-forming  minerals,  arranged  by  bases  with  refer- 
ence to  maximum  and  minimum  silica,  will  be  convenient.  The 
minerals  to  be  thus  considered  are  the  following: 


Rock-forming  minerals. 


Base. 

Maximum  silica. 

Minimum  silica. 

Potassium 

Sodium 

Calcium 

Magnesium 

Ferrous  iron 

Ferric  iron 

Aluminum 

Orthoclase,  KAlSi308 

Albite,  NaAlSi308 

Diopside,  CaMgSi206 

Enstatite,  MgSi03 

Pyroxene,  FeSi03 

Acmite,  FeNaSi906 

Albite,  NaAlSi308 

Leucite,  KAlSi206. 
Nephelite,  NaAlSi04. 
Anorthite,  CaAl2Si208.a. 
Forsterite,  Mg2Si04\ni-  . ^ 
Fayalite,  Fe|i04  |0Uvlne- 
Magnetite,  Fe304. 
Corundum,  A1203. 

a Melilite,  a basic  silicate,  is  here  left  purposely  out  of  account,  and  so,  too,  is  &kermanite. 


Intermediate  minerals,  such  as  analcite,  biotite,  muscovite,  etc., 
that  contain  water  can  form  only  under  pressures  or  conditions  of 
viscosity  which  prevent  the  water  from  expulsion. 

The  two  oxides  in  the  foregoing  list  can  only  appear  in  notable 
amounts  when  the  iron  or  alumina  is  largely  in  excess  of  the  silica. 
The  latter  will  go  to  the  formation  of  silicates  until  it  is  saturated, 
and  after  that  any  superfluous  oxide  can  be  deposited.  This  state- 
ment, however,  demands  qualification.  Free  silica  and  magnetite 
can  coexist  in  igneous  rocks  to  a very  limited  extent,  but  not  as  prin- 
cipal constituents.  The  conditions  of  their  coexistence  are  uncertain, 
but  are  possibly  due  to  dissociation  in  the  molten  magma.  It  is  con- 
ceivable that  the  latter  may  solidify  under  circumstances  of  viscosity 
which  prevent  some  of  the  separated  ions  from  uniting,  so  that  a little 
quartz  and  a little  magnetite  may  be  present,  side  by  side,  in  the  same 
rock.  This  explanation,  however,  is  merely  speculative  and  requires 
proof.  The  exception  does  not  invalidate  the  broad  general  state- 
ment that  the  two  species  are  essentially  incompatible.  Much  mag- 
netite and  much  quartz  do  not  occur  together  in  rocks  of  igneous 
origin. 

Similar  incompatibilities  are  shown  elsewhere  in  the  table.  Leucite 
and  silica  will  form  orthoclase;  nephelite  and  silica  yield  albite;  a 
member  of  the  olivine  family  with  silica  will  be  converted  into 


IGNEOUS  ROCKS. 


471 


pyroxene,  and  so  on.  With  an  excess  of  silica  over  that  required  to 
generate  compounds  which  appear  in  the  minimum  column  higher 
silicates  will  he  produced,  and  as  silica  is  abundant  in  the  lithosphere 
the  maximum  is  most  often  reached.  Feldspars  and  pyroxenes  are 
much  more  common  than  lenad  minerals  or  olivine.  The  occasional 
concurrence  of  quartz  and  olivine  in  some  basalts  and  gabbros  may 
perhaps  be  due  to  the  same  dissociation  as  that  suggested  by  the 
coexistence  of  quartz  and  magnetite.  The  general  tendency  in  a cool- 
ing magma  is  toward  the  generation  of  saturated  compounds.  When 
silica  exceeds  the  amount  which  can  be  taken  up  by  the  bases  the 
excess  appears  as  quartz,  tridymite,  or  opal,  or  else  it  becomes  an 
undifferentiated  portion  of  a residual  glass. 

With  adequate  silica,  then,  the  number  of  compounds  which  a 
magma  can  yield  is  small.  The  persilicic  rocks,  therefore,  are  rela- 
tively simple  in  their  mineralogical  constitution,  and  in  the  quanti- 
tative classification  their  modes  do  not  differ  very  greatly  from  their 
norms,  except  with  respect  to  the  micas,  hornblendes,  and  augite. 
But  as  silica  diminishes  in  amount  the  mineralogical  complexity  of 
a rock  is  likely  to  increase,  for  the  reason  that  a larger  range  of 
unions  has  become  possible.  For  each  base  a number  of  compounds 
are  capable  of  formation,  and  the  same  magma,  solidifying  under 
different  conditions,  may  yield  very  dissimilar  products.  In  other 
words,  we  encounter  the  well-known  fact  that  two  rocks  may  have 
the  same  ultimate  composition  and  yet  contain  different  mineral 
species.  The  difficulty  of  apportioning  the  several  bases  to  the  sev- 
eral minerals  in  a rock  is  familiar  to  everyone  who  has  tried  to 
discuss  any  large  number  of  rock  analyses.  Potassium  may  form 
orthoclase,  leucite,  muscovite,  or  biotite;  sodium  may  yield  albite, 
nephelite,  analcite,  alkali  hornblende,  or  acmite;  calcium  appears  in 
pyroxene,  amphibole,  anorthite,  or  melilite;  magnesium  in  pyroxene, 
amphibole,  olivine,  or  biotite;  iron  in  pyroxene,  amphibole,  olivine, 
acmite,  magnetite,  or  ilmenite;  and  aluminum  in  feldspars,  lenads, 
micas,  amphibole,  pyroxenes,  or  corundum.  The  conditions  of  equi- 
librium have  become  exceedingly  complicated,  and  it  is  only  as  we 
approach  the  subsilicic  magmas  that  simplicity  is  again  restored. 
With  deficient  silica  the  number  of  possibilities  is  lessened  and  such 
simple  rocks  as  the  peridotites  and  pyroxenites  are  formed.  An 
intermediate  magma  may  be  simple  from  lack  of  certain  constitu- 
ents, but  cases  of  that  kind  are  exceptional.  The  mediosilicic  rocks 
are  as  a rule  more  complex  mineralogically  than  the  persilicic  or 
subsilicic  extremes.  The  ends  of  the  petrographic  series,  free  silica, 
or  free  basic  oxides,  are  necessarily  the  simplest  rocks  of  all.  At 
one  end  we  have  segregations  of  quartz;  at  the  other,  corundum 
rocks  or  magnetite.  Bocks  midway  between  these  extremes,  with 
silica  ranging  from  45  to  55  per  cent,  contain  the  greatest  variety  of 


472 


THE  DATA  OF  GEOCHEMISTRY. 


minerals,  for  ortho-,  meta-,  and  tri-silicates  are  then  capable  of 
coexistence.  In  a rock  containing  silicates  of  all  three  classes,  with 
alumina,  lime,  magnesia,  the  two  alkalies,  and  both  oxides  of  iron 
as  bases,  the  possibilities  of  union  become  very  numerous.  In  the 
magma  itself  the  bases  will  be  apportioned  to  the  several  silicic 
acids  in  accordance  with  the  law  of  mass  action,  each  one  being  gov- 
erned by  the  relative  number  of  its  molecules  in  a unit  volume  of 
solution.  When  cooling  begins,  the  separation  of  each  mineral  will 
depend  upon  its  fusibility,  its  solubility,  and  its  relation  to  the 
possible  eutectic  ratios;  and  the  solubility  will  fluctuate  with  changes 
in  the  temperature  of  the  mass.  With  each  deposition  of  crystals 
all  of  the  foregoing  conditions  will  change,  for  the  composition  of  the 
residual  fluid  will  have  been  altered.  In  theory,  then,  the  physical 
and  chemical  conditions  of  solidification  are  most  complex,  except 
for  two-component  and  possibly  three-component  systems.  We 
are  therefore  compelled  to  deal  with  the  problem  of  rock  composition 
empirically  and  to  make  use  of  rules  based  upon  direct  observation. 
These  rules  are  by  no  means  rigorous,  for  although  the  separation 
of  minerals  from  a cooling  magma  generally  follows  a stated  order 
that  order  often  varies.  In  most  cases  it  is  the  order  described  by 
H.  Rosenbusch,1  as  follows: 

1.  Apatite,  zircon,  spinel,  the  titanates,  and  iron  ores.  These  are  almost  invariably 
the  first  minerals  to  crystallize. 

2.  The  Mg-Fe,  Mg-Ca,  and  Fe-Ca  silicates,  such  as  olivine,  amphibole,  and  py- 
roxene. Biotite  is  also  placed  in  this  class.  As  a rule  the  orthosilicates  precede  the 
metasilicates;  olivine,  for  example,  separating  before  pyroxene. 

3.  Feldspars  and  lenads  in  the  order  anorthite,  plagioclase,  alkali  feldspars,  nephe- 
lite,  leucite. 

4.  Any  excess  of  quartz. 

The  frequency  with  which  this  order  is  followed  is  probably  a 
consequence  of  the  fact  that  most  rocks  consist  mainly  of  alumo- 
silicates,  and  especially  of  feldspars  and  quartz.  That  is,  they  con- 
tain predominantly  compounds  of  the  same  class,  in  which  the  other 
rock-forming  minerals  are  dissolved.  The  latter  separate  from  solu- 
tion in  the  general  order  of  their  solubility,  the  least  soluble  first; 
but  that  property  varies  with  the  composition  of  the  mixture.  In 
an  isomorphous  series,  like  the  feldspars,  the  least  fusible  tend  to  be 
deposited  earlier  than  the  others,  but  fusibility  is  a minor  factor  in 
the  process  of  solidification.  Quartz,  which  solidifies  in  most  cases 
at  the  very  end  of  the  series,  is  a relatively  infusible  substance;  but, 
as  we  have  already  seen,  it  probably  forms  a eutectic  mixture  with 
the  feldspars  which,  by  virtue  of  its  depressed  melting  point,  is  the 
last  part  of  a magma  to  congeal.  The  minor  accessories  among  the 
rock-forming  minerals,  which  crystallize  first,  although  present  in 
trifling  amounts,  possibly  form  no  eutectics  with  the  feldspars. 
Otherwise  we  should  expect  them  to  remain  in  solution  much  longer. 


1 Elemente  der  Gesteinslehre,  1898,  p.  40. 


Igneous  rocks. 


473 


PROXIMATE  CALCULATIONS. 


It  is  clear,  from  what  has  been  already  said,  that  it  is  rarely  pos- 
sible to  predict,  with  anything  like  quantitative  accuracy,  what 
minerals  will  form  when  a magma  of  given  composition  solidifies. 
Partial  and  semiquantitative  forecasts  are  practicable;  we  can  say, 
for  instance,  that  the  proportion  of  orthoclase  will  lie  between 
assignable  limits;  and  if  the  analysis  shows  a ratio  of  silicon  to 
oxygen  lower  than  Si308,  or  1 : 2.667,  we  may  be  reasonably  sure  that 
a calculable  amount  of  silica  will  remain  uncombined.  Only  in  the 
simplest  cases  can  a complete  forecast  be  made,  and  they  are 
exceptional. 

Suppose,  however,  that  instead  of  a magma  or  an  analysis  repre- 
senting a magma  and  nothing  more,  we  attempt  to  discuss  the  com- 
position of  a rock  in  which  the  separate  minerals  have  been  identified 
by  the  microscope.  In  other  words,  suppose  we  have  the  bulk 
analysis  of  a rock  and  also  its  petrographic  description,  how  far  can 
we  compute  its  proximate  composition?  To  this  question  no  single 
answer  can  be  given;  in  some  cases  the  computation  is  easy,  in  others 
it  is  impossible.  The  conventional  “ norms’ ’ of  the  quantitative 
classification  can  always  be  calculated,  but  the  actual  composition 
may  be  quite  another  thing.  It  is  the  latter  which  concerns  us  now. 
Let  us  take  some  concrete  examples  for  discussion. 

Two  rocks  of  relatively  simple  composition  are  the  following,  for 
which  data  are-given  in  the  Survey  Bulletin  591,  and  also  in  Washing- 
ton’s tables. 


A.  Granite-syenite  porphyry,  Little  Rocky  Mountains,  Montana.  Analysis  by  H.  N.  Stokes.  Described 
by  W.  H.  Weed  and  L.  V.  Pirsson.  Contains  orthoclase,  quartz,  oligoclase,  muscovite,  and  iron  oxides. 
Liparose. 

B.  Biotite  granite,  El  Capitan,  Yosemite  Valley.  Analysis  by  W.  Valentine.  Described  by  H.  W. 
Turner.  Contains  alkali  feldspar,  plagioclase,  quartz,  biotite,  titanite,  apatite,  and  iron  oxides.  The 
analysis  shows  that  a trace  of  zircon  is  probably  present  also.  Toscanose. 


Analyses. 


Norms. 


A 

B 

Si02 

68.  65 

71.  08 

A1203 

18.31 

15.  90 

Fe203 

.56 

.62 

FeO 

.08 

1.  31 

MnO 

. 15 

MgO 

.12 

.54 

CaO 

1.  00 

2.  60 

SrO 

.10 

.02 

BaO 

.13 

.04 

Na20 

4.  86 

3.  54 

K20 

4.  74 

4.  08 

H20- 

. 27 

h20+ 

.83 

.30 

Ti02 

.20 

.22 

Zr02 

.08 

P„0* 

. 10 

Cl 

.03 

.02 

99.  88 

100.  60 

A 

B 

Q 

20.2 

27.8 

or 

27.8 

23.9 

ab 

40.9 

29.9 

an 

5.0 

k 13. 1 

C 

3.5 

.9 

hy 

.3 

3.3 

mt 

.2 

.9 

hm 

.4 

474 


THE  DATA  OE  GEOCHEMISTRY. 


In  calculating  the  actual  composition  of  these  rocks,  it  is  best  to 
first  eliminate  the  accessories.  Zr02  is  calculated  as  zircon,  Fe203 
as  hematite  or  magnetite,  P205  and  Cl  as  apatite,  and  Ti02  as  ilmenite, 
titanite,  or  rutile,  according  to  the  indications  given  in  the  petro- 
graphic descriptions.  All  remaining  CaO  is  then  reckoned  as  equiv- 
alent to  anorthite,  and  all  Na20  as  albite.  In  A the  trivial  amount 
of  MgO  is  assumed  to  be  in  the  form  MgSi03,  that  is,  as  pyroxene  or 
amphibole;  in  B the  magnesia  and  remaining  iron  oxide  are  to  be 
computed  as  biotite,  with  the  normal  formula  Al2(MgFe)2KHSi3012. 
Upon  comparing  K20  with  the  remainder  of  the  A1203,  the  latter,  in 
A,  is  found  to  be  in  excess  of  the  amount  required  for  orthoclase. 
That  excess  gives  a datum  for  the  calculation  of  muscovite;  and 
when  that  is  deducted,  only  quartz  and  orthoclase  remain  to  be  con- 
sidered. The  orthoclase  is  given  by  the  K20  and  A1203  still  unap- 
propriated, and  the  remaining  free  silica  represents  the  quartz.  The 
results  of  the  computation  are  shown  below,  the  trifling  amount  of 
MnO  being  consolidated  with  FeO,  and  the  SrO  and  BaO  with  lime. 
A little  water  is  left  unaccounted  for,  presumably  as  uncombined 
with  any  silicate. 

Calculated  composition  of  rocks  represented  in  preceding  table. 


A 

B 

Quartz ; 

19.  98 

29.  64 

Orthoclase 

18.  90 

19.  74 

Albite 

41.  07 

29.  87 

Anorthite 

5.  41 

12.23 

Muscovite 

13.  06 

Biotite 

6.  50 

MgSiO, 

.30 

Zircon 

. 12 

Titanite 

.54 

Apatite 

.24 

Ilmenite 

. 17 

Rutile 

.11 

Magnetite 

.93 

Hematite 

.56 

99.  56 

99.  81 

These  calculations  are  simple  enough,  and  the  results  are  fairly 
accurate.  The  chief  uncertainties  are  with  the  micas,  and  especially 
with  the  biotite  in  B,  for  rock-forming  biotite  is  a mineral  of  variable 
composition,  and  their  errors  affect  the  computations  with  regard  to 
orthoclase  and  quartz.  A comparison  of  the  last  table  with  that  of 
the  norms  will  show  how  far  the  two  methods  of  calculation  diverge. 

Suppose,  however,  that  we  are  called  upon  to  discuss  the  composi- 
tion of  a rock  containing  orthoclase,  plagioclase,  biotite,  augite,  oli- 
vine, and  magnetite,  with  the  femic  minerals  present  in  fairly  large 


IGNEOUS  ROCKS. 


475 


proportions.  In  such,  a case  the  alumina  goes  to  form  five  of  the  com- 
ponent minerals,  iron  to  four,  lime  to  two,  magnesia  to  three,  and 
potassium  to  two.  We  now  need  more  data  than  the  bulk  analysis 
and  the  usual  petrographic  description  can  give  us,  and  the  required 
information  may  be  obtained  either  from  chemical  or  from  physical 
sources.  Chemically,  we  may  separate  the  biotite,  augite,  and  olivine 
from  the  rock  and  analyze  each  one  by  itself.  In  that  way  we  can 
learn  something  of  the  distribution  of  the  bases,  and  so  become  able 
to  calculate  the  composition  of  the  rock.  Or,  olivine  being  soluble 
in  very  dilute  acids,  we  may  dissolve  it  out  from  a known  weight  of 
rock  and  determine  the  amount  of  iron  and  magnesia  which  belong 
to  it.  The  same  procedure  may  be  followed  for  the  determination  of 
nephelite  when  that  mineral  happens  to  he  present.  Physically,  the 
rock  may  be  studied  in  thin  sections  under  the  microscope,  when  the 
areas  occupied  by  the  several  minerals  can  be  measured  with  a 
micrometer.  Given  a sufficient  number  of  such  measurements,  and, 
the  densities  of  the  minerals  being  known,  the  relative  proportion  of 
the  elements  may  be  calculated,  and  the  results  obtained  can  be 
checked  by  the  chemical  analysis.1  A cruder  process  consists  in 
taking  an  enlarged  photomicrograph  of  the  thin  section,  cutting  the 
areas  representing  the  minerals  out  of  the  paper,  and  then,  by  weigh- 
ing the  latter,  ascertaining  their  relative  proportions.  In  some  cases 
a rock  powder,  in  known  quantity,  can  be  mechanically  separated  into 
its  mineral  constituents  by  means  of  Thoulet’s  or  other  heavy  solu- 
tions, and  the  individual  portions  so  determined  directly.  By  one 
method  or  another  the  problem  of  mineral  composition  can  generally 
be  solved.  Only  when  a rock  contains  much  glass  or  other  inde- 
terminate matter  is  the  problem  incapable  of  fairly  accurate  solution. 
If  alteration  products  are  present — chlorites,  zeolites,  kaolin,  limonite, 
etc. — the  discussion  of  modes  becomes  very  unsatisfactory,  and  the 
conclusions  which  are  then  reached  have  very  slender  value. 

Note. — The  composition  of  igneous  rocks  is  often  represented  graphically  by 
means  of  diagrams,  and  several  methods  for  doing  this  have  been  devised.  For  an 
exhaustive  memoir  upon  this  subject  see  J.  P.  Iddings,  Prof.  Paper  U.  S.  Geol.  Survey 
No.  18,  1903.  The  diagrams  are  of  considerable  service  to  the  petrographer,  for  they 
bring  chemical  relationships  and  differences  vividly  before  the  eye.  The  triangular 
diagrams  of  Osann,  Min.  pet.  Mitt.,  vol.  19,  1900,  p.  351,  are  much  used.  See  also 
papers  by  F.  Becke,  idem,  vol.  22,  1903,  p.  209;  L.  Finckh,  Monatsh.  Deutsch. 
geol.  Gesell.,  1910,  p.  285;  and  B.  G.  Escher,  Centralbl.  Min.,  Geol.  u.  Pal.,  1911, 
pp.  133,  166. 

1 This  method  is  fully  discussed  in  the  Quantitative  classification,  pt.  3,  pp.  186-230,  together  with  the 
subject  of  calculating  norms  and  modes.  According  to  Ira  A.  Williams,  however  (Am.  Geologist,  vol.  35, 
1905,  p.  34),  the  micrometer  method  is  unsatisfactory.  See  also  A.  Rosiwal,  Verhandl.  K.-k.  geol.  Reichs- 
anstalt,  1898,  p.  143. 


CHAPTER  XII. 

THE  DECOMPOSITION  OF  ROCKS. 

THE  GENERAL  PROCESS. 

When  a rock  is  exposed  to  atmospheric  agencies  it  undergoes  a 
partial  decomposition  and  becomes  gradually  disintegrated.  Some 
of  its  substance  is  dissolved  by  percolating  waters,  themselves  of 
atmospheric  origin,  and  is  so  carried  away;  the  remaining  material, 
partly  hydrated  and  partly  unchanged  in  composition,  contains 
products  which  are  easily  separable  from  one  another.  By  flowing 
streams  the  finer  clays  or  silts  are  taken  away  from  the  coarser  and 
heavier  sand  grains,  and  this  process  is  an  important  step  toward  the 
ultimate  formation  of  sandstones  and  shales.  Solution,  hydration, 
disintegration,  and  mechanical  sorting  are  the  successive  stages  of 
rock  decomposition.  I speak  now  in  general  terms.  The  subsidiary 
agents  of  decomposition  will  be  considered  in  their  proper  connection 
later. 

The  breaking  down  of  a rock  is  effected  partly  by  mechanical  and 
partly  by  chemical  means.  Mechanical  agencies,  such  as  the  grind- 
ing power  of  glaciers,  the  pounding  of  waves,  erosion  by  streams,  the 
disruptive  effects  of  frost,  or  the  action  of  wind-blown  sand,  tend  to 
separate  the  particles  of  a rock  and  to  furnish  fresh  surfaces  to  chem- 
ical attack.  Unequal  expansion,  due  to  alternations  of  heat  and  cold, 
also  assist  in  producing  disintegration.1  The  distribution  of  volcanic 
dust  is  still  another  mode  by  which  finely  subdivided  rock  is  ren- 
dered available  for  aqueous  decomposition.  The  latter  depends  for 
its  efficiency  partly  upon  the  water  itself  and  partly  upon  dissolved 
acids,  salts,  or  gases.  Rain  water  falls  upon  the  surface  of  a rock 
and  sinks  more  or  less  deeply  into  its  pores  and  crevices.  Rain,  as 
we  have  already  seen,2  carries  oxygen  and  carbon  dioxide  in  solu- 
tion, together  with  other  substances  in  varying  proportions.  Water 
and  gas  both  exert  a solvent  action,  and  the  fluid  which  then  satu- 
rates the  rock  becomes  charged  with  the  products  of  solution.  These 
may  intensify  or  inhibit  further  action,  according  to  circumstances. 
Some  of  the  dissolved  matter,  redeposited,  may  form  a protecting 
film  and  so  delay  or  prevent  further  solution.  This  retardation, 
however,  is  temporary,  for  mechanical  disintegration  is  accompanied 

1 This  subject  is  fully  discussed  by  J.  C.  Branuer,  in  his  paper  upon  the  decomposition  of  rocks  in  Brazil, 
Bull.  Geol.  Soc.  America,  vol.  7, 1896,  p.  255. 

2 See  ante,  p.  49  et  seq. 

476 


THE  DECOMPOSITION  OF  ROCKS.  477 

by  a rubbing  of  the  loosened  particles  together,  and  so  the  coating 
of  insoluble  matter  is  removed. 

Normal  air  contains,  in  round  numbers,  21  per  cent  by  volume  of 
oxygen  and  0.03  of  carbon  dioxide.  In  rain  water  these  active  gases 
are  concentrated,  as  shown  by  the  analyses  of  R.  W.  Bunsen.1  • Air 
extracted  from  rain  water  at  different  temperatures  has  the  compo- 
sition by  volume  given  below. 


Composition  of  air  extracted  from  rain  water  at  different  temperatures. 


0° 

5° 

10° 

15° 

20° 

Carbon  dioxide 

2.  92 

2.  68 

2.  46 

2.  26 

2. 14 

Oxygen 

33.  88 

33.  97 

34.  05 

34. 12 

34. 17 

Nitrogen  a 

63.  20 

63.  35 

63.  49 

63.  62 

63.  69 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

a Including  argon. 


As  waters  of  this  character  sink  deeper  into  a rock  mass,  a portion 
of  their  effectiveness  is  lost,  for  oxygen  and  carbon  dioxide  are  chiefly 
consumed  near  the  surface,  and  their  share  of  the  chemical  effect 
tends  to  become  zero.  The  decrease  in  the  case  of  oxygen  is  clearly 
shown  by  the  experiments  of  B.  Lepsius,2  who  has  analyzed  the  gase- 
ous contents  of  waters  from  three  bore  holes  of  different  depth.  Air 
extracted  from  water  at  12  meters  below  the  surface  contained  24.06 
per  cent  of  oxygen,  at  18  meters,  21.97  per  cent,  and  at  25  meters, 
only  12.90  per  cent.  In  rock  decomposition,  then,  oxidation  is  largely 
a surface  phenomenon,  and  the  action  of  carbon  dioxide,  so  far  as  it 
is  directly  obtained  from  the  atmosphere,  must  follow  the  same  rule. 
Carbonic  acid,  however,  is  also  derived  from  other  sources,  so  that  its 
effects  are  not  necessarily  limited  to  the  upper  strata.  Its  presence 
in  ground  waters  will  be  considered  presently.3 

When  meteoric  waters  act  upon  a mass  of  rock,  the  effects  produced 
will  depend  upon  the  nature  of  the  minerals  which  they  encounter. 
Let  us  confine  our  attention  for  the  moment  to  the  more  important 
species  of  magmatic  origin,  such  as  the  feldspars,  micas,  pyroxenes, 
amphiboles,  olivine,  leucite,  nephelite,  and  the  typical  sulphide, 
pyrite.  The  last-named  mineral,  although  found  in  relatively  small 
proportions,  is  nevertheless  important,  for  by  oxidation  and  hydra- 
tion it  yields  solutions  of  sulphates  having  a distinctly  acid  reaction. 
These  acid  solutions  act  strongly  upon  other  constituents  of  rocks, 
and  intensify  the  activity  of  the  percolating  waters.  The  sulphates 

1 Ann.  Chem.  Pharm.,  vol.  93, 1855,  p.  48.  See  also  M.  Baumert,  idem,  vol.  88,  1853,  p.  17. 

2 Ber.  Deutsch.  chem.  Gesell.,  vol.  18,  1885,  p.  2487.  Evidence  of  similar  purport  has  been  recorded 
by  other  observers. 

* W.  G.  Levison,  Annals  New  York  Acad.  Sci.,  vol.  19, 1909,  p.  121,  suggests  that  the  oxygen  liberated 
by  aquatic  plants  may  assist  in  the  decomposition  of  rock  material. 


478 


THE  DATA  OF  GEOCHEMISTRY. 


contained  in  natural  waters  are  largely  derived  from  this  source,  at 
least  primarily.  The  re-solution  of  secondary  sulphates  is  of  course 
not  to  be  overlooked,  but  it  is  obviously  a later  phenomenon. 

SOLUBILITY  OF  MINERALS. 

That  nearly  all  minerals  are  more  or  less  attacked  by  water  has 
long  been  known,  and  also  that  carbonated  waters  act  still  more  ener- 
getically. The  experiments  of  W.  B.  and  It.  E.  Rogers,1  in  1848, 
established  these  facts  conclusively.  Many  minerals  were  tested,  and 
all  were  perceptibly  soluble.  From  40  grains  of  hornblende,  digested 
during  forty-eight  hours  in  water  charged  with  carbonic  acid,  0.08 
grain  of  silica,  0.095  of  ferric  oxide,  0.13  of  lime,  and  0.095  of  mag- 
nesia, or  nearly  1 per  cent  in  all,  were  extracted.2  In  the  classical 
investigations  of  A.  Daubree  3 3 kilograms  of  orthoclase,  agitated 
with  pure  water  for  192  hours  in  a revolving  iron  cylinder,  yielded  a 
solution  containing  2.52  grams  of  K20,  with  trifling  amounts  of 
silica  and  alumina.  Two  kilograms  of  the  feldspar,  shaken  for  ten 
days  in  water  saturated  with  carbon  dioxide,  gave  0.270  gram  of  K20 
with  0.750  of  silica.  A 3 per  cent  solution  of  sodium  chloride  was  a 
much  less  effective  agent  than  water  alone.  Leucite  was  not  so 
vigorously  attacked  as  orthoclase. 

In  1867  A.  Kenngott 4 showed  that  many  minerals  gave  an  alka- 
line reaction  when  in  contact  with  moistened  test  paper;  and  in 
1877  R.  Muller5  published  an  important  memoir  upon  the  solu- 
bility of  various  species  in  carbonated  water.  The  powdered  sub- 
stances were  digested  in  the  solvent  during  seven  weeks,  and  after 
that  treatment  the  dissolved  portions  were  quantitatively  analyzed. 
The  results  are  summed  up  below.  The  percentages  of  the  several 
constituents  determined  refer  to  the  total  amount  of  each  in  a given 
mineral;  the  “sum”  is  the  percentage  of  all  dissolved  matter  in 
terms  of  the  original  substance.  That  is,  under  K20  1.3527  per  cent 
of  the  total  potash  in  orthoclase  was  dissolved,  while  only  0.328  per 
cent  of  the  entire  mineral  passed  into  solution. 

1 Am.  Jour.  Sci.,  2d  ser.,  vol.  5,  1848,  p.  401. 

2 The  temperature  at  which  the  experiment  was  conducted.was  60°,  presumably  Fahrenheit. 

3 Etudes  synthetiques  de  g6ologie  experimental,  pp.  271-275.  See  also  p.  252  for  an  experiment  upon 
the  solubility  of  granite. 

* Neues  Jahrb.,  1867,  pp.  77,  769. 

5 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  27,  Min.  Mitt.,  1877,  p.  25.  Muller  gives  a good  summary  of  previ- 
ous work  upon  the  subject,  and  cites,  in  addition  to  the  memoirs  mentioned  here,  papers  by  Dittrich, 
Haushofer,  Ludwig,  Hoppe-Seyler,  and  others.  A later  summary,  by  F.  K.  Cameron  and  J.  M.  Bell,  is  in 
Bull.  No.  30,  Bureau  of  Soils,  U.  S.  Dept.  Agric.,  1905,  p.  12.  P.  Pichard  (Annales  chim.  phys.,  5th  ser., 
vol.  15, 1878,  p.  529)  found  that  several  magnesian  silicates  gave  alkaline  reactions  with  litmus  paper.  F. 
Sestini  (abstract  in  Zeitschr.  Kryst.  Min.,  vol.  35, 1902,  p.  511)  made  similar  but  quantitative  observations 
on  augite,  amphibole,  and  tremolite.  According  to  F.  Cornu  (Min.  pet.  Mitt.,  vol.  24, 1905,  p.  417;  vol.  25, 
1907,  p.  489),  who  tested  many  minerals  with  litmus,  kaolinite,  pyrophyllite,  nontronite,  etc.,  give  acid 
reactions. 


THE  DECOMPOSITION  OF  ROCKS. 


479 


Material  extracted  from  minerals  by  carbonated  water. 


Si02. 

A1203. 

K2o. 

Na20. 

MgO. 

CaO. 

P206. 

FeO. 

Sum. 

Adularia. . . 
Oligoclase.. 
Hornblende 

0. 1552 

0. 1368 

1.  3527 

Trace. 

0.  328 

. 237 

9. 1713 

2.  367 

3. 213 

Trace. 

.533 

.419 

Trace. 

Trace. 

8.  528 

4.  829 

1.  536 

Magnetite. . 

.942 

.307 

Do. ... 

Trace. 

2. 428 

1.  821 

A patite 

1.  696 

1.  417 

1.  529 

Do. . . . 

2. 168 

1.  822 

2.  018 

Do 

1.  946 

2. 12 

Trace. 

1.  976 

Olivine .... 

.873 

Trace. 

1.  291 

8.  733 

2.  Ill 

Serpentine. 

.354 

2.  649 

1.  527 

1.  211 

The  relative  solubility  of  several  minerals,  chiefly  magnesian 
species,  in  ordinary  water  was  determined  by  E.  W.  Hoffmann  1 in 
1882.  His  method  of  procedure  consisted  in  allowing  water  to  per- 
colate through  the  powdered  material  for  two  months  and  measur- 
ing the  loss  of  weight;  a possibility  of  gain  by  hydration  seems  not 
to  have  been  considered.  The  data  given  are  as  follows: 


Relative  solubility  of  various  minerals  in  water. 


Grams 

taken. 

Loss  of 
weight. 

Vesuvianite 

4. 109 

0.  064 

Epidote 

3.  353 

.052 

Olivine 

3.  506 

.078 

Chlorite 

2.  591 

. 094 

Talc 

1. 1245 

. 105 

Muscovite 

.5058 

.056 

Biotite 

.9736 

.035 

The  excessive  solubility  here  shown  for  talc  and  muscovite  is  highly 
questionable.  Hoffmann’s  experiments  are  entitled  to  very  little 
weight.  It  has  been  shown  by  Alexander  Johnstone  2 that  micas 
exposed  to  the  action  of  pure  and  carbonated  waters  during  an  entire 
year  became  hydrated  and  increased  in  volume.  The  latter  phe- 
nomenon may  account  for  the  easy  weathering  of  micaceous  sand- 
stones. Muscovite  appeared  to  be  insoluble,  but  in  a solution  of  car- 
bonic acid  the  biotite  lost  magnesia  and  iron.  In  another  communi- 
cation3 Johnstone  states  that  olivine  is  slightly  attacked  by  carbo- 
nated water;  and  in  still  another4  he  described  the  action  of  that 
reagent  upon  orthoclase,  oligoclase,  labradorite,  hornblende,  augite, 
etc.  Among  the  feldspars,  orthoclase  was  the  least  and  labradorite 


1 Inaug.  Diss.,  Leipzig,  1882. 

2 Quart.  Jour.  Geol.  Soc.,  vol.  45,  1889,  p.  363. 

3 Proc.  Roy.  Soc.  Edinburgh,  vol.  15,  1888,  p.  436. 

* Trans.  Edinburgh  Geol.  Soc.,  vol.  5,  1887,  p.  282. 


480 


THE  DATA  OP  GEOCHEMISTRY. 


the  most  soluble;  hornblende  and  augite  were  acted  upon  even  more 
rapidly.  These  observations  seem  to  be  in  harmony  with  those  of 
Muller,  whose  figures  show  a similar  order  of  magnitude  among  the 
determined  solubilities. 

In  recent  years  a few  data  have  been  published  by  C.  Doelter 1 rela- 
tive to  anorthite,  nephelite,  and  some  zeolites.  The  nephelite  in  par- 
ticular was  strongly  attacked  by  carbonic  acid.  There  are  also  ex- 
periments by  F.  W.  Clarke 2 on  the  alkalinity  of  several  silicates, 
which  were  followed  by  some  quantitative  determinations  b.y  G. 
Steiger.3  Micas,  feldspars,  leucite,  nephelite,  cancrinite,  sodalite, 
spodumene,  scapolite,  and  a number  of  zeolites  were  studied,  and  in 
every  case  a distinct  solubility  was  observed.  Apophyllite,  natrolite, 
and  pectolite  gave  remarkably  strong  alkaline  reactions  when  mois- 
tened, but  the  intensity  of  the  coloration  produced  with  indicators 
gave  inaccurate  information  as  to  the  extent  to  which  decomposition 
had  occurred.  Between  the  qualitative  and  the  quantitative  data 
there  were  discrepancies,  which  have  been  cleared  up  only  within  the 
last  few  years.  A.  S.  Cushman,4  in  his  work  upon  rock  powders,  has 
shown  that  when  orthoclase  is  shaken  with  water  an  immediate  ex- 
traction of  alkaline  salts  takes  place,  but  it  is  only  a partial  measure  of 
the  amount  of  decomposition.  Colloidal  substances,  silica  or  alumi- 
nous silicates,  are  formed  at  the  same  time,  which  retain  a portion  of 
the  separated  alkali,  but  give  it  up  to  electrolytic  solvents.  For 
example,  25  grams  of  orthoclase  were  shaken  up  with  100  cubic  centi- 
meters of  distilled  water.  The  mixture  was  filtered,  and  the  filtrate 
on  evaporation  gave  0.0060  gram  of  residue.  With  a 2 per  cent  solu- 
tion of  ammonium  chloride  a soluble  residue  of  0.0608  gram  was 
obtained.  With  diabase  25  grams  in  pure  water  yielded  an  extract 
of  0.0064  solid  residue;  with  a 1 per  cent  solution  of  ammonium 
chloride  it  gave  0.1412  gram.  These  gains  do  not  imply  increased 
decomposition,  but  only  a liberation  of  the  soluble  compounds  which 
had  been  entangled  in  the  colloids  that  were  formed  at  the  same  time. 
Any  salt  in  solution  is  likely  to  affect  in  some  such  manner  the  appa- 
rent solubility  of  a rock  or  mineral,  a conclusion  which  is  in  harmony- 
with  many  observations  upon  the  tendency  of  soils  and  clays  to 
absorb  salts,  and  especially  salts  of  potassium,  from  percolating  waters. 
As  the  latter  change  in  composition,  their  decomposing  and  dissolving 

1 Min.  pet.  Mitt.,  vol.  11,  1890,  p.  319. 

2 Bull.  U.  S.  Geol.  Survey  No.  167,  1900,  p.  156. 

8 Idem,  p.  159. 

<U.  S.  Dept.  Agr.,  Bur.  Chemistry,  Bull.  No.  92,  1905,.  and  Office  Pub.  Roads,  Circular  No.  38.  See 
also  A.  S.  Cushman  and  P.  Hubbard,  Jour.  Am.  Chem.  Soc.,  vol.  30, 1908,  p.  779,  on  the  electrolytic  extrac- 
tion of  potash  from  feldspars.  Observations  similar  to  Cushman’s  have  been  made  by  G.  Andr£,  Compt. 
Rend.,  vol.  157,  p.  856,  1913.  Other  papers  on  the  solubility  of  rocks  are  by  W.  G.  Levison,  Bull.  New 
York  Mineralogical  Club  No.  2,  1909;  W.  Funk,  Zeitschr.  angew.  Chemie,  vol.  22,  1909,  p.  145;  J.  Dumont, 
Compt.  Rend.,  vol.  149,  1909,  p.  1390;  F.  Henrich,  Zeitschr.  prakt.  Geologic,  1910,  p.  85;  F.  Sicha,  Inaug. 
Diss.,  Leipzig,  1891;  and  C.  H.  Smyth,  jr.,  Jour.  Geology,  vol.  21,  p.  105,  1913. 


THE  DECOMPOSITION  OF  ROCKS. 


481 


capacities  are  altered;  and  since  the  rocks  differ  in  composition,  no 
general  rule  can  be  laid  down  to  determine  what  the  effects  of  water 
in  any  particular  case  will  he. 

Still,  in  spite  of  difficulties  and  uncertainties,  we  can  trace  the 
course  of  rock  decomposition  along  several  lines.  The  evidence,  both 
as  found  by  experiment  in  the  laboratory  and  by  field  observations, 
shows  that  practically  all  minerals,  certainly  all  of  the  important 
ones,  are  attacked  by  water  and  carbonic  acid.  The  pyroxenes  and 
amphiboles  yield  most  readily  to  waters,  then  follow  the  plagioclase 
feldspars,  then  orthoclase  and  the  micas,  with  muscovite  the  most 
resistant  of  all.  Even  quartz  is  not  quite  insoluble,  and  the  corrosion 
of  quartz  pebbles  in  conglomerates  has  been  noted  by  several  ob- 
servers.1 Among  the  commoner  accessories  apatite  and  pyrite  are 
most  easily  decomposed,  magnetite  is  less  attacked,  and  such  minerals 
as  zircon,  corundum,  chromite,  ilmenite,  etc.,  tend  to  accumulate 
with  little  alteration  in  the  sandy  rock  residues.  These  minerals  are 
not  absolutely  incorrodible,  but  they  are  nearly  so.  Corundum,  for 
example,  slowly  undergoes  hydration,2  and  is  converted,  at  least 
superficially,  into  gibbsite  or  diaspore. 

The  effect  of  rain  water  upon  a rock  must  now  be  divided  into  sev- 
eral phases.  First,  it  partially  dissolves  the  more  soluble  minerals, 
with  liberation  of  colloidal  silica,  and  the  formation  of  carbonates 
containing  lime,  iron,  magnesia,  and  the  alkalies.  The  iron  carbonate 
is  almost  instantly  oxidized,  forming  a visible  rusty  coating  or  pre- 
cipitate of  ferric  hydroxide.  The  lime,  magnesia,  and  alkali  salts 
remain  partly  in  solution,  to  be  washed  away,  together  with  much  of 
the  dissolved  silica. 

The  character  of  the  solution  thus  formed  by  the  decomposition  of 
feldspathic  rocks  has  been  investigated  by  W.  P.  Headden.3  After 
prolonged  treatment  of  orthoclase  with  water  containing  carbonic 
acid,  he  obtained  a solution  which,  upon  evaporation,  yielded  a resi- 
due carrying  over  40  per  cent  of  silica. 

The  second  phase  of  the  process  is  represented  by  a hydration  of  the 
undissolved  residues.  The  feldspars  are  transformed  into  kaolin,  the 
magnesian  minerals  into  talc  or  serpentine,  the  iron,  as  we  have  seen, 
becomes  essentially  limonite,  and  the  quartz  grains  are  but  little  if 
at  all  changed.  This  double  process  of  solution  and  hydration  is  ac- 
companied by  an  increase  of  volume,  which  may  or  may  not  assist 
in  effecting  disintegration.  On  the  surface,  the  weathered  rock 

i See  C.  W.  Hayes,  Bull.  Geol.  Soc.  America,  vol.  8, 1897,  p.  213;  M.  L.  Fuller,  Jour.  Geology,  vol.  10, 1902, 
p.  815;  C.  H.  Smyth,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19,  1905,  p.  282.  For  the  solubility  of  quartz  in  solutions 
of  borax  or  of  alkaline  silicates,  see  G.  Spezia,  Jour.  Chem.  Soc.,  vol.  78,  pt.  2,  1900,  p.  595;  vol.  80,  pt.  2, 
1901,  p.  605.  The  corrosion  of  quartz  is  attributed  by  G.  P.  Merrill  (Rocks,  rock  weathering,  and  soils, 
2d  ed.,  p.  252)  to  alkaline  carbonates  generated  during  the  decomposition  of  feldspars. 

* S.  J.  Thugutt,  Mineralchemische  Studien,  1901,  p.  104. 

8 Am.  Jour.  Sci.,  4th  ser.,  vol.  16,  1903,  p.  181. 

97270° — Bull.  616—16 31 


482 


THE  DATA  OF  GEOCHEMISTRY. 


crumbles  easily;  but  if  the  alterations  have  taken  place  at  consider- 
able depths  the  pressure  due  to  expansion  may  hold  all  the  particles 
in  place  and  the  rock  will  seem  at  a first  glance  to  be  unaltered.  Such 
a rock,  although  apparently  solid  when  it  is  first  exposed  to  the  ah*, 
rapidly  falls  to  pieces  and  becomes  a mass  of  sand  and  clay.  This 
peculiarity  was  noted  by  G.  P.  Merrill 1 in  certain  granites  of  the 
District  of  Columbia,  and  by  O.  A.  Derby2  at  railway  cuttings  in 
Brazil.  In  the  latter  case,  the  rocks,  when  first  uncovered,  were  so 
hard  that  they  were  removed  by  blasting;  but  they  soon  underwent  a 
sort  of  slacking  process  and  crumbled  away. 

By  solution,  oxidation,  and  hydration,  then,  a solid  rock  is  con- 
verted into  an  aggregate  of  loose  material,  which  may  remain  in  place 
as  soil  or  be  removed  by  the  mechanical  agency  of  running  waters. 
As  a rule  the  chemical  processes  are  incomplete ; some  of  the  minerals 
are  not  entirely  altered,  and  the  loose  products  therefore  exhibit 
many  variations.  In  general  terms,  the  streams  separate  the  dis- 
integrated materials  into  coarser  and  finer  or  lighter  and  heavier 
portions.  The  claylike  substances  are  generally  light  and  finely 
divided,  and  therefore  remain  longest  in  suspension.  The  heavier 
sands  and  gravels  are  not  carried  so  far,  and  thus  a separation  is 
effected.  In  these  coarser  portions  are  found  quartz,  together  with 
undecomposed  fragments  of  the  various  minerals;  the  lighter  silts 
are  less  variable  in  composition.  Between  silt  and  sand,  however, 
there  are  all  possible  gradations,  and  a corresponding  diversity  is 
shown  in  the  rocks  that  are  formed  by  their  reconsolidation.  Mud, 
sand,  and  gravel  yield  shales,  sandstones,  and  conglomerates;  but 
there  are  sandy  shales  and  argillaceous  sandstones.  The  separations 
are  sometimes  fairly  complete,  but  they  are  oftener  imperfect.  Swift 
waters  are  more  effective  than  sluggish  ones,  both  as  regards  prompt- 
ness of  action  and  the  thoroughness  of  the  separations.  A moun- 
tain torrent  becomes  quickly  turbid  and  quickly  clear,  while  a river 
flowing  through  a flat  alluvial  country  is  rarely  free  from  discolora- 
tion by  suspended  sediments.  Much  silt  goes  to  the  ocean;  the  coarser 
sands  and  gravels  subside  near  the  place  of  their  origin.  I speak 
now  of  stream  deposits,  but  the  sands  of  the  seashore,  which  repre- 
sent disintegration  through  the  action  of  waves,  follow  similar  rules. 
The  gravelly  portions  are  left  highest  on  the  beach,  then  come  the 
sands,  and  the  lighter  particles  are  carried  away  to  be  laid  down  as 
oceanic  ooze. 

But  rain  water  is  not  the  only  chemical  agent  for  effecting  rock 
decomposition.  Below  the  surface  the  ground  water  is  at  work,  and 
that  contains  an  accumulation  of  the  salts  formed  during  the  earlier 
stages  of  the  process.  It  is  poorer  in  oxygen  than  the  surface  waters, 

1 Bull.  Geol.  Soc.  America,  vol.  6,  1895,  p.  321. 

2 Jour.  Geology,  vol.  4,  1896,  p.  529.  Holland  (Quart.  Jour.  Geol.  Soc.,  vol.  59,  1903,  p.  64)  mentions  deep 
cuttings  in  India  where  the  minute  structure  of  the  gneiss  is  retained  on  surfaces  as  soft  as  putty. 


THE  DECOMPOSITION  OF  ROCKS. 


483 


but  richer  in  other  substances,  and  it  may  contain  a large  proportion 
of  organic  matter  derived  from  the  decay  of  vegetation.  This 
organic  matter  often  reverses  the  oxidation  which  had  previously 
taken  place,  reducing  ferric  to  ferrous  compounds  and  sulphates  to 
sulphides.  Pyrite,  dissolved  away  from  the  surface  rocks,  may  reap- 
pear as  marcasite  elsewhere.  Furthermore,  the  organic  decomposi- 
tion furnishes  large  amounts  of  carbonic  acid  to  the  ground  water, 
and  so  increases  its  activity.  At  the  surface  ferrous  salts  have 
yielded  the  insoluble  ferric  hydroxide;  in  the  soil,  by  reduction,  the 
solubility  is  partly  restored  and  in  the  form  of  ferrous  bicarbonate 
the  iron  may  be  more  or  less  washed  away.  When  alkaline  car- 
bonates have  been  generated  in  the  ground  water  its  solvent  power  is 
increased,  and  it  then  becomes  an  effective  agent  in  the  solution  and 
redeposition  of  silica.1  The  impregnation  of  any  solution  of  alka- 
line salts  by  free  carbonic  acid  yields  a solvent  of  this  kind.  Ground 
water,  then,  is  in  many  ways  different  from  rain  water.  As  the  latter 
sinks  deeper  and  deeper  into  a mass  of  rock  or  soil  it  undergoes  pro- 
gressive modifications,  and  some  of  the  changes  which  it  brought 
about  at  the  beginning  of  its  career  may  be  reversed,  while  others  are 
accentuated.  At  certain  depths  the  decomposing  action  of  the  water 
may  cease  almost  entirely,  when  the  process  of  cementation  begins, 
and  then  new  rocks  are  generated.  The  subject  of  reconsolidation, 
however,  belongs  in  another  chapter. 

In  volcanic  regions  the  gaseous  emanations  play  an  important  part 
in  altering  the  rocks,  and  so,  too,  do  the  acid  solfataric  waters.  In 
previous  chapters  these  gases  and  waters  have  been  sufficiently 
described,  and  their  powerful  solvent  effects  were  noted.2  Hot  waters 
charged  with  sulphuric  or  hydrochloric  acid,  attack  nearly  all  erup- 
tive rocks,  dissolve  nearly  all  bases,  and  leave  behind,  in  many  cases, 
mere  skeletons  of  silica.  This  thorough  disintegration  of  lavas, 
however,  is  only  local,  and  has  not  the  wide  general  significance  of 
the  gentler,  less  noticeable  effects  produced  by  rain. 

EFFECTS  OF  VEGETATION. 

Vegetation  exerts  a profound  influence  in  the  decomposition  of 
rocks.  Even  if  plants  did  no  more  than  to  retain  moisture,  making 
the  rock  beneath  them  damp,  their  action  would  be  important;  but 
that  is  only  part  of  the  story.  The  roots  of  plants  penetrate 
into  the  crevices  of  the  rocks,  and  as  they  expand  by  growth,  they 

1 See  E.  W.  Hilgard,  Am.  Jour.  Sci.,  4th  ser.,  vol.  2, 1896,  p.  100.  Hilgard  suggests  that  the  inclusions  of 
carbon  dioxide  found  in  quartz  may  supply  notable  quantities  of  that  substance  to  underground  waters. 

2 In  addition  to  previous  references,  see  W.  B.  Schmidt,  Min.  pet.  Mitt.,  vol.  4,  1882,  p.  1,  on  the  action  of 
sulphurous  acid  upon  volcanic  rocks,  and  H . Lotz,  Dissertation,  Giessen,  1912.  The  action  of  hot  solutions 
not  necessarily  acid,  has  been  compared  with  the  effects  of  weathering  by  E.  Steidtmann,  Econ.  Geology, 
vol.  2,  1908,  p.  381.  An  important  memoir  on  weathering,  by  K.  D.  Glinka,  is  in  Trav.  Soc.  Imp.  Nat.  St. 
P&ersbourg,  vol.  34,  1906,  p.  1.  On  the  decomposition  of  basalt,  see  H.  Stremme,  Monatsh.  Deutsch.  geol. 
Gesell.,  1910,  p.  180. 


484 


THE  DATA  OF  GEOCHEMISTRY. 


help  mechanically  in  the  work  of  disintegration.1  The  roots,  more- 
over, often  contain  organic  acids,  which  act  with  much  vigor  upon 
mineral  substances.  The  soil  or  decomposed  rock  about  the  roots  of  a 
tree  is  often  bleached  by  the  solution  and  removal  of  its  iron  contents. 
The  studies  of  H.  Carrington  Bolton  2 upon  the  solubility  of  min- 
erals in  organic  acids,  and  especially  in  citric  acid,  show  how  power- 
ful this  action  must  be.  This  acid  decomposes  many  silicates,  even  at 
ordinary  temperatures.  • Furthermore,  plants  take  large  amounts  of 
mineral  matter  from  the  soil,  which  is  returned  to  it  in  a different 
condition  after  the  vegetation  dies.  Lichens,  especially,  extract 
substances  directly  from  the  rocks  on  which  they  grow;  grass  and 
grain  crops  absorb  much  potash,  and  so  on.  These  substances  are 
found  in  the  ash  when  vegetable  matter  is  burned,  and  are  easily  de- 
terminable by  analysis.3 

The  number  of  organic  acids  which  find  their  way  into  the  soil, 
from  one  source  or  another,  is  quite  considerable,  and  their  action 
deserves  a much  more  systematic  investigation  than  it  has  yet  re- 
ceived. In  past  years  great  importance  was  attached  to  the  so-called 
“humus  acids/’  the  products  of  vegetable  decay.  These  substances, 
however,  are  not  true  acids  at  all,  but  vague  mixtures  of  colloids 
whose  precise  chemical  nature  is  yet  to  be  determined.  They  have 
some  geologic  significance,  and  H.  Gedroiz  4 has  shown  that  their 
alkaline  solutions,  percolating  downward,  and  meeting  lime  salts,  are 
precipitated,  forming  the  impervious  layer  known  as  hardpan.  They 
also  act  as  reducing  agents,  and  so  aid  in  the  formation  of  pyrite  or 
marcasite  and  in  the  deposition  of  iron  carbonates.  Their  alleged 
activity  as  solvents  of  silica  or  as  agents  in  rock  decomposition  is 
most  questionable.  Moor  waters  are  commonly  acid,  but,  as  K. 
Endell 5 has  proved,  the  acidity  is  usually  that  of  carbonic  acid, 
whose  value  as  a solvent  of  minerals  has  already  been  discussed. 
The  humus  substances  are  also  held  in  solution  by  alkaline  carbonates, 
which  readily  dissolve  silica.6 

1 See  A.  Geikie,  Text-book  of  geology,  4th  ed.,  p.  600,  and  G.  P.  Merrill,  Rocks,  rock  weathering,  and  soils, 

p.  201. 

2 Annals  New  York  Acad.  Sci.,  vol.  1,  1877,  p.  1;  vol.  2,  1880,  p.  1. 

3 On  this  theme  there  are  abundant  data,  which  have  been  collected  principally  with  reference  to  agri- 
cultural problems.  A long  table  of  ash  analyses  may  be  found  in  Jahresb.  Chemie,  1847-48,  p.  1074.  For 
estimates  of  the  amount  of  mineral  matter  taken  from  the  soil  by  hemp  and  buckwheat,  see  R.  Peter,  Ken- 
tucky Geol.  Survey,  Chemical  analyses,  vol.  A,  1884,  p.  441. 

* Chem.  Abstr.,  1909,  p.  2600.  From  Jour.  exp.  Landw.,  vol.  9, 1908,  p.  272. 

3 Neues  Jahrb.,  Beil.  Band  31, 1910,  p.  1,  and  Jour,  prakt.  Chemie,  2d  ser.,  vol.  82, 1910,  p.  414. 

6 See  A.  A.  Julien’s  monographic  paper  upon  the  geological  action  of  the  humus  acids,  Proc.  Am.  Assoc. 
Adv.  Sci.,  1879,  p.  311,  for  a complete  summary  of  the  earlier  work,  now  mostly  obsolete,  on  this  subject. 
Recent  papers  by  A.  Baumann  and  E.  Gully,  Mitt.  K.  Bayr.  Moorkulturanstalt,  Heft  3, 1909,  p.  52,  and 
Heft  4, 1910,  p.  131,  are  important,  and  also  two  by  H.  Stremme,  Zeitschr.  prakt.  Geologie,  1909,  p.  353; 
1910,  p.  389.  The  recent  literature  upon  the  humus  acids  is  very  voluminous. 


THE  DECOMPOSITION  QF  ROCKS. 


485 


INFLUENCE  OF  BACTERIA. 

Even  forms  of  life  so  low  as  the  bacteria  seem  to  exert  a definite 
influence  in  the  decomposition  of  rocks.  A.  Muntz  1 has  found  the 
decayed  rocks  of  Alpine  summits,  where  no  other  life  exists,  swarm- 
ing with  the  nitrifying  ferment.  The  limestones  and  micaceous 
schists  of  the  Pic  du  Midi,  in  the  Pyrenees,  and  the  decayed  cal- 
careous schists  of  the  Faulhorn,  in  the  Bernese  Oberland,  offer  good 
examples  of  this  kind.  The  organisms  draw  their  nourishment  from 
the  nitrogen  compounds  brought  down  in  snow  and  rain;  they  con- 
vert the  ammonia  into  nitric  acid,  and  that,  in  turn,  corrodes  the  cal- 
careous portions  of  the  rocks.  A.  Stutzer  and  R.  Hartleb  2 have 
observed  a similar  decomposition  of  cement  by  nitrifying  bacteria. 
The  effects  thus  produced  at  any  one  point  may  be  small,  but  in  the 
aggregate  they  may  become  appreciable.  J.  C.  Branner,3  however, 
has  cast  doubts  upon  the  validity  of  Muntz’s  argument,  and  further 
investigation  of  the  subject  seems  to  be  necessary.  That  microbes 
exert  a great  influence  in  the  soil  is  beyond  question.  Apart  from 
the  effects  produced  by  nitrification,  the  germs  aid  in  bringing 
about  the  decomposition  of  organic  matter,  and  in  that  way  enormous 
quantities  of  carbon  dioxide  are  generated.  Furthermore,  some 
species  decompose  sulphates,4  and  so  modify  the  composition  of  the 
ground  water. 

INFLUENCE  OF  ANIMAL  LIFE. 

The  influence  of  animal  life  in  decomposing  rocks  is  perhaps  sec- 
ondary rather  than  initiative.  An  ordinary  soil  contains  rock-form- 
ing minerals  which  have  been  incompletely  broken  down,  and  animals 
assist  in  completing  the  disintegration.  The  effects  produced  by 
guano  upon  the  rooks  immediately  beneath  it  may  be  more  direct,  but 
its  distribution  is  exceedingly  limited.  On  the  other  hand,  bur- 
rowing animals  bring  fresh  soil  to  the  surface  to  be  acted  upon  by 
rain  or  blown  away  by  winds;  and  ordinary  earthworms  perform 
this  kind  of  labor  upon  a vast  scale.  In  Brazil,  as  shown  by  J.  E. 
Mills  5 and  J.  C.  Branner,6  the  work  done  by  ants  is  of  the  greatest 
significance.  These  creatures  dig  tunnels  hundreds  of  yards  long  and 
carry  into  their  nests  great  quantities  of  leaves.  Through  their  vital 
processes  they  generate  carbon  dioxide,  and  the  decay  of  the  leaves 
must  develop  much  more.  The  ants  not  only  open  up  the  soil  to  the 
action  of  air  and  water,  they  also  help  to  saturate  it  with  carbonic 
acid,  and  the  solutions  so  produced,  by  the  joint  action  of  rain, 

1 Annales  chim.  phys.,  6th  ser.,  vol.  11,  1887,  p.  136;  Compt.  Rend.,  vol.  110, 1890,  p.  1370. 

2 Zeitschr.  angew.  Chemie,  1899,  p.  402. 

3 Am.  Jour.  Sci.,  4th  ser.,  vol.  3,  1897,  p.  438. 

* See  ante,  p.  148. 

6 Am.  Geologist,  vol.  3,  1889,  p.  351. 

8 Bull.  Geol.  Soc.  America,  vol.  7,  1896,  p.  255;  vol.  21, 1910,  p.  449. 


486 


THE  DATA  OF  GEOCHEMISTRY. 


respiration,  and  organic  decay,  penetrate  to  considerable  depths  below 
the  surface.  The  decomposition  of  the  underlying  rocks  is  thus  dis- 
tinctly promoted  and  over  great  areas  of  territory. 

Before  passing  on  to  consider  the  products  of  decomposition,  a 
word  must  be  said  upon  the  destructive  influence  of  man.  By  drain- 
ing, grading,  irrigating,  fertilizing,  and  cultivating  the  soil,  by  tun- 
neling, quarrying,  and  mining,  the  processes  of  rock  decomposition 
are  promoted  in  many  ways.  New  surfaces  of  rock  are  exposed  to 
the  action  of  air  and  water,  new  solvents  are  introduced  into  the  soil, 
coal  is  withdrawn  from  the  earth  to  be  restored  to  the  atmosphere  as 
carbon  dioxide,  and  by  the  destruction  of  forests  erosion  is  accel- 
erated. The  extent  to  which  man  assists  in  the  decomposition  of 
rocks  may  easily  be  overrated;  but  human  influence  is  one  of  the 
active  agencies  which  can  not  be  ignored. 

PRODUCTS  OF  DECOMPOSITION. 

The  products  of  decomposition  are  commonly  divided  into  two 
great  classes,  the  sedentary  and  the  transported.  The  sedentary 
products  are  those  which  remain  in  place,  such  as  residual  clays;  the 
transported  materials  are  represented  by  glacial  drift,  river  silt,  wind- 
blown dust,  etc.  On  the  one  hand  we  deal  with  substances  derived 
from  a single  lithologic  unit;  on  the  other  we  have  blended  or  assorted 
materials  from  various  sources.  Corresponding  to  these  differences 
of  origin  there  are  chemical  differences.  First  in  order  let  us  con- 
sider the  sedentary  products. 

When  a rock  is  decomposed  in  place,  the  changes  produced  are  rela- 
tively simple.  Soluble  constituents  are  leached  away  and,  to  offset 
the  loss,  oxygen,  water,  and  often  carbon  dioxide  are  gained.  Ordi- 
narily the  gains  exceed  the  losses,  both  in  weight  and  in  bulk,  and  the 
change  may  be  either  complete  or  partial.  Every  gradation  is  possible, 
from  incipient  alteration  to  the  most  thorough  decomposition.  The 
character  of  the  products  formed  will  depend  upon  the  composition 
of  the  original  rock,  and  also  upon  the  nature  of  the  decomposing 
agents.  A normal  granite,  for  example,  will  yield  a mixture  of 
quartz,  kaolin,  and  scales  of  mica,  commonly  commingled  with 
fragments  of  undecomposed  feldspar;  a peridotite  is  converted  into 
serpentine;  a rock  rich  in  iron  is  likely  to  give  much  ferric  hydroxide, 
and  so  on.  The  more  easily  alterable  minerals  naturally  form  the 
more  easily  alterable  rocks,  and  the  residues  which  they  furnish  will 
represent  the  maximum  amount  of  change.  That  change,  further- 
more, will  be  reflected  in  the  composition  of  the  percolating  waters, 
which  may  be  rich  in  silica,  or  carbonates,  or  sulphates,  according  to 
the  nature  of  the  minerals  upon  which  they  operate. 


THE  DECOMPOSITION  OF  ROCKS. 


487 


Many  comparative  analyses  of  rocks  and  their  decomposition  prod- 
ucts are  on  record.1  The  following  analyses,  representing  a few  typi- 
cal examples,  are  enough  for  present  purposes : 

Analyses  of  rocks  and  their  decomposition  products. 

A.  Micaceous  granite,  District  of  Columbia.  Described  by  Merrill,  Bull.  Geol.  Soc.  America,  vol.  6, 
1895,  p.  321.  Contains  quartz,  black  mica,  feldspar,  epidote,  apatite,  flakes  of  sericite,  and  a few  black 
tourmalines  and  iron  ores,  a,  The  fresh  rock;  b,  partly  decomposed  rock;  c,  derived  soil;  d,  fine  silt, 
separated  from  soil.  Analyses  a,  b,  c,  by  R.  L.  Packard;  d by  G.  P.  Merrill. 

B.  Micaceous  gneiss,  Albemarle  County,  Virginia.  Analysis  and  description  by  G.  P.  Merrill,  Bull.  Geol. 
Soc.  America,  vol.  8, 1897,  p.  157.  The  rock  contains  orthoclase,  plagioclase,  black  mica,  zircon,  quartz,  iron 
ores,  apatite,  garnets,  and  a zeolite,  a.  The  fresh  rock;  b,  the  residual  soil. 

C.  Elseolite  syenite,  Fourche  Mountain,  Arkansas.  Described  by  J.  F.  Williams,  Ann.  Rept.  Arkan- 
sas Geol.  Survey,  1890,  vol.  2,  pp.  81-82.  a,  The  fresh  rock,  analyses  by  W.  A.  Noyes;  b,  c,  the  decomposed 
rock,  partial  analyses  by  R.  N.  Brackett. 

D.  Augite  andesite,  Rockland  Ridge,  Washington.  Analyses,  description,  and  full  discussion  by  E.  A. 
Schneider,  Am.  Jour.  Sci.,  3d  ser.,  vol.  36,  1888,  p.  236.  According  to  A.  W.  Jackson,  the  rock  contains 
plagioclase,  augite,  apatite,  magnetite,  and  residual  glass,  a,  The  fresh  rock;  b,  the  derived  soil. 


A 

a 

b 

c 

d 

Si02 

69.  33 

66.  82 

65.  69 

49.  39 

ALOo * 

14.  33 

15.  62 

15.  23 

23.  84 
| 3.69 

Fe203 

1.  88 

| 4.39 

FeO 

3.  60 

1.  69 

MgO  

2.  44 

2.  76 

2.  64 

4.  60 

CaO 

3.  21 

3. 13 

2.  63 

4.  41 

Na20 

2.  70 

2.  58 

2. 12 

3.  36 
2.  49 

K20 

2.  67 

2.  04 

2.  00 

Ignition 

1.  22 

3.  27 

4.  70 

8. 12 

Ti02 

Undet. 

Undet. 

. 31 

P90, 

. 10 

Undet. 

.05 

99.  60 

99.  79 

99.  76 

99.  90 

B 

C 

D 

a 

b 

a 

b 

c 

a 

b 

Si02 

60.  69 

45.  31 

59.  70 

58.  50 

50.  65 

50.  85 

58. 16 

A1203 

16.  89 

26.  55 

18.  85 

25.  71 

26.  71 

12.  54 

15.  03 

Fe203 

\ 9.06 

\ 12. 18 

\ 4.85 

\ 3.74 

\ 4.87 

10.  03 

10.  59 

FeO 

/ 

/ 

| 

/ 

7. 11 

MgO 

1.  06 

.40 

.68 

J 

Trace. 

.21 

5.  57 

1.  99 

CaO 

4.  44 

Trace. 

1.  34 

.44 

.62 

9.  33 

4.  57 

Na20 

2.  82 

.22 

6.  29 

1.  37 

.62 

2.  37 

2.  56 

k2o 

4.  25 

1. 10 

5.  97 

1.  96 

1.  91 

1. 13 

1.  68 

Ignition 

. 62 

13.  75 

1.  88 

5.  85 

8.  68 

H20 

. 34 

1.  77 

Organic 

3.  52 

Ti09 

. 06 

. 25 

. 47 

. 76 

. 43 

sS3 

. 05 

. 07 

100.  08 

99.  98 

99.  56 

97.  57 

94.  33 

100.  08 

100.  37 

1 For  a good  general  discussion  of  the  data,  see  G.  P.  Merrill,  Rocks, rock  weathering,  and  soils, pp.  206-240. 
See,  also,  papers  by  J.  Lemberg,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  27,  1875,  p.  581;  vol.  28,  1876,  p.  519; 
vol.  35, 1883,  p.  559.  Other  groups  of  analyses  than  those  cited  here  are  given  by  E . Kaiser,  Zeitschr.  Deutsch. 
geol.  Gesell.,  vol.  56,  Monatsb.,  1904,  p.  17;  and  M.  Dittrich,  Zeitschr.  anorg.  Chemie,  vol.  47,  1905,  p.  151. 


488 


THE  DATA  OE  GEOCHEMISTRY. 


Analyses  of  rocks  and  their  decomposition  products — Continued. 

E.  Diabase,  Medford,  Massachusetts.  Analyses  and  discussion  by  G.  P.  Merrill,  Bull.  Geol.  Soc.  Amer- 
ica, vol.  7,  1896,  p.  350.  According  to  W.  H.  Hobbs  the  rock  contains  plagioclase,  augite,  biotite,  pyrite, 
apatite,  magnetite,  limenite,  and  some  secondary  products,  a,  The  fresh  rock;  b,  disintegrated  rock;  c, 
fine  silt.  For  data  concerning  a diabase  from  Chatham,  Virginia,  see  T.  L.  "Watson,  Am.  Geologist,  vol. 
22,  1898,  p.  85.  The  analyses  given  are  not  complete. 

F.  Diorite,  Albemarle  County,  Virginia.  Described  and  analyzed  by  G.  P.  Merrill,  Rocks,  rock  weather- 
ing, and  soils,  pp.  224,  225.  Contains  hornblende,  plagioclase,  and  titanic  iron,  a,  The  fresh  rock;  b, 
decomposed  rock. 

G.  Diabase,  Spanish  Guiana,  Venezuela.  Described  by  G.  Attwood,  Quart.  Jour.  Geol.  Soc.,  vol.  35, 
1879,  p.  586.  Analyses  made  in  the  Royal  School  of  Mines,  London,  a,  The  fresh  rock;  b,  weathered  rock; 
c,  highly  weathered  rock. 

H.  Diabase,  Island  of  Jersey.  Described  by  P.  Holland  and  E.  Dickson,  Proc.  Liverpool  Geol.  Soc., 
vol.  7, 1892-93,  p.  108.  a,  The  fresh  rock;  b,  decomposed  rock.  Holland  and  Dickson  also  give  data  relative 
to  the  decomposition  of  a granite  and  a sandstone. 

I.  Augite  diorite,  Magnetberg,  southern  Urals.  Described  by  J.  Morozewicz,  abstract  in  Zeitschr.  Kryst. 
Min.,  vol.  39,  1904,  p.  612.  The  rock  alters,  first  by  leaching,  free  iron  oxides  being  dissolved  and  partly 
redeposited  in  crevices;  second,  by  chloritization  of  the  augite  and  production  of  garnet  micro lites;  finally 
by  kaolinization  of  the  feldspars,  a,  The  fresh  rock,  specific  gravity  2.988;  b,  first  stage  of  decomposition, 
specific  gravity  2.918;  c,  second  stage,  specific  gravity  2.604. 


E 

F 

a 

b 

c 

a 

b 

Si02 

47.  28 

44.  44 

36.  61 

46.  75 

42.44 

A1203 

20.  22 

23. 19 

] 

17.  61 

25.  51 

Fe203 

3.  66 

\ 12.  70 

40.  68 

1 16.  79 

\ 19.20 

FeO. 

8.  89 

/ 

J 

c 

j 

/ 

MgO 

3. 17 

2.  82 

4.  02 

5. 12 

.21 

CaO 

7.  09 

6.  03 

3.  44 

9.  46 

.37 

Na20 

3.  94 

3.  93 

2. 14 

2.  56 

.56 

K20 

2. 16 

1.  75 

1.  82 

.55 

.49 

Ignition 

2.  73 

3.  73 

10.  97 

.92 

10.92 

P„0,  

. 68 

. 70 

.25 

. 29 

MnO 

. 77 

. 52 

100.  59 

99.  81 

99.  68 . 

100.  01 

99.  99 

Si02.. 

ai203. 

Fe203. 
FeO. . 
MgO.. 
CaO... 
Na90.. 


K20 


h20+.  . . 

Ti09 


C02 

MnO 


49.  57 
15.  37 


12.  34 
7.  41 
9.  65 
1.  99 
.85 
.17 
3. 10 


Trace. 


a 100.  45 


41.  77 
19.  34 
13.  21 

4.  63 

5.  01 
4.  98 

.83 
.69 
2.  55 
7.  30 


Trace. 


a 100.  31 


43.  46 
18.  39 
20.  43 


3.  46 

2.  37 
.14 
.59 

3.  39 
7.  95 


Trace. 


a 100. 18 


43.  56 
14.  58 
3.  84 
7.  00 
9.  95 
10.  78 
1.  86 
1.  02 

3.  85 

1.03 
1.  93 
.39 


99.  79 


b 

a 

b 

c 

44.  93 

46.  97 

50.  42 

47.  22 

16.  27 

16. 16 

16.  72 

20.  09 

13.  37 

10.  66 

4.  32 

5.  51 

4.  38 

2.  70 

2.  02 

6.  40 

4.  56 

3.  77 

4.  39 

1.  84 

9.  02 

13.  36 

6.  93 

2.  03 

4.  47 

4.24 

2.  56 

.84 

1.  26 

1.  52 

1.  52 

} 12.  55 

1 1.74 

} 2.24 

} 8.78 

1.  34 

J 

.14 

.07 

Trace. 

.28 

.75 

00 

CO 

.66 

99.  85 

100. 11 

100.04 

99.  68 

a Including  traces  of  Cu  and  S.  P absent. 


THE  DECOMPOSITION  OF  HOCKS. 


489 


All  of  these  comparative  groups  tell  essentially  the  same  story. 
Oxidation  of  the  iron  compounds,  assumption  of  water,  and  loss  of 
soluble  bases  by  leaching  are  changes  which  can  be  recognized  at  a 
glance.  The  concentration  of  the  slightly  soluble  alumina  and  ferric 
oxide  in  the  residual  substances  is  also  clearly  apparent.  But  the 
true  magnitude  of  each  alteration  is  not  so  easily  seen.  In  some  cases 
the  changes  appear  to  be  small,  when  actually  they  are  quite  note- 
worthy. The  apparent  gains  in  alumina  are  only  relative,  and  so,  too, 
are  all  the  other  percentage  variations.  In  order  to  determine  the 
true  alterations  we  must  eliminate  the  disturbances  due  to  oxidation 
and  hydration,  and  this  may  be  done  either  by  examining  molecular 
ratios  or  by  assuming  that  one  rock  constituent  is  constant  and  com- 
paring the  others  with  it.  The  latter  method  is  the  most  used  and 
has  been  applied  by  Merrill  to  the  several  groups  of  analyses  studied 
by  him.  Either  ferric  oxide  or  alumina  is  taken  as  invariable,  and 
from  that  as  a standard  the  relative  losses  of  the  other  constituents 
can  be  roughly  estimated.  The  process  is  not  rigorously  exact,  but 
it  gives  a fair  conception  of  what  has  really  occurred.  The  alumina 
is  not  absolutely  insoluble,  but,  relatively  to  the  other  bases,  it  is 
very  nearly  so. 

For  four  of  the  rocks  under  consideration  Merrill  gives  the  follow- 
ing computations.  The  first  table  shows  the  percentage  of  each  con- 
stituent lost  by  the  original  rock.  The  second  table  gives  the  per- 
centage lost  by  each  substance  referred  to  its  total  amount  as  one 
hundred. 

Results  of  decomposition  of  certain  roclcs. 


I.  Percentage  of  rock  lost. 


Granite. 

Gneiss. 

Diabase. 

Diorite. 

Si02 

10.  50 

31.  90 

8.  48 

17.  43 

A1203 

.46 

Standard. 

Standard. 

Standard. 

FeO,  Fe203 

Standard. 

1.  30 

2.  42 

3.  53 

MnO 

. 32 

MgO 

.36 

.80 

.68 

4.  97 

CaO 

.81 

4.  44 

1.  83 

9,20 

Na20 

.77 

2.  68 

.50 

2. 17 

k2o 

.85 

3.  55 

.62 

. 21 

P20, 

.04 

.08 

J o 

13.  79 

44.  67 

14.  93 

37.  51 

II.  Percentage  of  loss  of  each  constituent. 


Granite. 

Gneiss. 

Diabase. 

Diorite. 

Si02 

14.  89 

52.  45 

18.  03 

37.31 

ai2o3 

3.  23 

Standard. 

Standard. 

Standard. 

FeO,  Fe203 

Standard. 

14.  35 

18. 10 

21.03 

MnO 

41.  57 

MgO 

1.  49 

74.  70 

21.  70 

97. 17 

CaO 

25.  21 

100.  00 

25.  89 

97.  30 

Na20 

28.  62 

95.  03 

12.  83 

84.  87 

k2o 

31.  98 

83.  52 

29. 15 

38.  75 

P205 

40.  00 

11.  39 

19.  87 

490 


THE  DATA  OF  GEOCHEMISTRY. 


From  these  figures  we  can  see  more  clearly  what  has  happened  to 
each  rock,  but  we  can  not  compare  the  four  columns  with  one  another. 
There  are  still  too  many  variables.  The  rocks  contain  different 
minerals,  they  have  weathered  with  varying  completeness,  and 
they  were  not  exposed  to  the  same  percolating  waters.  Further- 
more, weathering  is  affected  by  the  texture  of  a rock,  and  a compact 
feldspar  will  change  less  readily  than  one  which  is  full  of  crevices. 
Coarseness  or  fineness  is  another  factor  to  be  taken  into  account. 
In  short,  the  quantities  are  incommensurable  and  no  general  rules, 
except  as  to  the  main  tendencies  to  alteration,  can  be  based  upon 
them.  Each  individual  rock  alters  in  accordance  with  the  conditions 
to  which  it  has  been  exposed,  but  the  general  trend  of  the  changes 
is  always  in  the  same  direction.  Lime  is  always  removed,  but  per- 
colating waters  rich  in  carbonic  acid  will  carry  it  away  more  easily 
than  waters  less  heavily  charged.  The  lime-soda  feldspars  decompose 
more  readily  than  orthoclase  or  microcline.  Olivine  will  lose  magnesia 
more  readily  than  enstatite.  The  solubility  of  silica  will  vary  with 
variations  in  the  leaching  agent.  Material  withdrawn  at  one  point 
may  be  redeposited  at  another.  Local  and  temporary  conditions 
meet  us  at  every  turn;  so  that  although  we  can  tell,  in  broad,  general 
terms,  how  a given  rock  will  change,  we  can  not  predict  the  alteration 
in  its  quantitative  details. 

RATE  OF  DECOMPOSITION. 

The  extent  to  which  rocks  undergo  decomposition  within  a given 
time  is  largely  dependent  upon  climatic  circumstances.  In  the 
polar  regions,  where  waters  are  frozen  during  a great  part  of  the 
year,  solution  goes  on  more  slowly  than  in  warmer  climates.  In  the 
Tropics  the  waters  not  only  act  continually,  but  their  energy  is 
increased  by  their  higher  temperatures.  Frost  is  most  effective  as  an 
agent  of  disintegration  in  climates  where  alternations  of  freezing  and 
thawing  are  most  frequent.  As  E.  W.  Hilgard  1 has  well  said, 
“The  chemical  processes  active  in  soil  formation  are  intensified  by 
high  and  retarded  by  low  temperatures,  all  other  conditions  being 
equal.’ ’ Disintegration,  however,  as  distinguished  from  decay,  is 
'very  active  in  high  latitudes  and  also  in  arid  regions.2  In  both 
cases  the  great  alternations  of  heat  and  cold  promote  disintegration, 
whereas,  for  lack  of  flowing  water,  solution  and  erosion  are  retarded. 
In  an  arid  region  the  diurnal  variations  of  temperature  are  extreme, 
and  inequalities  of  expansion  among  the  minerals  of  a rock  produce 
their  maximum  effects.  Furthermore,  the  dust  and  sandstorms  of  a 
desert  advance  the  disintegrating  process.  The  rocks  are  ground  to 
powder,  but  much  of  the  debris  remains  in  place  and  loses  compara- 

1 Report  on  the  relations  of  soil  to  climate:  Bull.  No.  3,  U.  S.  Weather  Bureau,  1892. 

2 See  I.  C.  Russell,  Bull.  Geol.  Soc.  America,  vol.  1,  1890,  p.  135.  Also  compare  G.  P.  Merrill,  Rocks, 
rock  weathering,  and  soils,  pp.  278,  285. 


THE  DECOMPOSITION  OF  ROCKS. 


491 


tively  little  by  leaching.  In  humid  climates  erosion  and  solution  go 
on  together,  and  an  abundance  of  vegetable  matter,  living  or  dead, 
helps  to  hasten  the  decomposition  of  the  rock-forming  silicates. 
Between  soils  of  arid  and  moist  climates  there  are  striking  differences 
of  composition,  as  Hilgard1  has  clearly  shown  by  means  of  the  follow- 
ing averages.  Under  A is  given  the  average  composition  of  466 
soils  from  the  humid  regions  of  the  Southern  States.  B represents 
the  average  of  313  soils  from  the  arid  areas  of  California,  Washington, 
and  Montana. 


Average  composition  of  soils  from  humid  and  arid  regions. 


A 

B 

Insoluble  in  HC1 

84.  031 

70.  565 

Soluble  Si02 

4.  212 

7.  266 

A1203 

4.  296 

7.  888 

Fe203 

3. 131 

5.  752 

Mn304 

. 133 

.059 

MeO 

. 225 

1.  411 

CaO 

..108 

1.  362 

Na20 

.091 

. 264 

K20 

. 216 

.729 

P9Cb 

.113 

. 117 

so3 

. 052 

.041 

Water  and  organic  matter 

3.  644 

4.  945 

100.  252 

100.  399 

That  a much  greater  proportion  of  soluble  matter,  unremoved  by 
leaching,  is  present  in  the  arid  regions  is  evident  at  a glance.  The 
desert  soils,  when  supplied  with  water,  are  exceptionally  fertile, 
because  they  have  retained  in  a large  measure  the  foods  that  plants 
require. 

KAOLIN. 

The  chemical  products  of  rock  decomposition  are  extremely  varied, 
as  might  be  naturally  inferred  from  the  mineralogical  complexity 
of  the  original  masses.  In  the  residues  which  remain  after  leaching 
we  find  free  silica,  either  as  quartz  or  opal,  fragments  of  various 
undecomposed  minerals,  hydroxides,  and  a number  of  the  rather 
indefinite  substances  known  as  clays.  Among  the  latter  kaolinite, 
H4Al2Si209,  and  its  ferric  equivalent,  nontronite,  H4Fe2Si209,  are 
perhaps  the  most  important.2  These  species  occur  admixed  with 
one  another  and  also  with  other  hydrous  silicates,  opaline  silica, 
and  hydroxides.  Kaolinite  is  a very  stable  compound,  but  non- 
tronite is  easily  decomposed,  either  by  acid  or  alkaline  solutions, 
yielding  a ferric  hydroxide,  limonite,  as  a final  product  of  aqueous 

1 Op.  cit.,  p.  30. 

2 This  equivalency  between  kaolinite  and  nontronite  was  suggested  by  E.  Weinschenk,  Zeitschr.  Kryst. 
Min.,  vol.  28,  1897,  p.  150.  A.  Bergeat,  however  (Centralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  161),  describing 
nontronite  derived  from  wollastonite,  assigns  it  a different  formula — H8Fe4Si90*j8. 


492 


THE  DATA  OE  GEOCHEMISTRY. 


action.  According  to  Weinschenk,  mixtures  of  kaolinite  and  non- 
tronite  are  sometimes  found,  in  which  the  structure  of  the  original 
gneiss  is  plainly  to  be  discerned.  That  kaolinite  is  the  chief  residual 
product  of  feldspathic  decay  is  the  commonly  accepted  view,  but 
some  writers  hold  that  it  is  not  formed  by  ordinary  weathering. 
According  to  H.  Rosier,1  kaolinite  is  only  produced  by  pneumato- 
lytic  action — that  is,  by  the  operation  of  thermal  waters  and  gaseous 
emanations.  This  theory,  which  applies  to  some  localities,  hut  not 
to  all,  has  led  to  much  controversy.  F.  H.  Butler,2  studying  the 
porcelain  clays  of  Cornwall  and  Devon,  ascribes  their  formation  to 
the  action  of  hot,  ascending  waters,  for  he  finds  the  degree  of  kaoliniza- 
tion  to  increase  with  depth,  with  fresher  rocks  near  the  surface. 
E.  Wiist3  regards  the  kaolin  near  Halle,  Germany,  as  derived  from 
feldspars  by  the  action  of  humus  acids.  That  kaolinization  often 
takes  place  under  moors  due  to  the  carbonated  waters  that  are  there 
present  has  been  urged  by  various  writers ; for  example  by  O.  Haehnel,4 
J.  E.  Barnitzke,5  F.  Weiss,6  K.  Endell,7  and  others.  H.  Stremme  8 
recognizes  the  almost  self-evident  fact  that  any  of  the  suggested  pro- 
cesses may  be  operative,  weathering,  pneumatolytic  action,  and 
kaolinization  by  moor  waters,  but  ascribes  their  efficiency  in  all 
cases  to  the  chemical  activity  of  carbonic  acid.  Jointly  with 
C.  Gagel 9 Stremme  describes  one  instance  of  kaolinization  by  the 
waters  of  a cold  carbonated  spring.  V.  Selle,10  who  has  studied  the 
kaolin  of  Halle,  which  is  derived  from  quartz  porphyry,  traces  it  to 
ordinary  weathering,  first  sericite  and  then  kaolinite  being  formed. 
Here  the  deposit  is  richest  in  kaolin  near  the  surface.  The  abundant 
kaolin  along  the  eastern  side  of  the  southern  Appalachians  is  evi- 
dently due  to  the  weathering  of  pegmatite. 

In  short,  kaolin,  like  many  other  substances,  may  be  formed  by 
any  one  of  several  processes,  in  all  of  which  water,  hot  or  cold,  and 
carbonic  acid  take  part.  Ho  one  interpretation  can  fit  all  its  occur- 
rences. 


1 Neues  Jahrb.,  Beil.  Band  15, 1902,  p.  231.  Rosier  gives  a bibliography  relative  to  kaolinization,  embrac- 
ing 303  titles.  See  also  O.  Stutzer,  Zeitschr.  prakt.  Geologie,  1905,  p.  333,  who  accepts  Rosler’s  view,  and  J. 
M.  van  Bemmelen,  Zeitschr.  anorg.  Chemie,  vol.  66, 1910,  p.  322.  Van  Bemmelen,  however,  does  not  accept 
the  theory  exclusively  but  admits  that  weathering  may  also  produce  kaolin.  In  a recent  paper,  Zeitsclir 
prakt.  Geologie,  1908,  p.  251,  Rosier  defends  his  views. 

2 Mineralog.  Mag.,  vol.  15,  1908,  p.  128. 

3 Zeitschr.  prakt.  Geologie,  1907,  p.  19. 

4 Jour,  prakt.  Chemie,  2d  ser.,  vol.  78, 1908,  p.  280. 

6 Zeitschr.  prakt.  Geologie,  1909,  p.  457. 

3 Idem,  1910,  p.  353. 

7 Sprechsaal,  Nos.  19, 20, 1910. 

s Zeitschr.  prakt.  Geologie,  1908,  pp.  122, 443.  Other  recent  papers  on  the  origin  of  clays  are  by  G.  Linck, 
Geol.  Rundschau,  vol.  4,  p.  289,  1913;  H.  Ries,  Trans.  Am.  Ceramic  Soc.,vol.  13, 1911, p.  15;  H.  O.  Buck- 
man,  idem,  vol.  13, 1911,  p.  336;  and  I.  Ginsburg,  Ann.  Inst.  Polytech.  St.  Petersburg,  vol.  17, 1912,  p.  245. 
Ginsburg’s  paper  is  in  Russian,  with  a German  abstract,  and  a copious  bibliography. 

9 Centralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  427. 

13  Jour.  Chem.  Soc.,  vol.  96,  pt.  2,  p.  63,  abstract  from  Zeitschr.  Naturwiss.,  vol.  79, 1907,  p.  321. 


THE  DECOMPOSITION  OF  ROCKS. 


493 


The  other  hydrous  silicates  of  aluminum  and  iron,  such  as  halloysite, 
cimolite,  pyrophyllite,  chloropal,  etc.,  are  of  more  or  less  uncertain 
origin.  Probably  different  crystalline  silicates  yield  different  resi- 
dues of  this  ill-defined  class,  and  any  or  all  of  them  may  exist  in 
residuary  clays.1 

EATERITE  AND  BAUXITE. 

In  tropical  and  subtropical  regions  the  processes  of  rock  decay 
are  often  carried  further  than  is  usually  the  case  within  the  tem- 
perate zones.  The  leaching  is  more  complete,  the  silicates  are  more 
thoroughly  decomposed,  and  the  residues  are  richer  in  hydroxides. 
In  India,  for  example,  large  areas  are  covered  by  a red  earth  known 
as  laterite,  which  in  some  cases  is  undoubtedly  a derivative  in  place 
of  preexisting  rocks,  such  as  granite,  gneiss,  basalt,  or  diorite.  In 
other  cases  the  laterite  is  detrital  in  character  and  far  distant  from 
its  place  of  origin.  The  term  has  been  vaguely  used,  and  as  em- 
ployed by  different  writers  it  has  meant  very  different  things.  It 
has  been  applied  to  ferruginous  clays,  sediments,  beds  of  iron  ore, 
and  products  of  volcanic  action,  and  its  formation  has  been  attrib- 
uted to  a variety  of  causes.2  W J McGee3  compares  laterite  with 
the  ferruginous  clays  and  soils  of  the  upper  Mississippi,  and  F.  It. 
Mallet4  regards  the  iron  ores  associated  with  the  basalts  of  Ulster 
as  having  a lateritic  character.  W.  Maxwell,5  describing  the  red 
soils  of  the  Hawaiian  Islands,  which  are  derived  from  lavas  by 
the  action  of  volcanic  acids,  points  out  their  similarity  to  laterite. 
T.  H.  Holland  6 suggests  that  lateritization  may  be  due,  in  part  at 
least,  to  the  activity  of  bacilli  or  other  micro-organisms  which  could 
live  in  a warm  climate  but  not  in  colder  regions.  J.  Walther7  and 
S.  Passarge 8 call  attention  to  the  relatively  large  proportion  of  nitric 
acid  in  rainfall  during  tropical  thunderstorms,  and  regard  it  as  a 
possible  cause  of  lateritization.  Brought  to  the  surface  of  a decom- 
posing rook,  it  might  extract  the  iron  as  ferric  nitrate,  and  that  com- 
pound is  either  easily  hydrolyzed  or  else  precipitated  by  alkaline 
carbonates.  In  short,  similar  products  may  have  been  formed  in 
several  different  ways,  and  identity  of  composition  does  not  always 

1 On  the  constitution  of  the  clay  silicates  see  H.  Le  Chatelier,  Zeitschr.  physikal.  Chemie,  vol.  1,  1887, 
p.  396.  See  also  J.  W.  Mellor,  Trans.  Ceramic  Soc.  (English)  vol.  10,  1910-11,  p.  94,  and  F.  W.  Clarke, 
Bull.  U.  S.  Geol.  Survey  No.  588,  1914. 

2 See  R.  D.  Oldham,  Manual  of  the  geology  of  India,  2d  ed.,  1893,  pp.  348-370.  P.  Lake  (Mem.  Geol. 
Survey  India,  vol.  24,  pt.  3, 1890,  pp.  17-46)  gives  a good  summary  of  earlier  views  upon  the  origin  of  laterite. 
Another  elaborate  summary  is  presented  by  G.  C.  Du  Bois,  Min.  pet.  Mitt.,  vol.  22,  1903,  pp.  4-18.  A 
good  chapter  on  laterite,  with  a bibliography,  is  in  Abhandl.  K.  preuss.  geol.  Landesanstalt,  new  ser., 
Heft  62, 1909. 

3 Geol.  Mag.,  1880,  p.  310. 

4 Rec.  Geol.  Survey  India,  vol.  14, 1881,  p.  139. 

6  Lavas  and  soils  of  the  Hawaiian  Islands,  Honolulu,  1898.  Maxwell  gives  many  analyses  of  decomposi- 
tion products  derived  from  lava,  both  by  volcanic  action  and  by  normal  weathering. 

6 Geol.  Mag.,  1903,  p.  59. 

7 Verhandl.  Gesell.  Erdkunde,  vol.  16, 1889,  p.  318. 

8 Rept.  Sixth  Intemat.  Geog.  Cong.,  London,  1895,  p.  671. 


494 


THE  DATA  OF  GEOCHEMISTRY. 


imply  identity  of  origin.  Whatever  its  derivation  may  be,  whether 
from  rocks  in  place  or  as  a transported  sediment,  true  laterite  is 
essentially  a mixture  of  ferric  hydroxide,  aluminum  hydroxide,  and 
free  silica  in  varying  proportions.  To  laterite  in  situ  this  state- 
ment applies  very  closely;  detrital  laterite  is  usually  contaminated 
by  admixtures  of  clay.  Just  as  in  the  formation  of  kaolin,  the  proc- 
ess of  lateritization  may  be  complete  or  partial;  the  typical  product 
appears  only  when  the  alteration  of  the  parent  rock  has  gone  on 
to  the  end.  Then  the  silicates  seem  to  be  completely  broken  down, 
whereas  in  kaolinization  a stable,  hydrous  silicate  remains.  In  one 
case  we  have  silica  plus  free  hydroxides,  in  the  other  silica  plus  kaolin. 
According  to  E.  C.  J.  Mohr  1 lateritio  decomposition  (and  the  forma- 
tion of  bauxite)  occurs  principally  where  there  are  plagioclase  feld- 
spars. Alkali  feldspars  yield  mainly  kaolin.  In  this  view  J.  B. 
Harrison,2  who  has  studied  the  laterites  of  British  Guiana,  concurs. 

In  India  laterite  may  be  derived  from  various  rocks,  and  in  some 
oases  its  source  has  been  in  beds  of  volcanic  ash.  According  to  P. 
Lake,3  the  laterite  of  Malabar  is  produced  in  situ  from  gneiss.  M. 
Bauer4  has  described  “ granite  laterite”  and  “diorite  laterite”  from 
the  Seychelle  Islands;  in  Surinam,  according  to  G.  C.  Du  Bois,5  its 
usual  parent  is  diabase;  in  the  Hawaiian  Islands  it  is  formed  from 
recent  lavas.6  There  are  many  analyses  of  laterite,  some  of  them 
relating  to  samples  of  known  origin,  others  to  detrital  material. 
For  example,  Bauer  gives  these  two  analyses  by  K.  Busz  of  laterite 
from  the  Seychelles: 

1 Bull.  Dept.  Agr.,  Indes  N^erlandaises,  No.  28,  1909.  An  earlier  paper  on  laterite  is  in  No.  17,  1908. 

2 Geol.  Mag.,  1910,  pp.  439,  488,  553.  On  laterite  from  diabase,  idem,  1911,  p.  120. 

3 Mem.  Geol.  Survey  India,  vol.  24,  pt.  3,  1890,  p.  17.  M.  Maclaren  (Geol.  Mag.,  1906,  p.  536)  regards  the 
Indian  laterite  as  formed,  not  directly  in  situ,  but  by  replacement  of  soil  or  decomposed  rock  by  deposits 
from  mineralized  solutions.  The  latter  he  attributes  to  subterranean  decomposition  of  silicates  by  car- 
bonated waters.  A similar  theory  is  advanced  by  J.  M.  Campbell  (Trans.  Inst.  Min.  and  Met.,  vol.  19, 
1910,  p.  432),  who  regards  the  hydroxides  of  laterite  as  deposited  from  ascending,  mineralized  waters.  Other 
recent  papers  on  laterite  are  by  J.  R.  Kilroe  (Geol.  Mag.,  1908,  p.  534),  J.  Chautard  (Compt.  Rend.  Soc. 
ind.  min.,  April,  1908,  p.  119),  Chautard  and  P.  Lemoine  (Bull.  Soc.  ind.  min.,  4th  ser.,  vol.  9,  1908,  p.  305, 
and  Compt.  Rend.,  vol.  146,  1908,  p.  239).  F.  P.  Mennell  (Geol.  Mag.,  1909,  p.  350)  has  described  laterite 
in  Rhodesia.  J.  M.  Van  Bemmelen  (Zeitschr.  anorg.  Chemie,  vol.  66,  1910,  p.  322)  discusses  laterite  and 
kaolin.  See  also  R.  Lenz,  Inaug.  Diss.,  Freiburg,  1908,  and  W.  Meigen,  Geol.  Rundschau,  vol.  2, p.  197, 1911. 
On  the  laterite  of  French  Guinea  see  A.  Lacroix,  Nouv.  Arch.  Mus.  Hist.  Nat.  (Paris),  5th  ser.,  vol.  15, 

1913,  p.  255,  reviewed  by  L.  L.  Fermor,  in  Geol.  Mag.,  1915,  pp.  28,  77,  123. 

4 Neues  Jahrb.,  1898,  Band  2,  p.  192.  Also  a later  paper  by  Bauer  in  Neues  Jahrb.,  Festband,  1907,  p. 33. 

s Min.  pet.  Mitt.,  vol.  22,  1903,  p.  1.  Du  Bois  gives  several  analyses  of  laterite. 

e W.  Maxwell,  Lavas  and  soils  of  the  Hawaiian  Islands.  C.  Element  (Min.  pet.  Mitt.,  vol.  8, 1886,  p.  26) 
gives  two  analyses  of  laterite  from  the  Congo  River  in  West  Africa.  Other  important  analyses  are  by 
H.  Arsandaux  (Compt.  Rend.,  vol.  149,  1909,  p.  682,  and  vol.  150,  1910,  p.  1698)  and  A.  Atterberg  (Cen- 
tralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  361).  In  certain  Indian  laterites  W.  R.  Dunstan  (Rec.  Geol.  Survey 
India,  vol.  37,  pt.  2, 1908,  p.  213)  found  unusual  amounts  of  Ti02,  up  to  13.76  per  cent.  On  laterite  in  West 
Australia  see  E.  S.  Simpson,  Geol.  Mag.,  1912,  p.  393.  On  laterite  in  Mozambique,  see  A.  Holmes,  idem, 

1914,  p.  529. 


THE  DECOMPOSITION  OF  ROCKS. 


495 


Analyses  of  laterite. 


Granite  lat- 
erite. 

Diorite  lat- 
erite. 

Si02 

52.  06 

3.  88 

ai20, 

29.  49 

49.89 

Fe203 

4.  64 

20. 11 

h2o 

14. 40 

25.  98 

100.  59 

99.  86 

If  from  these  mixtures  we  deduct  the  silica  as  quartz,  the  remainder 
will  approximate  to  the  general  formula  R03H3,  which  is  that  of 
gibbsite.  The  water,  however,  is  a little  too  low,  and  a careful  reduc- 
tion of  the  data  leads  to  the  supposition  that  the  residual  substance 
is  a mixture  of  gibbsite,  A103H3;  diaspore,  A102H,  and  limonite, 
Fe4H609.  In  short,  laterite  is  identical  in  type  with  bauxite,  and 
is  merely  an  iron-rich  variety  of  the  latter.  Between  the  aluminous 
bauxite  and  the  iron  compound  limonite  all  sorts  of  mixtures  may 
occur. 

From  this  point  of  view  the  analyses  of  Indian  laterite  published 
by  H.  and  F.  J.  Warth1  are  peculiarly  instructive.  A represents 
gibbsite,  B bauxite,  and  C,  D,  E,  and  F laterite,  found  in  situ. 

Analyses  of  gibbsite , bauxite,  and  laterite. 


A 

B 

C 

D 

E 

F 

Quartz 

10.  52 

Si02 

2.  78 

0.  93 

3.  90 

0.  37 

.23 

0.  90 

ALOo  

62.  80 

67.  88 

54.  80 

43.  83 

35.  38 

26.  27 

FeoO, 

.44 

4.  09 

13.  75 

26.  61 

34.  27 

56.  01 

Ma:0 

.03 

.20 
. 64 

CaO 

. 20 

.36 

. 35 

.86 

.40 

Ti02 

.04 

1.  04 

. 38 

4.  45 

. 10 

1.  59 

H20 

33.  74 

26.  47 

26.  82 

23.  88 

19.  00 

14.  39 

100.  03 

100.  77 

100.  00 

100.  00 

100.  00 

100.  00 

The  following  analyses  (G  to  J)  represent  detrital  laterites: 


Analyses  of  detrital  laterites. 


G 

H 

I 

J 

Quartz 

6.  67 

4.  53 

39.*53 

24.  39 

Kaolinite 

28.  77 

50.  26 

17. 16 

20.  22 

fALO, 

15.  40 

11.  86 

9.  58 

Fe203 

41.  50 

28.  99 

28.  38 

47.  39 

Balance,  identical  with  bauxite< 

MgO 

CaO 

None. 

None. 

None. 

None. 

Trace. 
' . 38 

Ti02 

.25 

.43 

.01 

.01 

H20 

7.  41 

3.  93 

5.  34 

7.  61 

100.  00 

100.  00 

100.  00 

100.  00 

1 Geol.  Mag.,  1903,  p.  154.  Only  a selection  from  among  a large  number  of  analyses  can  be  given  here. 
See  also  H.  Warth,  Mineralog.  Mag.,  vol.,  13, 1902,  p.  172,  for  a description  of  Indian  gibbsite,  and  L.  L. 
Fermor,  Ree.  Geol.  Survey  India,  vol.  34,  1906,  p.  167,  on  gibbsite  and  manganese  ores  in  laterite.  Fermor 
has  also  discussed  the  nature  of  laterite  in  Geol.  Mag.,  1911,  pp.  454, 507,  559. 


496 


THE  DATA  OF  GEOCHEMISTRY. 


Between  bauxite  and  laterite  there  is  no  dividing  line,  and  the  one 
shades  into  the  other.  The  detrital  laterites  differ  from  those  in 
situ  merely  in  having  taken  up  sand  and  clay  during  their  trans- 
portation from  one  point  to  another.  The  bauxite  itself,  if  we  restrict 
that  term  to  the  dominantly  aluminous  varieties,  is  probably  a mix- 
ture of  the  two  hydrates,  corresponding  to  gibbsite  and  diaspore,  the 
latter  compound,  however,  like  the  gibbsite,  being  in  an  amorphous 
condition.  Crystallized  gibbsite  or  hydrargillite  is  comparatively 
rare. 

Bauxite,  like  laterite,  occurs  under  a variety  of  conditions,  which 
suggest  a dissimilarity  of  origin.  Its  formation  has  been  explained 
in  various  ways,  but  no  one  theory  seems  to  fit  all  cases.1  The  French 
bauxites  are  found  mostly  associated  with  Cretaceous  rocks,2  and  they 
have  been  interpreted  by  several  writers  as  deposits  from  hot  springs 
or  other  thermal  waters.3  S.  Meunier,  for  example,  regards  bauxite 
as  precipitated  alumina  thrown  down  by  the  action  of  calcium  car- 
bonate upon  solutions  of  aluminic  salts.  Hot  waters,  rising  from  con- 
siderable depths,  are  supposed  to  have  dissolved  alumina  from  the 
rocks  and  brought  it  into  the  region  of  limestones.  The  fact  that 
certain  French  bauxites  rest  upon  corroded  limestones  gives  a plausi- 
bility to  Meunier’ s suggestion.  This  mode  of  occurrence,  however,  is 
not  general. 

In  several  German  localities  bauxite  is  found,  like  laterite,  as  a 
direct  residue  from  the  decomposition  of  basalt.4  The  bauxite  in 
some  cases  shows  the  structure  of  the  original  rock.  Auge  5 observed 
bauxite  at  one  locality  in  Auvergne  resting  on  gneiss  and  partly  over- 
lain  by  basalt.  In  Ireland  G.  A.  J.  Cole  6 has  described  bauxite 
which  was  apparently  derived  from  rhyolite  or  rhyolitic  ash,  and  one 
decomposing  rhyolite  was  found  to  contain  a considerable  proportion 
of  alumina  soluble  in  hot  sulphuric  acid.  Cole  supposes  that  the 
lavas  were  first  attacked  by  acid  vapors  and  that  the  alumina  so  dis- 
solved was  precipitated  by  waters  containing  alkaline  carbonates. 


1 See  T.  L.  Watson,  Bull.  Geol.  Survey  Georgia  No.  11,  1904,  for  a good  summary  of  the  literature  of 
bauxite,  and  a bibliography. 

2 See  H.  Coquand,  Bull.  Soc.  geol.  France,  2d  ser.,  vol.  28, 1870,  p.  98.  Auge,  idem,  3d  ser.,  vol.  16, 1880, 
p.  345.  F.  Laur,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  24,  1894,  p.  234.  For  a later  paper  by  Laur  see  Compt. 
Rend.  Soc.  ind.  min.,  1908,  p.  430.  On  the  composition  of  bauxite  see  H.  Arsandaux,  Compt.  Rend.,  vol. 
148,  1909,  pp.  937, 1115;  and  also  in  Bull.  Soc.  min.,  vol.  36,  p.  70, 1913. 

3 See  Coquand  and  Auge,  as  just  cited;  also  S.  Meunier,  Compt.  Rend.,  vol.  96,  1883,  p.  1737;  Bull.  Soc. 
g6ol.  France,  3d  ser.,  vol.  17, 1888,  p.  64.  Auge  argues  from  an  erroneous  datum  relative  to  supposed  bauxite 
formed  by  geysers  in  the  Yellowstone  National  Park.  F.  Parmentier  (Compt.  Rend.,  vol.  115, 1892,  p.  125) 
has  called  attention  to  the  occurrence  of  alumina  in  mineral  waters. 

4 See  A.  Streng,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  39,  1887,  p.  621.  A.  Liebrich,  Inaug.  Diss.,  Zurich, 
1891.  T.  Petersen,  Ber.  XXVI  Vers.  Oberrhein.  geol.  Vereins,  1893,  p.  38.  J.  Lang,  Ber.  Deutsch.  chem. 

Gesell.,  vol.  17, 1884,  p.  2892.  R.  Delkeskamp,  Zeitschr.  prakt.  Geologie,  1904,  p.  306.  Kobrich,  idem,  1905. 
p.  23.  H.  Munster,  Inaug.  Diss.,  Giessen,  1905,  on  laterite-bauxite  deposits  in  the  Vogelsgebirge.  On 
Hungarian  bauxite,  see  J.  von  Szadeczky,  Foldt.  Kozl.,  vol.  35,  1905,  p.  247,  and  R.  Lachmann,  Zeitschr. 
prakt.  Geologie,  1908,  p.  353. 

6 Loc.  cit. 

6 Trans.  Roy.  Dublin  Soc.,  2d  ser.,  vol.  6, 1896,  p.  105. 


THE  DECOMPOSITION  OF  ROCKS. 


497 


G.  H.  Kinahan,1  however,  describing  other  Irish  localities  where  the 
bauxite  is  associated  with  iron  ores,  suggests  that  the  mineral  was 
formed  by  the  leaching  action  of  organic  matter,  derived  from  super- 
incumbent peat,  upon  ferruginous  clays. 

In  the  United  States  the  chief  deposits  of  bauxite  are  found  in 
Georgia,  Alabama,  and  Arkansas.  The  Georgia- Alabama  field  has 
been  principally  described  by  J.  W.  Spencer,2  H.  McCalley,3  C.  W. 
Hayes,4  and  T.  L.  Watson.5  Spencer  regards  the  bauxite  as  a deposit 
from  lagoons,  and  calls  attention  to  its  evidently  common  genesis 
with  ores  of  manganese  and  iron.  Under  this  interpretation,  which 
has  not  been  generally  accepted,  bauxite  becomes  the  aluminous 
equivalent  of  bog  iron  ore.  Hayes  notes  its  association  with  gibbsite, 
halloysite,  and  kaolin,  and  attributes  its  formation  to  heated  ascend- 
ing waters,  which  have  decomposed  pyrite  in  the  underlying  shales. 
Aluminous  solutions  were  thus  brought  to  the  surface,  to  be  precipi- 
tated by  carbonate  of  lime.  A similar  intervention  of  sulphates  has 
been  suggested  by  A.  Liebrich 6 and  others.  The  occurrence  of 
bauxite  in  immediate  association  with  alunogen  on  the  upper  Gila 
River,  in  New  Mexico,  as  reported  by  W.  P.  Blake,7  gives  added 
emphasis  to  this  suggestion.  The  alteration  of  rhyolite  to  a quartz- 
alunite  and  a quartz-diaspore  rock  in  the  Rosita  Hills,  Colorado, 
described  by  W.  Cross,8  may  also  have  some  bearing  upon  the  prob- 
lem. As  for  the  Georgia-Alabama  bauxite,  its  composition,  as  shown 
by  many  analyses,  approximates  to  that  of  gibbsite.9  The  latter 
species,  it  may  be  observed,  was  prepared  synthetically  by  A.  De 
Schuiten,10  by  passing  a current  of  carbon  dioxide  through  a hot  alka- 
line solution  of  aluminum  hydroxide.  Distinct  crystals  of  gibbsite 
were  thus  obtained. 


1 Trans.  Manchester  Geol.  Soc.,  vol.  22, 1894,  p.  458.  In  the  same  volume,  p.  524,  analyses  of  Irish  bauxites 
by  W.  Peile  are  given,  and  there  is  still  another  paper  on  the  subject  by  G.  G.  Blackwell,  p.  525.  The 
analyses  show  large  admixtures  of  titanic  oxide  in  the  bauxite. 

2 Geol.  Survey  Georgia,  The  Palaeozoic  group,  1893,  p.  214. 

3 Geol.  Survey  Alabama,  pt.  2,  1897. 

4 Sixteenth  Ann.  Kept.  U.  S.  Geol.  Survey,  pt.  3,  1895,  p.  547.  See  also  Trans.  Am.  Inst.  Min.  Eng., 
1894,  p.  243. 

* Bull.  Geol.  Survey  Georgia  No.  11, 1904.  In  Bull.  No.  18, 1909,  p.  430,  O.  Veatch  describes  the  bauxite 
of  Wilkinson  County,  Georgia. 

6 Zeitschr.  prakt.  Geologie,  1897,  p.  212. 

i Trans.  Am.  Inst.  Min.  Eng.,  vol.  24,  1894,  p.  573. 

8 Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2, 1896,  p.  314.  A quartz-alunite  rock  in  California 
has  been  described  by  H.  W.  Turner,  Am.  Jour.  Sci.,  4th  ser.,  vol.  5,  1908,  p.  424.  The  same  mixture  of 
minerals  is  found  in  the  mines  of  Goldfield,  Nevada,  according  to  F.  L.  Ransome,  Econ.  Geology,  vol.  2, 
1907,  p.  673.  Ransome  also  reports  intergrowths  of  alunite  and  diaspore. 

£See  W.  B.  Phillips  and  D.  Hancock,  Jour.  Am.  Chem.  Soc.,  vol.  20, 1898,  p.  209.  Admixtures  of  kaolin, 
halloysite,  and  sand  were  noted.  See  also  Watson  bulletin,  loc.  cit.,  and  A.  E.  Hunt,  Trans.  Am.  Inst. 
Min.  Eng.,  vol.  24, 1894,  p.  855.  Titanic  oxide  is  almost  invariably  present,  in  some  cases  reaching  as  high 
as  9.80  per  cent.  It  also  appears  in  the  foreign  bauxites  already  mentioned,  and  in  the  Italian  bauxites 
described  by  C.  Formenti,  Gazz.  chim.  ital.,  vol.  32,  pt.  1, 1902,  p.  453.  On  Italian  bauxites  see  G.  Aichino, 
La  bauxite,  Torino,  1902.  Reprint  from  Rassegna  mineraria,  vol.  15. 

io  Bull.  Soc.  min.,  vol.  19, 1896,  p.  157. 

97270°— Bull.  616—16 32 


498 


THE  DATA  OF  GEOCHEMISTRY. 


The  bauxite  of  Arkansas  has  been  studied  by  J.  F.  Williams,1  J.  C. 
Branner,2  and  C.  W.  Hayes.3  According  to  all  of  these  observers,  it 
is  found  in  Tertiary  areas  near  eruptive  syenites,  and  there  are  no 
limestones  in  its  neighborhood.  Hayes  describes  two  varieties  of  the 
bauxite;  one,  granitic  in  character,  shows  the  structure  of  the  sye- 
nite from  which  it  was  probably  derived;  the  other  form  is  pisolitic 
and  may  be  a secondary  generation.  At  some  points,  according  to 
Branner,  the  bauxite  contains  so  much  iron  that  attempts  have  been 
made  to  work  it  as  an  iron  ore.  The  granitic  bauxite  seems  to  repre- 
sent a decomposition  of  the  syenite  in  place;  the  pisolitic  variety  was 
perhaps  precipitated  from  solution.  All  three  authorities  agree  in 
tracing  the  origin  of  the  bauxite  to  the  action  of  waters,  which  Hayes 
thinks  were  strongly  saline  or  alkaline,  upon  the  heated  syenites, 
but  they  differ  as  regards  the  details  of  the  process.  One  of  the 
Arkansas  deposits  is  near  Fourche  Mountain,  and  it  is  interesting  to 
recall  the  fact  that  that  is  a locality  for  elseolite  syenite.  Both 
gibbsite  and  diaspore  are  known  as  decomposition  products  of  elseo- 
lite  and  sodalite,4  and  it  is  conceivable  that  the  two  last-named  spe- 
cies may  have  been  the  parents  of  the  bauxite  here.  Like  the  Georgia 
bauxite,  the  Arkansas  mineral  approximates  to  gibbsite  in  compo- 
sition. It  also  contains  notable  amounts  of  titanium. 

Although  many  writers  have  regarded  bauxite  as  a distinct  mineral 
species,  having  the  empirical  formula  AJLjCt^H/),  few  samples  of 
it  have  exactly  that  composition.  It  is  usually  intermediate  between 
diaspore,  A^Og.HjO,  and  gibbsite,  A1203.3H20;  but  is  sometimes 
near  one  and  sometimes  near  the  other.  It  seems,  in  fact,  to  be  a 
mixture  of  the  two  hydrates,  but  in  an  amorphous  condition.5  When 
solutions  of  sodium  aluminate  are  decomposed  by  carbon  dioxide, 
only  the  trihydrate  is  thrown  down,  at  least  so  far  as  crystalline 
products  have  been  observed.6  The  ordinary,  precipitated,  gelat- 
inous hydroxide  has  the  same  composition,  according  to  E.  T. 
Allen;7  but  at  100°  it  loses  water  and  becomes  a dihydrate.  The 
latter,  in  moist  air,  regains  water  readily — an  order  of  change  which 
renders  its  occurrence  on  a large  scale  as  a natural  mineral  highly 
improbable.  Even  if  a dihydrate  were  formed,  it  would  speedily  be 

1 Ann.  Rept.  Arkansas  Geol.  Survey,  vol.  2, 1890,  p.  124. 

2 Jour.  Geology,  vol.  5, 1897,  p.  263.  This  review  contains  a bibliography  of  bauxite,  and  references  to 
earlier  papers  by  Branner. 

a Twenty-first  Ann.  Rept.U.  S.  Geol.  Survey,  pt.  3, 1901,  p.  435.  See  also  W.  J.  Mead,  Econ.  Geology, 
vol.  10, 1915,  p.  29. 

* See  S.  J.  Thugutt,  Neues  Jahrb.,  Beil.  Band  9, 1895,  p.  609.  Also  W.  C.  Brogger,  Zeitschr.  Kryst.  Min., 
vol.  16, 1890,  p.  50. 

5 On  the  hydration  of  bauxite,  see  also  H.  Lienau,  Chem.  Zeitung,  1905,  p.  1280;  and  T.  H.  Holland, 
Rec.  Geol.  Survey  India,  vol.  32, 1905,  p.  175.  Holland  gives  analyses,  and  in  one  of  them  the  TiOs  reaches 
12.21  per  cent. 

s See  De  Schulten,  already  cited.  Also  F.  Russ,  Zeitschr.  anorg.  Chemie,  vol.  41, 1904,  p.  216,  for  recent 
experiments  and  a summary  of  the  work  done  by  earlier  investigators. 

7 Chem.  News,  vol.  82, 1900,  p.  75.  On  this  subject. there  is  a voluminous  literature,  and  the  published 
data  are  very  discordant. 


THE  DECOMPOSITION  OF  ROCKS. 


499 


altered  into  something  more  nearly  resembling  gibbsite.  In  the  col- 
loidal form,  the  trihydrate  often  contains  large  quantities  of  entangled 
water,  a fact  which  accounts  for  many  discordant  observations. 
According  to  J.  M.  van  Bemmelen  1 this  form  can  pass  over  into  the 
crystalline  modification  and  the  latter  in  turn  may  become  amorphous. 
The  colloidal  variety  dissolves  to  a greater  or  less  extent  in  water, 
but  is  readily  precipitated  from  its  very  unstable  solutions.  Pre- 
cipitated alumina  often  contains  appreciable  quantities  of  carbonates, 
but  whether  they  are  chemically  combined  or  not  is  very  uncertain. 
The  basic  carbonates  of  aluminum  described  by  various  authors  are 
substances  of  doubtful  character,  and  it  is  therefore  not  desirable  to 
invoke  their  aid  in  the  interpretation  of  geological  phenomena.  This 
statement,  however,  needs  qualification.  One  basic  carbonate  of  alu- 
minum and  sodium,  the  rare  mineral  dawsonite,  is  known  to  exist,  but 
its  genesis  is  undetermined.  There  is  also  the  rare  dundasite,  a car- 
bonate of  aluminum  and  lead.  Although  rare  as  a recognizable  sub- 
stance, dawsonite  may  be  common  as  a diffused  ingredient  of  soils ; but 
this  is  only  a possibility.  There  is  no  evidence  upon  which  to  base  the 
supposition.  Free  alumina,  or  its  hydrate,  is  found  in  soils,  espe- 
cially in  the  Tropics.  T.  Schlosing,2  on  comparing  French  soils  with 
soils  from  Madagascar,  found  the  latter  to  contain  much  free  alu- 
mina, while  in  France  there  appeared  to  be  chiefly,  if  not  exclusively, 
silicates.  Similar  observations  were  made  by  J.  M.  van  Bemmelen 3 
on  volcanic  soils  from  Java  and  Sumatra,  in  which  free  hydroxides 
of  iron  and  aluminum  are  abundant;  and  W.  Maxwell’s  study  of 
Hawaiian  soils  4 leads  to  the  same  conclusions.  In  these  cases  the 
bauxite  or  laterite  substance  is  diffused  instead  of  being  concentrated. 
It  is  therefore  less  easily  recognized,  but  its  nature  is  the  same  as  if 
it  were  assembled  or  segregated  in  distinct  beds. 

Taking  all  of  the  evidence  into  account,  it  seems  clear  that  bauxite 
may  be  formed  by  more  than  one  process.  It  occurs  in  place,  like 
laterite,  as  a residue  from  the  decomposition  of  rocks;  it  is  found 
also,  apparently,  as  a precipitate,  and  sometimes,  like  any  other  prod- 
uct of  disintegration,  it  is  in  beds  which  represent  transported  mate- 
rial. In  the  last  instance  it  is  contaminated  by  mixture  with  sand 
and  clay.  Even  in  its  residual  or  primary  occurrence,  its  impuri- 
ties are  significant,  for  they  show  a concentration  of  the  insoluble 
portions  of  the  original  rock.  The  titanium,  for  example,  which 

1 Rec.  trav.  chim.,  vol.  7, 1888,  p.  75.  Zeitschr.  anorg.  Chemie,  vol.  18, 1898,  p.  132.  On  the  colloid  char- 
acter of  bauxite  see  E.  Dittler  andC.  Doelter,  Centralbl.  Min.,  Geol.  u.  Pal.,  1912,  p.  104;  and  A.  Luz,  Kolloid 
Zeitschr.,  vol.  14, 1914,  p.  81.  Also,  with  regard  to  Croatian  bauxites,  M.  Kispatic,  Neues  Jahrb.,  Beil. 
Band  34, 1912,  p.  513;  and  F.  Tudan,  idem,  p.  401,  and  Centralbl.  Min.,  Geol.  u.  PaL,  1913,  pp.  65,  495. 

2 Compt.  Rend.,  vol.  132,  1901,  p.  1203.  According  to  K.  Glinka  (Zeitschr.  Kryst.  Min.,  vol.  32,  1900, 
p.  79),  kaolin  commonly  contains  admixtures  of  aluminum  hydroxide,  sometimes  as  diaspore,  sometimes 
apparently  bauxite.  See  also  M.  G.  Edwards  (Econ.  Geology,  vol.  9, 1914,  p.  112)  on  aluminum  hydrates 
in  clays. 

3 Zeitschr.  anorg.  Chemie,  vol.  42,  1904,  p.  265. 

4 Lavas  and  soils  of  the  Hawaiian  Islands. 


500 


THE  DATA  OF  GEOCHEMISTRY. 


was  first  observed  in  bauxite  by  H.  Sainte-Claire  Deville/  is  such 
a product  of  concentration;  and  it  is  found,  not  only  in  bauxite,  but 
in  nearly  all  residual  clays.  It  is  possibly  present  in  some  cases  as  the 
hydrous  aluminum  titanate,  xanthitane,  a mineral  which  is  known 
as  an  alteration  product  of  sphene. 

The  processes  by  which  aluminous  silicates  are  transformed  into 
hydroxides  have  not  been  determined  with  certainty.  We  have  only 
probabilities  to  guide  us.  It  is  most  likely  that  in  many  cases  the 
formation  of  acid  solutions  by  oxidation  of  pyrite  is  the  first  step 
in  the  alteration;  they  dissolve  alumina  from  the  rocks  to  yield  it 
up  again  upon  mixture  with  alkaline  solutions  or  solutions  of  cal- 
cium carbonate.  In  the  latter  case  gypsum  would  also  be  formed 
and  then  leached  away.  The  precipitation  might  occur  in  place, 
almost  contemporaneously  with  the  formation  of  the  aluminous  solu- 
tions, or  the  dissolved  matter  could  be  carried  some  distance  before 
deposition.  Since  colloidal  alumina  is  soluble  in  water,  it  might  be 
transported  to  a considerable  distance  before  coagulation  occurred. 
The  solution  of  alumina  from  the  rock-forming  silicates  would  of 
course  be  accompanied  by  a liberation  of  silica  in  a colloidal  or  finely 
divided  form,  which  could  dissolve  readily  in  the  alkaline  matter 
of  the  ground  waters,  and  so  be  removed.  In  volcanic  regions,  of 
course,  as  in  Java,  Sumatra,  and  Hawaii,  the  acid  emanations  from 
volcanoes  doubtless  play  an  important  part  in  the  decomposition  of 
the  silicates  and  the  solution  of  alumina. 

The  agency  of  thermal  and  atmospheric  waters,  separately  or  con- 
jointly, must  also  be  considered  with  reference  to  the  formation  of 
bauxite.  E.  Kaiser,1 2  studying  the  alteration  of  German  basalts, 
supposes  that  carbonated  waters  first  transform  the  aluminous  sili- 
cates into  hydrous  compounds,  from  which,  by  alkaline  solutions,  the 
alumina  is  thrown  down;  that  is,  the  process  consists  of  two  stages, 
an  intermediate  hydrated  silicate  being  first  formed.  Kaolinite 
is  such  a silicate,  but  it  is  insoluble,  and  the  change  ends  with  its 
formation.  Possibly  halloysite,  which  has  the  composition  of  kao- 
linite plus  water,  but  which  is  decomposed  by  acids,  is  such  an  in- 
termediate compound.  The  association  of  halloysite  with  the 
Georgia  bauxite  is  suggestive  of  this  possibility;  but  alternatives, 
such  as  the  formation  of  zeolites,  must  also  be  taken  into  account. 
Any  relatively  soluble  or  unstable  silicate  of  aluminum 3 would  ful- 

1 Annales  chim.  phys.,  3d  ser.,  vol.  61, 1861,  p.  309.  Deville  also  found  vanadium  in  bauxite.  See  also 
the  references  to  analyses  of  bauxite  previously  cited.  The  almost  universal  distribution  of  titanium  in 
clays  seems  to  have  been  first  noted  by  E.  Riley,  Jour.  Chem.  Soc.,  vol.  15,  1862,  p.  311,  and  vol.  16, 1863, 
p.  387.  See  also  F.  P.  Dunnington,  Am.  Jour.  Sci.,  3d  ser.,  vol.  42, 1891,  p.  491. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  56,  Monatsb.,  1904,  p.  17. 

3 It  is  possible  that  some  of  the  supposed  hydrous  silicates  of  aluminum  which  have  been  described  are 
merely  mixtures  of  colloidal  silica  and  colloidal  alumina.  This  is  claimed  by  H.  Stremme,  Centralbl. 
Min.,  Geol.  u.  Pal.,  1908,  p.  661, 1911,  p.  197,  and  1914,  p.  80,  in  the  cases  of  allophane,  halloysite,  and  mont- 
morillonite.  Their  definiteness  as  compounds,  on  the  other  hand,  is  affirmed  by  S . J.  Thugutt,  idem,  1911, 
p.  97,  and  1912,  p.  35.  See  also  R.  Gans,  idem,  1913,  p.  699,  and  1914,  p.  365.  Several  of  these  minerals  have 
been  studied  physically  by  E.  Lowenstein,  Zeitschr.  anorg.  Chemie,  vol.  63, 1909,  p.  69,  whose  experiments 
are  favorable  to  their  integrity. 


THE  DECOMPOSITION  OF  ROCKS. 


501 


fill  the  conditions  required  by  Kaiser’s  hypothesis.  The  latter  has 
value  only  as  a suggestion,  and  it  remains  to  he  seen  whether  it  is 
possible  to  trace  the  transformation  of  an  igneous  rock  into  bauxite 
through  all  of  its  stages.  So  far,  that  has  not  been  done. 

By  dehydration,  bauxite  passes  into  emery.  Emery,  therefore, 
may  be  regarded  as  the  metamorphic  equivalent  of  bauxite.1 

ABSORPTION. 

In  any  study  of  the  phenomena  attending  rock  decomposition  it  is 
important  to  note  that  the  leached  products  can  regain  some  of  the 
substances  which  they  have  lost.  Clays,  soils,  and  other  finely  divided 
mineral  matter  can  extract  acids,  bases,  and  salts  from  percolating 
solutions  and  in  doing  so  they  act  selectively.  As  a rule  a soil  takes 
up  potash  more  readily  than  lime,  magnesia,  or  soda,  and  retains  it 
tenaciously.  This  absorption  or  adsorption  of  potassium  compounds 
was  long  ago  observed  by  J.  T.  Way,2  and  the  phenomenon  has  since 
been  studied  by  many  observers.  R.  Warington 3 found  that  hydrox- 
ides of  iron  and  aluminum,  particularly  the  former,  were  especially 
active  as  absorbents,  and  most  so  in  the  presence  of  calcium  carbo- 
nate. That  is,  calcium  carbonate  converted  other  alkaline  salts  into 
carbonates,  which  were  more  easily  absorbed.  J.  Lemberg’s  papers 4 
on  the  alteration  of  silicates  are  rich  in  data  illustrating  the  reac- 
tions which  occur  during  absorption.  The  cases  studied  by  Lem- 
berg are  of  the  nature  of  double  decompositions,  in  which  a silicate 
loses  one  base  to  a solution  only  to  take  up  another.  The  recent 
investigations  by  M.  Dittrich 5 relate  to  changes  of  the  same  order. 
Saline  solutions  were  made  to  act  upon  decomposed  rocks  and  their 
changes  in  composition  were  observed. 

Double  decomposition,  however,  is  not  the  only  process  to  be  con- 
sidered in  this  connection.  Warington’s  experiments  point  directly 
to  an  absorption  by  colloids,  namely,  the  colloidal  hydroxides  of  iron 
and  alumina.  According  to  J.  M.  van  Bemmelen,6  those  “ hydrogels,” 
as  they  are  called,  together  with  similar  hydrogels  of  manganese 
and  copper  oxides,  show  a marked  absorptive  power  for  salts  of  the 

1 See  A.  Liebrich,  Zeitschr.  prakt.  Geologie,  1895,  p.  275. 

2 Jour.  Roy.  Agr.  Soc.  England,  vol.  11, 1850,  p.  313;  vol.  13, 1852,  p.  123. 

3 Jour.  Chem.  Soc.,  vol.  21,  1868,  p.  1. 

* See  especially  the  memoir  in  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  28,  1876,  p.  519. 

& Mitth.  Gr.  badisch.  geol.  Landesanstalt,  vol.  4, 1903,  p.  339;  Zeitschr.  anorg.  Chemie,  vol.  47, 1905,  p.  151. 
The  two  papers  cover  the  same  ground  in  part,  but  are  not  absolutely  identical.  A later  paper  by  Dittrich 
is  inMitth.  Gr.  badisch.  geol.  Landesanstalt,  vol.  5, 1907,  p.  1.  See  also  J.  Dumont,  Compt.  Rend.,  vol.  142, 
1906,  p.  345,  on  the  decomposition  of  potassium  carbonate  by  clay,  etc.,  and  O.  Schreiner  and  G.  H.  Failyer, 
Bull.  Bur.  Soils,  No.  32,  U.  S.  Dept.  Agr.,  1906,  on  the  absorption  of  phosphoric  acid  and  potash  by  soils. 
Bull.  No.  52, 1908,  of  the  same  Bureau,  by  H.  E.  Patten  and  W.  H.  Waggaman,  is  a general  discussion  of 
absorption  by  soils,  with  many  references  to  literature.  See  also  E.  G.  Parker,  Jour.  Agric.  Research, 
vol.  1,  1913,  p.  179. 

6 Zeitschr.  anorg.  Chemie,  vol.  23, 1900,  p.  321.  See  especially  pp.  358  and  364.  An  earlier  paper  by  Van 
Bemmelen  in  Landw.  Versuchs-Stationen  (Berlin),  vol.  21,  p.  135,  should  also  be  noted.  J.  E.  Harris 
(Jour.  Physical  Chem.,  vol.  18,  p.  355,  1914)  has  shown  that  soils  and  kaolin  exert  a selective  influence  in 
the  absorption  of  salts;  the  bases  being  retained  and  the  acids  set  free. 


502 


THE  DATA  OF  GEOCHEMISTRY. 


alkalies  and  alkaline  earths.  There  are  also  colloidal  complexes  of  ferric 
and  aluminic  silicates,  and  of  humus,  which  act  in  the  same  way. 
These  substances  act,  first,  as  absorbents,  in  some  manner  which  is  not 
clearly  understood;  and  the  salts  which  they  take  up  can  react  later 
with  various  saline  solutions  by  double  decomposition.  When  the 
colloids  pass  over  into  crystalline  substances,  they  lose  in  great  meas- 
ure their  absorptive  capacity.  It  has  also  been  shown  by  Van  Bem- 
melen 1 that  plastic  clays  have  the  greatest  efficiency  as  absorbents  of 
water,  nonplastic  clays  being  inferior  in  this  respect.  It  is  now  gen- 
erally believed  that  the  plasticity  of  a clay  is  due  to  the  colloid  sub- 
stances which  it  happens  to  contain.  This  supposition  was  clearly 
stated  by  T.  Schlosing  2 as  long  ago  as  1888,  and  advocated  later  by 
P.  Kohland.3  It  has  recently  been  developed  more  fully  by  A.  S. 
Cushman,4  whose  experiments  upon  the  binding  power  of  road-making 
materials  are  apparently  conclusive.5 6 

SAND. 

The  complete  disintegration  of  a rock  is  commonly  followed  by  a 
removal  of  the  fragmentary  material  from  its  original  site.  The 
transported  products  are  much  more  abundant  than  the  sedentary. 
This  transportation  may  be  effected  in  various  ways — by  flowing 
streams,  by  glacial  ice,  or  by  winds — and  it  is  accompanied  to  a cer- 
tain extent  by  a separation  of  the  rock  residues  into  substances  of 
different  kinds.  A stream  deposits  its  load  first  as  coarse  gravel, 
then  as  sand,  and  finally,  often  with  extreme  slowness,  as  silt  or  clay. 
The  gravel  consists  merely  of  fragments,  more  or  less  rounded,  of 
the  original  rock  or  of  its  larger  inclusions.  The  sand  contains  finer 
particles  of  undecomposed  minerals,  with  quartz  usually  predomi- 
nating. The  silt  is  composed  largely  of  decomposition  products,  such 
as  kaolinite,  hydroxides  of  iron  or  aluminum,  and  the  like.  These 
substances  shade  into  one  another,  and  their  exact  nature  in  any 
specific  case  will  depend  upon  the  thoroughness  with  which  the  pri- 
mary decomposition  was  effected ‘and  upon  mechanical  factors  such 
as  the  velocity  of  the  stream. 

The  term  “sand”  is  vaguely  employed  to  denote  very  different 
substances.  Volcanic  sand,  for  example,  is  finely  divided  lava  or 
lava  spray;  coral  or  shell  sand  is  made  up  of  broken  corals  and 
shells,  and  so  on.  Even  if  we  restrict  the  use  of  the  word,  for  present 
purposes,  to  the  granular  products  of  rock  decomposition  we  shall 


1 Zeitschr.  anorg.  Chemie,  vol.  42,  1904,  p.  314. 

2 Chimie  agricole,  in  Fremy’s  Encyclopedic  chimique,  p.  67. 

3 Zeitschr.  anorg.  Chemie,  vol.  41,  1904, 325. 

* Bulls.  No.  85,  1904,  and  No.  92, 1905,  Bur.  Chemistry,  U.  S.  Dept.  Agr.,  and  Trans.  Am.  Ceramic  Soc., 

vol.  6, 1904.  Cushman  cites  several  other  authorities  than  those  mentioned  here. 

6 See  also  F.  E.  Grout,  Jour.  Am.  Chem.  Soc.,  vol.  27,  1905,  p.  1037.  Grout  admits  that  colloids  may 
assist  in  producing  plasticity,  but  thinks  that  "molecular  attraction  ” is  a more  important  cause.  A paper 
by  R.  Lucas  on  the  physical  properties  of  clays  appeared  in  Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  p.  33. 


THE  DECOMPOSITION  OF  ROCKS. 


503 


find  that  we  have  many  dissimilar  bodies  to  deal  with.  Quartz  and 
feldspar  are  the  commonest  minerals  in  the  rocks;  hence  quartz  and 
feldspar  fragments  are  the  chief  constituents  of  river  sands.  But 
the  feldspars  are  largely  decomposed,  and  therefore  the  sands  repre- 
sent most  frequently  a concentration  of  the  more  stable  quartz. 
Sands  also  contain  the  other  rock-forming  minerals,  and  these  may  be 
either  disseminated  throughout  the  larger  deposits  or  segregated  be- 
hind bars  or  in  hollows  by  the  action  of  gravity.  The  black  sands 
of  many  well-known  localities  represent  concentrations  of  heavy  and 
slightly  alterable  minerals,  such  as  magnetite,  ilmenite,  chromite,  etc. 
The  gem  gravels  of  Ceylon,  the  monazite  sands  of  North  Carolina 
and  Brazil,  and  similar  segregations  of  tinstone  all  serve  as  illustra- 
tions of  the  way  in  which  the  heavier  minerals  of  an  eroded  region 
may  be  concentrated  at  favorable  points.  The  accumulations  of  gold, 
platinum,  or  iridosmine  in  placer  deposits  are  other  examples  of  this 
mechanical  sorting.  It  is  merely  a separation  of  heavy  from  light 
minerals,  the  stable  from  the  unstable,  and  the  coarse  from  the  fine. 

There  have  been  many  examinations  of  sands  from  a mineralogical 
standpoint,  and  the  fact  that  they  contain  a large  number  of  mineral 
species  is  well  established.  The  Bagshot  sands  near  London  contain, 
according  to  A.  B.  Dick,1  about  75  per  cent  of  quartz,  20  of  feldspar, 
and  small  but  determinable  proportions  of  magnetic  grains,  zircon, 
rutile,  and  tourmaline.  In  river  sands  from  the  Mesvrin,  near  Autun, 
France,  A.  Michel-Levy 2 found  magnetite,  zircon,  olivine,  garnet, 
sphene,  chromite,  tourmaline,  and  corundum.  J.  Thoulet3  examined 
desert  sand  from  the  Algerian  Sahara  which  consisted  of  89.46  per 
cent  of  quartz  and  9.47  of  feldspar,  with  minute  quantities  of  mag- 
netite, chromite,  garnet,  olivine,  amphibole,  pyroxenes,  calcium  car- 
bonate, sodium  and  potassium  chlorides,  and  clay.  In  a glacial  sand 
from  the  Tyrol,  H.  Wichmann  4 discovered  quartz,  orthoclase,  micas, 
chlorite,  epidote,  hornblende,  actinolite,  garnet,  zircon,  rutile,  tour- 
maline, hematite,  and  altered  pyrite.  J.  A.  Phillips5  found  the  red 
sands  of  the  Arabian  Desert  to  consist  essentially  of  quartz  grains 
coated  with  oxide  of  iron.  After  washing  with  hydrochloric  acid  the 
grains  contained  98.53  per  cent  of  silica.  Probably  the  most  elab- 
orate investigation  of  this  general  kind  is  that  by  J.  W.  Retgers  6 on 
the  dune  sands  of  Holland.  In  these  the  principal  minerals  are  quartz, 
garnet,  augite,  hornblende,  tourmaline,  epidote,  staurolite,  rutile, 
zircon,  magnetite,  ilmenite,  orthoclase,  calcite,  and  apatite.  Subor- 
dinate species  are  plagioclase,  microcline,  iolite,  titanite,  sillimanite, 

1 Geology  of  London,  vol.  1,  1889,  p.  523;  Nature,  vol.  36,  1887,  p.  91. 

2 Bull.  Soc.  min.,  vol.  1, 1878,  p.  39. 

3 Idem,  vol.  4, 1881,  p.  262. 

4 Min.  pet.  Mitt.,  vol.  7, 1886,  p.  452.  The  list  of  minerals  found  by  W.  M.  Hutchings  (Geol.  Mag.,  1894, 

p.  300)  in  English  lake  sediments  is  very  similar  to  this. 

6 Quart.  Jour.  Geol.  Soc.,  vol.  38,  1882,  p.  110. 

6 Neues  Jahrb.,  1896,  vol.  1,  p.  16;  Rec.  trav.  chim.,  vol.  11,  1892,  p.  169. 


504 


THE  DATA  OF  GEOCHEMISTRY. 


olivine,  kyanite,  corundum,  and  spinel.  The  quartz,  however,  formed 
90  to  95  per  cent  of  the  mixture.  A beach  sand  from  Pensacola, 
Fla.,  analyzed  by  G.  Steiger  in  the  laboratory  of  the  United  States 
Geological  Survey,  contained  99.65  per  cent  of  Si02.  Many  sea  and 
river  sands  consist  of  nearly  pure  quartz,  pure  enough  to  be  used  in 
glass  making.  The  following  analyses,  by  W.  Mackie,1  represent 
sands  of  diverse  origin  from  various  points  in  Scotland. 

Analyses  of  sands. 

A.  B.  Glacial  sands. 

C.  Average  of  five  river  sands. 

D.  Sea  sand. 

E.  Sea  sand  derived  from  subsilicic  igneous  rocks. 

F.  Blown  sand. 


A 

B 

c 

D 

E 

F 

Si02 

77.  78 

90.  74 

82. 13 

89.  99 

55.  03 

91.  39 

ai2o3 

9.  95 

5. 16 

9.  04 

7.  36 

14. 12 

5.44 

Fe203 

2.  55 

1. 14 

2.94 

.72 

10. 15 

.89 

FeO 

.21 

.08 

. 13 

. 16 

MnO 

Trace. 

Trace. 

Trace. 

CaO 

.71 

.69 

1.  28 

.46 

6.  88 

Trace. 

MgO 

.17 

Trace. 

.53 

Trace. 

6.  38 

Trace. 

K20 

2.  50 

1. 19 

1.  93 

.84 

1.  66 

1. 19 

Na20 

1.  82 

.26 

.95 

.'33 

.87 

.70 

P2Os 

.20 

Ignition 

2.74 

1.  30 

1.  01 

.60 

4.  55 

.65 

98.  43 

100.  56 

100.  01 

100.  43 

99.  64 

100.  42 

SILT. 


Between  sand  and  silt  the  difference  is  partly  one  of  kind  and 
partly  one  of  degree.  Silt  consists  of  the  finer  particles  of  rock  sub- 
stance, which,  by  virtue  of  their  lightness,  are  carried  farthest  by 
streams.  This  difference  is  mechanical.  On  the  chemical  side  sand 
and  silt  differ  in  composition,  but  not  radically.  In  sand  quartz  is 
the  principal  mineral;  in  silt  the  hydroxides  and  hydrous  silicates 
predominate.  Neither  product  is  quite  free  from  the  other,  but  the 
distinction  holds  good  in  the  main.  The  separation  of  quartz  from 
clay  is  rarely  quite  complete,  but  is  often  approximately  so. 

Analyses  of  river  silt  or  mud  are  not  very  numerous,  nor  are  they 
always  comparable.  Some  samples  were  analyzed  after  drying  at 
100°;  others  were  air  dried.  Furthermore,  silts  represent  blended 


i Trans.  Edinburgh  Geol.  Soc.,  vol.  8, 1901,  p.  60.  On  the  mineralogical  examination  of  sands  see  also 
C.  H.  Warren,  Technology  Quart.,  vol.  19,  1906,  p.  317.  For  analyses  of  American  glass  sands  see  Bull. 
U.  S.  Geol.  Survey  No.  315,  1907,  pp.  376,  382.  A sand  rich  in  fluorite  is  found  at  St.  Ives  Bay,  Cornwall. 
See  T.  Crook  and  G.  M.  Davies,  Geol.  Mag.,  1909,  p.  120.  On  the  composition  of  soil  particles  see  G.  H. 
Failyer,  J.  G.  Smith,  and  H.  It.  Wade,  Bull.  Bur.  Soils,  No.  54,  U.  S.  Dept.  Agr.,  1908.  On  criteria  for 
the  recognition  of  different  types  of  sand  grains  see  W.  H.  Sherzer,  Bull.  Geol.  Soc.  America,  vol.  21, 1910, 
p.  625.  On  minerals  in  Ohio  sands  see  D.  D.  Condit,  Jour.  Geology,  vol.  20,  p.  153, 1912.  On  Scottish  sands 
see  T.  O.  Bosworth,  Geol.  Mag.,  1912,  p.  515. 


THE  DECOMPOSITION  OF  ROCKS. 


505 


material,  gathered  by  a river  from  various  sources  and  derived  from 
very  dissimilar  rocks.  Mississippi  silt,  for  instance,  if  collected  near 
New  Orleans,  will  be  made  up  of  contributions  from  various  tribu- 
taries of  the  river,  and  these  may  be  quite  unlike.  A region  rich  in 
femic  rocks  will  yield  sediments  rich  in  iron,  while  an  area  of  granite 
will  give  aluminous  residues.  Silts,  therefore,  are  by  no  means  uni- 
form in  character,  although  they  have  a general  family  resemblance. 
The  following  analyses  are  enough  to  show  the  more  obvious  differ- 
ences and  similarities : 


Analyses  of  silts. 

A.  Rhine  silt,  from  the  delta  in  the  Lake  of  Constance.  Analysis  by  G.  Bischof,  Lehrbuch  der 
chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  1,  p.  498.  Bischof  gives  other  data  also  concerning 
Rhine  deposits. 

B.  Danube  silt,  at  Vienna.  Analysis  by  Bischof,  op.  cit.,  512. 

C.  Vistula  silt,  at  Culm.  Analysis  by  Bischof,  op.  cit.,  p.  515. 

D.  Nile  mud.  Analysis  by  C.  v.  John,  Verhandl.  K.-k.  geol.  Reichsanstalt,  1896,  p.  259.  See  also 
analyses  cited  by  G.  Bischof,  op.  cit.,  pp.  518-521;  and  others  cited  by  L.  Horner,  in  two  memoirs  Philos. 
Mag.,  4th  ser.,  vol.  9,  1855,  p.  469;  Philos.  Trans.,  vol.  148,  1859,  p.  61.  In  Science,  vol.  23, 1906,  p.  364,  there 
is  an  incomplete  analysis  by  C.  H.  Stone  of  Mississippi  silt.  A much  more  complete  analysis  by  G.  Steiger  is 
given  in  Jour.  Washington  Acad.  Sci.,  vol.  4,  p.  59, 1914.  For  modern  analyses  of  siltfrom  the  Danube  and  its 
tributaries  see  J.  F.Wolfbauer,  Monatsh.  Chemie,  vol.  4, 1884,  p.  417,  and  A.  Schwager,  Geognost.  Jahreshefte, 
1893,  p.  87.  F.  Schucht  (Jahrb.  K.  preuss.  geol.  Landesanstalt,  vol.  25,  p.  442)  cites  analyses  of  Elbe  silt  by 
H.  Siissenguth. 


A 

B 

C 

D 

Si02 

50. 14 

45.  02 

49.  67 

45. 10 

A1203 

4.  77 

7.  83 

11.  98 

15.  95 

Fe90q 

2.  69 

9. 16 

11.  73 

13.  25 

MnO 

.35 

MgO 

.34 

.44 

. 27 

2.  64 

CaO 

. 77 

.32 

. 88 

4.  85 

K20 

.55 

(?) 

(?) 

24.  08 

1.  29 

1.  95 

Na20 

.54 

.69 

.85 

CaC03 

30.  76 

MgCOg 

1.  24 

6.  32 

FeC03 

5.  20 

so3 

. 34 

H20- 

} .99 

} 4.58 

) 

6.  70 

h2o+ 

| 23.  21 

a 8.  84 

Organic  matter 

J 

J 62.  25 

Loss 

1.  66 

J 

100.  00 

100.  00 

99.  72 

100.  47 

a Loss  on  ignition. 


b Probably  including  alkalies. 


The  higher  proportion  of  calcium  carbonate  in  the  silts  of  the 
upper  Rhine  and  Danube  is  probably  due  to  glacial  mud  produced 
by  the  grinding  of  limestones.  The  Nile  mud  is  a much  more  typical 
product. 

The  amount  of  sediment  carried  in  suspension  by  rivers  to  the  sea 
is  something  enormous.  The  quantity  delivered  annually  by  the 
Mississippi  to  the  Gulf  of  Mexico  is  estimated  by  A.  A.  Humphreys 


506 


THE  DATA  OF  GEOCHEMISTRY. 


and  H.  L.  Abbot 1 at  approximately  812,500,000,000  pounds,  or 
about  370,000,000  metric  tons.  The  Nile,  according  to  A.  Chelu,2 
carries  into  the  Mediterranean  51,428,500  metric  tons  a year.  These 
quantities,  vast  as  they  are  and  sustained  by  similar  estimates  for 
many  other  streams,  represent  only  a part  of  the  transported  sedi- 
ments. The  products  of  rock  decomposition  are  distributed  along 
the  entire  course  of  a river,  and  what  proportion  is  delivered  to  the 
ocean  no  one  can  say.  The  fraction  can  not  be  very  large.  Upon 
reaching  salt  water,  however,  the  silt  is  quickly  deposited,  and  only 
a small  part  of  it  is  carried  far  out  to  sea.3  Salts  in  solution  accelerate 
the  deposition  of  sediments,  and  so,  too,  do  acids  and  alkalies.  In 
general,  this  precipitation  is  effected  by  electrolytes,  but  the  explana- 
tion of  the  phenomenon  is  still  obscure.4  Colloid  substances  also 
promote  sedimentation,  a fact  which  has  many  practical  applications. 
The  clearing  of  coffee  by  white  of  egg  or  the  fining  of  sirups  by  blood 
or  gelatin  is  a phenomenon  of  the  most  familiar  kind.  W.  Spring 5 6 
has  shown  that  the  organic  matter  of  natural  waters  is  incompatible 
with  iron,  the  two  substances  separating  out  as  a flocculent  precipi- 
tate. One  part  of  colloidal  ferric  oxide  will  remove  ten  parts  of 
humus  from  solution.  The  use  of  alum  or  iron  salts  in  large  filtration 
plants  is  an  application  of  this  principle.  These  salts  hydrolyse, 
forming  partly  colloidal  substances.  The  organic  matter  or  humus 
of  natural  waters  is  itself  colloidal.  The  two  form  a flocculent  pre- 
cipitate which  quickly  subsides  and  carries  down  with  it,  mechanically 
inclosed,  even  the  finest  sediments.  The  remarkable  clearness  of 
swamp  waters  is  perhaps  due  to  the  flocculation  of  their  organic  mat- 
ter and  the  consequent  precipitation  of  all  suspended  particles. 
Sedimentation,  in  short,  is  a complex  phenomenon,  and  several  dis- 
tinct agencies  assist  in  bringing  it  about. 

1 Report  on  physics  and  hydraulics  of  Mississippi  River,  1876,  p.  148.  R.  B.  Dole  and  H.  Stabler  (U.  S. 
Geol.  Survey  Water-Supply  Paper  No.  234,  p.  83,  1909)  estimate  the  total  sediment  carried  to  tidewater 
annually  by  the  rivers  of  the  United  States  as  513,000,000  tons  of  2,000  pounds. 

2 Le  Nil,  le  Soudan,  PEgypte,  1891,  p.  177. 

3 For  a table  giving  the  amount  of  suspended  sediment  in  sea  water  at  various  points,  see  J.  Murray 
and  R.  Irvine,  Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1890-91,  p.  229.  The  Atlantic,  for  example,  in  latitude 
51°  20'  N.,  longitude  31°  W.,  carries  0.0052  gram  of  sediment  in  14  liters,  or  1,604  tons  per  cubic  mile.  In 
the  Firth  of  Forth  the  quantity  rises  to  0.0259  gram,  and  in  the  Red  Sea  it  falls  to  0.0006. 

4 See  C.  Schlosing,  Compt.  Rend.,  vol.  70,  1870,  p.  1345;  W.  H.  Brewer,  Am.  Jour.  Sci.,  3d  ser.,  vol.  29, 

1885,  p.  1;  C.  Barns,  Bull.  U.  S.  Geol.  Survey  No.  36, 1886;  Baras  and  E.  A.  Schneider,  Zeitschr.  physikal. 
Chemie,  vol.  8, 1891,  p.  285;  W.  Spring,  Rec.  trav.  chim.,  vol.  19,  1900,  p.  204;  and  G.  Bodlander,  Neues 
Jahrb.,  1903,  Band  2,  p.  147.  See  also  T.  S.  Hunt,  Proc.  Boston  Soc.  Nat.  Hist.,  vol.  16,  1874,  p.  302; 
W.  Ramsay,  Quart.  Jour.  Geol.  Soc.,  vol.  32,  1876,  p.  129;  J.  Joly,  Proc.  Roy.  Dublin  Soc.,  vol.  9,  1900, 
p.  325;  L.  F.  Vernon-Harcourt,  Proc.  Inst.  Civ.  Eng.,  vol.  142,  1900,  p.  272;  and  J.  Thoulet,  Annales  des 
mines,  8th  ser.,  vol.  19, 1891,  p.  5. 

6 Bull.  Acad.  roy.  sci.  Belgique,  3d  ser.,  vol.  34, 1897,  p.  578. 


THE  DECOMPOSITION  OF  ROCKS. 


507 


GLACIAL  AND  RESIDUAL  CLAYS. 

Between  the  silt  formed  by  the  decay  of  rocks  and  that  produced 
by  glaciers  there  is  a radical  distinction.  The  one  is  termed  by  T.  C. 
Chamberlin  and  R.  D.  Salisbury  1 rock  rot;  the  other  is  rock  flour. 
One  has  been  produced  by  a thorough  leaching  of  the  rocks  under 
atmospheric  agencies;  but  glacial  mud  is  composed  of  material  which 
was  ground  to  powder  under  conditions  that  protected  it  in  some 
measure  from  the  oxygen  and  carbonic  acid  of  the  air.  The  latter, 
therefore,  has  retained  a larger  proportion  of  soluble  matter  than  the 
former.  These  differences  appear  in  the  following  analyses,  made  by 
Riggs  in  the  laboratory  of  the  United  States  Geological  Survey,  and 
cited  by  Chamberlin  and  Salisbury  in  the  memoir  mentioned  above. 
With  them  I give  two  analyses  by  W.  Mackie  2 of  bowlder  clay  from 
Scottish  localities. 

Analyses  of  clays. 


(1)  Residuary  clays,  dried  at  100°: 

A.  From  Dodgeville,  Wisconsin,  4|  feet  below  surface. 

B.  The  same,  8J  feet  below  surface. 

C.  From  Cobb,  Wisconsin,  4|  feet  below  surface. 

D.  The  same,  8J  feet  below  surface. 

(2)  Glacial  or  drift  clays: 

E.  F.  From  Milwaukee.  Dried  at  100°. 

G,  H.  Scottish  bowlder  clays,  Mackie. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02 

71. 13 

49.  59 

49. 13 

53.  09 

40.  22 

48.  81 

80. 13 

74.89 

A1203 

12.  50 

18.  64 

20.  08 

21.  43 

8.  47 

7.  54 

9.  06 

12.  22 

Fe203 

5.  52 

17. 19 

11.  04 

8.  53 

2.  83 

2.  53 

1 0 A A 

l A 90 

FeO 

.45 

.27 

.93 

.86 

.48 

.65 

> Z.  44 

> 4.  zy 

MgO 

.38 

. 73 

1.  92 

1.  43 

7.  80 

7.  05 

.50 

.07 

CaO 

.85 

.93 

1.  22 

.95 

15.  65 

11.  83 

.72 

1.  58 

Na20 

2. 19 

.80 

1.  33 

1.  45 

.84 

.92 

.66 

1.  06 

K20 

1.  61 

.93 

1.  60 

.83 

2.  36 

2.  60 

2.  08 

2.  64 

H20 

4.  63 

10.  46 

11.  72 

10.  79 

1.  95 

2.  02 

a4. 11 

a 3.  21 

Ti02 

.45 

.28 

. 13 

. 16 

.35 

.45 

p2o5 

.02 

.03 

.04 

*03 

.05 

.13 

. 14 

.07 

MnO 

.04 

.01 

.06 

.03 

Trace. 

.03 

. 17 

C02 

.43 

. 30 

. 39 

.29 

18.  76 

15.  47 

Organic  C 

. 19 

. 34 

1.  09 

.22 

. 32 

. 38 

so3 

. 13 

.05 

Cl 

. 06 

.04 

100.  39 

100.  50 

100.  68 

100.  09 

100.  27 

100.  50 

99.  84 

100.  20 

« Loss  on  ignition.  Must  include  CO2  and  organic  matter. 


1 Sixth  Ann.  Rept.  U.  S.  Geol.  Survey,  1885,  pp.  249-250.  According  to  S.  Weidman  (private  communi- 
cation) the  clay  from  Dodgeville  is  really  loessial,  and  the  two  from  Milwaukee  are  lacustrine.  Accurate 
diagnosis  appears  to  be  difficult. 

2 Trans.  Edinburgh  Geol.  Soc.,  vol.  8, 1901,  p.  60. 


508 


THE  DATA  OF  GEOCHEMISTRY. 


In  the  two  Wisconsin  clays  the  carbonates  represent  magnesian 
limestone.  The  Scottish  clays  had  evidently  a different  parentage. 
Glacial  clays  often  contain  carbonates,  which  are  rarely  conspicuous 
in  rock  residues.1  Even  residual  soils  derived  from  the  decay  of 
limestones  are  practically  free  from  carbonates,  as  the  subjoined 
analyses  show.  The  residues  are  merely  clay  or  silt  entangled  with 
the  limestone  when  the  latter  was  laid  down  and  released  by  its 
solution. 

Analyses  of  residual  clays. 

A.  Residual  clay  from  so-called  Trenton  limestone,  Lexington,  Virginia.  Analysis  by  R.  B.  Riggs. 
Described  by  I.  C.  Russell,  Bull.  U.  S.  Geol.  Survey  No.  52, 1889.  Russell  especially  discusses  the  cause  of 
red  coloration  in  clays.  On  this  subject  see  also  W.  O.  Crosby,  Am.  Geologist,  vol.  8, 1891,  p.  72;  and  W. 
Spring,  Rec.  trav.  chim.,  vol.  17, 1898,  p.  202. 

B.  Residual  clay  from  limestone,  Staunton,  Virginia.  Analysis  by  George  Steiger,  U.  S.  Geol.  Survey. 

C.  Residual  clay  from  Knox  dolomite,  Morrisville,  Alabama.  Analysis  by  W.  F.  Hillebrand.  Described 
by  Russell,  op.  cit. 


A 

B 

c 

Si02 

43.  07 

55.  90 

55.  42 

A1203 

25.  07 

19.  92 

22. 17 

Fe90q 

15.16 

7.  30 

8.  30 

FeO 

.39 

Trace. 

MgO 

.03 

1. 18 

1. 45 

CaO 

. 63 

. 50 

. 15 

Na20 „ 

1.  20 

.23 

. 17 

K20 

2.  50 
} 12.  98 

4.  79 

2.  32 

H20- 

2.  54 

2. 10 

h2o+ 

6.  52 

7.  76 

Ti02 

J 

.20 

P20, 

. 10 

C02 

.38 

100.  64 

99.  95 

99.84 

i Innumerable  analyses  of  clays  and  soils  have  been  made  for  agricultural  and  other  industrial  purposes 
Several  States  have  issued  special  reports  upon  their  clay  industries.  Among  the  reports  of  geological 
surveys  are  those  of  Connecticut,  Bull.  No.  4,  1905,  G.  F.  Loughlin;  New  Jersey,  1878,  G.  H.  Cook;  New 
Jersey,  vol.  6, 1904,  H.  Ries  and  H.  B.  Kummel;  Maryland,  vol.  4,  pp.  203-503,  Ries;  Virginia,  Bdll.  No. 
11,  1906,  Ries;  West  Virginia,  vol.  3,  1905,  G.  P.  Grimsley;  South  Carolina,  Bull.  No.  1,  4th  ser.,  1904,  E. 
Sloan;  Georgia,  Bull.  No.  6 A,  1898,  G.  E.  Ladd;  Alabama,  Bull.  No.  6, 1900,  Ries;  Wisconsin,  Bull.  No.  7, 
1901,  E.  R.  Buckley;  Missouri,  vol.  11,  1896,  H.  A.  Wheeler;  Indiana,  Twenty-ninth  Ann.  Rept.,  1905, 
W.  S.  Blatchley;  Iowa,  vol.  14, 1904,  S.  W.  Beyer  and  I.  A.  Williams;  Wisconsin,  Bull.  No.  15, 1906,  Ries. 
See  also  the  volumes  on  chemical  analyses  published  by  the  geological  surveys  of  Pennsylvania  and  Ken- 
tucky; Bull.  New  York  State  Mus.,  vol.  3,  No.  12,  1895,  Ries;  and  Bull.  U.  S.  Geol.  Survey  No.  228,  pp. 
351-370.  Ries,  Sixteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  1895,  pp.  554-574,  gives  a long  table  of  analyses 
of  American  clays,  and  a general  report  by  Ries  forms  Prof.  Paper  11  of  the  Survey,  1903.  Bull.  U.  S. 
Geol.  Survey  No.  143,  1896,  by  J.  C.  Branner,  is  a bibliography  of  clays  and  ceramics.  The  American 
Ceramic  Society  has  since  (1906)  published  a more  elaborate  bibliography  by  the  same  author.  Geology 
of  North  Carolina,  vol.  1,  1875,  contains  much  material  on  soils,  and  so,  too,  do  the  volumes  on  cotton  pro- 
duction published  by  the  Tenth  U.  S.  Census.  The  literature  regarding  soils  is  too  voluminous  to  admit 
of  any  summary  here.  Recent  papers  of  interest  are  those  by  N.  Sibirtzew,  Compt.  rend.  VII  Cong, 
intemat.  geol.,  1897,  p.  73,  on  the  soils  of  Russia,  and  by  W.  Frear  and  C.  P.  Beistle,  Jour.  Am.  Chem. 
Soc.,  vol.  25, 1903,  p.  5.  Work  by  Schlosing  and  Van  Bemmelen  on  tropical  soils  has  already  been  cited. 
W.  Maxwell  (Lavas  and  soils  of  the  Hawaiian  Islands,  Honolulu,  1898)  and  A.  B.  Lyons  (Am.  Jour.  Sci., 
4th  ser.,  vol.  2,  1896,  p.  421)  have  also  contributed  to  this  phase  of  the  subject.  On  the  constitution  of 
arable  soils  see  L.  Cayeux,  Ann.  Soc.  g6ol?  du  Nord,  vol.  34, 1905,  p.  146.  On  the  origin  and  nature  of  soils 
see  N.  S.  Shaler,  Twelfth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1891,  p.  219.  On  fuller’s  earth  see  T.  W. 
Vaughan,  Bull.  U.  S.  Geol.  Survey  No.  213,  1903,  p.  392,  and  J.  T.  Porter,  Bull.  No.  315, 1907,  p.  268.  On 
soils  in  general  see  E.  W.  Hilgard’s  treatise  “Soils,”  published  in  1906. 


THE  DECOMPOSITION  OF  ROCKS. 


509 


LOESS. 

In  its  chemical  composition,  the  widespread  earthy  deposit  known 
as  loess  closely  resembles  the  glacial  clays.  It  commonly,  but  not 
invariably,  contains  much  calcium  carbonate,  and  the  same  is  true 
of  the  related  or  perhaps  identical  adobe  soil  of  the  more  arid  regions 
in  our  Western  States.  The  more  striking  peculiarities  of  the  loess 
are  its  light  color,  its  extremely  fine  state  of  subdivision,  the  angular- 
ity of  its  particles,  its  lack  of  stratification,  its  coherence,  and  its 
porosity.  Furthermore,  the  fossils  found  in  loess  are  almost  without 
exception  the  remains  of  land  animals,  which  indicate  that  it  can  not 
be  a deposit  from  permanent  waters. 

Over  the  origin  of  loess  there  has  been  much  controversy,  but  the 
subject  is  one  that  admits  of  only  the  briefest  summary  here.  The 
prevalent  view  is  essentially  that  of  F.  Richthofen,1  who  interprets 
the  loess  of  China  as  an  eolian  formation.  In  the  arid  regions  of 
central  Asia  the  products  of  rock  disintegration  are  sorted  by  the 
winds,  and  the  finest  blown  dust  finally  comes  to  rest  where  it  is 
entangled  and  protected  by  the  grasses  of  the  steppes.  Temporary 
streams,  formed  by  torrential  rains,  assist  in  its  concentration  and 
bring  about  accumulations  of  loess  in  valleys  and  other  depressions 
of  the  land.  According  to  I.  C.  Russell,2  the  adobe  of  the  Great 
Basin  is  formed  essentially  in  this  way,  and  the  sediments  deposited 
in  the  so-called  “playa”  lakes,  whose  beds  are  dry  during  a great 
portion  of  the  year,  consist  of  this  material.  The  adobe  contains  the 
finer  products  formed  by  subaerial  erosion  of  the  mountain  slopes, 
and  may  be  commingled  sometimes  with  dust  of  volcanic  origin.  The 
loess  of  the  Missouri  and  upper  Mississippi  valleys  is  given  nearly  the 
same  interpretation  by  C.  R.  Keyes,3  only  in  this  case  the  dust  is 
formed  from  river  silt  left  on  the  dried  mud  banks  in  times  of  low 
water. 

The  loess  of  Iowa  is  regarded  by  W J McGee 4 as  a glacial  silt, 
deposited  along  the  margins  of  glaciers  during  the  glacial  period. 
W.  F.  Hume,5  studying  the  Russian  loess,  described  that  also  as 
glacial  silt,  distributed  partly  by  winds  and  partly  by  floods.  C. 
Davison  6 considers  loess  to  be  a product  of  glacial  erosion,  accumu- 
lated first  in  banks  of  snow  and  concentrated  later  in  the  valleys 

1 China,  vol.  1,  p.  74;  Geol.  Mag.,  1882,  p.  297.  See  also  R.  Pumpelly,  Am.  Jour.  Sci.,  3d  ser.,  vol.  17, 1879, 
p.  133.  For  analyses  of  Chinese  loess  see  A.  Schwager,  Geognost.  Jahreshefte,  1894,  p.  87.  For  German 
loess,  H.  G.  Schering,  Inaug.  Diss.,  Freiburg,  1909.  For  South  American  loess,  E.  H.  Ducloux,  Rev. 
Museo  de  la  Plata,  vol.  15,  1908,  p.  162.  The  loess  of  Argentina  has  been  studied  by  P.  Werling,  Inaug. 
Diss.,  Freiburg,  1911.  Other  analyses  of  loess  are  to  be  found  in  the  older  treatises  of  Bischof  and  Roth. 

2 Geol.  Mag.,  1889,  pp.  289, 342. 

s Am.  Jour.  Sci.,  4th  ser.,  vol.  6,  1898,  p.  299.  Keyes  describes  the  dust  storms  of  the  Missouri  Valley, 
in  which  great  quantities  of  aerial  sediments  are  carried  from  place  to  place. 

4 Eleventh  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1,  1891,  pp.  291,  435.  See  also.F.  Leverett,  Mon.  U.  S. 

Geol.  Survey,  vol.  38, 1899,  pp.  153-184,  for  an  account  of  Iowan  loess.  The  loess  of  Colorado  is  described  by 
S.  F.  Emmons  in  Mon.  U.  S.  Geol.  Survey,  vol.  27,  1896,  p.  263. 

6 Geol.  Mag.,  1892,  p.  549. 

6 Quart.  Jour.  Geol.  Soc.,  vol.  50,  1894,  p.  472. 


510 


THE  DATA  OF  GEOCHEMISTRY, 


by  the  rush  of  water  following  a thaw.  T.  C.  Chamberlin  1 is  inclined 
to  combine  the  various  theories  concerning  loess  and  to  regard  it  as 
both  glacial  and  eolian.  Here,  again,  as  in  so  many  other  instances, 
we  must  remember  that  similar  products  may  be  formed  in  several 
different  ways.  The  loess  of  China  may  be  one  thing  and  that  of  the 
Mississippi  Valley  another.  They  are  alike  in  their  extreme  com- 
minution but  not  necessarily  identical  in  origin. 

A microscopic  examination  of  loess  from  Muscatine,  Iowa,  by  J.  S. 
Differ,2  showed  that  quartz  was  its  most  abundant  constituent. 
Orthoclase,  plagioclase,  and  hornblende  were  also  present,  with  occa- 
sional fragments  of  biotite  and  tourmaline,  some  carbonates,  and  clay 
colored  by  oxide  of  iron.  Chemical  analyses  of  loess  seem  not  to  be 
very  numerous.  The  following  were  made  in  the  laboratory  of  the 
United  States  Geological  Survey: 


Analyses  of  loess. 

A.  Near  Galena,  Illinois. 

B.  Near  Dubuque,  Iowa. 

C.  Vicksburg,  Mississippi. 

D.  Kansas  City,  Missouri.  Analyses  A to  D by  R.  B.  Riggs.  Discussed  by  T.  C.  Chamberlin  and  R.  D. 
Salisbury,  Sixth  Ann.  Rept.  U.  S.  Geol.  Survey,  1885,  p.  282.  Samples  dried  at  100°. 

E.  Cheyenne,  Wyoming. 

F.  Denver,  Colorado. 

G.  Highland,  Colorado.  Analyses  E to  G by  L.  G.  Eakins.  Discussed  by  S.  F.  Emmons,  Mon.  U.  S. 
Geol.  Survey,  vol.  27,  1896,  p.  263,  together  with  several  other  examples. 


A 

B 

C 

D 

E 

F 

G 

Si02 

64.  61 

72.  68 

60.  69 

74.  46 

67. 10 

69.  27 

60.  97 

ALOo 

10.  64 

12.  03 

7.  95 

12.  26 

10.  26 

13.  51 

15.  67 

Fe20, 

2.  61 

3.  53 

2.  61 

3.  25 

2.  52 

3.  74 

5.  22 

FeO 

.51 

.96 

. 67 

. 12 

.31 

1.  02 

.35 

MnO 

.05 

.06 

.12 

.02 

Trace. 

Trace. 

MgO 

3.  69 

1. 11 

4.  56 

1. 12 

1.  24 

1.  09 

1.  60 

CaO 

5.  41 

1.  59 

8.  96 

1.  69 

5.  88 

2.  29 

2.  77 

Na20 

1.  35 

1.  68 

1. 17 

1.  43 

1.  42 

1.  70 

.97 

K20 

2.  06 

2. 13 

1.  08 

1.  83 

2.  68 

3. 14 

2.  28 

H20 

2.  05 

2.  50 

1. 14 

2.  70 

5.  09 

4. 19 

9.  83 

Ti02 

.40 

.72 

.52 

. 14 

F oOk 

.06 

.23 

. 13 

.09 

. 11 

.45 

. 19 

C02 

6.  31 

.39 

9.  63 

.49 

3.  67 

Trace. 

.31 

C,  organic 

. 13 

.09 

. 19 

. 12 

so3 

. 11 

.51 

.12 

.06 

Cl 

.07 

.01 

.08 

.05 

100.  06 

100.  22 

99.  62 

99.  83 

100.  28 

100. 40 

100. 16 

The  following  analyses  of  adobe  soil  were  made  in  the  laboratory  of 
the  United  States  Geological  Survey,  by  L.  G.  Eakins. 


1 Jour.  Geology,  vol.  5,  1897,  p.  795.  See  also  T.  C.  Chamberlin  and  R.  D.  Salisbury,  Sixth  Ann.  Rept. 
U.  S.  Geol.  Survey,  1885,  p.  250. 

2 Bull.  U.  S.  Geol.  Survey  No.  150, 1898,  p.  65. 


THE  DECOMPOSITION  OF  ROCKS. 


511 


Analyses  of  adobe  soil. 


A.  Salt  Lake  City,  Utah.  B.  Santa  Fe,  New  Mexico.  C.  Fort  Wingate,  New  Mexico.  D.  Humboldt, 
Nevada. 


A 

B 

C 

D 

Si02 

19.  24 

66.  69 

26.  67 

44.  64 

A1203 

3.  26 

14. 16 

.91 

13. 19 

FetOo 

1.  09 

4.  38 

. 64 

5. 12 

MnO 

Trace. 

.09 

Trace. 

. 13 

2.  75 

1.  28 

.51 

2.  96 

CaO 

38.  94 

2.  49 

36.  40 

13.  91 

Na20 

Trace. 

. 67 

Trace. 

.59 

k2o 

Trace. 

1.  21 

Trace. 

1.  71 

h2o 

1.  67 

4.  94 

2.  26 

3.  89 

P,0« 

. 23 

. 29 

. 75 

. 94 

co2 

29.  57 

. 77 

25.  84 

8.  55 

Organic  matter 

2.  96 

2.  00 

5. 10 

3.43 

SO, 

.53 

.41 

.82 

.64 

Cl 

.11 

.34 

.07 

. 14 

100.  35 

99.  72 

99.  97 

99.  84 

The  extremely  variable  but  generally  calcareous  nature  of  these 
soils  is  sufficiently  indicated. 

MARINE  SEDIMENTS. 


The  oceanic  sediments  are  naturally  complex,  for  they  are  derived 
from  the  most  varied  sources.  Near  shore  are  found  the  products  of 
wave  erosion,  the  silt  brought  in  by  streams,  remnants  of  shells  and 
corals,  and  organic  matter  from  seaweeds.  In  some  localities,  as 
around  coral  islands,  the  debris  consists  chiefly  of  calcium  carbonate, 
and  that  compound,  as  shown  in  a previous  chapter,1  is  also  formed 
as  a chemical  precipitate. 

Floating  ice,  the  remnants  of  polar  glaciers,  deposits  more  or  less 
stony  material  in  the  warmer  parts  of  the  ocean;  and  volcanic  ash, 
from  either  submarine  or  subaerial  eruptions,  covers  large  areas  on 
the  bottom  of  the  sea.  Even  cosmic  dust,  which  has  been  gently  fall- 
ing throughout  all  geologic  time,  has  made  perceptible  contributions 
to  the  great  mass  of  oceanic  sediments.2 

Notwithstanding  the  diversity  of  these  deposits,  their  distribution 
is  not  entirely  fortuitous.  River  silt,  for  example,  is  an  important 
oceanic  sediment  only  in  a belt  surrounding  the  continents  and  com- 
paratively near  shore.  In  relatively  small  amounts  it  is  diffused 
through  all  parts  of  the  ocean,  but  beyond  a certain  limit  its  influence 
is  small.  The  yellow  silt  of  the  Chinese  Sea,  worn  by  the  Chinese 
rivers  from  erosion  of  the  loess,  may  be  observed  as  much  as  a hun- 
dred miles  from  land,3  and  the  turbidity  of  the  Amazon  is  evident  in 


1 See  p.  129,  ante. 

2 See  J.  Murray  and  A.  Renard,  Proc.  Roy.  Soc.  Edinburgh,  vol.  12,  1883-84,  p.  474. 

8 R.  Pumpelly,  Am.  Jour.  Sci.,  3d  ser.,  vol.  17,  1879,  p.  133. 


512 


THE  DATA  OF  GEOCHEMISTRY. 


the  ocean  at  still  greater  distances;  but  the  larger  part  of  the  deposits 
thus  formed  are  laid  down  in  relatively  shallow  water.  Glacial 
debris,  of  course,  occurs  only  near  glaciers  and  along  the  tracks  fol- 
lowed by  icebergs.  Certain  oceanic  areas  are  characterized  by  sedi- 
ments of  organic  origin;  and  in  the  deepest  abysses  of  the  ocean  its 
floor  is  covered  by  a characteristic  red  clay.  These  varied  deposits 
shade  into  one  another  through  all  manner  of  blendings,  and  yet 
they  are  distinct  enough  for  purposes  of  classification. 

In  their  great  volume  upon  Deep-sea  deposits,  Murray  and  Renard 1 
adopt  a classification  which  is  perhaps  as  good  as  any  yet  devised. 
The  following  table  shows  its  character  and  also  the  distribution  in 
depth  and  area  of  the  several  sediments  named. 

Mean  depth  and  area  covered  by  marine  sediments. 


Mean  depth, 
fathoms. 

Area,  square 
miles. 

Littoral  deposits  (between  tide  marks) 

62,  500 
10,  000,  000 

} 2,  556,800 

Shallnw-watfvr  fI*vnosit,s  How  watfir  to  1 00  fathoms') 

[Coral  mud 

740 

Coral  sand 

176 

Terrigenous  deposits,  near  land  . .< 

Volcanic  mud 

Volcanic  sand 

Green  mud 

1,  033 
243 

} 600, 000 

513 

} 850, 000 

Green  sand 

449 

Red  mud 

623 

100,  000 
14,  500,  000 
400,  000 
49,  520,  000 
10,  880,  000 
2,  290,  000 
51,  500,  000 

Blue  mud 

1, 411 
1,  044 

1,  996 
1, 477 

2,  894 
2,  730 

Pelagic  deposits,  deep  water,  far  from 
land 

[Pteropod  ooze 

Globigerina  ooze. . 
Diatom  ooze 

Radiolarian  ooze . . 
(.Red  clay 

For  these  various  products  many  analyses  are  given,  and  from 
among  them  a few  may  be  cited  here.  The  red  clay  which  covers  the 
largest  areas  is  regarded  by  Murray  and  Renard  as  derived  from 
. the  decomposition  of  volcanic  ejectamenta.  The  several  oozes  owe 
their  names  to  the  remains  of  living  creatures  which  they  contain, 
and  calcium  carbonate  is  one  of  their  important  constituents.  The 
distribution  of  calcium  carbonate  according  to  depth  was  discussed 
in  a former  chapter 2 of  this  work,  together  with  the  composition  of 
the  peculiar  manganese  and  phosphatic  nodules  which  are  often 
found  in  great  numbers  in  the  deeper  parts  of  the  sea. 


1 Challenger  Kept.,  Deep-sea  deposits,  1891,  table  on  p.  248. 

2 Chapter  IV,  p.  131,  ante. 


THE  DECOMPOSITION  OF  ROCKS. 


513 


Analyses  of  marine  sediments. 

A.  Red  clay.  Twenty-three  analyses  by  J.  S.  Brazier  are  tabulated  on  page  198  of  Deep-sea  deposits, 
and  there  is  a discrimination  between  the  portions  soluble  and  insoluble  in  hydrochloric  acid.  Some  of 
these  analyses  show  calcium  carbonate  up  to  60  per  cent;  the  one  selected  here,  as  representing  a more 
typical  clay,  contains  the  minimum  of  carbonate. 

B.  Radiolarian  ooze.  Rich  in  siliceous  organisms.  Analysis  by  Brazier,  page  436. 

C.  Diatom  ooze.  Rich  in  siliceous  organisms.  Analysis  by  Brazier,  page  436. 

D.  Globigerina  ooze.  Twenty-one  analyses  are  given  on  page  219.  Analysis  by  Brazier,  No.  42,  showing 
low  calcium  carbonate. 

E.  Globigerina  ooze.  Analysis  by  Brazier,  No.  53,  showing  very  high  carbonate. 

F.  Pteropod  ooze.  Analysis  by  Brazier,  page  448. 

All  samples  dried  at  110°  previous  to  analysis.  The  soluble  and  insoluble  portions  in  analyses  A,  B,  and 
D are  not  separated  in  the  following  table. 

See  also  J.  B.  Harrison  and  A.  J.  Jukes  Brown,  Quart.  Jour.  Geol.  Soc.,  vol.  51,  1895,  p.  313,  for  other 
analyses  of  red  clay  and  oceanic  oozes.  For  14  recent  analyses  of  red  clay,  see  "W.  A.  Caspari,  Proc.  Roy. 
Soc.  Edinburgh,  vol.  30, 1910,  p.  183. 


A 

B 

C 

D 

E 

F 

Ignition 

4.  50 

7.  41 

5.  30 

7.  90 

1.40 

2.  00 

Si02 

62. 10 

56.02 

67.  92 

31.  71 

1.  36 

3.  65 

A1203 

16.  06 

10.  52 

.55 

11. 10 

.65 

.80 

Fe203 

11.83 

14.  99 

.39 

7.03 

.60 

3.  06 

Mn02 

.55 

3. 23 

Trace. 

CaO 

.28 

.39 

.41 

MgO 

.50 

.25 

. 12 

CaC03 

.92 

3.  89 

19.  29 

37.  51 

92.  54 

82.  66 

Oa3P20g 

.19 

1.39 

.41 

2.80 

.90 

2.44 

CaS04 

.37 

.41 

.29 

.29 

.19 

.73 

MgC03 

2.  70 

1.50 

1. 13 

1. 13 

.87 

.76 

Insoluble  a 

4.  72 

1.49 

3.  90 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

o Contains  silica,  alumina,  and  ferric  oxide,  not  separated. 


G.  Blue  mud.  Analysis  by  J.  S.  Brazier,  page  448. 

H.  Red  mud.  Analysis  by  M.  Hornung,  page  445.  Dried  at  100°. 

I.  Green  mud.  Analysis  by  Brazier,  page  449. 

J.  Green  sand.  Analysis  by  Brazier,  page  449. 

K.  Volcanic  mud.  Analysis  by  Brazier,  page  450. 

Analyses  G to  IC  represent  “terrigenous  ” deposits.  Brazier’s  samples  were  all  dried  at  110°.  The  soluble 
and  insoluble  portions  are  here  united. 


G 

H 

I 

J 

K 

Ignition 

5.  60 

6.02 

3.30 

9. 10 

6.  22 

Si02 

64.  20 

31.  66 

31.27 

29.  70 

34. 12 

A1203 

13.  55 

9.21 

4.  08 

3.25 

9.  22 

Fe203 

8.38 

4.  52 

12.  72 

5.  05 

15.  46 

Mn02 

Trace. 

CaO 

2.  51 

25.  68 

.30 

.22 

1.  44 

MgO 

.25 

2.  07 

.12 

.13 

.22 

Na20 

1.  63 

K20 

1. 33 

CaC03 

2.  94 

46.36 

49.  46 

32.  22 

Ca3P208 

1.39 

. 70 

Trace. 

Trace. 

CaS04 

.42 

. 58 

1.  07 

. 27 

MgC03 : 

.76 

.57 

2.02 

.83 

so3 

.27 

co2 

17. 13 

Cl 

2.  46 

Less  0=C1 

100.  00 

101.  98 
.87 

100.  00 

100.  00 

100.  00 

101. 11 

97270°— Bull.  616—16 33 


514 


THE  DATA  OF  GEOCHEMISTRY. 


These  analyses  serve  well  enough  to  show  the  variable  character 
of  the  oceanic  sediments,  but  they  are  in  several  respects  incomplete. 
In  order  to  determine  the  composition  of  the  oceanic  clays  more 
minutely,  two  analyses  have  been  made  in  the  laboratory  of  the 
United  States  Geological  Survey  upon  material  kindly  furnished 
by  Sir  John  Murray.  The  samples  analyzed  were  composites  of 
many  individual  specimens,  brought  together  from  all  of  the  great 
oceans  and  collected  partly  by  the  Challenger  and  partly  by  other 
expeditions.  The  data  are  as  follows,  reduced  to  uniformity  by  rejec- 
tion of  sea  salts,  calcium  carbonate,  and  hygroscopic  water,  and  recal- 
culation of  the  remainder  to  100  per  cent. 

Analyses  of  composite  samples  of  marine  clays. 

A.  Composite  of  fifty-one  samples  of  the  ‘‘red  clay.”  Analyzed  by  G.  Steiger,  with  special  determina- 
tions by  W.  F.  Hillebrand  and  E.  C.  Sullivan. 

B.  Composite  of  fifty-two  samples  of  “terrigenous  clays,”  namely,  four  “green  muds”  and  forty-eight 
“blue  muds.”  Analysis  by  G.  Steiger. 


Si02 

Ti02 

A1203 

Cr203 . . . . 

Fe203 

FeO 

NiO,  CoO. 

MnO 

Mn02. . . . 

MgO 

CaO 

SrO 

BaO 

K20 

Na20 

V203 

•A-S203.  . . . 
Mo03.  . . . 
P205 

s 

CuO 

PbO 

ZnO 

C 

h2o 


54.  48 
.98 
15.  94 
.012 
8.  66 
.84 
.039 


1.  21 
3.  31 

1.  96 
.056 
.20 

2.  85 
2. 05 

.035 

.001 

Trace. 

.30 


.024 

.008 

.005 


7.04 


57.  05 

1.  27 
17.  22 

.05 
5.  07 

2.  30 
.0630 
.12 

2.  i7 
2.  04 
.03 
.06 
2.  25 
1.  05 
.03 
Trace. 

\*2i" 

.13 
.0160 
.0004 
.0070 
1.  69 
7. 17 


100.  000 


99.  9964 


These  figures  give  the  average  composition  of  the  two  oceanic  sedi- 
ments and  show  the  distribution  in  them  of  the  minor  and  rarer  con- 
stituents. Even  these  analyses  need  to  be  supplemented  by  others,  of 
which  many  can  be  found  scattered  through  the  literature  of  ocean- 


THE  DECOMPOSITION  OF  ROCKS. 


515 


ography.1  The  data  are  abundant,  but  their  value  upon  the  purely 
chemical  side  is  very  uneven.  Few  conclusions  can  be  deduced  from 
them.  J.  Y.  Buchanan,2  who  found  free  sulphur  in  a number  of 
marine  muds,  thinks  that  sulphates  were  reduced  to  sulphides  by 
passing  through  the  digestive  organs  of  marine  ground  fauna,  and 
points  out  that  matter  at  the  bottom  of  the  sea  is  subject  also  to 
reoxidation  by  dissolved  oxygen.  When  oxidation  is  in  excess  of 
reduction  red  sediments  are  formed;  if  the  reducing  process  prepon- 
derates, the  sediments  are  blue.  In  the  Black  Sea,  according  to  N. 
Androussow,3  the  sulphates  contained  in  the  water  are  also  partly 
reduced  by  micro-organisms,  which  liberate  hydrogen  sulphide.  A 
portion  of  this  gas  is  reoxidized,  with  some  liberation  of  sulphur; 
another  part  takes  up  iron  from  the  sediments  and  forms  abundant 
deposits  of  pyrites. 

The  calcareous  oozes  obviously  represent  calcium  carbonate 
absorbed  by  living  organisms  from  its  solution  in  sea  water  and  depos- 
ited with  their  remains  after  death.  It  therefore  owes  its  origin  to 
rock  decomposition,  during  which  the  lime  was  removed  to  be  carried 
in  solution  by  rivers  to  the  sea.  The  siliceous  oozes  were  formed  in 
a similar  manner  by  radiolarians  and  diatoms,  which,  as  J.  Murray 
and  R.  Irvine  4 have  shown,  are  able  to  decompose  the  suspended 
particles  of  clay  that  reach  the  ocean  and  to  assimilate  their  silica. 
A slimy  mass  of  siliceous  algae  analyzed  by  Murray  and  Irvine  con- 
tained 77  per  cent  of  silica,  1.38  of  alumina,  16.75  of  organic  matter, 
and  4.87  of  water.  From  materials  of  this  kind,  which  are  very 
abundant  in  the  ocean,  these  particular  oozes  were  produced,  but 
their  primary  substance — silt,  or  volcanic  ash,  or  atmospheric  dust — 
came  from  the  decomposition  of  rocks  upon  the  land.  In  some  cases 
siliceous  deposits  have  been  developed  in  another  way,  namely,  by 
the  silicification  of  shells  and  corals.  Remains  of  this  kind  are  plen- 
tifully found  in  sedimentary  rocks,  and  the  process  of  their  forma- 
tion can  be  imitated  artificially.  A.  H.  Church,5  by  allowing  a 
very  weak  solution  of  colloidal  silica  to  percolate  through  a frag- 
ment of  coral,  succeeded  in  dissolving  away  the  calcium  carbonate 
and  leaving  in  its  place  a siliceous  pseudomorph. 


1 See,  for  example,  K.  Natterer,  on  Mediterranean  muds,  Monatsh.  Chemie,  vol.  14,  1893,  p.  624;  vol.  15, 
1894,  p.  530;  also  upon  Red  Sea  deposits,  idem,  vol.  20,  1899,  p.  1.  L.  Schmelck  (Den  Norske-Nordhavs 
Expedition,  pt.  9)  gives  many  analyses  of  marine  clays.  J.  Y.  Buchanan  (Proc.  Roy.  Soc.  Edinburgh, 
vol.  18,  1890-91,  p.  131)  reports  partial  analyses  of  Mediterranean  samples.  A.  and  H.  Strecker  (Liebig’s 
Annalen,  vol.  95,  1855,  p.  177)  describe  a peculiar  mud  from  the  Sandefjord,  Norway.  A later  study  of  the 
same  substance  was  published  by  E.  Bodtker  (Liebig’s  Annalen,  vol.  302, 1898,  p.  43).  For  a bibliography 
of  oceanic  sedimentation  see  K.  Andrde,  Geol.  Rundschau,  vol.  3,  p.  324, 1912. 

2 Proc.  Roy.  Soc.  Edinburgh,  vol.  18,  1890-91,  p.  17. 

* Guide  des  excursions  du  VII  Cong.  gdol.  intemat.,  No.  29, 1897,  p.  6. 

* Proc.  Roy.  Soc.  Edinburgh,  vol.  18,  1890-91,  p.  229. 

& J our.  Chem.  Soc.,  vol.  15, 1862,  p.  109. 


516 


THE  DATA  OF  GEOCHEMISTRY. 


GIjAUCONITE. 

In  oceanic  sediments,  and  chiefly  near  the  “mud  line”  surrounding 
the  continental  shores,  the  important  mineral  glauconite  is  found  in 
actual  process  of  formation.  This  green,  granular  silicate  of  potas- 
sium and  iron  occurs  in  rocks  of  nearly  all  geologic  ages,  from  the 
Cambrian  down  to  the  most  recent  horizons,  and  there  has  been  much 
discussion  over  its  nature  and  origin.  In  composition  it  is  exceed- 
ingly variable,  for  the  definite  compound  is  never  found  in  a state  of 
purity,  but  is  always  contaminated  by  alteration  products  and  other 
extraneous  substances.  As  an  oceanic  deposit  glauconite  is  devel- 
oped principally  in  the  interior  of  shells,  and  organic  matter  is  be- 
lieved to  play  a part  in  its  formation.  According  to  Murray  and 
Renard,1  the  shell  is  first  filled  with  fine  silt  or  mud  upon  which  the 
organic  matter  of  the  dead  animal  can  act.  Through  intervention  of 
the  sulphates  contained  in  the  sea  water,  the  iron  of  the  mud  is  con- 
verted into  sulphide,  which  oxidizes  later  to  ferric  hydroxide.  At 
the  same  time  alumina  is  removed  from  the  sediments  by  solution 
and  colloidal  silica  is  liberated.  The  latter  reacts  upon  the  ferric 
hydroxide  in  presence  of  potassium  salts  extracted  from  adjacent 
minerals,  and  so  glauconite  is  produced.  This  view  is  sustained  by 
other  evidence,  namely,  the  constant  association  of  the  glauconite 
shells  with  the  debris  of  rocks  in  which  potassium-bearing  minerals, 
such  as  orthoclase  and  muscovite,  occur.2 

This  theory  of  Murray  and  Renard  seems  to  be  fairly  satisfactory, 
so  far  as  it  goes,  but  it  does  not  cover  the  entire  ground.  It  applies 
to  the  glauconite  which  is  now  forming  upon  the  sea  bottom,  but  not 
to  all  occurrences  of  glauconite  in  the  sedimentary  rocks.  In  an 
important  memoir  L.  Cayeux  3 has  shown  that  in  certain  instances 
glauconite  has  formed  subsequent  to  the  consolidation  of  its  rocky 
matrix,  and  while  he  admits  that  organic  matter  has  assisted  its 
development  within  shells,  the  mineral  can  be  produced  by  some 
quite  different  process.  What  this  process  is  he  does  not  explain; 
he  merely  shows  that  glauconite  can  form  without  the  intervention 
of  organisms  and  that  its  mode  of  genesis  is  at  least  twofold.  Inci- 
centally  also  he  states  that  ferric  hydroxide  and  pyrite  are  produced 
by  the  decomposition  of  glauconite,  an  observation  which  seems  to 
indicate  that  the  reactions  predicated  by  Murray  and  Renard  may  be 
reversible. 


1 Challenger  Rept.,  Deep-sea  deposits,  1891,  p.  383. 

2 For  other  discussions  relative  to  the  origin  of  glauconite  see  C.  W.  von  Giimbel,  Sitzungsb.  K.  Akad. 
Wiss.  Miinchen,  vol.  16,  1886,  p.  417;  vol.  28,  1896,  p.  545.  Also  D.  S.  Calderon,  D.  F.  Chaves,  and  P.  del 
Pulgar,  Anales  Soc.  espan.  hist,  nat.,  vol.  23,  1894,  p.  8.  The  older  literature  of  the  subject  is  unimpor- 
tant for  present  purposes. 

* Contributions  & l’&ude  micrographiquo  des  terrains  s&limentaires:  M&n.  Soc.  g&>l.  du  'Cord,  vol.  4, 
pt.  2,  1897,  pp.  163-184. 


THE  DECOMPOSITION  OF  ROCKS. 


517 


The  granules  of  glauconite  from  marine  mud  and  from  the  sedi- 
mentary rocks,  although  not  found  as  definite  crystals,  have  never- 
theless a distinct  cleavage,  and  are  interpreted  by  A.  Lacroix  1 as 
monoclinic  and  analogous  to  the  micas.  There  is,  however,  another 
mineral,  celadonite,  which  is  regarded  by  Dana  and  other  writers  as 
a separate  species,  but  which  resembles  glauconite  so  closely  in  com- 
position that  it  may  be  the  same  thing.  It  occurs  as  a decomposition 
product  of  augite  in  various  basaltic  rocks,  is  green  like  glauconite, 
but  earthy  in  texture,  and  never  granular.  It  is  easily  confounded 
with  other  green  chloritic  minerals  and  its  diagnosis  is  never  certain 
unless  supported  by  a complete  chemical  analysis.  C.  W.  von  Gum- 
bel 2 and  K.  Glinka 3 both  identify  it  chemically  with  glauconite, 
despite  its  entirely  different  origin,  a conclusion  which,  if  sustained, 
gives  us  another  illustration  of  the  fact  that  a chemical  compound 
may  be  produced  by  several  distinct  processes.  Still  another  min- 
eral, found  in  the  iron-bearing  rocks  of  the  Mesabi  district,  and 
named  greenalite  by  C.  K.  Leith  4 has  been  confounded  with  glau- 
conite, although  it  is  free  from  potassium  and  its  iron  is  practically 
all  in  the  ferrous  state.  In  glauconite  the  iron  is  mainly  ferric,  and 
potassium  is  one  of  its  essential  constituents.  According  to  the  best 
analyses,  glauconite  probably  has,  when  pure,  the  composition  repre- 
sented by  the  formula  Fe///KSi206.aq.,  in  which  some  iron  is  replaced 
by  aluminum,  and  other  bases  partly  replace  K.5  This  formulation 
is  not  final,  neither  does  it  suggest  any  relationship  between  glau- 
conite and  the  micas.  It  rests  upon  Glinka’s  analyses  of  Russian 
glauconite,  in  which  the  material  was  freed  from  impurities  by  means 
of  heavy  solutions.  The  water  in  the  formula  is  probably  for  the 
most  part  “zeolitic”  and  not  constitutional,  as  in  the  case  of  analcite, 
a silicate  of  similar  chemical  type. 

The  following  analyses  of  glauconite  and  celadonite  will  serve  to 
show  the  variability  of  the  material.6 


1 Min6ralogie  de  la  France,  vol.  1,  1893-1895,  p.  407.  Lacroix  gives  a number  of  analyses  of  French  and 
Belgian  glauconites. 

2 Sitzungsb.  K.  Akad.  Wiss.  Miinchen,  vol.  26,  1896,  p.  545. 

s Zeitschr.  Kryst.  Min.,  vol.  30,  1899,  p.  390.  Abstract  from  a Russian  original. 

4 Mon.  U.  S.  Geol.  Survey,  vol.  43,  1903,  p.  240.  Leith  gives  a long  table  of  glauconite  analyses. 

5 See  discussion  by  F.  W.  Clarke  in  Mon.  U.  S.  Geol.  Survey,  vol.  43,  1903,  p.  243.  Compare  L.  W.  Collet 
and  G.  W.  Lee,  Compt.  Rend.,  vol.  142,  1906,  p.  999.  The  authors  give  an  analysis  of  very  pure  marine 
glauconite.  Two  other  analyses  are  given  by  W.  A.  Caspari,  Proc.  Roy.  Soc.  Edinburgh,  vol.  30, 1910,  p. 
364.  Caspari  also  describes  the  synthesis  of  a compound  resembling  glauconite.  An  important  mono- 
graph by  Collet,  Les  d6p6ts  marins,  was  published  at  Paris  in  1908. 

6 Many  analyses  of  greensand  marls  are  given  by  G.  H.  Cook,  in  Geology  of  New  Jersey,  1868,  pp.  414 
et  seq.  On  New  Jersey  greensands  see  also  W.  B.  Clark,  Jour.  Geology,  vol.  2, 1894,  p.  161.  On  Irish  glau- 
conite, see  A.  J.  Hoskins,  Geol.  Mag.,  1895,  p.  317. 


518 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  glauconite  and  celadonite. 

A.  Glauconite,  from  Woodburn,  Antrim,  Ireland.  Analysis  by  A.  P.  Hoskins,  Geol.  Mag.,  1895,  p.  320. 

B.  Glauconite  from  Cretaceous  sandstone,  Padi,  Government  Saratoff,  Russia.  One  of  ten  analyses, 
by  K.  Glinka  (Zeitscbr.  Kryst.  Min.,  vol.  30,  1899,  p.  390),  of  Russian  material  from  the  Lower  Silurian, 
Jurassic,  Eocene,  and  Cretaceous.  This  sample  lost  4.43  per  cent  of  water  at  100°,  but  regained  it  in 
twenty -four  hours. 

C.  Glauconite  from  greensand  marl,  Hanover  County,  Virginia.  Analysis  by  M.  B.  Corse  and  C.  Bas- 
kerville,  Am.  Chem.  Jour.,  vol.  14,  1892,  p.  627.  8.22  per  cent  of  the  silica  is  stated  separately  as  quartz. 

D.  Oceanic  glauconite,  mean  of  four  analyses  made  by  L.  Sipocz  for  Murray  and  Renard,  Challenger 
Rept.,  Deep-sea  deposits,  1891,  p.  387. 

E.  Glauconite,  Monte  Brione,  Lake  Garda,  Italy.  Analysis  by  A.  Sch wager.  Described  by  C.  W.  von 
Giimbel,  Sitzungsb.  Akad.  Miinchen,  vol.  26,  1896,  p.  545. 

F.  Celadonite,  Monte  Baldo,  near  Verona,  Italy.  Analysis  by  Sch  wager.  See  Giimbel,  loc.  cit. 

G.  Celadonite,  mean  of  four  analyses  of  material  from  Scottish  localities,  by  M.  F.  Heddle.  Trans.  Roy. 
Soc.  Edinburgh,  vol.  29,  1880,  p.  102. 


A 

B 

C 

D 

E 

F 

G 

Si02 

40.  00 

48.  95 

51.  56 

53.  61 

50.  36 

55.  80 

54.  84 

A1203 

13.  00 

7.  66 

6.  62 

9.  56 

7.  04 

3.  20 

3.  52 

Fe90, 

16.  81 

23.  43 

15. 16 

21.  46 

19. 13 

16.  85 

12.  64 

FeO 

10. 17 

1.  32 

8.  33 

1.  58 

3.  95 

3.  88 

4.  90 

MnO 

Trace. 

.06 

. 12 

.24 

MgO 

1.  97 

2.  97 

.95 

2.  87 

4.  08 

5.  32 

6.  65 

CaO 

1.  97 

.57 

.62 

1.  39 

.91 

. 16 

.89 

Na20 

2. 16 

. 98 

1.  84 

.42 

1.  58 

1. 12 

. 39 

K20 

8.  21 

9.  54 

4. 15 

3. 49 

6.  62 

9.  04 

7.00 

Li20 

.01 

H20 

6. 19 

4.  93 

10.  32 

5.  96 

4.  67 

9.  62 

Organic 

} 6.32 

Trace. 

Ti02 

.02 

. 24 

P,(X 

.26 

.07 

100.  48 

100.  35 

99.  55 

100.  34 

100.  34 

100.  47 

100.  69 

If,  now,  we  assume  that  celadonite  and  glauconite  are  at  bottom 
the  same  ferripotassic  silicate,  differing  only  in  their  impurities,  we 
may  begin  to  see  that  the  several  modes  of  its  formation  are  not  ab- 
solutely different  after  all.  Probably,  in  all  their  occurrences,  the 
final  reaction  is  the  same,  namely,  the  absorption  of  potassium  and 
soluble  silica  by  colloidal  ferric  hydroxide.  In  the  ocean  these 
materials  are  prepared  by  the  action  of  decaying  animal  matter  upon 
ferruginous  clays  and  fragments  of  potassium-bearing  silicates.  In 
the  sedimentary  rocks,  when  glauconite  appears  as  a late  product, 
the  action  of  percolating  waters  upon  the  hydroxide  would  account 
for  its  formation.  In  igneous  rocks  the  hydroxide  is  derived  from 
augite,  or  perhaps  from  olivine,  and  percolating  waters  again  come 
into  play.  Thus  the  various  productions  of  glauconite  and  celado- 
nite become  the  results  of  a single  process,  which  is  exactly  equivalent 
to  that  in  which  potassium  compounds  are  taken  up  by  clays.  The 
observation  of  L.  Cayeux  1 that  glauconite  is  frequently  present  in 
arable  soils,  in  all  conditions  from  perfect  freshness  to  complete 
alteration  into  limonite,  suggests  that  perhaps  the  formation  of  the 
species  is  one  of  the  modes  by  which  potassium  is  withdrawn  from 
its  solution  in  the  ground  waters. 


i Annales  Soc.  g6ol.  du  Nord,  vol.  34,  1905,  p.  146 


THE  DECOMPOSITION  OF  ROCKS. 


519 


PHOSPHATE  ROCK. 

Among  the  phosphates  of  the  igneous  and  crystalline  rocks,  only 
one,  apatite,  has  any  large  significance.  Monazite  and  xenotime  are 
altogether  subordinate.  Apatite,  as  was  shown  in  previous  chap- 
ters 1 is  widely  distributed,  but  in  relatively  small  proportions; 
although  it  is  sometimes  concentrated  into  large  deposits  or  in  veins. 
The  commercially  important  apatites  of  Canada,  Norway,  and  Spain 
are  segregations  of  this  kind.2 

By  various  processes,  which  are  not  yet  fully  understood,  apatite 
undergoes  alteration,  and  by  percolating  carbonated  waters  it  is 
slowly  dissolved.  Some^of  the  phosphoric  acid,  thus  removed  in 
solution,  is  carried  by  rivers  to  the  sea,  where  it  is  largely  absorbed 
by  living  organisms.  Some  of  it  reacts  upon  other  products  of  rock 
decomposition,  forming  new  secondary  phosphates.  Another  portion 
is  retained  by  the  soil,  whence  it  is  extracted  by  plants,  to  pass  from 
them  into  the  bodies  of  animals.  From  organic  sources,  such  as 
animal  remains,  the  largest  deposits  of  phosphates  are  derived. 
Between  the  original  apatite  and  a bed  of  phosphorite  there  are  many 
stages  whose  sequence  is  not  always  the  same. 

The  solubility  of  apatite  and  of  the  other  forms  of  calcium  phos- 
phate has  been  studied  by  many  investigators.3  R.  Muller 4 has 
shown  that  apatite  dissolves  in  carbonated  waters,  and  the  fact  that 
the  solubility  of  calcium  phosphate  is  increased  by  humus  acids  has 
been  observed  by  H.  Minssen  and  B.  Tacke.5  C.  L.  Reese,6  in  a series 
of  experiments  upon  calcium  phosphate,  found  that  it  dissolved  per- 
ceptibly in  swamp  waters  rich  in  organic  matter.  Carbonated  waters 
also  dissolved  it  freely,  but  it  was  redeposited  when  the  solution  was 
allowed  to  stand  over  calcium  carbonate.  In  presence  of  the  car- 
bonate, then,  the  phosphate  would  probably  not  be  dissolved,  while 
carbonate  could  pass  into  solution.  Other  salts  in  solution  may  assist 
or  hinder  the  solubility  of  calcium  phosphate,  and  since  natural 
waters  differ  in  composition  the  solvent  process  is  necessarily  variable. 
Cameron  and  Hurst,7  who  studied  the  solution  of  iron,  aluminum, 
and  calcium  phosphate,  showed  that  the  process  is  one  of  hydrolysis, 

1 See  p.  355  and  also  the  analyses  of  igneous  rocks  given  in  Chapter  XI. 

2 For  good  summaries  relative  to  the  occurrence  of  economically  important  phosphates  of  lime/  see  R.  A.  F. 
Penrose,  Bull.  U.  S.  Geol.  Survey  No.  46,  1888;  A.  Carnot,  Annales  des  mines,  9th  ser.,  vol.  10, 1896,  p.  137; 
and  E.  Nivoit,  in  Fremy’s  Encyclopedic  chimique,  vol.  5,  sec.  1,  pt.  2,  1884,  p.  83.  All  these  memoirs 
contain  numerous  analyses,  and  Penrose  gives  a bibliography  of  the  subject  down  to  1888. 

3 See  F.  K.  Cameron  and  L.  A.  Hurst,  Jour.  Am.  Chem.  Soc.,  vol.  26,  1904,  p.  885.  These  writers  give 
abundant  literature  references.  See  also  Cameron  and  A.  Seidell,  idem,  vol.  26,  1904,  p.  1454;  vol.  27,  1905, 
p.  1503.  Earlier  papers  by  S.  P.  Sharpies  (Am.  Jour.  Sci.,  3d  ser.,  vol.  1,  1871,  p.  171)  and  T.  Schlosing 
(Compt.  Rend.,  vol.  131,  1900,  p.  149)  may  also  be  noticed. 

4 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  27,  Min.  Mitt.,  1877,  p.  25.  See  also  ante,  p.  355. 

6 Jour.  Chem.  Soc.,  vol.  78,  pt.  2,  1900,  p.  618.  Abstract. 

6 Am.  Jour.  Sci.,  3d  ser.,  vol.  43,  1892,  p.  402. 

7 Loc.  cit. 


520 


THE  DATA  OF  GEOCHEMISTRY. 


the  solution  becoming  acid,1  and  less  soluble  basic  phosphates  being 
left  behind;  that  is,  the  solution  contains  acid  ions,  corresponding  " 
either  to  free  acid  or  to  acid  salts — a condition  which  must  materially 
affect  the  action  of  the  liquid  upon  the  substances  with  which  it 
comes  in  contact.  R.  Warington,2  for  example,  found  that  a solu- 
tion of  calcium  phosphate  in  carbonated  water  was  perfectly  decom- 
posed by  hydroxides  of  iron  and  aluminum — a reaction  which  must 
often  occur  in  soils.  By  reactions  of  this  kind,  probably,  many  well- 
known  minerals  have  been  produced;  but,  since  iron  compounds  occur 
in  natural  solutions  more  largely  than  salts  of  aluminum,  the  iron 
phosphates  are  more  numerous  and  more  widely  distributed.  The 
“blue  earth,”  vivianite,  Fe3P208.8H20,  for  example,  is  not  uncom- 
mon in  clays;  it  is  found  lining  belemnites  and  other  fossils  at  Mul- 
lica  Hill,  New  Jersey;  and  near  Edgeville,  Kentucky,  W.  L.  Dudley 3 
found  plant  roots  almost  completely  transformed,  by  a process  of  re- 
placement, into  this  mineral.  Other  phosphates  of  iron,  commonly 
found  associated  with  sedimentary  beds  of  limonite,  are  dufrenite, 
strengite,  phosphosiderite,  barrandite,  koninckite,  cacoxenite,  be- 
raunite,  ludlamite,  calcioferrite,  borickite,  etc.  The  aluminum 
phosphates,  omitting  several  of  doubtful  character,  are  wavellite, 
fischerite,  variscite,  turquois,  callainite,  peganite,  sphaerite,  evansite, 
wardite,  and  zepharovichite.  Most  of  these  minerals  are  rare 
species,  found  in  very  few  localities,  and  need  no  further  consideration 
here.4  Wavellite,  however,  has  been  mined  near  Mount  Holly 
Springs,  Pennsylvania,  and  used  as  a source  of  phosphoric  acid.5 

Aluminum  phosphates  are  sometimes  formed  by  the  direct  action 
of  phosphatic  solutions  upon  igneous  rocks,  or  even  upon  limestones 
containing  much  clay.  The  source  of  the  phosphates  in  several  such 
cases  is  found  in  beds  of  guano  deposited  by  sea  fowl  upon  rocky 
islets,  or  by  colonies  of  bats  in  caves.  Guano  is  rich  in  phosphatic 

material,  and  a number  of  distinct  mineral  species  have  been  dis- 
covered in  guano  beds.6  The  following  compounds  are  the  best 
known  among  them: 

Monetite HCaP04 . 

Brushite HCaP04. 2H20 . 

Metabrushite 2HCaP04.3H20 . 

Martinite 2H2Ca5(P04)4.H20 . 


1 Apatite  gives  alkaline  reactions.  F.  K.  Cameron  and  A.  Seidell,  Jour.  Am.  Chem.  Soc.,  vol.  27,  1905, 
p.  1510. 

2 Jour.  Chem.  Soc.,  vol.  19, 1866,  p.  296. 

3 Am.  Jour.  Sci.,  3d  ser.,  vol.  40, 1890,  p.  120. 

* For  details  concerning  these  minerals,  see  Dana’s  System  of  Mineralogy  and  its  supplements.  On 
the  varieties  of  calcium  phosphate  known  as  osteolite  and  staffelite,  see  A.  Schwantke,  Centralbl.  Min., 

Geol.  u.  Pal.,  1905,  p.  641. 

6 See  G.  W.  Stose,  Bull.  U.  S.  Geol.  Survey  No.  315, 1907,  p.  474. 

6 On  the  phosphates  found  in  the  bat  guano  of  the  Skipton  Caves,  Australia,  see  R.  W.  E.McIvor,  Chem. 
News,  vol.  55,  1887,  p.  215;  vol.  85,  1902,  pp.  181,  217.  Mclvor  names  three  of  the  ammonium-magnesium 
phosphates— dittmarite,  muellerite,  and  schertelite. 


THE  DECOMPOSITION  OF  ROCKS. 


521 


Collophanite Ca3P208 . H20 . 

Bobierrite Mg3P 208 .8H20 . 

Newberyite HMgP04.3H20. 

Hannayite. Mg3P208.2H2NH4P04.8H20. 

Struvite NH4MgP04.6II20 . 

Stercorite HNaNH4P04 .4H20 . 


Several  of  these  compounds,  it  will  be  observed,  are  acid  phos- 
phates, and  three  of  them  contain  ammonium.  Dissolved  by  atmos- 
pheric waters,  they  react  upon  the  decomposing  rocks  beneath  the 
guano  and  produce  changes  of  a notable  kind.  Where  they  find 
limestone,  they  convert  it  into  calcium  phosphate;  when  they  attack 
igneous  rocks,  they  produce  a phosphate  of  aluminum.  The  last- 
named  substance  may  also  be  formed  from  the  hydroxide  of  alumi- 
num which  is  present  in  many  clays.  On  the  islands  of  Navassa,  Som- 
brero, Mona,  and  Moneta,  in  the  West  Indies,1  limestones  have  been 
thus  transformed;  the  other  reaction  may  be  more  fully  considered 
now. 

On  Clipperton  Atoll,  in  the  North  Pacific,  J.  J.  H.  Teall 2 found 
a phosphatized  trachyte,  the  alteration  being  clearly  due  to  leachings 
from  guano.  A similar  alteration  of  andesite  was  discovered  by 
A.  Lacroix  3 on  Pearl  Islet,  off  the  coast  of  Martinique.  In  both 
cases  feldspars  furnished  the  alumina  for  the  phosphate  that  was 
found.  Another  phosphate  of  similar  character,  from  the  island  of 
Redonda,  in  the  West  Indies,  was  described  by  C.  U.  Shepard,4  but 
nothing  is  said  of  its  petrologic  origin.  Another  example,  ana- 
lyzed by  A.  Andouard,5  came  from  the  islet  of  Grand-Connetable, 
near  the  coast  of  French  Guiana.  All  of  these  represent  changes 
brought  about  by  percolations  from  bird  guano. 

In  the  Minerva  grotto,  Department  of  THerault,  France,  A.  Gau- 
tier 6 found  brushite,  tribasic  calcium  phosphate,  and  a phosphate 
of  aluminum  to  which  he  gave  the  name  minervite.  To  this  he 

1 For  the  Navassa  phosphate,  see  E.  V.  dTnvilliers,  Bull.  Geol.  Soc.  America,  vol.  2, 1891,  p.  75.  W.  B. 
M.  Davidson  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  21,  1892-93,  p.  139)  thinks  it  may  be  a residual  concentra- 
tion from  phosphatic  limestone  and  not  a guano  product.  For  Sombrero,  see  A.  A.  Julien,  Am.  Jour.  Sci., 
2d  ser.,  vol.  36,  1863,  p.  424.  For  Mona  and  Moneta,  see  C.  U.  Shepard,  jr.,  Am.  Jour.  Sci., 3d  ser.,vol.  23, 
1882,  p.  400.  See  also  S.  P.  Sharpies,  Proc.  Boston  Soc.  Nat.  Hist.,  vol.  22, 1883,  p.  242,  on  phosphates  from 
the  guano  caves  of  the  Caicos  Islands,  which  contain  considerable  admixtures  of  calcium  sulphate.  K. 
Martin  (Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  31, 1879,  p.  473),  has  described  the  deposits  of  phosphate  on  the 
island  of  Bonaire.  N.  H.  Darton  (Am.  Jour.  Sci., 3d  ser.,  vol.  41, 1891,  p.  102)  and  W.  H.  Dali  and  G.  D. 
Harris  (Bull.  U.  S.  Geol.  Survey  No.  84,  1892)  regard  the  phosphates  of  Florida  as  possibly  due  to  guano 
leachings.  The  same  view  was  also  advocated  by  L.  C.  Johnson,  Am.  Jour.  Sci.,  3d  ser.,  vol.  45,  1893, 
p.  407.  On  the  Aruba  phosphates  see  G.  Hughes,  Quart.  Jour.  Geol.  Soc.,  vol.  41, 1885,  p.  80. 

2 Quart.  Jour.  Geol.  Soc.,  vol.  54, 1898,  p.  230. 

* Bull.  Soc.  min.,  vol.  28,  1905,  p.  13.  Lacroix  (Compt.  Rend.,  vol.  143,1906,  p.  661)  has  also  reported 
an  occurrence  of  phosphatized  trachyte  on  the  island  of  San  Thome,  in  the  Gulf  of  Guinea.  In  this  case 
again,  guano  was  the  agent  of  alteration. 

* Am.  Jour.  Sci.,  2d  ser.,  vol.  47,  1869,  p.  428.  See  also  C.  H.  Hitchcock,  Bull.  Geol.  Soc.  America,  vol.  2, 

1891,  p.  6. 

6 Compt.  Rend.,  vol.  119, 1894,  p.  1011. 

6 Annales  des  mines,  9th  ser.,  vol.  5,  1894,  p.  1.  Compt.  Rend.,  vol.  116,  1893,  pp.  928,  1023.  Recent 
papers  by  Gautier  are  in  Compt.  Rend.,  vol.  158,  p.  912,  1914,  and  Bull.  Soc.  chim.,  4th  ser.,  vol.  15,  1914, 
p.  533. 


522 


THE  DATA  OF  GEOCHEMISTRY. 


first  assigned  the  formula  A12P208.7H20,  but  later  investigations 
have  shown  that  potassium  is  an  essential  constituent  of  the  mineral. 
This  was  proved  by  A.  Carnot/  who  also  described  a substance 
similar  to  minervite,  from  a cave  near  Oran,  in  Algeria.  In  this 
case  the  phosphatic  deposits  seem  to  have  been  formed  by  infiltra- 
tions from  without  the  cavern,  and  the  same  is  true  of  a white, 
pulverulent  substance  described  by  J.  C.  H.  Mingaye1  2 from  the 
Jenolan  caves  in  New  South  Wales.  Here  no  evidence  of  guano 
could  be  found,  and  Mingaye  ascribed  the  phosphatic  solution  to 
leachings  of  river  silt  containing  bones  or  other  organic  matter  and 
directly  overlying  the  caves.  The  analyses  are  as  follows: 

Analyses  of  phosphatic  deposits. 

A.  Clipperton  Atoll,  Teall.  E.  Minerva  Grotto,  Carnot. 

B.  Martinique,  analysis  by  Arsandaux.  F.  Oran,  Carnot. 

C.  Redonda,  Shepard.  G.  Jenolan  caves,  Mingaye. 

D.  Minerva  Grotto,  Gautier,  recent.  H.  Controne,  Sicily,  Casoria. 


A 

B 

c 

D 

E 

F 

G 

Ho 

PXL 

38.5 

41.  20 

43.  20 

40.  40 

37.  28 

35. 17 

40.  83 

37. 10 

A1203 

25.9 

34.  20 

14.  40 

21.  60 

18.  59 

18. 18 

20.  70 

22.  89 

Fe*Oo . 

7.4 

16.  60 

.50 

.83 

.20 

1. 17 

Trace. 

.33 

Trace. 

Trace. 

CaO 

Trace. 

.57 

.13 

1.40 

.31 

Trace. 

k2o... 

7.  00 

8.  28 

5.  80 

9.  01 

8.  04 

Na20  

.30 

.02 

(NHJoO 

.47 

nh3 

.52 

.48 

.61 

F 

Trace. 

Trace. 

CaF2  

.31 

Cl 

Trace. 

Trace. 

so3 

Trace. 

Trace. 

Si02 

} 5.0 

1.  60 

11.  60 

.36 

Insol 

. 14 

| 4.  35 

1. 12 

H20 

J 23.0 

24.  50 

24.  00 

28.  73 

28.  20 

28.  20 

27.  69 

b 29. 16 

99.8 

99.  90 

100.  37 

99.  58 

99.  78 

99.  74 

99.  55 

99.  35 

a This  substance,  named  palmerite  by  E.  Casoria  (Zeitschr.  Kryst.  Min.,  vol.  42,  1906,  p.  87),  from  near 
Controne,  Sicily,  is  probably  identical  with  minervite.  It  was  found  in  a layer  under  bat  guano.  See  also 
A.  Lacroix,  Bull.  Soc.  min.,  vol.  33,  1910,  p.  34.  Lacroix  assigns  a very  complex  formula  to  minervite. 
b Loss  in  ignition. 

Although  these  analyses  do  not  represent  pure  compounds,  they 
yield  approximations  to  simple  formula.  A and  B are  not  far 
from  variscite,  A1P04.2H20.  C suggests  the  analogous  barrandite, 
(Al,Fe)P04.2H20.  Minervite,  especially  as  shown  in  Mingaye’s  analy- 
sis, probably  contains  a salt  of  the  composition  H2KA12(P04)3.6H20. 
Gautier  assigns  it  a more  complex  formula  and  further  investigation 
of  it  is  desirable. 


1 Annales  des  mines,  9th  ser.,  vol.  8, 1895,  p.  319.  Compt.  Rend.,  vol.  121, 1895,  p.  152. 

2 Rec.  Geol.  Survey  New  South  Wales,  vol.  6, 1899,  p.  111.  Mingaye  gives  analyses  of  several  other  phos- 
phates found  in  these  caverns.  Phosphates  of  similar  origin  are  described  by  D.  Mawson  and  W.  T.  Cooke 
in  Trans.  Roy.  Soc.  South  Australia,  vol.  31,  1907,  p.  65. 


THE  DECOMPOSITION  OF  ROCKS. 


523 


The  phosphates  of  the  Minerva  grotto,  according  to  Gautier,1  were 
formed  by  the  action  of  decomposing  animal  matter  upon  gibbsite, 
clay,  and  limestone.  In  order  to  support  this  opinion,  he  proved 
experimentally  that  solutions  of  ammonium  phosphate,  which,  as 
we  have  seen,  may  be  derived  from  guano,  will  produce  the  required 
transformations.  Gelatinous  alumina,  digested  with  ammonium 
phosphate,  gave  a crystalline  product  resembling  minervite,  and 
even  a clay  was  altered  by  the  reagent.  Siderite,  FeC03,  similarly 
treated  with  ammonium  phosphate,  was  converted  into  a salt  of  the 
composition  Fe3(P04)2.6H20;  and  limestone  was  found  to  be  trans- 
formed into  calcium  phosphate.  That  is,  a known  product  of 
organic  decomposition  will  so  act  upon  mineral  substances  as  to 
generate  phosphates  resembling  those  that  were  actually  found.  An 
outline  is  thus  furnished  for  a general  theory  of  phosphatization, 
which  is  supported  both  by  laboratory  investigation  and  by  the 
observation  of  natural  occurrences.  The  decaying  animal  matter,  in 
presence  of  bones  or  phosphatic  shells,  can  form  soluble  phosphates, 
and  the  latter,  acting  in  solution  upon  clays,  hydroxides,  or  carbon- 
ates, bring  about  the  final  transformations. 

The  larger  deposits  of  calcium  phosphate,  or  phosphorite,  are 
probably  all  of  marine  origin.2  Unlike  the  crystalline  apatite  they 
are  amorphous,  and  may  be  either  compact,  earthy,  or  concretionary. 
Nodular  or  pebble  forms  are  common.  In  composition  the  purest 
phosphorites  approach  apatite,  or,  more  specifically,  fluorapatite, 
Ca5(P04)3F;  but  some  varieties  are  more  nearly  the  normal  trical- 
cium phosphate,  Ca3(P04)2.  According  to  A.  Carnot,3  the  concre- 
tionary phosphates  are  deficient  in  fluorine,  while  in  the  sedimentary 
forms  it  is  present  in  nearly  the  apatite  ratio.  In  the  phosphorites 
of  France,  A.  Lacroix4  identifies  collophanite,  dahllite 


(Ca6(P04)4.CaC03.JH20) 


and  francolite,  which  also  contains  calcium  carbonate.  To  the  phos- 
phorite of  Quercy,  which  is  a mixture  of  the  other  species,  he  gives 
the  name  quercylite. 

To  apparently  homogeneous  brown  grains  from  the  chalk  of  Ciply, 
in  Belgium,  J.  Ortlieb5  assigned  the  formula  4Ca0.2P205.Si02, 
regarding  the  substance  as  a definite  mineral  species  to  which  he 
gave  the  name  ciplyte.  In  an  Algerian  phosphate,  G.  Schuler  6 found 

1 Annales  des  Mines,  9th  ser.,  vol.  5,  1894,  p.  1.  Compt.  Rend.,  vol.  116, 1893,  pp.  928,  1023. 

2 Even  the  highly  crystallized  Canadian  apatites  of  the  Grenville  series  are  regarded  by  W.  H.  McNaim 
as  originally  marine  deposits  which  have  undergone  metamorphism.  Trans.  Canadian  Inst.,  vol.  8,  p.  495. 

3 Compt.  Rend.,  vol.  114,  1892,  p.  1003. 

* Idem,  vol.  150, 1910,  pp.  1213, 1388.  See  also  his  Min&alogie  de  la  France,  vol.  4,  pp.  555-586.  On  dahllite, 

etc.,  see  also  A.  F.  Rogers,  Am.  Jour.  Sci.,  4th  ser.,  vol.  33,  1912,  p.  475,  and  Mineralog.  Mag.,  vol.  17, 1914, 
p.  155.  To  a mineral  of  the  composition  CasPaOs.CaO  Rogers  gives  the  name  voelckerite. 

6 Annales  Soc.  g4ol.  du  Nord,  vol.  16,  1888-89,  p.  270. 

e Zeitschr.  angew.  Chemie,  1898,  p.  1101. 


524 


THE  DATA  OF  GEOCHEMISTRY. 


chromium  to  an  average  amount  of  0.057  per  cent  of  Cr203.  Oxides 
of  iron,  alumina,  magnesia,  calcium  carbonate,  gypsum,  silica, 
sand,  and  clay  are  common  impurities.  Nitrogenous  organic  matter 
is  also  often  present.  Some  so-called  phosphate  rocks  are  merely 
phosphatized  limestones,  sandstones,  or  shales.  In  certain  Cre- 
taceous sandstones  of  Russia,  calcium  phosphate  occurs  as  a cement 
for  the  sand  grains  and  also  in  the  form  of  fossil  bones  and  fossil 
wood.  The  wood  has  been  completely  replaced  by  phosphate.1 
Although  bone  is  itself  largely  composed  of  calcium  phosphate,  fossil 
bones  are  not  identical  chemically  with  recent  bones.  The  fossils 
show  an  enrichment  in  calcium  carbonate,  iron  oxide,  and  fluorine, 
as  A.  Carnot 2 has  shown,  and  especially  in  fluorine.  Modern  bones, 
from  various  animals,  were  found  by  Carnot  to  contain  a minimum 
proportion  of  fluorine;  Tertiary  bones  were  much  richer;  Triassic  and 
Cretaceous  bones  still  more  so;  and  in  bones  from  Silurian  and  Devo- 
nian formations  the  ratio  of  fluoride  to  phosphate  was  nearly  that 
of  apatite.  This  progressive  enrichment  in  fluorine  Carnot  attributes 
to  the  agency  of  percolating  waters,  carrying  small  quantities  of  fluo- 
rides in  solution.  He  cites  a number  of  references  to  the  presence 
of  fluorides  in  mineral  springs,  and  in  water  from  the  Atlantic  he 
found  fluorine  to  the  extent  of  0.822  gram  in  a cubic  meter.  Iodine, 
which  is  also  of  oceanic  origin,  has  repeatedly  been  detected  in 
phosphorites,  but  the  presence  of  bromine  is  more  doubtful.3 

The  small  traces  of  phosphates  which  are  present  in  sea  water  are 
more  or  less  absorbed  into  the  shells,  bones,  and  tissues  of  marine 
animals,  and  so  concentrated  to  some  extent.  When  the  animals  die 
their  remains  are  scattered  through  the  ooze  of  the  sea  bottom,  and 
feebly  phosphatic  deposits  are  thus  formed.  The  calcium  phosphate, 
however,  tends  to  become  still  more  concentrated,  for  the  carbonate 
with  which  it  is  commingled  is  more  freely  soluble,  and  so  is  par- 
tially removed.  This  process  is  assisted  by  the  carbonic  acid  formed 
during  the  decomposition  of  the  animal  matter.4  Some  phosphate 
is  also  dissolved,  but  it  is  in  part  redeposited  around  nuclei,  such  as 
shells  or  fragments  of  bone,  forming  the  phosphatic  nodules  which 
are  so  often  found  upon  the  ocean  floor.5 6  Similar  nodules  are  com- 
mon in  beds  of  phosphorite  and  in  some  localities  they  constitute  its 
valuable  portions.  They  are  also  found  disseminated  in  deposits  of 
green  sand,  associated  with  the  glauconite  which  was  laid  down  at 

1 See  a table  of  18  analyses  by  A.  Engelhardt,  Claus,  P.  Latschinow,  and  P.  Kostychew  in  Revue  de 
geologie,  vol.  7,  1867-68,  p.  320.  The  wood,  bone,  and  cement  have  practically  the  same  composition. 

2 Annales  des  mines,  9th  ser.,  vol.  3, 1893,  p.  155.  In  a dinosaurian  bone  from  Colorado,  L.  G.  Eakins,  in 
the  laboratory  of  the  United  States  Geological  Survey,  found  2.12  per  cent  of  fluorine. 

3 See  F.  Kuhlmann,  Compt.  Rend.,  vol.  75, 1872,  p.  1678. 

* See  discussion  by  L.  Kruft,  Neues  Jahrb.,  Beil.  Band  15, 1902,  p.  1.  This  memoir  relates  to  the  distri- 

bution of  phosphorite  in  the  older  Paleozoic  formations  of  Europe. 

6 See  J.  Murray  and  A.  F.  Renard,  Challenger  Rept.,  Deep-sea  deposits,  1891,  pp.  397-400.  Also  ante, 
in  Chapter  IV,  p.  135. 


THE  DECOMPOSITION  OF  ROCKS. 


525 


the  same  time.  The  replacement  of  calcareous  shells  by  phosphates 
was  clearly  traced  by  A.  F.  Renard  and  J.  Cornet 1 in  their  study  of 
the  Cretaceous  phosphorites  of  Belgium. 

The  organic  remains  which  contribute  to  the  formation  of  phos- 
phorites vary  widely  as  regards  richness  in  phosphates.  Bones  are 
the  richest;  crustacean  remains  probably  come  next;  mollusks  and 
corals  are  the  poorest.  As  a rule,  molluscan  shells  and  corals  consist 
mainly  of  calcium  carbonate,  but  some  brachiopods  are  highly  phos- 
phatic.  In  a recent  lingula,  for  instance,  W.  E.  Logan  and  T.  S.  Hunt2 
found  85.79  per  cent  of  calcium  phosphate.  The  fossil  casts  of  a gas- 
tropod, Cyclora,  are  also,  according  to  A.  M.  Miller,3  rich  in  phos- 
phate. The  Cambrian  phosphates  of  Wales  are  regarded  by  H. 
Hicks  4 as  derived  in  large  part  from  crustaceans,  a supposition  which 
is  borne  out  by  W.  H.  Hudleston’s  analyses.5  The  shell  of  a giant 
trilobite  contained  17.05  per  cent  of  P205;  the  shell  of  a recent  lobster 
yielded  3.26  per  cent,  and  the  average  amount  found  in  an  entire 
lobster  was  0.76  per  cent.  Where  crustacean  remains  are  abundant, 
the  proportion  of  phosphoric  acid  ought  to  be  relatively  high. 

The  deposits  thus  formed  by  animal  remains,  upon  the  bottom  of 
the  sea,  are  at  best  but  moderately  phosphatic.  A further  concentra- 
tion is  effected  after  the  sediments  have  been  elevated  into  land  sur- 
faces, when  atmospheric  agencies  begin  to  work  upon  them.  First, 
beds  of  phosphatic  chalk  or  limestone  are  formed,  from  which,  by 
leaching  with  meteoric  or  subterranean  waters,  the  excess  of  calcium 
carbonate  is  washed  away.  The  less  soluble  phosphate  then  remains 
as  a residuary  deposit,  more  or  less  impure,  and  varying  much  in 
richness.  The  beds  near  Mons,  in  Belgium,  according  to  F.  L. 
Cornet,6  were  thus  derived  from  phosphatic  chalk,  from  which  the 
calcareous  shells  have  disappeared,  while  the  flints,  siliceous  sponges, 
and  vertebrate  bones  are  unchanged.  According  to  Chateau  7 the 
Eocene  phosphates  of  Algeria  were  concentrated  in  the  same  way, 
from  animal  and  vegetable  debris  laid  down  in  shallow  salt-water 
lagoons.  The  beds  also  show  signs  of  local  precipitation  of  phos- 
phates which  had  previously  been  dissolved.  So  long  ago  as  1870 
this  theory  of  concentration  by  leaching  was  proposed  by  N.  S. 

1 Bull.  Acad.  roy.  sci.  Belgique,  vol.  21, 1891,  p.  126. 

2 Am.  Jour.  Sci.,  2d  ser.,  vol.  17, 1854,  p.  236.  The  phosphatic  character  of  lingula  has  since  been  verified 
in  the  laboratory  of  the  U.  S.  Geological  Survey. 

s Am.  Geologist,  vol.  17, 1896,  p.  74. 

* Quart.  Jour.  Geol.  Soc.,  vol.  31,  1875,  p.  368.  On  p.  357  of  the  same  journal  there  is  another  paper  by 

D.  C.  Davies  on  the  same  region.  W.  D.  Matthew  (Trans.  New  York  Acad.  Sci.,  vol.  12,  p.  108)  has  de- 
scribed phosphatic  nodules  from  the  Cambrian  of  New  Brunswick. 

6 Quart.  Jour.  Geol.  Soc.,  vol.  31,  1875,  p.  376. 

e Idem,  vol.  42,  1886,  p.  325. 

7 M6m.  Soc.  ingtfn.  civils,  August,  1897,  p.  193.  Analyses  of  Algerian  phosphates,  by  H.  and  A.  Malbot, 
are  given  in  Compt.  Rend.,  vol.  121, 1895,  p.  442.  The  phosphorites  of  Tunis  are  described  by  P.  Thomas 
in  Bull.  Soc.  g6ol.  France,  3d  ser.,  vol.  19,  1891,  p.  370.  See  also  O.  Tietze,  Zeitschr.  prakt.  Geologie, 
1907,  p.  229,  on  the  phosphates  of  Tunis  and  Algeria.  Tietze  gives  numerous  references  to  the  literature  of 
these  deposits.  See  also  C.  Pilotti,  Pub.  Corpo  reale  delle  miniere,  Rome,  1908. 


526 


THE  DATA  OF  GEOCHEMISTRY. 


Shaler,1  to  account  for  the  nodular  phosphates  of  South  Carolina, 
and  it  seems  to  apply  equally  well  to  the  other  phosphorite  deposits 
of  the  United  States. 

The  phosphorites  of  Tennessee,  which  have  been  somewhat  ex- 
haustively studied,2  furnish  an  excellent  illustration  of  the  several 
processes,  chemical  and  mechanical,  which  have  taken  part  in  their 
formation.  As  interpreted  by  Hayes  and  Ulrich,  these  phosphorites, 
which  are  partly  Ordovician  and  partly  Devonian,  were  first  laid 
down  in  a shallow  sea  as  phosphatic  limestones,  deriving  their  phos- 
phates in  all  probability  from  phosphatic  brachiopods,  such  as  lingula. 
Some  bones  and  teeth  of  Devonian  fishes  are  also  found  in  these  beds. 
The  limestones  then  were  subjected  to  the  leaching  process,  which 
removed  carbonates,  leaving  a mixture  of  phosphates,  clay,  and  iron 
hydroxide.  The  soil  thus  formed  was  again  concentrated  by  mechan- 
ical washing,  the  moving  waters  carrying  away  the  clay  and  finer  silt 
from  the  heavier  phosphatic  nodules.  Some  phosphates  were  also 
dissolved  by  percolating  waters,  to  be  precipitated  as  a secondary 
deposit  in  the  underlying  limestones,  or  concentrated  in  limestone 
caverns. 

The  phosphorites  of  Arkansas,3 * * * * 8 * *  which  occur  in  an  interval  between 
the  Lower  Silurian  and  11  Lower  Carboniferous/'  are  probably  of 
similar  origin  to  those  of  Tennessee.  At  some  localities  in  Arkansas, 
however,  phosphates  occur  as  bands  of  pebbles  in  Cretaceous  beds, 
sometimes  associated  with  greensand.  This  association  and  also 
the  neighborhood  of  manganese  ores  are  strongly  suggestive  of  the 
similar  association  of  these  substances  in  the  deep-sea  deposits 
described  by  Murray  and  Renard.  The  same  processes  were  followed 
in  both  the  ancient  and  the  modern  seas. 

Phosphorites  and  phosphatic  marls  are  found  at  many  other  points 
in  the  southeastern  parts  of  the  United  States,  but  they  probably  all 
originated  in  the  same  way,  at  least  so  far  as  chemical  processes  are 
concerned.  The  mechanical  transportation  of  phosphatic  silt  and  its 
accumulation  in  hollows  or  depressions  have  doubtless  happened  in 


1 Proc.  Boston  Soc.  Nat.  Hist.,  vol.  13, 1870,  p.  222,  and  also  later  in  the  introduction  to  R.  A.  F.  Penrose’s 
Bull.  U.  S.  Geol.  Survey  No.  46,  1888.  For  other  matter  relative  to  the  South  Carolina  phosphates,  see 
O.  A.  Moses,  Mineral  Resources  U.  S.  for  1882,  U.  S.  Geol.  Survey,  1883,  p.  504;  P.  E.  Chazal,  Sketch  of  the 
South  Carolina  phosphate  industry,  Charleston,  1904;  F.  Wyatt,  The  phosphates  of  America,  New  York, 
1891;  and  C.  C.  H.  Millar,  Florida,  South  Carolina,  and  Canadian  phosphates,  London,  1892.  The  earlier 
literature  is  well  summed  up  in  Penrose’s  bulletin. 

2 See  publications  of  the  U.  S.  Geol.  Survey  as  follows:  C.  W.  Hayes,  Sixteenth  Ann.  Rept.,  pt.  4,  1895, 

p.  610;  Seventeenth  Ann.  Rept.,  pt.  2, 1896,  p.  539;  Twentieth  Ann.  Rept.,  pt.  6,  cont.,  1899,  p.  633;  Twenty- 

first  Ann.  Rept.,  pt.  3, 1901,  p.  473;  and  Bull.  No.  213, 1903,  p.  418.  L.  P.  Brown,  Nineteenth  Ann.  Rept., 
pt.  6,  cont.,  1898,  p.  547.  E.  C.  Eckel,  Bull.  No.  213,  1903,  p.  424.  The  latest  discussion,  by  Hayes  and 

E.  O.  Ulrich,  is  given  in  Geol.  Atlas  U.  S.  Folio  95,  1903.  See  also  T.  C.  Meadows  and  L.  Brown,  Trans. 

Am.  Inst.  Min.  Eng.,  vol.  24,  1895,  p.  582;  Hayes,  idem,  vol.  25,  1896,  p.  19;  J.  M.  Safford,  Am.  Geologist, 

vol.  18,  1896,  p.  261;  and  W.  B.  Phillips,  Eng.  and  Min.  Jour.,  vol.  57,  1894,  p.  417. 

8 See  J.  C.  Branner,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  26, 1896,  p.  580;  also  Branner  and  J.  F.  Newsom,  Bull. 

Arkansas  Agr.  Exp.  Sta.  No.  74,  and  A.  H.  Purdue,  Bull.  U.  S.  Geol.  Survey  No.  315,  1907,  p.  463.  The 

Devonian  black  phosphates  of  the  Pyrenees,  described  by  D.  Levat  (Annales  des  mines,  9th  ser.,  vol.  15, 

1899,  p.  4),  are  also  comparable  with  those  of  Tennessee  and  Arkansas. 


THE  DECOMPOSITION  OF  ROCKS. 


527 


many  instances,  but  have  no  chemical  significance.  In  the  Florida 
field,  as  described  by  G.  H.  Eldridge,1  every  step  of  phosphorite  for- 
mation seems  to  he  represented.  Phosphates  have  been  concentrated 
from  limestones  and  also  by  mechanical  washing;  they  have  formed 
secondary  replacements,  and  some  were  deposited  from  solution. 
The  following  analyses  were  made  by  George  Steiger  in  the  laboratory 
of  the  United  States  Geological  Survey,  upon  material  collected  by 
Eldridge.  They  show  the  variability  of  the  Florida  rock,  a variability 
observed  in  all  other  regions. 

Analyses  of  Florida  phosphates. 


A.  From  near  Sunnyside,  Taylor  County. 

B,  C.  From  Luraville  district,  Suwanee  County. 
B.  From  Albion  district,  Levy  County. 


A 

B 

c 

D 

Si02 

3.44 

5.36 

10.  63 

10.  51 

Ti02 

.13 

.26 

.86 

. 58 

A1203 

1.49 

5. 41 

12.  42 

21. 17 

Feo(h  

1.43 

2.  86 

2.  90 

3. 10 

CaO  

48.  81 

42. 13 

30.  93 

23.  95 

MeO  

.23 

.47 

.29 

.15 

k2o  

Trace. 

None. 

. 20 

Na20  

Trace. 

None. 

. 27 

| .40 

PXL 

35.  93 

33.37 

30.  35 

25.  38 

co2 

2.  71 

2. 15 

1.  72 

2. 14 

so3  

. 10 

. 09 

. 13 

. 15 

F 

2.  55 

2. 10 

1 95 

1.  42 

H20  at  105° 

. 90 

1.  84 

1.  27 

1.  27 

Ignition 

1.  98 

4.  76 

7.  69 

10.35 

Less  O 

99.  70 
1.05 

100.  80 
.88 

101.  61 
.82 

100.  57 
.60 

Organic  C 

98.  65 

99.  92 
.18 

100.  79 
.12 

99.  97 
.22 

A new  phosphate  field,  probably  the  largest  known,  is  in  the  States 
of  Idaho,  Wyoming  and  Utah.  At  the  date  of  writing  it  is  still  under 
investigation.2  The  subjoined  partial  analyses  of  rock  from  this 
region  are  also  by  Steiger. 


1 Trans.  Am.  Inst.  Min.  Eng.,  vol.  21,  1893,  p.  196.  See  also  W.  B.  M.  Davidson,  idem,  p.  139.  Eldridge 
cites  a number  of  incomplete  analyses  of  Florida  phosphates  by  T.  M.  Chatard,  all  made  in  the  Survey 
laboratory.  Other  papers  on  the  Florida  phosphates  by  E.  T.  Cox,  G.  M.  Wells,  andE.  W.  Codington,  may 
be  found  in  Trans.  Am.  Inst:  Min.  Eng.,  vol.  25,  1896,  pp.  36,  163,  423;  also  one  by  N.  A.  Pratt,  in  Eng.  and 
Min.  Jour.,  vol.  53,  1892,  p.  380.  See  also  E.  H.  Sellards,  Third  Ann.  Rept.  Florida  State  Geol.  Survey, 
1909-10,  and  G.  C.  Matson,  Bull.  U.  S.  Geol.  Survey  No.  604, 1915. 

2 See  report  by  H.  S.  Gale  and  R.  W.  Richards,  Bull.  U.  S.  Geol.  Survey  No.  430,  1910,  p.  457;  and  E. 
Blackwelder,  idem,  p.  537.  Other  reports  appear  in  Survey  Bulls.  Nos.  470, 530,  543,  and  580.  Earlier 
reports  by  F.  B.  Weeks  and  W.  F.  Ferrier  are  in  Bulls.  315  and  340. 


528 


THE  DATA  OF  GEOCHEMISTKY. 


Analyses  of  western  phosphates. 

A.  2\  miles  west  of  Cokeville,  Wyoming. 

B.  Dunellan  lode,  8 miles  southwest  of  Sage,  Utah. 

C.  Elsinore  claim,  3 miles  west  of  Devils  Slide,  Utah. 

D.  Eight  miles  southeast  of  Georgetown,  Idaho. 


A 

B 

C 

D 

Insoluble 

2.  62 

1.  82 

9.40 

10.  00 

Si02 

.46 

.30 

Undet. 

None. 

A1203 

. 97 

. 50 

.90 

.89 

Fe203 

.40 

.26 

.33 

. 73 

MgO 

.35 

.22 

.26 

.28 

CaO 

48.  91 

50.  97 

46.80 

45.  34 

N a20 

. 97 

2.  00 

2.  08 

1. 10 

K20 

.34 

.47 

.58 

.48 

H20- 

1.  02 

.48 

. 61 

1.  04 

h2o+ 

1.  34 

. 57 

. 75 

1. 14 

C02 : 

2.42 

1.  72 

2. 14 

6.  00 

33.  61 

36.  35 

32.  05 

27.  32 

so3 

2. 16 

2.  98 

2.34 

1.  59 

F 

.40 

.40 

.66 

. 60 

Cl 

Trace. 

Trace. 

Trace. 

Trace. 

95.  97 

99.04 

98.  90 

96.  51 

Note. — For  other  data  on  American  phosphates,  see  B.  A.  F.  Penrose,  Bull.  U.  S. 
Geol.  Survey  No.  46,  1888,  and  also  the  following  publications:  Phosphates  and  marls 
of  Alabama,  E.  A.  Smith,  Bull.  Geol.  Survey  Alabama  No.  2,  1892;  and  W.  C.  Stubbs, 
Mineral  Besources  U.  S.  for  1883-84,  U.  S.  Geol.  Survey,  1885,  p.  794.  The  Alabama 
localities  yield  phosphatic  marls  and  greensands,  of  Cretaceous  age.  S.  W.  McCallie, 
Phosphates  and  marls  of  Georgia:  Bull.  Geol.  Survey  Georgia  No.  5-A,  1896.  D.  T. 
Day,  North  Carolina  phosphates:  Mineral  Besources  U.  S.  for  1883-84,  U.  S.  Geol. 
Survey,  1885,  p.  788.  M.  C.  Ihlseng,  Phosphates  of  Juniata  County,  Pennsylvania: 
Seventeenth  Ann.  Bept.  U.  S.  Geol.  Survey,  pt.  3,  1896,  p.  955. 

For  phosphorite  in  Japan,  see  K.  Tsuneto,  Chem.  Zeitung,  vol.  23,  1899,  pp.  800, 
825.  This  phosphate  occurs  in  Miocene  sandstone  and  contains  some  glauconite. 
Good  analyses  are  given. 

On  phosphate  rock  in  New  Zealand,  see  A.  B.  Andrew,  Trans.  New  Zealand  Inst., 
vol.  38,  1905,  p.  447.  On  Christmas  Island,  Indian  Ocean,  E.  W.  Skeats,  Bull.  Mus. 
Comp.  Zool.,  vol.  42,  1903,  p.  103.  On  nodules  in  eastern  Thuringia,  J.  Lehder, 
Neues  Jahrb.,  Beil.  Band  22,  1906,  p.  48.  On  French  phosphates,  A.  Nantier, 
Compt.  Bend.,  vol.  108,  1889,  p.  1174;  and  H.  Lasne,  Bull.  Soc.  geol.  France,  3d  ser., 
vol.  18,  1889-90,  p.  441.  On  Bussian  phosphorites,  W.  Tschirwinski,  Neues  Jahrb., 
1911,  Band  2,  p.  51.  See  also  a work  by  C.  Elschner,  Die  corallogene  Phosphat- 
Inseln  Austral-Oceaniens,  Liibeck,  1913;  and  an  address  by  J.  J.  H.  Teall,  Proc. 
Geologists’  Assoc.,  1900,  p.  369. 

FERRIC  HYDROXIDES. 

An  important  class  of  products,  derived  from  the  decomposition  of 
rocks,  is  that  which  includes  the  oxides  and  hydroxides  of  iron  and 
manganese.  The  residual  deposit  of  ferric  hydroxide,  known  as  lat- 
erite,  has  already  been  described;  other  modes  of  occurrence  remain 
to  be  considered  now. 


THE  DECOMPOSITION  OF  ROCKS. 


529 


Several  hydroxides  of  iron  have  been  given  definite  rank  as  mineral 
species.  They  are : 


Turgite 2Fe203.H20.  Contains  94.6  per  cent  Fe203. 

Goethite Fe203.H20.  Contains  89.9  per  cent  Fe203. 

Limonite 2Fe203.3H20.  Contains  85.5  per  cent  Fe203. 

Xanthosiderite Fe203.2H20.  Contains  81.6  per  cent  Fe203. 

Limnite Fe203.3H20.  Contains  74.7  per  cent  Fe203. 


Of  these  only  one,  goethite,  is  crystalline;  the  others  are  amorphous, 
and  all  sorts  of  mixtures  between  them  are  likely  to  occur.1  They 
are  also  often  admixed  with  siderite,  FeC03,  which  is  itself  an  impor- 
tant ore  of  iron.  .Other  impurities  are  sand,  clay,  calcium  and  mag- 
nesium carbonates,  aluminum  hydroxides,  manganese  compounds, 
phosphates,  such  as  vivianite,  organic  matter,  etc.  Some  of  the 
rarest  metals — like  gallium,  indium,  thallium,  and  rubidium — are 
also  very  commonly  present  in  ores  of  this  class,  but  only  in  minute 
traces.  They  have  been  detected  spectroscopically.2  From  an  eco- 
nomic point  of  view,  all  of  these  minerals  are  grouped  together  as 
limonite,  for  the  reason  that  that  species  is  by  far  the  most  abundant 
and  forms  large  ore  bodies. 

The  processes  by  which  deposits  of  ferric  hydroxide  are  produced 
have  already  been  partly  indicated.  Residual  deposits  may  be  formed 
as  in  the  case  of  laterite,  or  as  represented  by  the  gossan  caps  over 
bodies  of  sulphide  ores.  Great  outcrops  of  such  ores,  especially  of 
pyrite  or  chalcopyrite,  are  often  altered  to  a considerable  depth  into 
masses  of  porous  limonite.  Pseudomorphs  of  limonite  after  pyrite 
are  exceedingly  common.3  When  sulphides  containing  iron  are  thus 
oxidized,  some  iron  is  removed  in  solution  as  sulphate,  from  which  it 
may  be  precipitated  later  as  hydroxide.  Carbonated  waters  also 
extract  iron  from  silicate  rocks,  or  from  disseminated  magnetite, 
again  forming  solutions  from  which  limonite  may  be  deposited.  The 
rusty  sediments  around  chalybeate  springs  are  illustrations  of  the 
latter  process.  Organic  acids  also  assist  in  the  solution  of  ferrous 
compounds,  and  furnish  to  swamp  waters  the  material  from  which 
bog  iron  ores  are  formed.  Stagnant  swamp  waters  are  often  covered 
by  iridescent  films  of  ferric  hydroxide,  produced  by  atmospheric  oxi- 
dation of  ferrous  carbonate,  in  visible  exemplification  of  the  process 
described  above.  The  following  analysis  of  a spring  water,  which 
rises  under  a layer  of  ore  at  Ederveen,  Netherlands,  is  cited  by  Van 
Bemmelen4  to  indicate  the  source  from  which  the  iron  oxides  were 
derived.  The  figures  refer  to  milligrams  per  liter. 


1 Perhaps  the  hydrogoethite,  3F6203.4H20,  of  P.  A.  Zemjatschensky  (Zeitschr.  Kryst.  Min.,  vol.  20, 
p.  185)  is  such  a mixture. 

2 See  W.  N.  Hartley  and  H.  Ramage,  Jour.  Chem.  Soc.,  vol.  71, 1896,  p.  533. 

3 On  the  pyritic  origin  of  iron  ores  see  H.  M.  Chance,  Eng.  Min.  Jour.,  vol.  86,  1908,  p.  408,  and  Trans. 
Am.  Inst.  Min.  Eng.,  vol.  39,  1909,  p.  522.  Chance  regards  this  origin  as  very  general. 

4 J.  M.  van  Bemmelen,  C.  Hoitsema,  and  E.  A.  Klobbie,  Zeitschr.  anorg.  Chemie,  vol.  22,  1900,  p.  337. 
Analysis  by  G.  Moll  van  Charante.  The  phosphoric  acid  of  the  water  goes  to  the  formation  of  vivianite. 


97270°— Bull.  616—16 34 


530 


THE  DATA  OF  GEOCHEMISTRY. 


Analysis  of  spring  water  at  Ederveen,  Netherlands. 


Ca.... 

Mg... 

Fe... 

Mn... 

K.... 

Na... 

ai203 

Cl.... 


107.6 

S04.... 

5.6 

h3po4.. 

19.6 

co3 

11.4 

Si02 

0.9 

Organic 

10.0 

3.3 

15.2 

0.9 

10.9 

207.6 

18.0 

56.0 


467.0 


From  waters  of  this  kind  deposits  are  formed  under  swamps  and 
bogs  as  an  impervious  hardpan,  and  also  frequently  in  lakes  or  ponds. 
Their  formation  is  sometimes  very  rapid,  and  instances  are  cited  by 
A.  Geikie 1 of  Swedish  lakes  in  which  layers  of  bog  ore  several  inches 
thick  accumulated  in  the  course  of  26  years.  According  to  N.  S. 
Shaler,2  bog  ores  are  most  abundant  along  the  margins  of  swamps, 
and  often  wanting  at  the  centers.  When  the  waters  deposit  their 
load  in  presence  of  much  carbonic  acid  or  decaying  organic  mat- 
ter, the  carbonate,  siderite,  is  laid  down;  but  where  the  air  has  free 
access  limonite  is  produced.  In  muddy  waters  the  silt  goes  down 
with  the  iron  compounds,  forming  clay  ironstone;  and  the  black  band 
ores  of  the  coal  measures  represent  what  was  once  a carbonaceous 
mud.3  In  many  cases  the  decomposition  of  ferrous  carbonate  solu- 
tions is  effected  or  aided  by  the  so-called  “ iron  bacteria,”  which  absorb 
the  iron  and  redeposit  it  later  as  ferric  hydroxide.4  These  organisms 
are  found  in  the  ground  water  and  the  soil.  From  sulphate  solutions 
the  iron  may  be  precipitated  by  carbonates,  phosphates,  or  by  organic 
matter  contained  in  admixed  waters.  Ferrous  sulphate  first  oxidizes, 
yielding  ferric  hydroxide  and  insoluble  basic  salts. 

Beds  of  limonite  sometimes  represent  a different  mode  of  origin 
from  those  just  described.  R.  A.  F.  Penrose 5 suggests  that  in  some 
cases  limonite  has  been  derived  from  glauconite  by  a process  of  alter- 
ation. It  may  be  formed  by  pseudomorphous  replacement  of  lime- 
stones, when  solutions  of  iron  compounds  percolate  through  them.6 
Ferriferous  limestone,  also,  may  yield  residuary  deposits  of  limo- 


1 Text-book  of  geology,  4th  ed.,  p.  187. 

2 Tenth  Ann.  Rept.  U.  S.  Geol. 'Survey,  pt.  1,  1890,  p.  305. 

3 The  literature  of  these  ores  is  very  abundant  and  voluminous.  See  especially  F.  M.  Stapfl,  Zeitschr. 
Deutsch.  geol.  Gesell.,  vol.  18,  1865,  p.  86;  J.  S.  Newberry,  School  of  Mines  Quart.,  vol.  2,  1880,  p.  1; 
H.  Sjogren,  Neues  Jahrb.,  1893,  Band  2,  p.  273,  ref.;  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1894,  p.  30,  and 
1895,  p.  38;  G.  Reinders,  Verhandl.  Akad.  Wet.  Amsterdam,  sec.  2,  vol.  5,  No.  5;  A.  Gaertner,  Arch. 
Ver.  Mecklenburg,  vol.  51,  1897,  p.  73;  and  J.  M.  van  Bemmelen,  Zeitschr.  anorg.  Chemie,  vol.  22,  1900, 
p.  313.  On  the  origin  of  bog  iron  ore  see  also  E.  J.  Moore,  Econ.  Geology,  vol.  5, 1910,  p.  528. 

4 See  Van  Bemmelen,  loc.  cit.;  G.  Tolomei,  Zeitschr.  anorg.  Chemie,  vol.  5,  1894,  p.  102;  and  authorities 
cited  by  C.  R.  Van  Hise,  A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  p.  826.  Also 
E.  M.  Mumford,  Jour.  Chem.  Soc.,  vol.  103, 1913,  p.  645. 

5 Ann.  Rept.  Geol.  Survey  Arkansas,  vol.  1,  1892,  p.  124.  See  also  L.  Cayeux,  Compt.  Rend.,  vol.  142, 
1906,  p.  895. 

6 See  J.  P.  Kimball,  Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  231.  See  also  C.  W.  Hayes,  Trans.  Am.  Inst. 
Min.  Eng.,  vol.  30, 1900,  p.  403;  Hayes  and  E.  C.  Eckel,  Bull.  U.  S.  Geol.  Survey  No.  213, 1903,  p.  233;  and 
S.  W.  McCallie,  Bull.  No.  10-A,  Geol.  Survey  Georgia,  1900,  p.  19,  on  the  iron  ores  of  that  State. 


THE  DECOMPOSITION  OF  ROCKS. 


531 


nite,  the  oxidation  of  ferrous  carbonate  and  the  solution  of  calcium 
carbonate  going  on  at  the  same  time.  The  Clinton  ores  are  regarded 
by  A.  F.  Foerste  1 as  formed  by  the  replacement  of  lime  in  bryozoan 
remains ; although  C.  H.  Smyth  2 has  shown  that  in  the  oolitic  varie- 
ties each  spherule  is  made  up  of  concentric  layers  around  a nucleus 
of  quartz.  He  argues  that  the  ores  were  deposited  in  the  shoal  waters 
of  the  Silurian  sea,  presumably  upon  a sandy  bottom.  The  essential 
process,  however,  precipitation  from  solution,  whether  by  oxidation, 
by  organic  matter,  or  by  carbonate  of  lime,  is  the  same  in  all  cases. 
The  ironVas  dissolved,  in  the  first  instance,  from  ferruginous  rocks, 
and  then  thrown  down  by  any  one  of  the  several  reactions  indicated. 
The  iron  ores  of  eastern  Cuba  3 are  essentially  lateritic  in  character, 
being  residues  from  the  decomposition  of  serpentine,  and  the  same  is 
true  of  the  Clealum  ores  in  the  State  of  Washington.4 

The  precipitated  hydroxides  of  iron  vary  much  in  character  and 
appearance,  and  their  exact  chemical  nature,  despite  the  plausible 
formulae  assigned  to  some  of  the  minerals,  is  by  no  means  clear.  In 
color  they  range  from  yellow  through  various  shades  of  brown  and 
red,  and  in  texture  they  differ  as  widely.  J.  M.  van  Bemmelen5 
regards  them  as  colloidal  complexes  of  ferric  oxide  and  water,  to 
which  chemical  formulae  are  not  properly  applicable;  and  the  same 
view  is  held  by  him  concerning  the  humus  acids  and  the  so-called 
ferrohumates.6  According  to  P.  Nicolardot,7  however,  whose  inves- 
tigation is  most  recent,  ferric  hydroxide  exists  in  at  least  six  modi- 
fications which  differ  in  their  physical  and  chemical  properties  and 
in  their  content  of  water.  They  are  all,  he  says,  polymers  of  the 
simplest  hydroxide. 

From  what  has  been  said  in  the  preceding  paragraphs,  it  is  evident 
that  the  composition  of  sedimentary  iron  ores  must  range  between 
widely  separated  limits.  They  may  be  mainly  ferrous  carbonate, 
either  crystalline  or  amorphous,  or  principally  limonite  with  all  sorts 
of  admixtures  of  other  substances.  The  following  analyses  of  bog 
ore,  “raseneisenstein,”  from  Ederveen,  are  given  in  the  memoir  by 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  41, 1891,  p.  28. 

2 Idem,  vol.  43, 1892,  p.  487. 

3 See  A.  C.  Spencer,  Bull.  U.  S.  Geol.  Survey  No.  340,  1908,  p.  318;  C.  M.  Weld,  Bull.  Am.  Inst.  Min. 
Eng.  No.  32,  1909,  p.  749;  C.  K.  Leith  and  W.  J.  Mead,  idem,  No.  51, 1911,  p.  217.  The  last  bulletin  con- 
tains five  other  papers  on  the  Cuban  ores. 

4 See  G.  O.  Smith  and  B.  Willis,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  30, 1901,  p.  356. 

6 Rec.  trav.  chim.,  vol.  7,  1888,  p.  106;  vol.  18,  1899,  p.  86;  Zeitschr.  anorg.  Chemie,  vol.  20,  1899,  p.  185, 
vol.  22, 1900,  p.  313,  vol.  42, 1904,  p.  281.  Also  J.  M.  van  Bemmelen  and  E.  A.  Klobbie,  Jour,  prakt.  Chemie, 
2d  ser.,  vol.  46,  1892,  p.  529. 

6 See  also  W.  Spring,  Bull.  Acad.  roy.  sci.  Belgique,  3d  ser.,  vol.  34, 1897,  p.  578,  on  the  relations  of  humus 
to  iron  in  natural  waters,  already  cited  on  p.  506,  ante.  The  same  subject  has  recently  been  discussed  by 
O.  Aschan,  Zeitschr.  prakt.  Geologie,  vol.  15, 1907,  p.  56. 

7 Annales  chim.  phys.,  8th  ser.,  vol.  6, 1905,  p.  334.  Nicolardot  cites  many  references  to  former  investiga- 
tions upon  the  precipitated  hydroxides.  See  also  Otto  Ruff,  Ber.  Deutsch.  chem.  Gesell.,  vol.  34,  1901, 
p.  3417. 


532 


THE  DATA  OF  GEOCHEMISTRY. 


J.  M.  van  Bemmelen,  C.  Hoitsema,  and  E.  A.  Klobbie.1  These  varia- 
tions are  shown  in  ore  from  a single  locality,  and  the  substances  men- 
tioned are  mostly  crystalline.  The  Fe203  represents  the  amorphous 
variety. 

Analyses  of  bog  ore. 


A.  By  G.  Reinders.  B.  By  E.  A.  Klobbie.  C.  By  F.  M.  Jager.  D.  By  C.  H.  Kettner. 


A 

B 

c 

D 

Fe203 

10.  58 

2. 49 

8.0 

36. 49 

FeC03 

20.  77 

37.  70 

30?  6 

6. 12 

MnCOg  

4.04 

.67 

2.  91 

CaC03 

2.  27 

4. 46 

4.0 

4. 10 

MgCO, 

. 17 

.10 

.21 

Fe,(PO.)o 

4.  30 

2.9 

5.  47 

Fe///P04 

1.  75 

1.  76 

CaS04 

.07 

A1203 

.93 

.21 

.60 

KC1 

.03 

Trace. 

Trace. 

NaCl 

.23 

Trace. 

Trace. 

Soluble  Si02  

.82 

} 49.1 

6.  30 

Sand 

} 49.  30 

50.  02 

19.  30 

Organic  matter 

1.  57 

.03 

1.8 

1.  20 

H20  at  100° 

3.  68 

.95 

12. 10 

H20,  ignition  

2.  06 

1. 12 

} 3. 3 

J 

4.00 

100.  00 

100.  32 

99.7 

100.  56 

The  subjoined  analyses  of  limonitic  bog  iron  from  Mittagong, 
Australia,  are  cited  by  A.  Liversidge.2  They  are  quite  different  from 
those  shown  in  the  preceding  group. 


Analyses  of  Australian  bog  ores. 


E 

F 

G 

H 

Fe203 

68.  37 

57.  61 

74.  71 

65.  84 

A1203 

4.  63 

24.  30 

3.  04 

4.  49 

MnO 

Trace. 

6.  41 

Trace . 

1.  40 

MgO 

Trace. 

Trace. 

.43 

.48 

CaO 

Trace. 

Trace. 

Trace. 

Trace. 

Si02 

14. 10 

10. 10 

14.  27 

Trace. 

Trace. 

Trace. 

.25 

so, 

Trace . 

Trace. 

Trace. 

. 11 

H20,  hygroscopic 

3. 00 

1.  20 

2.  20 

2.  30 

H20,  combined 

9.  72 

10. 38 

9.  70 

10.  86 

99.  82 

99.  90 

100. 18 

100.  00 

1 Zeitschr.  anorg.  Chemie,  vol.  22, 1900,  p.  319. 

2 Minerals  of  New  South  Wales,  p.  99.  The  analyses  were  made  by  the  "government  analyst/ 


THE  DECOMPOSITION  OF  ROCKS. 


533 


MANGANESE  ORES. 

Manganese,  like  iron,  is  also  dissolved  out  from  the  crystalline 
rocks,  in  which  it  is  almost  invariably  present,  and  by  the  same  agen- 
cies. It  may  go  into  solution  as  sulphate,  or  as  carbonate,  to  be  rede- 
posited as  carbonate,  oxide,  or  hydroxide,  under  various  conditions 
and  in  a variety  of  forms.  A deposition  as  dioxide,  hydrous  or 
anhydrous,  is  very  common  and  is  often  seen  in  the  dendritic  infiltra- 
tions which  occur  in  many  rocks  and  in  the  black  coatings  which  some- 
times cover  river  pebbles  or  surround  manganiferous  mineral  springs. 
Nodules  consisting  chiefly  of  manganese  dioxide  are  abundant  on 
the  bottom  of  the  deep  sea,  as  described  in  a previous  chapter,1 
and  similar  nodular  forms  have  been  observed  that  were  of  recent 
terrestrial  origin.  May  Thresh 2 discovered  small  hard  black  nodules 
resembling  seeds  in  the  bowlder  clay  of  Essex,  England;  and  similar 
bodies  were  found  by  W.  M.  Doherty3  on  the  surface  of  the  ground 
in  Australia. 

Manganese  differs  from  iron,  however,  in  its  degrees  of  oxidation. 
Ferrous  oxide  and  hydroxide,  as  such,  are  unknown  in  nature;  but 
manganosite,  MnO,  and  pyrochroite,  Mn(OH)2,  are  well-known  min- 
erals. Manganite,  Mn203.H20,  corresponds  in  type  with  goethite 
and  diaspore;  and  hausmannite,  Mn304,  is  the  equivalent  of  magnet- 
ite, although  the  two  species  are  crystallographic  ally  unlike.  Polia- 
nite  and  pyrolusite,  two  crystallized  forms  of  the  dioxide,  Mn02,  are 
not  matched  by  any  compound  of  iron,  and  this  oxide  forms  the 
chief  manganese  ore.  Braunite,  to  which  the  formula  3Mn203.MnSi02 
is  assigned,  is  also  a crystallized  mineral,  but  its  composition,  as 
shown  by  analyses,  is  somewhat  variable.  The  hydrous  psilomelane, 
of  uncertain  constitution,  is  often  associated  with  pyrolusite,  and 
allied  to  it  are  many  varieties  which  have  received  distinct  names. 
These  latter  ores  are  amorphous,4  and  probably  represent  colloidal 
complexes,  such  as  were  mentioned  in  connection  with  the  sedimen- 
tary ores  of  iron.  The  following  analyses  represent  substances  in  this 
class,  ranging  from  the  crystalline  pyrolusite  to  the  earthy  wad,  or 
bog  manganese,  the  cupriferous  lampadite,  etc. 

1 See  p.  134,  ante. 

2 Jour.  Chem.  Soc.,  vol.  82,  pt.  2,  ref.  567,  1902. 

3 Rept.  Australasian  Assoc.  Adv.  Sci.,  1898,  p.  339. 

4 According  to  A.  Gorgeu  (Bull.  Soc.  min.,  vol.  13,  1890,  p.  27),  the  variety  known  as  wad  is  sometimes 
crystallized. 


534 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  manganese  ores. 

A.  Pyrolusite,  Crimora  mine,  Augusta  County,  Virginia.  Analysis  by  J.  L.  Jarman,  Am.  Chem.  Jour., 
vol.  11,  1889,  p.  39. 

B.  Psilomelane,  near  Silver  Cliff,  Colorado.  Analysis  by  W.  F.  Hillebrand,  Bull.  U.  S.  Geol.  Survey 
No.  220,  1903,  p.  22. 

C.  Psilomelane,  Roman&che,  France.  Analysis  by  A.  Gorgeu,  Bull.  Soc.  min.,  vol.  13, 1890,  p.  23.  Partly 
recalculated  from  the  original. 

D.  Wad,  Romaneche,  France.  Analysis  by  Gorgeu,  idem,  p.  27.  Partly  recalculated.  Gorgeu  gives 
many  analyses  of  natural  oxides  and  hydroxides  of  manganese.  See  Bull.  Soc.  min.,  vol.  13,  1890,  p.  21; 
vol.  16, 1898,  pp.  96, 133.  Also  Bull.  Soc.  chim.,  3d  ser.,  vol.  9, 1893,  pp.  496, 650. 

E.  Varvicite,  Austinville,  Wythe  County,  Virginia.  Analysis  by  P.  H.  Walker,  Am.  Chem.  Jour., 
vol.  10, 1880,  p.  41. 

F.  Lampadite,  or  lepidophaeite,  Kamsdorf,  Thuringia.  Analysis  by  Jenkins,  for  A.  Weisbach,  Neues 
Jahrb.,  1880,  Band  2,  p.  109.  This  mineral  shows  exceptionally  high  hydration. 


A 

B 

c 

D 

E 

F 

Mn02 

95.  88 

76. 18 
5.  71 
.34 
1.81 

66.  88 
8.  22 
1.  45 

64.  98 
7.  27 

} 1.10 

.30 

Trace. 

68.  86 
7.  51 

} 2.23 

58.  77 
9.  59 

MnOl 

Fe203 

.62 

A1203 

PbO 

} .10 

CuO 

11.  48 

NiO 

.22 

.27 

CoO 

Trace. 
2.  80 
.83 

Trace. 
Trace. 
1.  65 
15.  45 
Trace. 
Trace. 
.80 

} 5.00 

.05 

.60 

ZnO 

Trace. 
.40 
16.  20 
.20 

} .10 

} 4.65 

Trace. 
1.  50 

CaO 

.09 

BaO 

14.  42 

MgO 

.29 
3.  46 
.81 
1.  41 
3.  94 

k2o 

.18 

.23 

} 2.08 

Na20 : 

HoO- 

} 5.08 

} 21.05 

h2o+ 

p9o, ; 

A&jOj 

Sb205 

.12 

CaS04 

.40 
.80 
1.  40 

Si02 

2.  30 

.25 

.15 

1.  98 

Insoluble 

.29 

99.  86 

100.  00 

100. 10 

99.  80 

100.  08 

100.  89 

Asbolite  is  an  earthy  psilomelane  containing  much  cobalt,  which  is 
a common  impurity  in  manganese  ores.  Barium,  as  shown  in  the 
analyses,  is  also  a frequent  constituent  of  them.  The  crystalline 
hollandite,  described  by  L.  L.  Fermor,1  contains  both  barium  and 
iron,  in  addition  to  the  manganese.  Coronadite,  an  oxide  of  man- 
ganese and  lead,  described  by  W.  Lindgren  and  W.  F.  Hillebrand,2 
is  a mineral  of  similar  character.  The  minerals  of  this  class  are 
commonly  interpreted  as  manganites,  that  is,  as  salts  of  manganous 
acid.  Their  definiteness  is  questionable. 

These  sedimentary  ores,  and  the  similar  ores  produced  by  the  altera- 
tion of  manganiferous  minerals,  have  diverse  origins.  F.  R.  Mallet 3 


1 Rec.  Geol.  Survey  India,  vol.  36, 1908,  p.  295.  Vol.  37  of  the  Memoirs  of  the  same  Survey,  1909,  in  four 
parts,  is  an  exhaustive  monograph  by  Fermor  on  the  manganese  ores  of  India.  In  it  he  describes  as  new 
species  three  other  mixed  oxides  of  manganese  and  iron,  to  which  he  gives  the  names  vredenburgite,  sita- 
parite,  and  beldongrite. 

* Am.  Jour.  Sci.,  4th  ser.,  vol.  18, 1904,  p.  448. 

3 Rec.  Geol.  Survey  India,  vol.  12, 1879,  p.  99;  vol.  16,  1883,  p.  116. 


THE  DECOMPOSITION  OF  ROCKS. 


535 


has  observed  lateritic  pyrolusite  or  psilomelane  as  an  integral  portion 
of  some  Indian  laterites.  The  manganese  ores  of  Queluz,  Brazil, 
according  to  O.  A.  Derby,1  are  residual  deposits  derived  from  rocks 
in  which  manganese  garnet  was  the  most  constant  and  characteristic 
silicate.  Bog  or  swamp  deposits  are  common,  and  so,  in  short,  the 
sedimentary  and  residual  ores  of  iron  are  very  fully  paralleled.  Only 
the  gossan  ores  have  no  true  manganic  equivalent.  The  sulphides 
of  manganese  are  relatively  rare,  and  their  oxidation  products  occur 
only  in  sporadic  cases.2 

Manganese  and  iron,  then,  are  dissolved  out  from  the  rocks  by  the 
same  reagents,  at  the  same  time,  and  in  essentially  the  same  way. 
They  are  redeposited  under  similar  conditions,  but  not  absolutely 
together,  for  a separation  is  more  or  less  perfectly  effected.  True, 
nearly  all  limonites  contain  some  manganese,  and  nearly  all  psilome- 
lanes  contain  some  iron;  but  in  very  many  cases  the  ores  of  the  two 
metals  are  thrown  down  separately.  How  is  the  separation  brought 
about?  To  this  question  various  answers  have  been  suggested,  but 
only  two  or  three  of  them  have  any  modern  significance. 

According  to  C.  R.  Fresenius,3  who  has  analyzed  the  deposits 
formed  by  the  warm  springs  of  Wiesbaden,  the  iron  is  precipitated 
first  as  ferric  hydroxide.  The  manganese  of  the  water  remains  in 
solution  much  longer  as  bicarbonate,  and  is  finally  laid  down  as  car- 
bonate as  an  impurity  in  calcareous  sinter;  that  is,  solutions  of 
manganese  carbonate  are  more  stable  than  solutions  of  ferrous  car- 
bonate, and  the  manganese  is  therefore  carried  farther.  A partial 
separation  of  the  two  metals,  from  the  same  solution,  is  thus  effected. 

The  thermochemical  arguments  of  L.  Dieulafait 4 * * * 8 are  quite  in  har- 
mony with  the  foregoing  observations,  and,  indeed,  help  to  explain 
them.  These  arguments  rest  upon  the  general  principle  that  when 
several  reactions  may  conceivably  take  place,  that  one  which  is 
attended  by  the  greatest  evolution  of  heat  will  occur.  The  thermo- 
chemical equations  used  by  Dieulafait  are  as  follows: 

2FeO  + O = Fe203  + 26.6  Cal. 

2MnO  + 20  = 2Mn02  + 21.4  Cal. 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  12, 1901,  p.  18. 

2 A very  full  monograph  on  manganese  ores,  by  R.  A.  F.  Penrose,  forms  vol.  1 of  the  Annual  Report  of 

the  Arkansas  Geological  Survey  for  1890.  See  also  an  article  by  Penrose,  Jour.  Geology,  vol.  1, 1893,  p.  356. 
J.  D.  Weeks  has  reported  on  the  manganese  deposits  of  the  United  States  in  Mineral  Resources  U.  S.  for 

1892,  U.  S.  Geol.  Survey,  1893,  p.  171.  T.  L.  Watson  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  34,  1904,  p.  207) 
has  described  the  manganese  ores  of  Georgia.  The  manganese  ore  of  Golconda,  Nevada,  which  contains 
tungsten,  is  interpreted  by  Penrose  (Jour.  Geology,  vol.  1,  1893,  p.  275)  as  probably  a spring  deposit.  On 

the  carbonate  ores  of  Las  Cabesses,  in  the  Pyrenees,  see  C.  A.  Moreing,  Trans.  Inst.  Min.  Met.,  vol.  2,  1894, 
p.  250.  See  also  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1906,  p.  217,  for  an  elaborate  paper  on  bog  man- 

ganese. Bull.  427  of  the  U.  S.  Geol.  Survey,  1910,  is  a report  by  E.  C.  Harder  on  the  manganese  ores  of  the 

United  States. 

8 Cited  by  G.  Bischof,  Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  1,  p.  540. 

* Compt.  Rend.,  vol.  101, 1885,  pp.  609,  644,  676. 


536 


THE  DATA  OF  GEOCHEMISTRY. 


Hence,  if  oxygen  acts  on  a mixture  of  FeO  and  MnO,  or  upon  sub- 
stances equivalent  to  them,. ferric  oxide  will  form  first  and  be  the 
more  stable. 

FeO  + C02  = FeCOg  + 5.0  Cal. 

MnO  + C02  = MnCOg  + 6.8  Cal. 

When  carbon  dioxide  unites  with  these  oxides,  then,  the  manganese 
compound  will  form  first  and  be  the  more  stable.  If  oxygen  and 
carbon  dioxide  act  together  in  considerable  excess,  Fe203  and  Mn02 
will  both  be  formed;  but  if  they  act  slowly,  in  small  quantities,  the 
oxygen  will  go  to  produce  Fe203,  and  MnC03  can  be  generated  at 
the  same  time.  The  manganese  carbonate,  being  somewhat  soluble, 
may  then  be  separated  from  the  ferric  oxide  by  leaching,  either  to 
be  deposited  as  carbonate,  or  perhaps  to  be  oxidized  to  Mn02  and 
C02  later. 

In  the  last  of  Dieulafait’s  papers  he  gives  the  heat  of  formation 
of  several  manganese  compounds: 

Mn  + S,  22.6  Cal. 

Mn  + O,  47.4  Cal. 

Mn  + 0 + C02,  54.2  Cal. 

Mn  + 02,  58.1  Cal. 

From  these  figures  it  appears  that  the  dioxide  is  the  most  stable 
compound  in  the  series;  it  is  therefore  the  easiest  formed,  and  is  the 
principal  manganese  ore.  The  thermochemical  and  geological  data 
are  in  complete  harmony. 

It  is  more  than  probable,  as  F.  P.  Dunnington  1 has  shown,  that 
manganese  sulphate  plays  an  important  part  in  the  separation  of 
the  two  metals.  He  has  proved  experimentally  that  acid  solutions 
of  ferrous  sulphate,  such  as  are  formed  by  the  oxidation  of  pyrites, 
will  dissolve  manganese  oxides  to  a very  marked  extent.  At  the 
same  time  ferric  sulphate  and  ferric  hydroxide,  under  favorable 
conditions,  may  also  be  formed.  In  contact  with  manganese  carbon- 
ate, in  presence  of  air,  ferrous  sulphate  is  rapidly  oxidized,  pro- 
ducing manganese  sulphate,  ferric  hydroxide,  and  carbon  dioxide. 
Both  sulphates  of  iron  react  with  calcium  carbonate,  and  the  ferric 
salt  generates  carbon  dioxide,  ferric  hydroxide,  and  calcium  sul- 
phate. Manganese  sulphate  acts  but  little,  if  at  all,  upon  calcium 
carbonate,  if  protected  from  access  of  air;  in  presence  of  air,  how- 
ever, manganese  oxide  is  gradually  formed. 

From  these  reactions  it  is  easy  to  see  that  limestones  may  be  impor- 
tant factors  in  the  separation  of  manganese  and  iron.  Where  sul- 
phates of  the  two  metals  percolate  through  limestones,  the  iron 
will  be  by  far  the  more  easily  precipitated,  while  the  manganese  will 
remain  in  solution  until  it  is  exposed  to  both  air  and  calcium  carbon- 
ate simultaneously. 


Am.  Jour.  Sci.,  3d  ser.,  vol.  36, 1888,  p.  175. 


CHAPTER  XIII. 

SEDIMENTARY  AND  DETRITAL  ROCKS. 

SANDSTONES. 

By  pressure,  or  by  the  injection  of  cementing  materials,  the  prod- 
ucts of  rock  decomposition  may  be  reconsolidated.  From  the  sands 
sandstones  are  formed;  from  the  clays,  shales  are  derived;  and  cal- 
careous deposits  yield  the  limestones.  These  rocks  shade  into  one 
another,  through  intermediate  gradations,  and  exhibit  the  same  varia- 
tions in  composition  that  are  observed  in  sands  and  soils.  Their 
classification  depends  upon  their  typical  forms,  and  their  modifica- 
tions are  indicated  by  a simple  nomenclature.  Such  terms  as  cal- 
careous sandstone,  argillaceous  limestone,  and  sandy  shale  explain 
themselves,  for  they  are  clearly  descriptive.  Although  not  rigorous, 
they  are  sufficient  for  most  practical  purposes.1 

A sandstone  differs  chemically  from  a sand  chiefly  in  the  addition 
of  a cementing  substance.  This  is  furnished  by  percolating  waters, 
or  else,  in  certain  cases,  by  the  slight  solution  of  the  moist  surfaces 
of  mineral  particles  in  contact  with  one  another.  Any  substance 
which  the  waters  can  deposit  in  a relatively  insoluble  condition  may 
serve  as  a cement.  Such  substances  as  silica,  calcium  carbonate, 
hydroxides  of  iron  and  aluminum,  calcium  sulphate,  phosphate,  and 
fluoride,  barium  sulphate,  etc.,  fulfill  this  condition.  Clay  and  bitu- 
minous substances  also  act  as  cementing  materials.  The  additions 
thus  made  to  a sand  may  be  small  in  amount  or  even  very  large,  some- 
times equaling  in  quantity  the  cemented  particles.  Such  an  extreme 
case  is  furnished  by  the  well-known  Fontainebleau  calcites,  which 
have  crystallized  around  sand  and  contain  sometimes  50  per  cent  of 
calcium  carbonate.  A.  von  Morlot 2 reports  crystals  from  this  locality 
containing  58  per  cent  of  sand,  and  others  with  as  high  as  95  per 
cent.  Analogous  crystals  from  the  Badlands  of  South  Dakota,  de- 
scribed by  S.  L.  Penfield  and  W.  E.  Ford,3  contain  approximately 
40  per  cent  of  calcite  to  60  per  cent  of  sand.  These  are  mixtures  of 
sand  and  calcite  in  which  £he  crystalline  form  of  the  latter  has  been 
perfectly  developed.  Gypsum  crystals  containing  sand  up  to  48.58 
per  cent  have  been  found  on  the  Astrakhan  steppe,  according  to 
B.  Doss,4  who  also  mentions  gypsiferous  sandstones.  Crystals  of 

1 On  a classification  of  the  sedimentary  rocks,  see  A.  W.  Grabau,  Am.  Geologist,  vol.  33, 1904,  p.  228. 

2 Haidinger’s  Ber.,  vol.  2,  1846-47,  p.  107. 

3 Am.  Jour.  Sci.,  4th  ser.,  vol.  9, 1900,  p.  352. 

4 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  49,  1897,  p.  143. 


537 


538 


THE  DATA  OF  GEOCHEMISTRY. 


barite  inclosing  sand  are  also  well  known.  J.  E.  Pogue  1 has  described 
crystallized  barite  inclosing  44  to  53  per  cent  of  sand  from  the  oasis  of 
Kharga,  Egypt;  and  H.  W.  Nichols  2 reports  similar  material  found  in 
Oklahoma.  As  a rule,  however,  the  cementing  material  of  a sand- 
stone is  subordinate.  Between  a sand  and  a sandstone  the  difference 
in  composition  is  generally  slight  and  may  be  almost  inappreciable. 

When  silica  serves  as  the  cementing  substance,  it  may  assume 
either  the  amorphous  or  the  crystalline  form.  In  the  latter  case  the 
quartz  fragments  often  exhibit  a secondary  enlargement  and  become 
the  nuclei  of  distinct  quartz  crystals.3  As  amorphous  silica  it  simply 
fills  the  interstitial  spaces  of  the  rock  and  binds  the  sand  grains 
together.  These  spaces  or  pores  vary  in  magnitude,  and  may  make 
up  a considerable  portion  of  the  total  volume  of  a rock.  According 
to  G.  F.  Becker,4  the  interstitial  space  in  a sandstone  made  up  of 
closely  packed  spherical  grains  amounts  to  25.96  per  cent.  C.  R. 
Van  Hise  5 estimates  the  minimum  pore  space  at  24  per  cent,  and 
claims  that  it  may  be  much  greater.  The  character  of  the  rock  pro- 
duced by  the  consolidation  of  such  a bed  will  obviously  depend  upon 
the  extent  to  which  the  cementing  material  has  filled  the  interstitial 
spaces.  One  sandstone  is  loosely  compacted,  another  is  solid,  and  by 
thorough  silicification  the  rock  may  become  transformed  into  a hard, 
vitreous  quartzite.  In  an  ordinary  sandstone  the  fracture  is  around 
the  grains;  in  a quartzite  it  is  just  as  likely  to  be  across  them. 

After  silica,  and  often  with  silica,  the  commonest  cements  of  sand- 
stone consist  of  carbonates.6  Calcium  carbonate  is  the  most  abun- 
dant salt  derivable  from  percolating  waters,  and  is  easily  deposited 
therefrom;  hence  its  frequency  in  the  sediments,  even  in  those  which 
were  not  laid  down  in  proximity  to  limestones.  Calcareous  sandstones 
are  exceedingly  common,  and  at  the  other  end  of  the  series  arena- 
ceous limestones  are  not  rare.  The  following  analysis  of  a greenish 
sandstone  from  Lohne,  Westphalia,  by  W.  von  der  Marck,7  may 
illustrate  the  complexity  of  these  mixtures. 

1 Proc.  U.  S.  Nat.  Mus.,  vol.  38, 1910,  p.  17.  Pogue  gives  a good  list  of  other  occurrences. 

2 Pub.  No.  Ill,  Field  Columbian  Mus.,  1906,  p.  31. 

s See  A.  Knop,  Neues  Jahrb.,  1874,  p.  281;  A.  S.  Tomebohm,  Neues  Jahrb.,  1877,  p.  210;  H.  C.  Sorby, 
Quart.  Jour.  Geol.  Soc.,  vol.  36, 1880,  Proc.,  p.  46;  A.  A.  Young,  Am.  Jour.  Sci.,  3d  ser.,  vol.  34, 1882,  p.  47; 
R.  D.  Irving  and  C.  R.  Van  Hise,  Buil.  U.  S.  Geol.  Survey  No.  8, 1884;  Irving,  Fifth  Ann.  Rept.  U.  S.  Geol. 
Survey,  1885,  p.  218.  “Crystallized  sands”  from  Peru  are  mentioned  by  L.  Crosnier,  Annales  des  mines, 
5th  ser.,  vol.  2,  1852,  p.  5;  and  A.  Daubree  (Etudes  synth<5tiques  de  geologie  exp6rimentale,  pp.  226-230) 
cites  a number  of  European  examples.  m 

* Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  399. 

s Idem,  vol.  47,  1904,  p.  863. 

6 Calcium  carbonate,  up  to  nearly  30  per  cent,  is  the  cementing  substance  of  the  sandstone  reefs  found 
on  the  coast  of  Brazil.  See  the  important  monograph  by  J.  C.  Branner,  which  forms  vol.  44  of  Bull. 
Mus.  Comp.  Zool.,  1904.  Branner  mentions  similar  reefs  in  the  Levant. 

7 Verhandl.  Naturhist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  vol.  12,  1855,  p.  269.  Many  other, 
similar  analyses  are  given.  G.  Bischof  (Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed., 
vol.  3,  pp.  137-149)  gives  abundant  data  upon  the  cementing  materials  of  sandstones.  In  analyses  of 
these  rocks  it  is  commonly  assumed  that  the  portion  soluble  in  hydrochloric  acid  belongs  wholly  to  the 
cement.  This  is  probably  true  in  most  cases,  but  not  always.  Soluble  minerals  may  occur  in  a sandstone 
among  its  granular  components. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


539 


Analysis  of  sandstone  from  Westphalia. 

39.  50 
7.  23 
7.  54 
3.  90 
.82 
2. 12 
36.  65 
.91 
.03 
.62 

99.  32 

In  this  analysis  calcium  phosphate  appears  among  the  cementing 
substances,  and  many  other  examples  of  its  occurrence  under  like  con- 
ditions are  known.  Phosphatic  sandstones  from  Perry  County,  Ten- 
nessee, have  been  described  by  C.  W.  Hayes,1  and  also  a phosphatic 
breccia.  In  these  rocks  the  calcium  phosphate  forms  the  matrix  of 
the  sand  grains.  In  a brown  sandstone  from  Kursk,  Russia,  C.  Claus  2 
found  13.60  per  cent  of  P205,  equivalent  to  22.64  of  Ca3P208.  In  the 
same  sandstone  4.98  per  cent  of  calcium  fluoride  was  also  present. 
Calcium  fluoride  has  also  been  reported  by  W.  Mackie  3 as  a cement- 
ing material  in  a Triassic  sandstone  from  Elginshire,  Scotland — in 
one  specimen  as  much  as  25.88  per  cent.  These  figures,  of  course, 
represent  exceptional  samples — concentrations,  so  to  speak;  in  ordi- 
nary cases  the  cementing  compounds  are  found  in  small  amounts. 

Barium  sulphate  has  repeatedly  been  observed  as  a cement  in 
sandstones.  F.  Clowes 4 has  described  specimens  containing  from 
28.20  to  60.06  per  cent  of  BaS04.  Clowes  suggests  that  the  barite 
was  probably  formed  in  situ,  by  double  decomposition  between 
barium  carbonate  and  sulphates  contained  in  percolating  waters. 
Barium  has  often  been  detected  in  the  waters  of  mineral  springs.5 6 
The  b ary  tic  sandstones,  so  far  as  they  have  been  described,  are 
remarkably  durable,  because  of  the  insoluble  character  of  the  cement. 
Calcareous  sandstones  are  easily  disintegrated  by  weathering,  for 
the  carbonates  are  readily  dissolved  by  atmospheric  waters. 

Apart  from  the  cements,  sandstones  vary  in  composition  exactly 
as  do  the  sands.  A sandstone  may  be  nearly  pure  quartz,  or  quartz 
and  feldspar,  or  micaceous,  or  glauconitic,  and  it  can  exhibit  any 
texture  from  the  finest  to  the  coarsest.  Textural  differences,  how- 
ever, do  not  concern  the  chemist.  From  a chemical  point  of  view  it 


Soluble  portion. 


Insoluble  portion 


fCaC03. . 
MgC03. 
FeC03. 
Ca3P2Og 
Fe203. . 
A1203. . 
fSi02.... 
LA1203... 
k2o.... 
h2o.... 


1 Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2, 1896,  pp.  527,  539. 

2 Jahresb.  Chemie,  1852,  p.  980. 

3 Rept.  Brit.  Assoc.  Adv.  Sci.,  1901,  p.  649.  See  also  O.  Miigge,  Centralbl.  Min.,  Geol.  u.  Pal.,  1908,  p.  33. 

4 Proc.  Roy.  Soc.,  vol.  46,  1889,  p.  363;  vol.  64, 1899,  p.  374.  See  also  W.  Mackie,  Rept.  Brit.  Assoc.  Adv. 
Sci.,  1901,  p.  649;  C.  B.  Wedd,  Geol.  Mag.,  1899,  p.  508;  and  C.  C.  Moore,  Proc.  Liverpool  Geol.  Soc.,  vol.  8, 

1898,  p.  241.  Moore  gives  several  good  analyses  of  sandstones.  In  some  of  them  small  amounts  of  cobalt 
and  nickel  were  found. 

6 See  ante,  p.  204.  See  also  R.  Delkeskamp,  Notizbl.  Ver.  Erdkunde,  4th  ser.,  Heft  21, 1900,  p.  47. 


540 


THE  DATA  OF  GEOCHEMISTRY. 


is  immaterial  whether  the  sand  grains  are  coarse  or  fine,  rounded  or 
angular.  Such  rocks  as  conglomerates,  breccias,-  arkoses,  gray- 
wackes,  etc.,  have  no  distinct  chemical  peculiarities;  they  are  made 
up  of  detrital  material,  and  vary  from  their  parent  formations  only 
in  the  extent  to  which  their  component  fragments  have  been  decom- 
posed and  in  the  nature  of  their  cementing  substances.  Any  sand 
or  detritus  may  be  reconsolidated  by  any  one  of  the  cements  above 
mentioned.  When  a mixture  of  sand  and  clay  consolidates,  it  may 
form  an  argillaceous  sandstone  or  a sandy  shale,  according  to  the 
relative  proportions  of  the  two  ingredients.  In  such  a sandstone  the 
colloidal  substances  of  the  admixed  clay  appear  to  act  as  binders, 
their  function  being  somewhat  different  from  that  of  the  cements 
deposited  by  solutions.  Their  binding  power  is  probably,  in  most 
cases,  reinforced  by  the  addition  of  true  cements,  usually  either 
calcium  carbonate  or  silica.  By  secondary  reactions,  due  to  addi- 
tions of  this  kind,  the  clay  substances  may  be  transformed  into 
other  things,  as  shown  in  the  graywacke  of  Hurley,  Wisconsin.1 
This  is  a detrital  rock,  which  originally  consisted  largely  of  quartz 
and  feldspar,  with  a little  hornblende,  and  dark  fragments  of  older 
rock  material,  held  together  by  clay.  In  the  graywacke  the  clay 
has  been  transformed  into  what  is  principally  a chlorite,  with  sec- 
ondary quartz  and  some  other  minor  minerals.  The  cement,  which 
was  at  first  amorphous,  is  now  entirely  crystalline.  Metasomatic 
changes  of  this  order  are  very  common,  and  the  reactions  which  can 
occur  are  many.  With  different  detritus,  different  cements,  and  differ- 
ent salts  in  the  circulating  waters,  a vast  number  of  transformations 
are  possible.  On  this  subject  it  would  be  difficult  to  generalize. 

In  a microscopic  study  of  about  150  psammites,  as  rocks  of  the 
sandstone  class  are  sometimes  called,  G.  Klemm 2 identified  the  fol- 
lowing substances  among  their  components:  Quartz,  feldspars,  micas, 
iron  ores,  zircon,  rutile,  apatite,  tourmaline,  garnet,  titanite,  augite, 
hornblende,  opaline  silica,  glauconite,  carbonates  of  calcium,  magne- 
sium, and  iron,  rock  fragments,  clastic  dust,  and  clay.  Even  this  list 
is  probably  far  from  being  exhaustive.  An  arkose  sandstone  from 
the  quicksilver  region  of  California,  made  up  of  granitic  detritus, 
was  found  by  G.  F.  Becker 3 to  contain  quartz,  orthoclase,  oligoclase, 
biotite,  muscovite,  hornblende,  titanite,  rutile,  tourmaline,  and 
apatite.  In  short,  all  of  the  rock-iorming  minerals  which  can  in  any 
way  survive  the  destruction  of  a rock  may  be  found  in  its  sands,  and 
therefore  in  the  sandstones.  The  feldspars  and  ferromagnesian  min- 
erals, however,  are  quite  commonly  altered  or  even  removed,  the  more 

1 Described  by  W.  S.  Bayley  in  Bull.  U.  S.  Geol.  Survey  No.  150,  1898,  p.  84.  Compare  C.  R.  Van  Hise, 
Am.  Jour.  Sci.,  3d  ser.,  vol.  31,  1886,  p.  453,  for  data  concerning  other  similar  rocks  in  the  same  region. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  34,  1882,  p.  771. 

3 Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  59.  Several  other  sandstones  are  described  by  J.  S.  Diller 
in  Bull.  U.  S.  Geol.  Survey  No.  150, 1898,  pp.  72-84. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


541 


stable  minerals,  like  quartz,  being  much  more  persistent.  Quartz  is 
the  most  abundant  mineral  in  these  rocks,  while  in  rocks  of  the 
crystalline  and  eruptive  classes  it  is  subordinate  to  the  feldspars. 

The  following  analyses,  which,  with  one  exception,  were  all  made 
in  the  laboratory  of  the  United  States  Geological  Survey,  will  suffice 
to  show  the  general  composition  of  the  sandstones : 1 

Analyses  of  sandstones. 

A.  Potsdam  sandstone,  Ablemans,  W isconsin.  Analysis  by  E.  A.  Schneider.  Described  by  J.  S.  D iller, 
Bull.  U.  S.  Geol.  Survey  No.  150,  1898,  p.  80.  Nearly  pure  quartz. 

B.  Brown  sandstone,  Hummelstown,  Pennsylvania.  Analysis  by  Schneider.  Described  by  D iller,  op. 
cit.,  p.  77.  Composed  chiefly  of  quartz,  with  some  feldspar,  kaolin,  etc.  The  cement  is  iron  oxide. 

C.  Ferruginous  sandstone,  “carstone,”  from  Hunstanton,  Norfolk,  England.  Analysis  and  description 
by  J.  A.  Phillips,  Quart.  Jour.  Geol.  Soc.,  vol.  37,  1881,  p.  6.  Consists  of  quartz  grains  cemented  by  brown 
iron  ore,  with  very  little  feldspar  and  mica.  Phillips  also  gives  five  other  analyses  of  British  sandstones. 

D.  From  a “sandstone  dike”  in  Shasta  County,  California.  Analysis  by  T.  M.  Chatard.  Described  by 
J.  S.  Diller,  Bull.  Geol.  Soc.  America,  vol.  1,  1889,  p.  411.  Made  up  of  quartz,  feldspar,  and  biotite,  with  a 
calcite  cement.  Contains  also  serpentine,  titanite,  magnetite,  and  zircon.  Other  “sandstone  dikes,”  near 
Pikes  Peak,  Colorado,  have  been  described  by  W.  Cross.  They  probably  represent  quicksands  which  were 
injected  into  fissures.  See  also  C.  O.  Crosby,  Bull.  Essex  Inst.,  vol.  27,  1895,  p.  113. 

E.  Miocene  sandstone,  Mount  Diablo,  California.  Analyzed  and  described  by  W.  H.  Melville,  Bull. 
Geol.  Soc.  America,  vol.  2, 1890,  p.  403. 

F.  Composite  analysis  of  253  sandstones.  By  H.  N.  Stokes. 

G.  Composite  analysis  of  371  sandstones  used  for  building  purposes.  By  H.  N.  Stokes. 

H.  Graywacke,  Hurley,  Wisconsin.  Analysis  by  H.  N.  Stokes.  Described  by  W.  S.  Bayley,  Bull. 
U.  S.  Geol.  Survey  No.  150,  1898,  p.  84.  Contains  quartz,  feldspars,  iron  oxides,  and  probably  kaolin.  In 
the  cement  are  chlorite,  quartz,  magnetite,  pyrite,  rutile,  sometimes  biotite.  and  either  muscovite,  or  kaolin. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

99.  42 

88. 13 

49.  81 

48. 13 

44.  54 

78.  66 

84.  86 

76.  84 

Ti02 . 

. 24 

.25 

.41 

A1203 

} .31 

5.  81 

5. 17 

11. 19 

12.  63 

4.  78 

5.  96 

11.  76 

Fe203 

1.  77 

29. 17 

1.  25 

2.  50 

1.  08 

1.  39 

.55 

FeO 

.31 

.35 

1.  47 

3.  08 

.30 

.84 

2.  88 

MnO 

.29 

.44 

Trace. 

Trace. 

Trace. 

CaO 

.20 

2.  43 

16.  39 

14.  65 

5.  52 

1. 05 

.70 

SrO 

[ Trace. 

None. 

BaO 

.04 

.05 

.01 

MgO 

.53 

.95 

2.  22 

5.  55 

1. 17 

.52 

1.  39 

Na20 

.06 

.84 

2.  29 

3.  35 

.45 

.76 

2.  57 

K20 

2.  63 

.48 

1. 17 

1.  37 

1.  32 

1. 16 

1.  62 

Li20 

‘ 

Trace. 

Trace. 

H20- 

} .18 

.23 

3.  85 

.78 

1. 43 

.31 

.27 

} 1.87 

H20+ 

.26 

6.  56 

1.  78 

2.  25 

fll.  33 

al.  47 

P90„ 

.42 

. 14 

. 29 

.08 

.06 

C02 

12.  73 

7.  76 

5.  04 

1.  01 

so3 

. 07 

. 09 

Cl 

Trace. 

Trace. 

99.  91 

99.  93 

100.  03 

100. 11 

99.  84 

100. 41 

99.  86 

100. 18 

a Includes  organic  matter. 


A peculiar  rock,  which  is  sometimes  called  a calcareous  sandstone, 
is  the  gaize  of  the  French  geologists.  It  has  been  fully  described  by 

1 For  additional  analyses,  see  Bull.  U.  S.  Geol.  Survey  No.  228,  1904,  pp.  291-296.  W.  Wallace  (Proc. 
Philos.  Soc.  Glasgow,  vol.  14,  1883,  p.  22)  and  W.  Mackie  ( Trans.  Edinburgh  Geol.  Soc.,  vol.  8, 1899,  pp.  58, 
59)  give  a number  of  good  analyses  of  Scottish  sandstones.  See  also  C.  C.  Moore,  Proc.  Liverpool  Geol. 
Soc.,  vol.  8,  1898,  p.  241,  for  English  examples. 


542 


THE  DATA  OF  GEOC.HEMISTRY. 


L.  Cayeux 1 as  a siliceous  rock,  rich  in  the  debris  of  siliceous  organ- 
isms, containing  quartz  and  glauconite  cemented  by  opal  and  clay, 
with  sometimes  chalcedony,  and  very  little  carbonate  of  lime.  The 
silica  in  gaize  ranges  from  76  to  92  per  cent,  and  a large  part  of  it, 
75.3  per  cent  in  the  maximum,  is  soluble  in  caustic  alkalies.  It  is,  as 
defined  by  Cayeux,  a sedimentary  rock,  consisting  largely  of  non- 
clastic  silica,  and  seems  to  have  been  originally  a marine  ooze. 

FLINT  AND  CHERT. 

It  is  at  once  evident  that  a considerable  variety  of  rocks  may  be 
formed  from  siliceous  oozes,  such  as  the  radiolarian  and  diatomaceous 
oozes  of  the  Challenger  expedition.  These  fine  sediments  may  be 
mixed  with  more  or  less  clay,  spud,  or  calcareous  matter,  shading, 
when  consolidated,  into  shales,  sandstones,  or  siliceous  limestones. 
Their  geological  relations  and  their  content  of  amorphous  or  opaline 
silica  must  be  depended  upon  to  define  them.  In  the  same  category 
we  must  place  infusorial  earth,  which  consists  mainly  of  the  siliceous 
remains  of  diatoms;  and  such  rocks  as  flint,  chert,  and  novaculite 
fall  in  some  cases,  if  not  always,  under  this  general  classification. 
With  some  exceptions  these  rocks  are  commonly  of  organic  origin. 
The  novaculite  of  Arkansas,  however,  has  been  differently  interpreted.2 
It  is  regarded  by  L.  S.  Griswold  as  a siliceous  sediment  or  silt;  in 
other  words,  as  sandstone  of  extremely  fine  grain.  No  organisms 
could  be  positively  detected  in  it,  nor  does  it  contain  an  appreciable 
amount  of  soluble  silica.  It  is,  according  to  Griswold,  essentially 
a shale  minus  the  argillaceous  component,  and  it  forms  part  of  a 
sedimentary  series  in  which  all  gradations  from  shale  to  novaculite 
occur.  F.  Rutley,3  however,  dissents  from  Griswold’s  views,  and 
has  sought  to  show  that  the  novaculite  is  a siliceous  replacement  or 
pseudomorph  after  limestone  or  dolomite.  It  has  also  been  re- 
garded as  a chemical  precipitate,  analogous  to  siliceous  sinter. 
In  composition  the  novaculite  is  very  nearly  pure  silica. 

The  much  commoner  variety  of  compact  silica  known  as  chert  has 
also  been  diversely  interpreted.  A number  of  writers,4  studying  chert 
from  different  localities,  have  argued  in  favor  of  the  replacement 

1 M4m.  Soc.  g6ol.  du  Nord,  vol.  4,  pt.  2,  1897.  Several  incomplete  analyses  of  gaize  are  given.  The  deter- 
mination  of  amorphous  silica  by  its  solubility  in  caustic  alkalies,  it  must  be  observed,  is  not  very  accurate. 
Silica  in  any  form  will  dissolve,  the  rate  of  solution  depending  upon  the  fineness  of  its  subdivision,  and  the 
concentration  of  the  alkali.  Opaline  silica,  however,  dissolves  rapidly  in  weak  alkali,  and  so  can  be  roughly 
estimated.  Quartz  dissolves  very  slowly. 

2 See  Griswold’s  monograph  on  this  rock  (Rept.  Arkansas  Geol.  Survey,  vol.  4,  1890)  and  a paper  by  the 
same  author  in  Proc.  Boston  Soc.  Nat.  Hist.,  vol.  26, 1894,  p.  414.  Compare  also  O.  A.  Derby,  Jour.  Geology, 
vol.  6, 1898,  p.  366;  and  J.  C.  Branner,  idem,p.  368.  Branner  sums  up  very  concisely  the  different  theories 
which  have  been  advanced  to  account  for  rocks  of  this  character. 

* Quart.  Jour.  Geol.  Soc.,  vol.  50,  1894,  p.  380. 

* E.  Hull  and  E.  T.  Hardman,  Sci.  Trans.  Roy.  Dublin  Soc.,  new  ser.,  vol.  1,  1878,  pp.  71,  85,  on  the 
Carboniferous  cherts  of  Ireland;  A.  Renard,  Bull.  Acad.  roy.  sci.  Belgique,  vol.  46,  1878,  p.  471,  on  the 
phthanites  of  Belgium;  T.  Rupert  Jones,  Proc.  Geol.  Assoc.  London,  vol.  4,  1876,  p.  439;  and  others. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


543 


theory.  That  the  replacement  of  calcium  carbonate  by  silica  is 
possible,  no  one  can  deny,  for  sihcified  shells  and  corals  are  common. 
The  pseudomorphs  of  chalcedony  or  opal  after  coral,  from  Tampa 
Bay,  Florida,  are  conspicuous  examples  of  this  change.  Furthermore, 
A.  H.  Church  1 has  effected  the  transformation  artificially.  A piece 
of  recent  coral  was  almost  completely  silicified,  losing  nearly  all  its 
carbonate  of  lime,  when  an  aqueous  solution  of  silica  was  allowed  to 
filter  through  it  very  gradually.  Some  chert,  then,  may  have  been 
formed  in  this  way. 

On  the  other  hand,  chert  and  flint  often  exhibit  evidences  of  organic 
derivation.  The  radiolarian  cherts  of  California,  described  by  A.  C. 
Lawson,  C.  Palache,  and  F.  L.  Bansome,2  are  principally  composed 
of  radiolarian  remains.  Lawson  regards  these  cherts  as  having  been 
formed  by  precipitations  of  colloidal  silica  from  submarine  springs, 
which  produced  a sort  of  ooze  in  which  the  radiolaria  became  em- 
bedded. In  other  cases  cherts  were  probably  derived  from  sponges, 
whose  spicules  consist  very  largely  of  opaline  silica.3  Cherts  crowded 
with  these  spicules  have  been  described  by  various  authors,  espe- 
cially by  W.  J.  Sollas 4 and  G.  J.  Hinde.5  Hinde  studied  especially 
the  cherts  of  the  Greensand  formation  in  southern  England,  the 
cherts  of  Spitzbergen,  and  also  the  Irish  cherts,  described  by  Hull 
and  Hardman.  In  all  of  them  the  sponge  spicules  were  abundant. 
The  same  thing  is  true  of  the  flint  nodules  found  in  chalk,  which 
almost  invariably  show  signs  of  a similar  origin.6  In  order  to  ac- 
count for  these  nodules,  Sollas  suggests  that  sponge  spicules  accu- 
mulated in  a calcareous  ooze,  where,  in  presence  of  sea  water  under 
pressure,  they  partly  dissolved.  The  silica  thus  taken  into  solution 
was  later  reprecipitated  around  suitable  nuclei,  at  the  same  time 
replacing  carbonate  of  lime.  It  is  possible,  however,  as  A.  A. 
Julien 7 has  shown,  that  the  organic  matter  of  the  decaying  sponges 
may  have  exerted  much  influence  in  bringing  about  the  solution  of 
silica.  It  is  difficult  to  see  how  the  nodules  could  have  developed 
except  from  silica  which  had  been  first  dissolved.  Their  growth 
around  organic  nuclei  can  hardly  be  explained  otherwise. 

Sedimentary  rocks  consisting  almost  entirely  of  silica  may  orig- 
inate in  divers  ways.  As  siliceous  sinter8  the  silica  is  simply  a 
deposit  from  hot  springs.  As  sandstone  it  is  an  aggregate  of  finely 

1 Jour.  Chem.  Soc.,  vol.  15,  1862,  p.  107. 

2 Lawson,  Fifteenth  Ann.  Kept.  U.  S.  Geol.  Survey,  1895,  p.  420;  Lawson  and  Palache,  Bull.  Dept.  Geol- 

ogy Univ.  California,  vol.  2, 1902,  pp.  354, 365;  Ransome,  idem,  vol.  1, 1894,  p.  193. 

a See  Thoulet,  Bull.  Soc.  min.,  vol.  7, 1884,  p.  147. 

* Ann.  and  Mag.  Nat.  Hist.,  5th  ser.,  vol.  6, 1880,  pp.  384,  437;  vol.  7, 1881,  p.  141. 

6 Philos.  Trans.,  vol.  176, 1885,  p.  403;  Geol.  Mag.,  1887,  p.  435;  idem,  1888,  p.  241. 

6 See  Hinde  and  Sollas,  loc.  cit.,  and  G.  C.  Wallich,  Quart.  Jour.  Geol.  Soc.,  vol.  36,  1880,  p.  68.  J.  A. 
Merrill  (Bull.  Mus.  Comp.  Zool.,  vol.  28,  1895,  p.  1)  has  described  fossil  sponges  from  flints  found  in  the 
Cretaceous  near  Austin,  Texas. 

'•  Proc.  Am.  Assoc.  Adv.  Sci.,  1879,  p.  396. 

8 See  ante,  p.  205. 


544 


THE  DATA  OP  GEOCHEMISTRY. 


divided  quartz.  In  gaize  and  some  cherts  the  rock  is  composed  in 
great  part  of  organic  remains.  In  some  cases  calcium  carbonate  has 
been  obviously  replaced  by  silica.  There  are  also  siliceous  concre- 
tion-like flints,  as  well  as  the  oolites  which  are  formed  by  the  deposi- 
tion of  silica  from  solution  around  quartz  grains.  Such  an  oolite 
from  Pennsylvania  has  been  studied  by  several  investigators.1  It  is 
possible  that  a single  formation  may  represent  more  than  one  of 
these  processes.  R.  D.  Irving  and  C.  R.  Van  Hise,2  for  example, 
describing  the  chert  of  the  Penokee  iron  region,  which  was  laid  down 
simultaneously  with  the  iron  carbonates,  suggest  that  it  may  have 
been  partly  derived  from  organic  remains  and  also  be  partly  a chem- 
ical sediment.  In  short,  no  one  process  can  account  for  all  the 
occurrences  of  amorphous  or  cryptocrystalline  silica,  and  each  local- 
ity must  be  studied  in  the  light  of  its  own  evidence. 

The  following  analyses  of  chert,  novaculite,  etc.,  will  serve  to 
illustrate  the  chemical  uniformity  of  these  rocks : 3 

Analyses  of  chert  and  allied  rocks. 

A.  Novaculite,  Rockport,  Arkansas.  Analysis  by  R.  N.  Brackett.  From  Griswold’s  monograph,  p.  167. 

B.  Chert,  Belleville,  Missouri.  Analysis  by  E.  A.  Schneider,  Bull.  U.  S.  Geol.  Survey  No.  228,  1904, 
p.  297.  Other  analyses  are  given  on  the  same  page. 

C.  Chert  from  the  Upper  Carboniferous  of  Ireland.  Analysis  by  E.  T.  Hardman,  Sci.  Trans.  Roy.  Dub- 
lin Soc.,  new  ser.,  vol.  1, 1878,  p.  85.  Some  of  the  Irish  cherts  are  highly  calcareous,  representing  transitions 
to  siliceous  limestone. 

D.  Siliceous  oolite,  Center  County,  Pennsylvania.  Analysis  by  Bergt,  Abhandl.  Gesell.  Isis,  1892,  p.  115. 

E.  Infusorial  earth,  Nevada.  Analysis  by  R.  W.  Woodward,  Rept.  U.  S.  Geol.  Expl.  40th  Par.,  vol.  2, 
1877,  p.  768. 


A 

B 

c 

D 

E 

Si02 

99. 47 

98. 17 
} .83 

95.50 

98. 72 
} .54 

86.70 

ALO1 

.17 

.10 

4.09 

Fe203 

.12 

1.95 

FeO 

J 

.15 

1.26 

CaO 

.09 

.05 

.09 

.14 

CaC03. . 

.87 

CaS04 

Trace. 

MgO 

.05 

.01 

Trace. 

.51 

k2o 

.07 

} .26 

.41 

NaaO 

.15 

Trace. 

.77 

PoO- 

/ 

Trace. 

^ 2”5  * 

Ignition 

.12 

.78 

1.43 

.34 

5.99 

100. 24 

99.84 

100. 00 

99. 95 

99.87 

i E.  H.  Barbour  and  J.  Torrey,  Am.  Join-.  Sci.,  3d  ser.,  vol.  40, 1890,  p.  246;  E.  O.  Hovey,  Bull.  Geol.  Soc. 
America,  vol.  5,  1893,  p.  627;  and  Bergt,  Abhandl.  Gesell.  Isis,  1892,  p.  115.  See  also  G.  R.  Wieland,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  4, 1897,  p.  262,  who  ascribes  these  oolites  to  the  agency  of  hot  springs.  E.  S.  Moore 
(Jour.  Geology,  vol.  20,  p.  259, 1912)  has  also  studied  these  minerals. 

* Tenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1890,  p.  397.  See  also  C.  R.  Van  Hise,  A treatise  on  meta- 
morphism: Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  pp.  847-853. 

3 For  other  analyses  see  Griswold’s  monograph  on  novaculite,  Hardman’s  paper  on  the  Irish  cherts,  Bar- 
bour and  Torrey  on  the  oolite,  and  Hovey  (Am.  Jour.  Sci.,  3d  ser.,  vol.  48, 1894,  p.  401)  on  cherts  from  Mis- 
souri. In  a large  number  of  cherts  from  Kentucky,  J.  H.  Kastle,  J.  C.  W,  Frazer,  and  G.  Sullivan  (Am. 
Chem.  Jour.,  vol.  20, 1898,  p.  153)  found  appreciable  amounts  of  phosphates  ranging  from  0.18  up  to  3.5  per 
cent  of  P205. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


545 


Other  analyses,  in  considerable  number,  show  intermediate  grada- 
tions between  chert  and  limestone.  These  represent  comminglings 
in  any  proportion  between  the  cherty  silica  and  calcium  carbonate. 
That  is,  silica  and  calcium  carbonate  may  be  deposited  together  in 
the  same  mud  or  ooze,  forming  a nearly  homogeneous  mixture. 

SHALE  AND  SLATE. 

When  the  finest  products  of  sedimentation  consolidate,  they  tend 
to  form  a close-grained,  laminated,  or  fissile  rock,  which  is  called 
shale.  As  thus  used,  the  term  is  very  vague  and  has  little  chemical 
significance.  Sand,  reduced  to  the  fineness  of  flour,  may  form  a 
rock  which  is  shaly  in  structure,  and  so  too  may  limestone.  In  these 
cases,  however,  there  is  commonly  more  or  less  argillaceous  impurity 
in  the  rocks,  so  that  it  is  better  to  call  them  argillaceous  sandstones 
or  limestones. 

As  the  term  is  generally  used,  a shale  is  supposed  to  be  a consoli- 
dated mud  or  clay  in  which  the  aluminous  silicates  are  the  more 
important  and  characteristic  constituents.  Shales,  therefore,  vary  in 
composition  exactly  as  do  the  materials  from  which  they  form,  and 
may  contain  sandy  or  calcareous  impurities.  Bituminous  and  car- 
bonaceous shales  are  also  common.  Many  shales  contain  pyrite  or 
marcasite,  which  oxidize  and  give  rise  to  the  formation  of  sulphates. 
These  rocks  are  called  alum  shales  and  exhibit  aluminous  efflores- 
cences. The  alum  shales  and  calcareous  shales  are  easily  alterable; 
those  which  consist  chiefly  of  aluminous  silicates,  having  been  formed 
from  the  final  products  of  rock  decomposition,  are  remarkably  stable. 
Their  disintegration,  when  it  occurs,  is  largely  a mechanical  process 
and  involves  very  little  chemical  change. 

Between  typical  sandstones  and  typical  shales  there  are  pronounced 
structural  differences.  A sandstone  is  made  up  of  grains  which  are 
discernible  to  the  eye,  and  is  therefore  distinctly  porous.  In  conse- 
quence of  this  peculiarity  it  is  easily  permeable  to  percolating  waters, 
the  source  from  which  its  cementing  substances  are  derived.  A shale, 
on  the  other  hand,  consists  of  much  finer  particles,  which  are  closely 
packed,  and  its  porosity  is  small.1  In  its  formation  the  cementing 
process  is  less  prominent  than  in  the  case  of  sandstone,  and  its  con- 
solidation seems  to  have  been  effected  by  a sort  of  welding.  The 
colloidal  matter  contained  in  most  muds  and  clays  is  capable  of 
binding  under  the  influence  of  pressure  alone;  and  to  unions  of  this 
kind  a shale  mainly  owes  its  coherence.  Cementation  is  not  excluded, 
but  it  has  become  a subordinate  factor.  Under  the  influence  of 


1 For  data  on  the  fineness  of  sand  and  mud  particles,  see  C.  R.  Van  Hise,  A treatise  on  metamorphism: 
Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  p.  892. 


97270°— Bull.  616—16 35 


546 


THE  DATA  OF  GEOCHEMISTRY. 


pressure,  the  water  of  a mud  is  largely  expelled,  so  that  the  resulting 
shale  is  much  less  hydrous. 

The  following  analyses  of  shales  were  all  made  in  the  laboratory  of 
the  United  States  Geological  Survey.  Some  constituents,  reported 
in  “ traces”  only,  are  omitted  from  the  table.  A number  of  other 
analyses  are  given  in  Bulletin  591,  pages  250-258. 


Analyses  of  shales. 

A.  Composite  analysis  of  fifty-one  Paleozoic  stales,  by  H.  N.  Stokes. 

B.  Composite  analysis  of  twenty-seven  Mesozoic  and  Cenozoic  shales,  by  H.  N.  Stokes. 

C.  Black  Devonian  shale,  near  Longfellow  mine,  Horenci  district,  Arizona.  Analyzed  by  W.  F. 
Hillebrand. 

D.  Middle  Cambrian  shale,  Coosa  Valley,  Alabama.  Analysis  by  Stokes. 

E.  Bituminous  shale,  Dry  Gap,  Georgia.  Analysis  by  L.  G.  Eakins. 

F.  Shale,  near  Rush  Creek,  Pueblo  quadrangle,  Colorado.  Analysis  by  George  Steiger. 

G.  Carboniferous  shale,  Elliott  County,  Kentucky.  Analysis  by  T.  M.  Chatard. 

H.  Cretaceous  shale,  Mount  Diablo,  California.  Highly  calcareous.  Analysis  by  W.  H.  Melville. 


Si02. 

Ti02. 

A120. 

Fe20 

FeO. 

MnO 

ZnO. 


3 


CaO 


BaO 


MgO.. 
Na20. . 
K20. . 
Li20.. 
H20- 

h2o+ 

PA.. 

co2... 

soa... 

s 

c 


Hydrocarbons. 
Organic  matter 

Pyrite 

Chalcopyrite. . . 


A 

B 

c 

D 

E 

F 

G 

H 

60. 15 

55.  43 

61.  25 

55.  02 

51.  03 

45.  89 

41.  32 

25.  05 

.76 

.46 

. 66 

. 65 

.52 

.48 

16.  45 

13.  84 

15.  60 

21.  02 

13.  47 

13.  24 

20.  71 

8.  28 

4.  04 

4.  00 

1.  35 

5.  00 

8.  06 

3. 88 

2.  59 

.27 

2.  90 

1.74 

3.  04 

1.54 

5. 46 

2.41 

Trace. 

Trace. 

.07 

Trace. 

. 17 

4. 11 

. 03 

1.  41 

5.  96 

3.  40 

1.  60 

.78 

12.09 

9.91 

27.  87 

.04 

.06 

Trace. 

.04 

2.  32 

2.  67 

4. 16 

2.  32 

1. 15 

2. 12 

1.91  1 

2.61 

1.  01 

1.  80 

.44 

.81 

.41 

.47 

7.19  1 



3.  60 

2.  67 

6.  74 

3. 19 

3. 16 

2. 31 

.88  ! 

Trace. 

Trace. 

Trace. 

.03 

.89 

2. 11 

.62 

2.44 

1.  38 

1.44 

3.  82 

3.45 

2.09 

5.  65 

} -81 

4. 16 

8.  78 

2.  86 

.15 

.20 

.08 

.06 

.31 

.17 

.08 

.08 

1.  46 

4.  62 

.83 

10.  38 

. 55 

24.  20 

.58 

.78 

.02 

7.  29 

.88 

. 69 

a 32 

13. 11 

3.  32 

3. 47 



.25 

.03 

100.  46 

100.  48 

99.  81 

100.54 

&102.  90 

100.08  ( 

100.  03 

99. 18 

° Carbonaceous  matter.  & Less  0=S,  100.17. 

The  most  noticeable  feature  in  these  analyses,  as  compared  with 
analyses  of  similar  clays,  is  the  change  in  the  iron  oxides.  In  the 
shales  the  proportion  of  ferrous  relatively  to  ferric  oxide  has  increased; 
probably  because  of  the  reducing  action  of  organic  matter  in  the 
sediments  as  they  were  first  laid  down.  Ferric  oxide  has  been  evi- 
dently reduced,  and  organic  substances  furnish  the  most  obvious 
reagents  for  producing  such  an  alteration. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


547 


Under  the  long-continued  influence  of  pressure  the  shales  become 
more  compact  and  less  hydrous,  and  pass  into  the  rocks  known  as 
clay  slates.  By  further  change,  of  a metasomatic  character,  the 
slates  are  transformed  into  the  metamorphic  mica  schists,  in  which 
various  new  minerals  appear.  The  schists  will  he  considered  in  the 
next  chapter.  Even  in  the  slates  the  effects  of  metasomatism  are 
manifest,  for  micas  and  chlorites  appear  conspicuously  in  them. 
These  minerals  have  been  formed  at  the  expense  of  the  clay  silicate 
and  the  residual  feldspars.  Scales  of  detrital  mica  are,  of  course, 
common  in  the  sediments;  but  in  the  slates  the  feldspar  grains  have 
been  more  or  less  transformed  into  particles  made  up  of  interlocking 
quartz  and  mica;  the  latter  usually  appearing  in  the  fibrous  sericitio 
form.  Even  in  Carboniferous  clays  and  shales  W.  M.  Hutchins  1 
found  little  kaolin,  but  more  or  less  secondary  quartz,  chlorite,  and 
mica.  The  chlorites,  evidently,  were  derived  from  the  debris  of 
ferromagnesian  minerals. 

The  mineralogical  composition  of  the  clay  slates  has  been  studied 
by  several  investigators,2  and  the  results  are  thoroughly  summed  up 
by  Dale  in  his  memoir  upon  the  slate  belt  of  eastern  New  York  and 
western  Vermont.  In  these  rocks  he  observed  clastic  particles  of 
quartz,  feldspar,  zircon,  muscovite,  and  carbonaceous  matter;  and 
autogenous  quartz,  chlorite,  muscovite,  pyrite,  and  carbonates  of 
lime,  magnesia,  iron,  and  manganese.  Rutile,  hematite,  and  tourma- 
line were  also  noted.  The  pyrite  was  often  altered  to  limonite. 
Other  observers,  studying  other  slates,  have  found  ottrelite,  stauro- 
lite,  garnet,  biotite,  hornblende,  epidote,  apatite,  pyrrhotite,  gypsum, 
and  magnetite  in  them. 

The  subjoined  analyses  of  roofing  slates  were  all  made  by  W.  F. 
Hillebrand  in  the  laboratory  of  the  United  States  Geological  Survey.3 

1 Geol.  Mag.,  1894,  pp.  36,  64;  idem,  1896,  pp.  309,  343. 

2 See  especially  W.  M.  Hutchins,  loc.  cit.;  H.  C.  Sorby,  Quart.  Jour.  Geol.  Soc.,  vol.  36,  Proc.,  1880,  pp. 
'66-80;  and  F.  A.  Anger,  Jahrb.  K.-k.  geol.  Reichsanstalt,  Min.  Mitt.,  vol.* 25,  1875,  p.  162.  T.  N.  Dale 
.(Nineteenth  Ann.  Kept.  U.  S.  Geol.  Survey,  pt.  3, 1899,  pp.  153-307;  also  Bull.  275, 1906)  has  made  a special 
study  of  the  roofing  slates.  His  bulletin  contains  a report  by  W.  F.  Hillebrand  on  the  composition  of  the 
slates,  and  closes  with  a valuable  bibliography. 

8 See  Dale,  loc.  cit.,  who  cites  other  analyses.  Still  others  are  given  in  Bull.  U.  S.  Geol.  Survey  No.  228, 
1904,  pp.  337-346.  J.  Roth  (Allgemeine  undchemische  Geologie,  vol.  2,  p.  588)  tabulates  15  analyses  of 
European  clays  and  shales,  and  H.  Rosenbusch(Elemente  der  Gesteinslehre,  2d  ed.,  p.  442)  gives  a table 
of  19.  See  also  E.  C.  Eckel,  Jour.  Geology,  vol.  12, 1904,  p.  25,  for  the  average  composition  of  36  American 
roofing  slates. 


548 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  roofing  slates. 

A.  Sea-green  slate,  Pawlet,  Vermont.  B.  Purple  slate,  Castleton,  Vermont.  C.  Black  slate,  Benson, 
Vermont.  D.  Red  slate,  near  Hampton  Village,  New  York.  E.  Green  slate,  near  Janesville,  New  York. 
F.  Black  slate,  Slatington,  Pennsylvania. 


A 

B 

c 

D 

E 

F 

Si02 

67.  76 

60.  96 

59.  70 

67.  61 

56.  49 

56.  38 

ai203 

14. 12 

16. 15 

16.  98 

13.  20 

11.  59 

15.  27 

FeA 

.81 

5. 16 

.52 

5.  36 

3.  48 

1.  67 

FeO 

4.  71 

2.  54 

4.  88 

1.  20 

1.  42 

3.  23 

MgO 

2.  38 

3.  06 

3.  23 

3.  20 

6.  43 

2.  84 

CaO 

.63 

. 71 

1.  27 

.11 

5. 11 

4.  23 

Na20 

1.  39 

1.  50 

1.  35 

.67 

.52 

1.  30 

K20 

3.  52 

5.  01 

3.  77 

4.  45 

3.  77 

3.  51 

h2o- 

.23 

.17 

.30 

.45 

.37 

.77 

h20+ 

2.  98 

3.  08 

3.  82 

2.  97 

2.  82 

4.  09 

Ti02 

.71 

.86 

.79 

.56 

.48 

.78 

C02 

.40 

.68 

1.  40 

None. 

7.  42 

3.  67 

PA 

.07 

.23 

.16 

.05 

.09 

.17 

MnO 

.10 

.07 

.16 

.10 

.30 

.09 

BaO 

.04 

.04 

.08 

.04 

.06 

.08 

FeS2 

.22 

None. 

1. 18 

.03 

.03 

1.  72 

nh3 

.01 

c 

None. 

.46 

.59 

100.  07 

100.  23 

100.  05 

100.  00 

100.  38 

100.  39 

LIMESTONE. 

The  carbonate  rocks,  which  may  be  either  sedimentary,  detrital,  or 
metamorphic,  are  represented  principally  by  limestone  and  dolomite. 
Limestone  consists  of  calcium  carbonate  more  or  less  impure,  and  it 
occurs  in  many  forms  of  very  diverse  origin.  Some  limestone,  the 
variety  known  as  calcareous  tufa  or  travertine,  is  a chemical  pre- 
cipitate, but  in  its  larger  masses  the  rock  is  generally  of  organic 
origin.  Chalk  is  probably  derived  from  a marine  ooze;  other  lime- 
stones are  made  up  of  shells  and  corals.  In  some  the  organic  remains 
are  conspicuous;  in  many  cases  they  are  quite  obliterated.  Sandy, 
argillaceous,  glauconitic,  ferruginous,  phosphatic,  and  bituminous 
limestones  owe  their  names  to  their  manifest  impurities.  Even 
gaseous  inclusions  may  give  a limestone  its  name,  as  in  the  case  of 
the  fetid  limestones  or  “stinkstone”  of  certain  well-known  localities. 
This  peculiarity  is  well  shown  by  a bed  of  calcite  in  Chatham  Town- 
ship, Canada,  described  by  B.  J.  Harrington,1  which  contains  0.016 
per  cent  of  hydrogen  sulphide.  A cubic  foot  of  the  rock  contains 
about  500  cubic  inches  of  the  inclosed  gas,  to  which  its  offensive 
odor,  when  struck  or  bruised,  is  due. 

The  primary  source  of  limestone  is  obviously  to  be  found  in  the 
decomposition  of  igneous  rocks  by  carbonated  waters.  Calcium 
carbonate  is  thus  produced;  it  passes  into  solution  in  ground  water, 


i Am.  Jour.  Sci.,  4th  ser.,  vol.  19, 1905,  p.  345. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


549 


springs,  and  streams,  and  is  thence  withdrawn  by  a variety  of  proc- 
esses. Its  deposition  as  a chemical  sediment,  especially  from  hot 
springs,  and  even  from  sea  water,  was  considered  in  a previous  chap- 
ter,1 but  the  evidence  may  well  be  repeated  here  and  developed  a 
little  more  fully.  Much  of  the  dissolved  carbonate  is  precipitated 
as  a cement  in  other  rocks,  but  that  point  needs  no  further  examina- 
tion now. 

When  waters  charged  with  calcium  carbonate  are  allowed  to  evap- 
orate, they  deposit  their  load  in  the  form  of  sinter,  or  tufa.  This 
process  can  be  observed  at  many  thermal  and  “ petrifying”  springs, 
and  also  in  the  formation  of  stalactites  and  stalagmites  in  limestone 
caverns.  In  this  way  large  masses  of  compact  carbonate  may  be 
formed,  which  are  oftentimes  of  great  beauty.  The  so-called  “onyx 
marbles,”  of  which  the  Mexican  “onyx”  is  a familiar  example,  are 
formed  in  this  way.  Some  rock  of  this  class  is  stalagmitic,  from 
caverns,  and  some  of  it  is  formed  by  springs.2  Its  variations  in  color 
and  texture,  to  which  its  ornamental  character  is  largely  due,  are 
commonly  produced  by  impurities  or  inclusions,  such  as  oxide  of 
iron,  or  even  mud  and  clay.3 

WTaen  fresh  waters,  charged  with  carbonates,  enter  the  sea,  a direct 
precipitation  of  calcium  carbonate  may  occur.  This  form  of  deposi- 
tion, however,  is  exceptional,  and  few  authentic  examples  of  it  are 
recorded.  It  happens  only  when  the  supply  of  carbonate  is  in  excess 
of  that  which  can  be  consumed  by  living  organisms  and  when  the 
conditions  of  temperature  and  evaporation  are  such  as  to  expel  the 
solvent  carbon  dioxide.  By  this  is  meant  the  carbon  dioxide  required 
to  hold  the  carbonate  in  solution  as  bicarbonate.  These  conditions 
are  found,  according  to  Lyell,4  in  the  delta  of  the  Rhone,  and  a 
similar  precipitate  has  been  reported  along  the  coast  of  Florida.5 

G.  H.  Drew,6  however,  has  shown  that  bacteria  are  responsible  for 
a great  part  of  the  marine  precipitation  of  calcium  carbonate,  at 
least  along  the  coast  of  Florida,  and  doubtless  elsewhere.  This  is  a 
different  process  from  that  described  above. 

At  Pyramid  and  Winnemucca  lakes,  in  Nevada,  great  masses  of 
calcareous  tufa  are  formed,  and  sometimes,  according  to  I.  C.  Rus- 
sell,7 the  deposit  takes  the  shape  of  oolitic  sand.  In  the  latter  instance 
the  precipitated  carbonate  is  deposited  around  nuclei,  which  may  be 

1 See  ante,  p.  203.  Analyses  of  tufa  and  travertine  are  there  given. 

2 For  a general  account  of  the  onyx  marbles  see  G.  P.  Merrill,  Kept.  U.  S.  Nat.  Mus.,  1893,  p.  541.  A good 
table  of  analyses  is  given  in  this  memoir.  The  onyx  marbles  are  usually  calcite,  rarely  aragonite. 

a On  the  solubility  of  calcium  carbonate  and  other  carbonates  of  the  series  RCO3  in  pure  and  carbonated 
water,  see  J.  von  Essen,  Thesis,  Univ.  Geneva,  1907. 

4 Principles  of  geology,  12th  ed.,  vol.  1,  1875,  p.  426. 

6 See  S.  Sanford,  Second  Ann.  Rept.  Florida  Geol.  Survey,  1908-9,  pp.  224-5,  228.  Also  T.  W.  Vaughan, 
Pub.  133,  Carnegie  Inst.  Washington,  1910,  pp.  114, 168  et  seq. 

8 Carnegie  Inst.  Washington,  Pub.  182, 1914.  See  also  K.  F.  Kellerman  and  N.  R.  Smith,  Jour.  Wash- 
ington Acad.  Sci.,  vol.  4,  p . 400,  1914. 

7 Mon.  U.  S.  Geol.  Survey,  vol.  11, 1885,  pp.  61, 189. 


550 


THE  DATA  OF  GEOCHEMISTRY. 


grains  of  sand  or  other  foreign  bodies.  Similar  formations  occur 
around  Great  Salt  Lake,  but  only,  as  G.  K.  Gilbert 1 reports,  where 
there  is  much  agitation  of  the  waves.  The  tufa  is  not  formed  in 
sheltered  bays,  but  where  there  is  surf  the  overcharge  of  carbon  diox- 
ide is  easily  driven  out  of  the  water,  and  calcium  carbonate  is  precipi- 
tated. Oolitic  sand  is  also  found  at  Great  Salt  Lake,  and  in  this 
case  its  deposition  has  been  traced  by  A.  Rothpletz  2 to  the  action  of 
minute  algae.  This  mode  of  formation  needs  to  be  considered  further. 

In  1864  Ferdinand  Cohn  3 studied  the  formation  of  travertine  at 
the  waterfalls  of  Tivoli.  He  found  there  that  many  aquatic  plants, 
especially  species  of  Ohara,  mosses,  and  algae,  became  incrusted  with 
calcium  carbonate — a fact  which  he  attributed  to  their  activity  in 
absorbing  carbon  dioxide  and  so  setting  the  carbonate  free;  that  is, 
plants  consume  carbon  dioxide  and  exhale  oxygen.  When  they  do 
this  in  water  containing  calcium  bicarbonate,  they  deprive  that  salt 
of  its  second  molecule  of  carbonic  acid,  and  the  insoluble  neutral 
carbonate  is  thrown  down.  The  sinter  or  travertine  is  thus  formed 
primarily,  but  it  is  afterwards  transformed  into  a compact  mass  by 
the  deposition  of  calcite  in  its  interstices;  and  in  times  of  flood,  when 
the  waters  are  muddy,  layers  of  sediment  are  laid  down  with  it. 

The  same  sort  of  plant  activity  has  been  repeatedly  observed  in 
connection  with  the  marl  deposits  of  certain  fresh-water  lakes.  The 
term  “marl,”  it  must  be  noted,  is  very  vague,  and  has  been  applied  not, 
only  to  earthy  forms  of  calcium  carbonate,  but  also  to  glauconitic 
sands  containing  no  carbonate  at  all.  Shell  marl,  as  its  name  indi- 
cates, is  largely  made  up  of  fragmentary  shells;  the  marl  here  men- 
tioned is  of  a different  kind.  As  long  ago  as  1854  W.  Kitchell4 
pointed  out  that  Ohara  took  an  active  part  in  the  production  of  fresh- 
water marl.  In  1900  C.  A.  Davis  5 6 discussed  the  subject  much  more 
fully,  with  reference  to  some  lakes  in  Michigan,  and  came  to  essen- 
tially the  same  conclusions  as  Cohn.  Davis,  however,  regards  the 
oxygen  liberated  by  the  aquatic  plants,  Ohara,  etc.,  as  assisting 
in  some  way  the  precipitation  of  the  carbonate;  but  his  equation 
showing  the  supposed  reaction  rests  on  no  experimental  basis.  The 
activity  of  plants  in  marl  formation  was  also  considered  by  W.  S. 


1 Mon.  U.  S.  Geol.  Survey,  vol.  1, 1890,  p.  167. 

2 Am.  Geologist,  vol.  10,  1892,  p.  279.  See  also  E.  B.  Wethered,  Quart.  Jour.  Geol.  Soc.,  vol.  51,  1895, 
p.  196,  on  oolite  from  other  localities.  Virlet  d’Aoust  (Compt.  Rend.,  vol.  45,  1857,  p.865), studying  the 
formation  of  oolite  in  some  Mexican  lakes,  argues  that  insect  eggs,  which  are  deposited  in  great  numbers 
on  the  surface  of  the  water,  may  act  as  nuclei. 

* Neues  Jahrb.,  1864,  p.  580.  An  earlier  paper  by  Cohn  (1862),  on  the  Carlsbad  “sprudelstein,”  I have 
not  been  able  to  see.  It  is  often  quoted.  W.  H.  Weed  (Ninth  Ann.  Kept.  U.  S.  Geol.  Survey,  1889,  p.  613) 
has  shown  that  the  travertine  formed  around  the  hot  springs  of  the  Yellowstone  National  Park  is  pro- 
duced by  the  aid  of  algae. 

* First  Ann.  Rept.  Geol.  Survey  New  Jersey,  1855,  p.  50.  See  also  G.  H.  Cook,  Geology  of  New  Jersey, 

1868,  p.  172. 

6 Jour.  Geology,  vol.  8,  1900,  pp.  485,  498;  vol.  9,  1901,  p.  491. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


551 


Blatchley  and  G.  H.  Ashley  1 in  their  report  on  the  lakes  of  Indiana, 
but  these  writers  attach  fully  as  much  importance  to  inflowing,  lime- 
bearing springs.  The  attention  which  these  deposits  have  received 
is  due  to  their  value  for  fertilizing  purposes.  It  is  possible,  as  Mr. 
Bailey  Willis  has  suggested  to  me,  that  some  marine  limestones  have 
been  formed  by  plant  agencies.  In  the  shallow  seas  which  are 
thought  to  have  covered  a large  part  of  the  North  American  conti- 
nent the  calcium  carbonate  may  well  have  been  thrown  down  by  algse. 
To  produce  a permanent  deposit,  however,  the  water  must  have  been 
too  warm  to  carry  much  carbonic  acid  in  solution,  and  too  shallow 
for  the  precipitate,  while  sinking,  to  redissolve. 

Another  process  by  which  calcium  carbonate  may  be  precipitated 
was  pointed  out  by  G.  Steinmann.2  He  found  that  albumen,  which 
is  present  in  the  organic  parts  of  all  aquatic  animals,  was  a distinct 
precipitating  agent.  Apparently,  by  fermentation,  the  albuminoids 
generate  ammonium  carbonate,  and  to  that  compound  the  precipita- 
tion of  calcium  carbonate  is  due.  This  or  any  other  alkaline  car- 
bonate, entering  waters  saturated  with  calcium  carbonate,  would 
bring  about  the  separation  of  the  last-named  salt. 

In  studying  the  formation  of  shell  limestone  or  coral  rock,  it  is 
desirable  to  take  account  of  the  fact  that  calcium  carbonate  exists 
in  at  least  two  geologically  important  modifications — calcite  and 
aragonite.  Calcite  crystallizes  in  the  rhombohedral  division  of  the 
hexagonal  system,  and  has,  when  pure,  a specific  gravity  between 
2.71  and  2.72.  Aragonite  is  orthorhombic,  and  its  specific  gravity  is 
near  2.94.  Calcite  is  by  far  the  more  abundant  form,  and  it  is  also 
the  more  stable.3  Aragonite  alters  easily  to  paramorphs  of  calcite, 
but  the  reverse  change  rarely,  if  ever,  occurs.  The  reported  para-, 
morphs  of  aragonite  after  calcite  are  of  doubtful  authenticity.  Ac- 
cording to  P.  N.  Laschenko  4 aragonite  when  heated  to  445°  begins 
to  change  into  calcite.  The  change  is  complete  at  470°.  A mono- 
clinic variety  of  calcium  carbonate,  lublinite,  has  recently  been  de- 
scribed by  R.  Lang.5  Another  crystalline  modification  since  named 

1 Twenty-fifth  Ann.  Rept.  Dept.  Geology,  etc.,  Indiana,  1900,  pp.  31-322.  The  memoir  contains  analyses 
of  marls  by  W.  A.  Noyes.  See  also  a criticism  by  C.  E.  Siebenthal,  Jour.  Geology,  vol.  9,  1901,  p.  354. 
W.  C.  Kerr,  in  Geology  of  North  Carolina,  vol.  1,  p.  187,  gives  many  analyses  of  marl  from  that  State. 
An  elaborate  report  on  marl,  by  D.  J.  Hale,  and  others,  forms  part  3 of  volume  8,  Michigan  Geol.  Survey, 
1900. 

2 Ber.  Naturforsch.  Gesell.  Freiburg,  vol.  4,  1889,  p.  288. 

3 See  the  physicochemical  researches  of  H.  W.  Foote  (Zeitschr.  physikal.  Chemie,  vol.  33,  1900,  p.  740),  in 
which  this  point  is  developed  quantitatively.  Important  modem  papers  on  the  relations  between  calcite 
and  aragonite  are  by  H.  Vater,  Zeitschr.  Kryst.  Min.,  vol.  21, 1893,  p.  433;  vol.  22, 1894,  p.  209;  vol.  24, 
1895,  pp.  366,  378;  vol.  27,  1897,  p.  477;  and  vol.  30,  1899,  pp.  295,  485.  See  also  O.  Miigge,  Neues  Jahrb., 
Beil.  Band  14, 1901,  p.  246,  and  H.  Leitmeier,  Neues  Jahrb.,  1910,  Band  1,  p.  49.  On  the  conditions  under 
which  calcite  and  aragonite  are  formed  as  chemical  precipitates  see  W.  Meigen,  Ber.  Naturforsch.  Gesell. 
Freiburg,  vol.  13,  1903,  p.  40,  and  vol.  15,  1905,  p.  38,  and  H.  Warth,  Centralbl.  Min.,  Geol.  u.  Pal.,  1902, 
p.  492.  According  to  W.  Vaubel  (Jour,  prakt.  Chem.,  ser.  2,  vol.  86,  1912,  p.  366),  aragonite  contains  a 
small  admixture  of  a hydrobasic  carbonate. 

* Chem.  Abstracts,  vol.  6, 1912,  p.  464.  From  a Russian  original. 

5 Neues  Jahrb.,  Beil.  Band  38,  p.  121, 1914.  According  to  O.  Miigge  (Centralbl.  Min.,  Geol.  u.  Pal.,  1914, 
p.  673),  lublinite  is  merely  a pseudomorph  and  not  a species. 


552 


THE  DATA  OF  GEOCHEMISTRY. 


vaterite,  forming  spherulitic  aggregates,  was  first  observed  by  H. 
Vater  (loc.  cit.),  but  it  is  not  known  to  occur  in  nature.  It  was  pro- 
duced artificially. 

In  recent  years  two  other  varieties  of  calcium  carbonate  have  been 
described  as  distinct  from  calcite  and  aragonite.  The  carbonate  of 
some  molluscan  shells,  which  had  been  called  aragonite,  was  made 
into  a distinct  species  by  Agnes  Kelley,1  who  named  it  conchite.  The 
pisolite  formed  at  the  hot  springs  of  Hammam-Meskoutine,  Algeria, 
was  given  specific  rank  by  A.  Lacroix,2  under  the  name  ktypeite. 
Both  of  these  alleged  species  have  since  been  identified  with  aragon- 
ite 3 and  need  no  further  consideration  here. 

Calcite  and  aragonite  may  be  distinguished  from  each  other,  when 
not  distinctly  crystallized,  either  by  their  differences  in  specific 
gravity  or  in  their  optical  properties.  There  are  also  two  chemical 
tests  discovered  by  W.  Meigen.4  When  aragonite  is  immersed  in  a 
dilute  solution  of  cobalt  nitrate,  it  is  colored  lilac,  and  the  color  per- 
sists on  boiling.  Calcite,  under  like  treatment,  remains  white  in  the 
cold,  but  becomes  blue  on  long  boiling.  Again,  calcite,  in  a solution 
of  ferrous  sulphate,  produces  a yellow  precipitate  of  ferric  hydroxide; 
while  aragonite  gives  a dark-greenish  precipitate  of  ferrous  hydrox- 
ide. These  tests  were  applied  by  Meigen  to  a large  number  of  shells 
and  corals,  both  recent  and  fossil,  and  the  mineralogical  character  of 
each  species  was  determined.  A list  of  the  determinations  is  given 
in  his  memoir. 

The  importance  of  discriminating  between  calcite  and  aragonite 
was  pointed  out  very  clearly  by  H.  C.  Sorby,5  in  his  address  upon 
the  origin  of  limestones.  He  too,  much  earlier  than  Meigen,  gave 
data  concerning  the  calcareous  parts  of  different  classes  of  animals, 
and  showed  that  shells  composed  of  aragonite  rarely  appeared  as 
fossils.  The  same  subject  was  also  discussed  by  V.  Cornish  and 
P.  F.  Kendall 6 on  the  basis  of  experiments  in  which  they  found  that 
carbonated  waters  decompose  and  disintegrate  aragonite  shells  much 
more  readily  than  shells  formed  of  calcite.  The  difference,  however, 


1 Hineralog.  Mag.,  vol.  12,  1900,  p.  363. 

2 Compt.  Rend.,  vol.  126, 1898,  p.  602.  For  another  description  of  this  deposit  see  L.  Duparc,  Arch.  sci. 
phys.  nat.,  3d  ser.,  vol.  20, 1888,  p.  537. 

3 On  conchite,  see  R.  Brauns,  Centralbl.  Min.,  Geol.  u.  Pal.,  1901,  p.  134.  H.  Vater  (Zeitschr.  Kryst. 
Min.,  vol.  35, 1902,  p.  149),  examined  both  conchite  and  ktypeite.  Vater  also  describes  the  Carlsbad  “spru- 
delstein,”  which  is  aragonite. 

* Centralbl.  Min.,  Geol.  u.  Pal.,  1901,  p.  577;  Ber.  Oberrhein.  geol.  Verein,  1902,  p.  31;  Ber.  Naturforsch. 

Gesell.  Freiburg,  vol.  15,  1905,  p.  55.  See  also  A.  Hutchinson,  Mineralog.  Mag.,  vol.  13,  Proc.,  1903,  p. 
xxviii;  G.  Wyroubofl,  Bull.  Soc.  min.,  vol.  24, 1901,  p.  371;  and  S.  Kreutz,  Min.  pet.  Mitt.,  vol.  28, 1909, 
p.  487.  S.  J.  Thugutt  (Centralbl.  Min.,  Geol.  u.  Pal.,  1910,  p.  786)  describes  color  discriminations  based 
upon  the  use  of  organic  dyes.  See  also  Vaubel  (loc.  cit.),  and  K.  Niederstadt,  Zeitschr.  angew.  Chemie, 
vol.  25, 1912,  p.  1219.  According  to  G.  Panebianco  (abstract  in  Zeitschr.  Kryst.  Min.,  vol.  40, 1905,  p.  288), 
the  “hydroxides”  of  Meigen’s  reaction  are  really  carbonates.  On  the  ferrous-sulphate  test  see  also  W. 
Diesel,  Zeitschr.  Kryst.  Min.,  vol.  49,  p.  250, 1911. 

6 Quart.  Jour.  Geol.  Soc.,  vol.  35,  Proc.,  1879,  p.  56. 

6 Geol.  Mag.,  1888,  p.  66.  See  also  P.  Tesch,  Proc.  Sec.  Sci.,  Amsterdam  Acad.,  vol.  11, 1908,  p.  236;  A. 
R.  Honvood,  Geol.  Mag.,  1910,  p.  173;  and  G.  A.  J.  Cole  and  O.  H.  Little,  idem,  1911,  p.  49. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


553 


is  attributed  to  structure  rather  than  to  mineralogical  distinctions. 
But  be  that  as  it  may,  while  calcite  organisms  remain  permanently 
in  fossil  form,  aragonite  shells  largely  disappear.  Only  the  larger, 
denser,  heavier  aragonite  structures  seem  to  be  preserved  to  any 
considerable  extent.  Kendall 1 has  applied  these  observations  to  the 
study  of  oceanic  oozes.  The  pteropod  shells,  being  mainly  aragonite, 
disappear  below  1,500  fathoms  depth,  while  the  calcitic  globigerina 
is  found  in  ooze  at  2,925  fathoms.  From  the  fact  that  the  Upper 
Chalk  of  England  contains  only  calcite  organisms,  Kendall 2 infers 
that  it  was  deposited  at  a depth  of  at  least  1,500  fathoms.  Attempts 
have  been  made  to  identify  chalk  with  the  globigerina  ooze,  but  L. 
Cayeux  3 has  shown  that  the  two  substances  are  markedly  different. 
Chalk,  however,  is  composed  of  organic  remains,  largely  foraminif- 
eral,  and  undoubtedly  represents  an  ooze  of  some  kind.4  It  also 
contains  detrital  impurities,  and  in  chalk  from  northern  France 
Cayeux  5 has  identified  microscopic  particles  of  quartz,  zircon,  tour- 
maline, rutile,  magnetite,  muscovite,  orthoclase,  plagioclase,  anatase, 
brookite,  chlorite,  staurolite,  garnet,  apatite,  ilmenite,  and  corundum. 
These  impurities  exist  in  very  small  proportions,  and  for  practical 
purposes  chalk  may  be  regarded  as  nearly  pure  carbonate  of  lime  in 
exceedingly  fine  subdivision. 

In  his  study  of  the  oolites  G.  Linck  6 has  shown  that  all  recent 
deposits,  so  far  as  he  was  able  to  examine  them,  were  composed  of 
aragonite,  while  the  older  “fossil”  occurrences  were  calcite — that  is, 
according  to  his  observations,  oolite  forms  as  aragonite  and  slowly 
changes  to  the  more  stable  calcite.  By  experimenting  directly  with 
sea  water  it  was  found  that  precipitation  with  sodium  or  ammonium 
carbonate  produced  aragonite,  as  determined  by  Meigen’s  reaction 
with  cobalt  nitrate.  When  solutions  of  calcium  bicarbonate  alone 
were  allowed  to  evaporate,  Linck  further  found  that  at  ordinary 
atmospheric  temperature  calcite  was  deposited,  but  that  at  60°  arago- 
nite was  formed.  In  sea  water,  then,  the  separation  of  calcium  car- 
bonate in  one  modification  or  the  other  is  conditional  upon  the  proc- 
ess of  precipitation  and  probably  also  upon  climate.  Where  organic 
decay  is  prominent,  the  ammonium  carbonate  produced  thereby  may 
act  as  precipitant,  and  that  is  more  likely  to  be  the  case  in  warm 
climates  than  in  cold.  The  direct  deposition  of  calcium  carbonate 
is  commonly  in  the  calcite  form,  because  the  temperature  of  oceanic 
water  is  usually  low.  The  two  minerals  in  certain  cases  may  be 
formed  together,  and  this  actually  happens  in  the  growth  of  some 

1 Rept.  Brit.  Assoc.  Adv.  Sci.,  1896,  p.  789. 

2 Idem,  1896,  p.  791. 

3 Mem.  Soc.  g6ol.  du  Nord,  vol.  4,  pt.  2,  1897,  p.  518. 

4 See  C.  Wyville  Thomson,  Depths  of  the  sea,  London,  1874,  pp.  467,  501. 

6 Op.  cit.,  p.  257. 

fi  Neues  Jahrb.,  Beil.  Band  16,  p.  495.  Linck  gives  a good  summary  of  previous  literature  upon  oolite. 
See  also  H.  Fischer,  Monatsh.  Deutsch.  geol.  Gesell.,  1910,  p.  247. 


554 


THE  DATA  OP  GEOCHEMISTRY. 


shells.  A shell  may  consist  of  a principal  mass  of  calcite,  coated  by 
a pearly  layer  of  aragonite,  and  other  associations  of  the  two  species 
in  a single  animal  are  well  known.  In  the  fossilization  of  such  a 
shell  the  aragonite  portion  is  commonly  destroyed,  while  the  calcitic 
layer  or  fragment  is  preserved. 

In  what  manner  do  plants  and  animals  withdraw  or  segregate 
calcium  carbonate  from  sea  water  ? To  this  question  there  have  been 
many  answers  proposed,1  but  the  problem  is  essentially  physiological, 
and  its  full  discussion  would  be  inappropriate  here.  Some  of  the 
answers,  however,  were  framed  before  the  modern  theory  of  solutions 
had  been  developed,  and  are  therefore  no  longer  relevant.  It  is  not 
necessary  to  ask  whether  the  living  organisms  derive  their  calcareous 
portions  from  the  sulphate  or  chloride  of  calcium  or  absorb  the  car- 
bonate directly,  for  these  salts  are  largely  ionized  in  sea  water.  It 
is  only  essential  that  calcium  ions  and  carbonic  ions  shall  be  simul- 
taneously present;  then  the  materials  for  coral  and  shell  building 
are  at  hand.  The  carbonic  ions  may  be  of  atmospheric  origin,  or 
brought  to  the  sea  by  streams,  or  developed  by  the  physiological 
processes  of  marine  animals,  or  a product  of  organic  decay;  all  of 
these  sources  contribute  to  the  one  end  and  help  to  supply  the  mate- 
rial from  which  limestones  are  made.  Where  marine  life  is  abun- 
dant, there  also  the  carbonic  ions  abound.  This  fact  is  strikingly 
shown  by  W.  L.  Carpenter’s  analyses  2 of  the  gases  extracted  from 
sea  water  and  their  correlation  with  the  results  obtained  by  dredging. 
In  one  series  of  three  samples  from  different  depths,  but  at  the  same 
locality,  the  gases  were  composed  as  follows : 

Gases  extracted  from  sea  water  collected  at  different  depths. 


862  fathoms 
(bottom). 

800  fathoms. 

750  fathoms. 

o2 

17.  22 

17.  79 

18.  76 

n2 

34.  50 

48.  46 

49.  32 

co2 

48.  28 

33.  75 

31.  92 

100.  00 

100.  00 

100.  00 

On  the  bottom,  where  the  proportion  of  C02  was  highest,  animal 
life  was  abundant,  and  the  dredge  brought  up  a rich  haul.  At 
another  point,  where  the  C02  at  the  sea  bottom  fell  to  7.93  per  cent, 
the  dredge  made  a very  bad  haul.  In  short,  from  the  composition 
of  the  dissolved  gases,  it  was  possible  to  assert  whether  living  forms 
were  scarce  or  plentiful  upon  a particular  point  of  the  ocean  floor. 


1 See  R.  Brauns,  Chemische  Mineralogie,  pp.  377-378,  for  a summary  of  this  subject. 

2 In  C.  Wyville  Thomson’s  Depths  of  the  Sea,  London,  1874,  pp.  502-511.  On  p.  513  is  given  a table  of 
analyses  of  sea  water  by  Frankland,  in  which  the  presence  of  abundant  organic  matter  is  shown. 


SEDIMENTARY  AND  DETRITAL  ROCKS.  555 

The  most  obvious  occurrence  of  limestone  building  from  shells  is 
that  which  may  be  observed  on  many  sea  beaches.  The  coquina  of 
Florida  is  a familiar  example  of  this  kind.  Masses  of  shell  frag- 
ments are  there  compacted  together,  cemented  by  calcium  carbonate 
which  has  been  deposited  from  solution  between  the  bits  of  shell,  and 
a fairly  substantial  rock,  available  for  building  purposes,  is  produced. 
Some  quartz  sand  is  commingled  with  the  shell  material,  and  at  one 
locality,  noted  by  W.  H.  Dali,1  limonite,  deposited  by  a chalybeate 
spring,  serves  as  the  cementing  substance. 

In  the  Bay  of  Naples,  according  to  J.  Walther,2  calcareous  algae, 
especially  of  the  genus  Lithothamnium,  are  conspicuous  makers  of 
limestone;  and  similar  observations  have  been  made  elsewhere  by 
others.  Lithothamnium  is  a seaweed  whose  framework  or  skeleton 
consists  of  calcite;  another  genus,  Halimeda,  which  is  also  active  in 
limestone  making,  contains  aragonite.3 

From  a genetic  point  of  view  the  coralline  limestones  have  probably 
been  the  limestones  most  carefully  studied.  Their  formation  around 
coral  islands  and  in  coral  reefs  can  be  observed  with  the  greatest 
ease,  and  the  process  may  be  followed  step  by  step.  First,  the 
living  coral;  then  its  dead  fragments,  broken  into  sand  by  the  waves; 
then  their  cementation  by  solution  and  redeposition  of  calcium  car- 
bonate; and  finally  the  solid  rock,  made  up  visibly  of  organic  remains, 
may  be  seen.  In  such  limestones,  according  to  E.  W.  Skeats,4  both 
calcite  and  aragonite  occur,  directly  deposited  from  the  sea  water. 
In  composition,  when  recent,  they  are  like  the  coral  itself,  nearly 
pure  carbonate  of  lime,  but  a little  organic  matter  is  also  present, 
some  earthy  matter,  and  very  small  quantities  of  calcium  phosphate. 
In  corals  from  the  Gulf  Stream  S.  P.  Sharpies  5 found  from  95.37 
to  98.07  per  cent  of  CaC03,  and  0.28  to  0.84  of  Ca3P208.  These 
results  are  concordant  with  those  obtained  by  many  other  analysts,6 
and  need  no  further  illustration  just  now.  The  alteration  of  coral 
rock  to  dolomite  will  be  considered  later. 

From  what  has  been  said  in  the  preceding  pages,  it  is  evident 
that  important  limestones  may  be  formed  in  various  ways,  which, 


1 Am.  Jour.  Sci.,  3d  ser.,  vol.  34,  p.  163, 1887. 

2 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  37,  p.  329,  1885. 

a E.  J.  Garwood  (Geol.  Mag.,  1913,  pp.  440,  490,  552)  has  pointed  out  the  great  geologic  importance  of  the 
calcareous  algae. 

* Bull.  Mus.  Comp.  Zool.,  vol.  42,  pp.  53-126, 1903. 

b Am.  Jour.  Sci.,  3d  ser.,  vol.  1, 1871,  p.  168. 

6 See  for  example,  G.  Forchhammer,  Neues  Jahrb.,  1852,  p.  854,  and  A.  Liversidge,  Proc.  Roy.  Soc.  New 
South  Wales,  vol.  14, 1880,  p.  159,  on  coral  from  New  Hebrides,  and  coral  rock  from  Duke  of  York  Island. 
Also  A.  J.  Jukes-Brown  and  J.  B.  Harrison,  Quart.  Jour.  Geol.  Soc.,  vol.  47,  1891,  p.  224,  on  coral  rocks 
from  Barbadoes.  A number  of  analyses  of  coquina,  coralline  limestones,  etc.,  are  given  in  Bull.  U.  S. 
Geol.  Survey  No.  228, 1904.  Several  analyses  by  H.  W.  Nichols  appear  in  Pub.  Ill,  Field  Columbian  Mus., 
1906,  p.  31.  Several  analyses  of  Brazilian  corals  by  L.  R.  Lenox  are  in  Bull.  Mus.  Comp.  Zool.,  vol.  44, 
1904,  p.  264.  Others  from  Florida,  the  Bahamas,  etc.,  have  been  recently  analyzed  in  the  laboratory  of 
the  U.  S.  Geological  Survey.  A monographic  paper  entitled  Untersuchungen  ueber  organische  Kalkge- 
bilde,  by  O.  Biitschli  is  in  Abhandl.  K.  Gesell.  Wiss.,  Gottingen,  new  series,  vol.  6,  No.  3, 1908.  This 
paper  is  rich  in  references  to  literature. 


556 


THE  DATA  OF  GEOCHEMISTRY. 


however,  are  chemically  the  same.  Calcium  carbonate,  withdrawn 
from  fresh  or  salt  water,  is  laid  down  under  diverse  conditions, 
yielding  masses  which  resemble  one  another  only  in  composition. 
An  oceanic  ooze  may  produce  a soft,  flourlike  substance  such  as 
chalk,  or  a mixture  of  carbonate  and  sand,  or  one  of  carbonate  and 
mud  or  clay.  Calcium  carbonate,  transported  as  a silt,  may  solidify 
to  a very  smooth,  fine-grained  rock,  while  shells  and  corals  yield  a 
coarse  structure,  full  of  angular  fragments  and  visible  organic  remains. 
Buried  under  other  sediments,  any  of  these  rocks  may  be  still  further 
modified,  the  fossils  becoming  more  or  less  obliterated,  until  in  the 
extreme  case  of  metamorphism  a crystalline  limestone  is  formed. 
All  trace  of  organic  origin  has  then  vanished,  a change  which  both 
heat  and  pressure  have  combined  to  bring  about,  aided  perhaps  by 
the  traces  of  moisture  from  which  few  rocks  are  free.  Several  experi- 
mental investigations  bear  directly  upon  this  class  of  transformations. 

To  illustrate  the  influence  of  pressure  alone,  we  have  an  important 
experiment  by  W.  Spring.1  A quantity  of  dry,  white  chalk,  inclosed 
in  a steel  tube,  was  placed  in  a screw  press  under  a pressure  of  6,000 
to  7,000  atmospheres,  and  left  there  for  a little  over  seventeen  years. 
At  the  end  of  that  time  it  had  become  hard  and  smooth,  with  a 
glazed  surface,  and  was  somewhat  discolored  by  iron  from  the  tube. 
It  was  also  in  part  distinctly  crystalline;  in  short,  it  resembled  to 
some  extent  a crystalline  limestone,  although  the  change  was  not 
absolutely  complete. 

When  heated  above  redness  at  ordinary  pressures,  limestone  decom- 
poses into  carbon  dioxide  and  lime.  This  is  the  common  change 
produced  in  a limekiln.  Under  pressure,  however,  this  dissociation 
is  prevented  and  calcium  carbonate  may  be  apparently  fused. 
Over  a century  ago  Sir  James  Hall 2 heated ' limestone  in  closed 
vessels  and  obtained  from  it  a product  identical  in  general  character 
with  crystalline  marble.  Since  Hall’s  time  the  experiment  has  been 
repeated  by  a number  of  other  investigators,  under  varying  condi- 
tions, with  various  degrees  of  success,  and  with  quite  dissimilar 
interpretations.  It  was  supposed  at  first  that  Hall  had  fused  lime- 
stone, and  this  belief  was  prevalent  for  many  years.  G.  Bose,3 
however,  transformed  a compact  limestone  into  marble  as  Hall  had 
done,  but  without  evidence  of  fusion;  and  A.  Becker,4  in  a more 
extended  research,  found  that  by  moderate  heat  and  relatively  slight 
pressure  calcium  carbonate  could  be  converted  into  a finely  granular 

\ Zeitschr.  anorg.  Chemie,  vol.  11, 1896,  p.  160. 

2 Trans.  Roy.  Soc.  Edinburgh,  vol.  6,  1812,  p.  71.  The  experiments  were  performed  in  1805.  For  a 
summary  of  the  results  obtained  by  Bucholz,  Petzholdt,  and  Richthofen,  see  J.  Lemberg,  Zeitschr.  Deutsch. 
geol.  Gesell.,  vol.  24,  1872,  pp.  237-241.  Lemberg  criticizes  the  conclusions  drawn  from  Hall's  data,  and 
expresses  a strong  doubt  as  to  whether  fusion  actually  occurred. 

3 Pogg.  Annalen,  vol.  118,  1863,  p.  565. 

4 Min.  pet.  Mitt.,  vol.  7, 1886,  p.  122.  Becker  also  gives  a good  summary  of  the  earlier  literature  of  the 
subject. 


SEDIMENTARY  AND  DETRITAL  ROCKS.  557 

mass.  A fine  powder  of  the  carbonate  even  developed  into  larger 
grains  of  calcite  without  either  fusing  or  softening. 

In  the  experiments  of  H.  Le  Chatelier 1 an  actual  fusion  of  the 
carbonate  was  perhaps  effected.  The  chemically  precipitated  car- 
bonate was  inclosed  in  a steel  cylinder  between  two  pistons,  under  a 
pressure  of  about  1,000  kilograms  to  the  square  centimeter.  Heat 
was  applied  by  an  electric  current  passing  through  a spiral  of  plati- 
num wire  embedded  in  the  mass,  and  the  temperature  attained  was 
about  1,050°.  Under  these  conditions  the  calcium  carbonate  near 
the  spiral  was  fused  to  a translucent  mass  resembling  some  marbles. 
Between  the  fused  and  unfused  portions  there  was  a sharp  demarca- 
tion, with  no  indication  of  any  intermediate  state.  In  his  second 
paper  Le  Chatelier  states  that  even  at  1,020°  and  under  slight  or 
insignificant  pressure  calcium  carbonate  agglomerates  to  a crystal- 
line mass.  In  similar  experiments  A.  Joannis  2 was  able  to  transform 
chalk  into  something  like  marble  at  a temperature  above  the  melt- 
ing point  of  gold  and  under  a pressure  of  15  atmospheres.  Joannis 
suggests  that  the  melting  point  of  calcium  carbonate  may  perhaps 
be  lowered  by  pressure.  H.  E.  Boeke,3  however,  has  obtained  a 
true  fusion  of  calcium  carbonate  at  1289°,  under  a pressure  of  110 
atmospheres. 

From  all  of  this  evidence  we  may  conclude  that  the  change  from 
apparently  amorphous  calcium  carbonate  to  a distinctly  crystalline 
limestone  or  marble  may  be  effected  by  pressure  alone,  heat  alone,  or 
both  together.  Actual  fusion  may  or  may  not  occur;  at  all  events 
it  seems  to  be  -unnecessary.  Furthermore,  it  is  highly  probable  that 
water  plays  some  part  in  bringing  about  the  transformation,  for  in 
geological  phenomena  its  influence  is  rarely  excluded.  If  water  did 
no  more  than  to  dissolve  and  redeposit  particles  of  carbonate,  it 
would  go  far  toward  producing  the  observed  change  in  structure. 
Under  those  conditions  the  carbonate  would,  in  time,  become  a 
coarsely  crystalline  or  granular  mass  of  calcite. 

The  following  analyses  of  limestones  are  all  taken  from  the  lab- 
oratory records  of  the  United  States  Geological  Survey.4 

1 Compt.  Rend.,  vol.  115,  1892,  pp.  817, 1009.  Two  papers. 

2 Idem,  vol.  115, 1892,  pp.  934,  1236.  Two  papers. 

3 Neues  Jahrb.,  1912,  Band  1,  p.  91.  In  another  paper,  Mitt.  Naturforsch.  Gesell.  Halle,  vol.  3, 1913,  Boeke 
has  also  determined  the  melting  point  of  barium  carbonate,  1,600°  under  90  atmospheres  pressure,  and 
strontium  carbonate,  1,497°  under  60  atmospheres. 

4 See  Bull.  No.  228,  1904,  pp.  301-336,  where  234  analyses  of  carbonate  rocks  are  given.  For  other  data 
see  T.  C.  Hopkins,  Ann.  Rept.  Arkansas  Geol.  Survey,  vol.  4,  1890;  S.  W.  McCallie,  Bull.  Geol.  Survey 
Georgia  No.  1,  1904.  F.  G.  Clapp,  Bull.  U.  S.  Geol.  Survey  No.  249,  1905,  gives  many  analyses  compiled 
from  the  geological  reports  of  Pennsylvania.  H.  Ries  and  E.  C.  Eckel,  Bull.  New  Y ork  State  Mus.  No.  44, 
1901;  Ries,  Fifty-first  Ann.  Rept.  New  York  State  Mus.,  pt.  2, 1899,  pp.  357-467;  E.  C.  Eckel,  Bull.  U.  S. 
Geol.  Survey  No.  243,  1905,  on  cement  materials;  W.  G.  Miller,  Rept.  Bur.  Mines  (Ontario),  pt.  2,  1904; 
T.  C.  Hopkins  and  C.  E.  Siebenthal,  Twenty-first  Ann.  Rept.  Dept.  Geology,  etc.,  Indiana,  1896,  pp.  293- 
427.  On  the  evolution  of  limestones  and  the  relation  of  their  composition  to  geologic  age  R.  A.  Daly, 
Bull.  Geol.  Soc.  America,  1909,  vol.  20,  p.  153. 


558 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  limestones. 

A.  Limestone,  Lee,  Massachusetts.  Analysis  by  G.  Steiger. 

B.  Limestone,  Silverdale,  Kansas.  Analysis  by  C.  Catlett. 

C.  Lithographic  stone,  Solenhofen,  Bavaria.  Analysis  by  Steiger. 

D.  Oolitic  sand,  Great  Salt  Lake,  Utah.  Analysis  by  T.  M.  Chatard. 

E.  Coquina,  Key  West,  Florida.  Analysis  by  F.  W.  Clarke. 

F.  Recent  coral  ( Siderastrea ),  Bermuda.  Analysis  by  L.  G.  Eakins. 

G.  Composite  analysis,  by  H.  N.  Stokes,  of  345  limestones. 

H.  Composite  analysis,  by  Stokes,  of  498  limestones  used  for  building  purposes.  Does  the  high  pro- 
portion of  silica  determine  the  availability  of  these  rocks  to  structural  ends? 

Ideally  pure  calcium  carbonate  contains  56.04  per  cent  of  CaO  and  43.96  of  CO2. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02  

0.  95 

5.  27 

1. 15 

a 4.  03 

0.  25 

0.  23 

5. 19 

14.  09 

Ti02  

.06 

.08 

A1203 

.09 

1.  07 

1 .45 

1 .20 

} .56 
J 

jTrace. 

J 

. 81 

1.  75 

FeoO->  

None. 

. 71 

1 .54 

1 .77 

FeO 

.10 

.32 

.26 

J 

MnO  

. 05 

.03 

CaO 

54.  75 

50.  36 

53.  80 

51.  33 

51.  52 

55. 16 

42.  61 

40.  60 

MrO  

.56 

.56 

.56 
} .07 

.72 

2.  08 

.20 

7.  90 

4.  49 

K20 

. 15 

. 10 

. 33 

.58 

Na20 

.02 

.20 

} . 63 

.05 

. 62 

Li20 

) 

Trace. 

Trace. 

H20- 

} .08 

} .78 

.23 

| .83 

} 3. 19 

J 

) .54 

J 

. 21 

.30 

H20+ 

.69 

&.  56 

&.  88 

P90, 

.03 

.06 

Trace. 

.04 

.42 

C02 

43.  38 

40.  34 

42.  69 

41.  07 

41.  58 

43.  74 

41.  58 

35.  58 

s 

.09 

.07 

SOo 

.05 

.07 

None. 

.89 

.05 

.07 

Cl. 

.02 

.01 

Organic 

.27 

100. 16 

99.  84 

99.  90 

99.  97 

99. 18 

99.  87 

100.  09 

100.  34 

a Insoluble  in  hydrochloric  acid.  & Includes  organic  matter. 


Limestones  undergo  alteration  in  several  ways.  They  may  be  silici- 
fied  by  percolating  waters,  or  phosphatized,  as  is  often  seen  on 
guano  islands.1  By  oxidation  of  inclosed  pyrite,  acid  sulphates  can 
be  formed,  and  these  will  alter  the  limestone  partially  or  entirely  to 
gypsum.  Acid  waters  dissolve  limestone  with  evolution  of  carbon 
dioxide;  and  some  effervescent  springs  may  owe  their  sparkling 
qualities  to  reactions  of  this  kind.  A honeycombed  limestone  at  the 
bottom  of  Lake  Huron  was  possibly  corroded  by  water  of  an  acid  type. 
R.  Bell2  found  the  water  of  the  lake  over  the  limestones  to  be  distinctly 
acid,  the  acidity  having  been  possibly  derived  from  sulphides  in 
Huronian  rocks  to  the  northward.  By  thermal  metamorphism  a lime- 
stone may  be  profoundly  altered;  but  that  class  of  changes  is  to  be 
considered  in  another  chapter.  By  far  the  most  important  alteration 


1 On  the  silicification  of  limestones  see  F.  Kuhlmann,  Ann.  Chem.  Pharm.,  vol.  41,  1842,  p.  220;  J.  Lem- 
berg, Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  28,  1876,  p.  562;  and  W.  Clemm,  Inaug.  Diss.  Freiburg,  1909. 
On  the  silicification  of  fossils,  R.  S.  Bassler,  Proc.  U.  S.  Nat.  Mus.,  vol.  35, 1908,  p.  133.  Onphosphatiza- 
tion  see  R.  Irvine  and  W.  S.  Anderson,  Proc.  Roy.  Soc.  Edinburgh,  vol.  18, 1891,  p.  52;  L.  Gassner,  Inaug. 
Diss.  Freiburg,  1906,  and  references  in  the  section  on  phosphate  rock  in  the  preceding  chapter. 

2 Bull,  GeoL  Soc.  America,  vol.  6, 1894,  p.  30?. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


559 


however,  is  that  produced  by  waters  containing  carbon  dioxide, 
especially  meteoric  waters.  These  dissolve  limestone,  and  the  caverns 
formed  in  limestone  regions  are  produced  in  this  way.  Great  masses 
of  limestone  are  thus  removed,  to  be  deposited,  generally  in  a diffused 
form,  elsewhere.  At  the  same  time,  the  insoluble  residual  impurities 
are  left  behind,  in  the  form  of  sand,  clay,  ores  of  manganese  and  iron, 
etc.1  Some  analyses  of  such  residual  clays  are  given  in  the  preceding 
chapters.  These  residues  are  very  variable  in  composition,  and  rarely 
approximate  to  kaolin.  This  point  was  developed  by  H.  Le  Chate- 
lier,2  who  dissolved  several  calcareous  marls  in  acetic  acid,  and 
analyzed  the  residual  silicates.  Kaolinite  was  not  found  in  them; 
but  hydrous  silicates  of  aluminum,  ill  defined  and  impure,  were  gen- 
erally obtained.  In  one  sample  from  the  French  Congo,  the  residue 
was  a silicate  of  magnesium.  According  to  A.  L.  Ewing,3  the  rate  of 
limestone  erosion  in  Spring  Creek  Valley,  Center  County,  Pennsyl- 
vania, amounts  to  275  tons  per  square  mile  per  annum.4  This  cor- 
responds to  a lowering  of  the  land  surface  in  that  region  of  about 
one  foot  in  nine  thousand  years. 

DOLOMITE. 

In  the  foregoing  pages  upon  limestone,  the  magnesian  varieties 
have  been  purposely  left  out  of  account.  They  represent  transitions 
from  calcium  carbonate  to  dolomite,  CaMg(C03)2,  a rock  of  great 
importance  both  practically  and  theoretically,  and  one  which  de- 
mands separate  consideration.  In  addition  to  dolomite,  it  is  neces- 
sary also  to  consider  magnesium  carbonate  itself,  magnesite,  and  its 
hydrous  derivatives,  of  which  several  are  known.  Like  calcium  car- 
bonate, these  species  originate  in  very  different  ways,  and  some  of 
the  processes  by  which  they  form  must  be  discussed  in  connection 
with  the  subject  of  serpentine  later.  Only  the  compounds  of  sedi- 
mentary or  organic  origin  fall  within  the  scope  of  this  chapter. 

The  double  carbonate,  dolomite,  can  be  produced  artificially  by 
several  methods,  and  its  accidental  formation  has  also  been  observed. 
C.  de  Marignac 5 obtained  it  by  heating  calcium  carbonate  with  a 
solution  of  magnesium  chloride  to  200°,  under  a pressure  of  15  atmos- 
pheres. J.  Durocher6  heated  fragments  of  porous  limestone  with 
dry  magnesium  chloride  to  dull  redness  in  a closed  gun  barrel,  in 
such  manner  that  the  carbonate  was  impregnated  by  the  vapor  of  the 
chloride.  Under  those  conditions  the  limestone  was  partly  changed 
to  dolomite.  The  local  formation  of  dolomite  by  volcanic  action  is 

1 See  I.  C.  Russell,  Bull.  U.  S.  Geol.  Survey  No.  52,  1889,  for  a discussion  of  this  subject.  Russell  regards 
the  Clinton  iron  ores  of  Alabama  as  residues  of  this  kind,  but  his  views  on  that  matter  have  been  contested. 

2 Compt.  Rend.,  vol.  118,  1894,  p.  262. 

3 Am.  Jour.  Sci.,  3d  ser.,  vol.  29, 1885,  p.  29. 

* Or  29.173  grams  per  square  meter. 

6 Cited  in  a memoir  by  A.  Favre,  Compt.  Rend.,  vol.  28,  1849,  p.  364. 

• Idem,  vol.  33,  1851,  p.  64. 


560 


THE  DATA  OF  GEOCHEMISTRY. 


explained  by  this  experiment,  but  that  mode  of  occurrence  is  of 
minor  import.  C.  Sainte-Claire  Deville 1 saturated  chalk  with  a 
solution  of  magnesium  chloride  and  heated  the  mass  upon  a sand 
bath.  A partial  replacement  of  lime  by  magnesia  was  thus  effected, 
and  similar  results  were  obtained  with  corals.  A.  von  Morlot,2  by 
heating  powdered  calcite  with  magnesium  sulphate  to  200°  in  a sealed 
tube,  transformed  the  carbonate  into  a mixture  of  dolomite  and  gyp- 
sum. This  reaction  had  been  suggested  by  Haidinger,  in  order  to 
account  for  the  frequent  association  of  the  two  last-named  species. 
The  process,  however,  is  reversible,  and  solutions  of  gypsum  will 
transform  dolomite  into  calcium  carbonate  and  magnesium  sulphate. 
Efflorescences  of  the  latter  salt  are  not  uncommon  in  gypsum  quar- 
ries, and  H.  C.  Sorby3  has  observed  them  in  Permian  limestones. 
Because  of  this  reaction,  according  to  Sorby,  the  upper  beds  of  mag- 
nesian limestone  are  often  more  calcareous  than  the  lower.  Their 
content  in  magnesia  has  been  diminished  in  this  way. 

The  elaborate  experiments  of  T.  Sterry  Hunt 4 upon  the  precipi- 
tation of  calcium  and  magnesium  carbonates,  especially  by  alkaline 
carbonates  from  bicarbonate  solutions,  are  too  complex  to  admit  of 
anything  like  a full  summary  here.  In  most  of  the  experiments 
mixtures  of  calcium  carbonate  with  the  hydrated  magnesium  com- 
pound were  obtained.  When,  however,  the  pasty  mass  formed  by 
precipitating  the  two  carbonates  together  was  heated  to  temperatures 
above  120°,  union  took  place  and  dolomite  was  formed.  From  the 
fact  that  a sedimentary  dolomite  could  thus  be  produced,  Hunt  con- 
cluded that  dolomite  is  generally  a chemical  precipitate,  a view  which 
is  not  widely  held  to-day. 

Still  more  recently  G.  Linck  5 has  reported  a synthesis  of  dolomite 
effected  in  the  following  way:  Solutions  of  magnesium  chloride, 
magnesium  sulphate,  and  ammonium  sesquicarbonate  were  mixed, 
and  to  the  mixture  a solution  of  calcium  chloride  was  added.  An 
amorphous  precipitate  formed,  which  upon  prolonged  gentle  heating 
in  a sealed  tube  became  crystalline,  and  had  the  composition  and 
optical  properties  of  dolomite.  Linck  believes  that  the  conditions  of 
this  synthesis  are  fulfilled  in  nature,  and  that  ammonium  salts  derived 
from  organic  decomposition  play  an  important  part  in  the  formation 
of  marine  dolomite.  Following  Linck,  K.  Spangenberg  6 succeeded 
in  producing  dolomite  by  heating  vaterite  with  a solution  of  sodium 
carbonate  and  magnesium  chloride  at  180°-200°  in  an  autoclave 
under  a pressure  of  50  atmospheres  of  carbon  dioxide. 

1 Compt.  Rend.,  vol.  47,  1858,  p.  91. 

2 Jahresb.  Chemie,  1847-48,  p.  1290.  Also  Compt.  Rend.,  vol.  26,  1848,  p.  311. 

2 Rept.  Brit.  Assoc.  Adv.  Sci.,  1856,  p.  77. 

4 Am.  Jour.  Sci.,  2d  ser.,  vol.  28, 1859,  pp.  170,  365;  vol.  42,  1866,  p.  49. 

6 Monatsh.  Deutsch.  geol.  Gesell.,  1909,  p.  230.  W.  Meigen  (Geol.  Rundschau,  vol.  1,  p.  131,  1900), 
repeated  Linck’s  experiment,  but  without  success. 

6 Zeitschr.  Kryst.  Min.,  vol.  52,  p.  529,  1913. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


561 


In  several  instances  the  deposition  of  magnesian  travertine  and 
even  of  crystallized  dolomite  from  natural  waters  has  been  observed. 
According  to  J.  Girardin,1  the  travertine  formed  by  the  mineral 
spring  of  St.  Allyre,  near  Clermont,  in  France,  is  rich  in  magnesium 
carbonate.  In  recent  travertine  he  found  28.80  per  cent  of  MgCOs 
with  24.40  of  CaC03,  and  in  old  travertine  the  proportions  were  26.86 
and  40.22,  respectively.  Whether  this  represents  dolomite  or  a mix- 
ture of  the  carbonates  was  not  determined.  A.  Moitessier 2 found 
that  in  a badly  closed  bottle  of  water  from  another  French  spring 
distinct  crystals  of  dolomite  had  been  deposited.  In  another  water 
from  a hot  spring  near  the  Dead  Sea,  which  was  transported  to  Paris 
in  a sealed  tube,  similar  crystals  were  found  by  A.  Terreil.3  From 
this  observation  Lartet  concludes  that  the  dolomites  of  the  Dead  Sea 
region  were  probably  formed  through  the  impregnation  of  limestones 
by  magnesian  waters. 

On  the  other  hand,  E.  von  Gorup-Besanez  4 found  that  springs 
from  the  dolomites  of  the  Jura,  which  contain  calcium  and  mag- 
nesium carbonates  in  the  dolomite  ratio,  deposit  the  mixed  salts 
upon  evaporation  and  not  the  double  compound.  Gorup-Besanez 
observed,  however,  that  carbonated  waters,  acting  upon  dolomite, 
dissolve  the  mineral  with  its  ratios  undisturbed.  The  occurrence 
of  dolomite  geodes  in  magnesian  limestones  would  seem  to  show 
that  in  such  cases  at  least  the  double  salt  can  be  re-formed.  Similar 
results  were  earlier  obtained  by  T.  Scheerer,5  when  artificial  solutions 
of  calcium  and  magnesium  bicarbonate  were  allowed  to  evaporate 
spontaneously  at  ordinary  temperatures.  Only  mixtures  were 
formed,  no  dolomite.  He  also  found  that  powdered  chalk  precipi- 
tated magnesium  carbonate  from  a bicarbonate  solution,  although 
carbonated  waters  dissolved  calcium  carbonate  out  of  magnesian 
limestones.  The  last  observation,  however,  had  been  made  by 
other  chemists  previously. 

In  Hunt’s  investigations  it  became  evident  that  temperature  is 
an  important  factor  in  the  formation  of  dolomite.  The  same 
conclusion  is  to  be  drawn  from  F.  Hoppe-Seyler’s  experiments.6 
At  ordinary  temperatures  a solution  of  magnesium  chloride  acting 
upon  calcium  carbonate  for  several  months  yielded  no  dolomite. 
Sea  water  mixed  with  an  excess  of  calcium  carbonate  and  saturated 
with  carbon  dioxide,  after  standing  four  months  in  a closed  flask, 

1 Annales  des  mines,  3d  ser.,  vol.  11,  1837,  p.  460. 

2 Jahresb.  Chemie,  I860,  p.  178. 

3 Cited  by  L.  Lartet,  Bull.  Soc.  g6ol.  France,  2d  ser.,  vol.  23,  1866,  p.  750. 

4 Liebig’s  Annalen,  Beil.  Band  8, 1872,  p.  230. 

5 Neues  Jahrb.,  1866,  p.  1. 

6 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  27, 1875,  p.  509.  In  this  connection  it  may  be  noted  that  H.  C.  Sorby 
(Quart.  Jour.  Geol.  Soc.,  vol.  35,  Proc.,  1879,  p.  56)  found  that  Iceland  spar,  in  a solution  of  magnesium 
chloride,  became  slowly  incrusted  with  magnesium  carbonate. 

97270°— Bull.  616—16 36 


562 


THE  DATA  OF  GEOCHEMISTRY. 


also  failed  to  form  dolomite.  But  when  magnesium  salts  or  sea 
water  were  heated  with  calcium  carbonate  in  sealed  tubes,  then 
both  dolomite  and  magnesite  were  formed.  Carbonate  of  lime, 
heated  to  over  100°  with  a solution  of  magnesium  bicarbonate,  gave 
this  result. 

In  the  earlier  researches  upon  the  conversion  of  limestone  into 
dolomite  little  or  no  attention  seems  to  have  been  paid  to  the 
mineralogical  character  of  the  initial  substance.  In  C.  Klemenfs 
experiments  1 aragonite,  the  less  stable  form  of  calcium  carbonate 
and  the  form  which  is  abundant  in  coral  reefs,  was  especially  studied. 
It  was  found  that  a concentrated  solution  of  magnesium  sulphate 
at  60°  would  partially  transform  aragonite  into  magnesium  car- 
bonate, and  coral  was  altered  in  the  same  way.  Calcite,  by  similar 
treatment,  was  but  slightly  attacked.  Magnesium  sulphate  and 
sodium  chloride  used  together  altered  aragonite  strongly,  forming 
a product  containing  as  high  as  41.5  per  cent  of  MgC03.  Normal 
dolomite,  ideally  pure,  would  contain  45.7  per  cent.  Magnesium 
chloride  proved  to  be  less  active  than  the  sulphate.  The  products 
of  these  reactions  consisted,  however,  not  of  dolomite,  but  of  the 
mixed  carbonates,  and  Klement  suggests  that  mixtures  of  this  kind 
would  probably  in  time  recrystallize  into  the  double  salt.  He 
attributes  the  formation  of  dolomite  to  the  action  of  sea  water  in 
closed  lagoons  upon  aragonite — that  is,  upon  coral  rock.  The  latter, 
as  will  be  shown  presently,  is  often  the  parent  of  dolomite.  It  must 
be  observed,  however,  that  aragonite  is  not  the  only  parent  of  dolo- 
mite, for  pseudomorphs  of  dolomite  after  calcite  are  well  known.2 

Two  other  investigations  upon  the  synthesis  of  dolomite  remain 
to  be  mentioned.  L.  Bourgeois  and  H.  Traube 3 obtained  it  by 
heating  a solution  of  magnesium  chloride,  calcium  chloride,  and 
potassium  cyanate,  KCNO,  to  130°  in  a sealed  tube.  This  mode  of 
production  has  no  geological  significance,  except  in  so  far  as  it 
shows  that  the  necessary  carbonic  acid  may  be  supplied  from  organic 
or  semiorganic  sources.  Such  sources  are  considered  by  F.  W. 
Pfaff,4  who  has  shown  that  the  products  of  organic  decomposition, 
as  derived  from  the  coral-building  organisms,  probably  take  part  in 
the  dolomitic  process.  Not  alone  carbonic  acid  is  generated  during 
organic  decay,  but  ammonium  carbonate,  ammonium  sulphide,  and 
hydrogen  sulphide  are  also  produced,  and  these  compounds,  accord- 
ing to  Pfaff,  appear  to  assist  in  the  formation  of  dolomite.  In  a 

1 Bull.  Soc.  Beige  geol.,  vol.  9,  Mem.  3,  1895.  Min.  pet.  Mitt.,  vol.  14,  1894,  p.  526.  See  also  experiments 
by  O.  Mahler,  Inaug.  Diss.,  Freiburg,  1906. 

2 See  Blum’s  Pseudomorphosen,  p.  51,  and  Nachtrag,  p.  23. 

3 Bull.  Soc.  min.,  vol.  15,  1892,  p.  13. 

4 Neues  Jahrb.,  Beil.  Band  9, 1894,  p.  485.  A later  paper  by  Pfaff  is  published  in  vol.  23,  1907,  p.  529. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


563 


later  paper,  however,  Pfaff  1 states  that  when  a current  of  carbon 
dioxide  is  passed  for  a long  time  through  a warm  solution  of  the 
sulphates  and  chlorides  of  magnesium  and  calcium  the  solution, 
upon  slow  evaporation  at  a temperature  of  20°  to  25°,  yields  a 
residue  which  contains  a double  carbonate  insoluble  in  weak 
hydrochloric  acid.  That  is,  under  these  conditions,  which  might 
be  approximately  paralleled  in  the  concentration  of  sea  water, 
dolomite  may  be  formed. 

Under  certain  exceptional  conditions  magnesium  carbonate  may 
be  deposited  alone.  A solution  of  the  bicarbonate  on  evaporating 
spontaneously  forms  the  hydrous  salt  MgC03.3H20,  which  corre- 
sponds to  the  rare  mineral  nesquehonite.  This  species,  described  by 
F.  A.  Genth  and  S.  L.  Penfield,2  from  the  Nesquehoning  anthracite 
mine  in  Pennsylvania,  was  there  produced  by  the  alteration  of  a 
basic  carbonate,  lansfordite,3  3MgC03.Mg(0H)2.2lH20,  which  first 
formed  as  stalactites  in  one  of  the  galleries.  Nesquehonite  has  since 
been  identified  by  C.  Friedel4  as  a similar  formation  in  a French 
coal  mine.  Such  stalactiform  minerals  are  obviously  deposited 
from  solution  in  carbonated  waters. 

The  term  “ dolomite”  is  sometimes  loosely  used  by  geologists  as 
equivalent  to  magnesian  limestone.  Any  limestone  containing  nota- 
ble amounts  of  magnesia  may  be  described  by  this  name.  Properly, 
the  word  should  be  restricted  to  the  definite  double  carbonate, 
which  occurs  both  as  a well-crystallized  mineral  and  as  a massive 
rock.  When,  after  allowing  for  natural  impurities,  the  molecular 
ratio  of  lime  to  magnesia  in  such  a rock  is  1:1,  it  is  legitimately,  at 
least  in  most  cases,  a dolomite,  but  exceptional  mixtures  are,  of  course, 
possible.  Ordinarily,  a magnesian  limestone  is  a mixture  of  dolo- 
mite and  calcite,  with  such  impurities  as  sedimentary  rocks  and  lime- 
stones in  general  are  likely  to  contain.  In  these  rocks  the  ratio  of 
lime  to  magnesia  is  greater  than  1:1;  but  in  computation  it  must 
be  remembered  that  some  dolomites  contain  iron,  which  replaces 
magnesia  in  equivalent  amounts.  Ferruginous  dolomite,  or  ankerite, 
is  not  rare.  All  the  iron  of  a carbonate  rock,  however,  is  not  neces- 
sarily a part  of  the  carbonate.  It  may  be  present  as  hydroxide  or 
in  claylike  impurities,  and  these  possibilities  must  be  taken  into 
account  in  any  interpretation  of  the  dolomites.  In  some  cases  free 

1 Centralbl.  Min.,  Geol.  u.  Pal.,  1903,  p.  659.  Pfaff  regards  pressure  as  an  important  factor  in  the  forma- 
tion of  dolomite.  His  conclusions  are  criticized  in  an  important  paper  by  E.  Philippi  (Neues  Jahrb. 
Festband,  1907,  p.  397),  who  cites  evidence  to  show  that  certain  dolomitic  nodules  have  been  formed  by 
chemical  precipitation.  F.  Tucan  (Centralbl.  Min.,  Geol.  u.  Pal.,  1909,  p.  506)  finds  that  the  Karst  dolo- 
mites of  Croatia  contain  sodium  chloride  and  calcium  sulphate,  which  suggests  a marine  origin.  E. 
Steidtmann(Jour.  Geology,  vol.  19, 1911)  has  also  studied  the  marine  relationships  of  dolomite. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  39,  1890,  p.  121. 

3 Described  by  Genth,  Zeitschr.  Kryst.  Min.,  vol.  14,  1888,  p.  255. 

4 Bull.  Soc.  min.,  vol.  14, 1891,  p.  60.  See  also  H.  Leitmeier  (Zeitschr.  Kryst.  Min.,  vol.  47,  1909,  p.  118) 
on  the  deposition  of  magnesian  hydrocarbonates  by  the  mineral  springs  of  Rohitsch,  Styria. 


564 


THE  DATA  OF  GEOCHEMISTRY. 


magnesian  carbonates  must  also  be  considered,  and  in  certain  alter- 
ation products,  brucite,  Mg02H2,  may  also  occur.  Commonly  the 
dolomites  are  fairly  simple  in  composition,  and  difficulties  in  inter- 
preting the  analyses  rarely  arise. 

In  the  study  ‘of  natural  dolomites  as  well  as  in  the  synthetic  ex- 
periments which  have  just  been  described,  it  is  often  necessary  to 
discriminate  between  the  separate  carbonates  and  the  true  double 
salt.  In  most  cases  this  is  easily  done  by  taking  advantage  of  differ- 
ences in  solubility.  Calcite  and  aragonite  dissolve  easily  in  weak 
acetic  or  hydrochloric  acid;  dolomite  and  magnesite,  at  ordinary 
temperatures,  are  attacked  slowly.1  These  magnesian  carbonates 
are  not  absolutely  insoluble  in  dilute  acids,  but  they  are  sufficiently 
resistant  to  admit  of  a rough  separation  from  calcite,  and  their  subse- 
quent identification.  From  a mixture  of  dolomite  and  calcite,  cold 
dilute  acetic  acid  will  dissolve  the  latter  mineral,  leaving  nearly  all 
of  the  dolomite  unattacked.  From  mixtures  of  calcite  and  magne- 
site, on  the  other  hand,  all  of  the  lime  will  be  thus  removed.  Some 
magnesia  also  may  pass  into  solution,  for  as  Vesterberg  has  shown, 
there  are  magnesian  carbonates,  probably  basic  or  hydrous,  which 
dissolve  with  ease.  Magnesite  is  even  more  refractory  toward  sol- 
vents than  dolomite. 

Furthermore,  discrimination  between  calcite  and  dolomite  can  be 
effected  by  microchemical  tests.  Among  the  best  of  these  is  that 
described  by  J.  Lemberg,2  whose  reagent  consists  of  a solution  of 
aluminum  chloride  and  hsematoxylin  (extract  of  logwood).  This 
reagent  deposits  a violet  coating  upon  calcite  surfaces,  but  leaves 
dolomite  uncolored.  According  to  F.  Cornu,3  the  two  minerals  are 
easily  distinguished  by  covering  the  powdered  material  with  water 
and  adding  a few  drops  of  phenolphthalein  solution.  Calcite  gives 
a strong  coloration;  dolomite  is  affected  but  slightly.  E.  Hinden4 
states  that  limestone  is  colored  red-brown  by  ferric  chloride  solution, 
and  blue  by  copper  sulphate,  dolomite  remaining  unchanged. 

So  far  as  the  experimental  evidence  goes,  dolomite  can  be  formed 
in  several  ways.  In  specific  cases,  however,  field  evidence  must  be 
brought  to  bear.  First,  dolomite  may  exist  as  a true  chemical  sedi- 
ment, although  occurrences  of  this  kind  are  probably  rare.  G.  Leube5 6 

1 Upon  these  differences  in  solubility  there  is  an  abundant  literature,  which  has  been  well  summarized 
by  A.  Vesterberg,  Bull.  Geol.  Inst.  Upsala,  vol.  5,  1901,  p.  97;  vol.  6, 1905,  p.  254.  See  also  the  synthetic 
papers  already  cited,  and  Haushofer,  Sitzungsb.  K.  Akad.  Wiss.  Miinchen,  vol.  11, 1881,  p.  220. 

2Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  40,  1888,  p.  357.  In  vol.  39,  1887,  p..  489,  Lemberg  describes  tests 
based  upon  the  use  of  ferric  chloride  and  ammonium  sulphide.  In  a still  earlier  paper  (op.  cit.,  vol.  24, 1872, 
p.  226)  Lemberg  gives  tests  with  silver  nitrate,  which  stains  calcite  and  dolomite,  after  ignition,  unequally. 
See  also  Otto  Meyer,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  31, 1879,  p.  445. 

3 Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  p.  550. 

* Verhandl.  Naturforsch.  Gesell.  Basel,  vol.  15,  1903,  p.  201.  O.  Mahler  (Inaug.  Diss.,  Freiburg,  1906) 

finds  the  ferric  chloride  unsatisfactory  but  obtained  good  results  with  the  copper  salt.  On  the  copper  test 
see  also  K.  Spangenberg,  Zeitschr.  Kryst.  Min.,  vol.  52,  p.  529, 1913. 

6 Neues  Jahrb.,  1840,  p.  371. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


565 


described  a “ fresh-water  dolomite”  near  Ulm,  in  Bavaria;  and  C. 
W.  Giimbel,1  studying  the  dolomites  of  the  same  region,  which  are 
interbedded  with  limestones,  likewise  asserts  their  sedimentary  ori- 
gin. T.  Scheerer2  also  argues  that  the  oldest  dolomites  were  formed 
as  chemical  precipitates;  and  T.  Sterry  Hunt’s3  positive  views  on 
this  subject  are  well  known.  Hunt’s  experiments  help  us  to  under- 
stand how  sediments  of  dolomite  may  perhaps  be  formed;  and  it  is 
also  possible  that  algae  may  precipitate  mixed  carbonates  just  as  they 
do  calcareous  marl.  When  the  carbonates  are  thrown  down  together, 
heat  and  pressure  may  combine  to  bring  about  their  union.  These 
suggestions  relate  to  possibilities  only;  and  it  would  be  rash  to  assert 
positively  that  dolomites  are  ever  formed  on  a large  scale  by  direct 
sedimentation. 

Magnesian  carbonates  are,  however,  deposited  with  calcium  carbon- 
ate by  marine  organisms,  albeit  in  small  relative  amounts.  G.  Forch- 
hammer4  made  many  analyses  of  shells  and  corals,  finding  mag- 
nesium carbonate  in  them  in  percentages  ranging  from  0.15  to  7.64, 
1 per  cent  being  rather  above  the  average.  This  result  has  been  con- 
firmed by  many  other  investigators.  In  Lithothamnium  nodosum 
Giimbel5  found  2.66  per  cent  of  MgO  and  47.14  of  CaO;  and  A.  G.  Hog- 
bom6  in  fourteen  analyses  of  algse  belonging  to  this  genus  reports 
from  1.95  to  13.19per  cent  of  MgC03.  To  these  higher  figures  refer- 
ence will  be  made  later. 

In  1906  H.  W.  Nichols  7 published  an  analysis  of  the  skeleton  of  a 
recent  crinoid,  and  found  in  it  about  11  per  cent  of  magnesium 
carbonate.  Several  years  later  C.  Palmer,  in  the  laboratory  of  the 
U.  S.  Geological  Survey,  analyzed  two  more  crinoids,  and  obtained 
similar  results.  In  1914  the  subject  was  taken  up  more  extensively 
by  F.  W.  Clarke  and  W.  C.  Wheeler,8  and  24  analyses  were  made, 
representing  21  genera  of  crinoids  and  a wide  range  of  habitat.  In  all 
of  them  magnesium  carbonate  was  found,  in  proportions  ranging  from 
7.28  to  12.69  per  cent,  the  amount  varying  with  the  temperature  of 
the  water  in  which  the  creatures  lived.  In  cold-water  forms  the 
figure  for  magnesia  was  low,  while  in  tropical  forms  the  figure  was 
high;  a sharply  defined  relation  for  which  an  explanation  is  yet  to  be 
found.  This  research  was  followed  up  by  a series  of  analyses  of  the 


1 Sitzungsb.  K.  Akad.  Wiss.  Miinchen,  1871,  Heft  1,  p.  45. 

2 Neues  Jahrb.,  1866,  p.  1. 

3 See  Chemical  and  geological  essays,  p.  80,  and  the  literature  already  cited. 

* Neues  Jahrb.,  1852,  p.  854.  The  highest  figure  in  Forchhammer’s  series  was  for  an  annelid,  Serpula. 

^ Abhandl.  K.  Akad.  Wiss.  Miinchen,  vol.  11, 1871,  p.  26. 

6 Neues  Jahrb.,  1894,  Band  1,  p.  262.  The  analyses  were  made  by  a number  of  chemists  for  Hog- 
bom,  who  gives  data  for  several  shells  and  corals  also.  In  the  latter  organisms  the  magnesia  was  low. 
R.  C.  Wallace  (Jour.  Geology,  vol.  21,  p.  416, 1913)  has  considered  the  relation  of  calcareous  algse  to  the 
production  of  dolomite. 

7 Field  Columbian  Museum,  Pub.  Ill,  p.  31, 1906.  See  also  A.  H.  Clark,  Proc.  U.  S.  Nat.  Mus.,  vol.  39,  p. 
487,  1911. 

8 Prof.  Paper  U.  S.  Geol.  Survey  No.  90-D,  1914. 


566 


THE  DATA  OP  GEOCHEMISTRY. 


inorganic  parts  of  sea  urchins,  starfishes,  and  brittle  stars,  with  results 
strictly  comparable  with  and  parallel  to  those  found  for  the  crinoids.1 
Similar  quantities  of  magnesia  were  found,  and  the  same  temperature 
regularity  was  observed.  In  short  it  seems  to  be  established  that  the 
inorganic  constituents  of  any  echinoderm  will  have  the  composition 
of  a moderately  magnesian  limestone,  and  the  largest  proportion  of 
magnesia  will  be  found  in  organisms  from  relatively  warm  waters.2 
It  is  not  to  be  assumed,  however,  that  magnesian  sediments  follow 
the  same  rule.  A dense  population  of  forms  low  in  magnesia  would 
deposit  a larger  amount  of  it  than  a sparse  population  of  richer 
organisms.  Clarke  and  Wheeler  also  report  analyses  of  10  fossil 
crinoids,  ranging  from  the  Ordovician  up  to  the  Eocene,  but  with 
inconclusive  results.  Alterations  due  to  leaching  and  to  infiltration 
of  foreign  substances  such  as  silica  and  the  carbonates  of  iron  and 
manganese  effectually  obliterated  all  the  regularities  shown  by  the 
recent  living  forms.  The  calcareous  algae  analyzed  by  Hogbom 
show  no  such  temperature  relations  as  are  exhibited  by  echinoderms. 

From  these  data  it  is  clear  that  limestones  formed  by  marine 
organisms  must  contain  magnesia,  and  evidence  shows  that  as  a rule 
they  contain  rather  more  of  it  proportionally  than  the  remains  from 
which  they  are  made.  The  analyses  of  oceanic  oozes  collected  by  the 
Challenger  expedition,  as  discussed  by  Hogbom,3  show  this  fact  very 
well,  and  also  illustrate  the  tendency  of  the  magnesium  carbonate 
to  accumulate,  while  the  more  soluble  calcium  carbonate  is  dissolved 
away.  That  is,  by  the  leaching  of  these  deposits  they  become  rela- 
tively enriched  in  magnesia,  until  in  the  extreme  cases  something 
very  near  the  true  dolomite  ratio  is  attained.  In  short,  a dolomite 
may  be  produced  by  concentration  from  a magnesian  limestone,  and 
either  sea  water  or  percolating  waters  of  atmospheric  origin  may 
operate  in  this  way.  Grand  jean  4 was  probably  the  first  to  interpret 
certain  dolomites  as  having  been  formed  by  this  process,  a view  which 
various  other  writers  have  adopted  and  which  is  well  developed  in 
Hogbom’s  memoir.  Hogbom,  in  addition  to  the  facts  already  cited, 
brings  other  important  evidence  to  bear  upon  the  problem.  He 
shows  that  stalactites  from  caverns  in  the  coral  rocks  of  Bermuda 
contain  only  0.18  to  0.68  per  cent  of  magnesium  carbonate,  while  the 
rocks  themselves  carry  about  five  times  as  much.5  Here  the  lime 

1 Prof.  Paper  U.  S.  Geol.  Survey  No.  90-L,  1915.  A similar  temperature  relation  has. been  found  by 
Clarke  and  Wheeler  in  a series  of  analyses  of  alcyonarians  not  yet  published. 

2 A few  other  analyses  of  echinoderms,  namely,  sea  urchins  and  starfishes,  are  on  record.  See  L.  Schmelck, 
Norske  Nordhavs-Expedition,  No.  XXVIII,  p.  129,  1901;  and  O.  Biitschli,  Abhandl.  K.  Gesell.  Wiss. 
Gottingen,  new  ser.,  vol.  6,  No.3,pp.  81-83,  1904.  In  a holothurian,  Stichopus  regalis,  8.37  per  cent  of 
magnesium  carbonate  was  found.  Another  holothurian  analyzed  by  A.  Hilger  (Arch,  gesammte  Physio- 
logic, vol.  10,  p.  214,  1875)  contained  12.10  per  cent,  calculated  on  the  calcined  ash  of  the  creature.  Locali- 
ties and  temperatures  were  not  given  with  these  analyses. 

3 Op.  cit.,  p.  267. 

* Neues  Jahrb.,  1844,  p.  543. 

6 It  is  well  known  that  stalactites  from  caverns  in  dolomitic  limestones  consist  essentially  of  calcium 
carbonate,  with  little  or  no  magnesia. 


Sedimentary  and  detrital  rocks. 


567 

salt  has  dissolved  much  more  freely  than  the  magnesium  compound. 
Hogbom  also  studied  the  marine  marls  of  Sweden,  and  found  that 
the  transported  material  contained  progressively  larger  proportions 
of  magnesium  carbonate  as  its  distance  from  the  parent  limestone 
increased.  Near  its  point  of  origin  the  marl  carried  3.7  parts  of 
MgC03  to  100  of  CaC03;  and  from  these  figures  the  ratio  was 
gradually  raised  to  36  MgC03  and  100  CaC03.  In  these  finely 
divided  sediments  the  leaching  out  of  calcium  carbonate  by  atmos- 
pheric and  glacial  waters  is  naturally  rapid,  and  the  concentration 
of  the  dolomitic  portion  is  effected  with  great  ease.  This  mode  of 
concentration,  then,  must  be  recognized  as  real,  and  as  accounting 
in  part  at  least  for  the  formation  of  dolomite;1  but  it  is  not  the 
whole  story.  It  accounts  for  some  occurrences  but  not  all. 

Coral  rock,  it  will  be  remembered,  consists  chiefly  of  calcium  car- 
bonate, which  in  the  living  forms  is  mineralogically  aragonite;  but 
in  1843  J.  D.  Dana,2  in  a rock  from  the  coral  island  of  Makatea,  in 
the  Pacific,  reported  magnesium  carbonate  to  the  extent  of  38.07  per 
cent.  This  approached  the  dolomite  ratio,  which  requires  45.7  per 
cent,  and  the  thought  was  at  once  suggested  that  the  rock  had  been 
dolomitized  by  the  introduction  of  magnesia  from  sea  water,  the 
latter  having  possibly  been  first  concentrated  by  evaporation  in  a 
shallow  lagoon. 

Since  Dana’s  observation  was  made,  many  other  investigators 
have  recorded  similar  enrichments  of  coral  reefs,  and  the  synthetic 
experiments  of  various  chemists,  as  cited  in  the  preceding  pages,  have 
shown  that  the  indicated  reaction  can  actually  take  place.  Element ’s 
experiments,  especially,  have  helped  to  make  this  point  clear.  In  a 
coral  reef  from  Porta  do  Mangue,  Brazil,  J.  C.  Branner3  reports 
6.95  per  cent  of  magnesia,  equivalent  to  14.5  of  carbonate,  while  the 
corals  themselves  contained  only  0.20  to  0.99  per  cent  of  MgO.  In 
the  islands  of  the  Pacific  Ocean  a large  number  of  similar  cases  have 
been  observed,  the  analyses  by  E.  W.  Skeats  4 rising  to  a maximum 
of  43.3  per  cent  of  MgCOa.  From  instances  of  this  kind,  and  from 
the  resemblance  of  many  dolomites  to  reef  rocks,  it  has  been  com- 
monly inferred  that  dolomitization  is  generally,  or  at  least  often, 
effected  in  this  way,  lime  being  gradually  removed  and  replaced  by 
magnesia  from  the  sea.5 6 

1 For  an  elaborate  discussion  of  this  side  of  the  dolomite  problem  see  G.  Bischof,  Lehrbuchder  chemischen 
und  physikalischen  Geologie,  2d  ed.,  pp.  52-91.  The  older  data  are  wellsummarized.  See  also  C.  W.  Hall 
and  F.  W.  Sardeson,  Bull.  Geol.  Soc.  America,  vol.  6, 1894,  p.  189. 

2 See  Dana’s  Coral  and  coral  islands,  3d  ed.,  p.  393.  Analyses  by  B.  Silliman,  jr.  The  island  is  called 
Metia  by  Dana. 

8 Bull.  Mus.  Comp.  Zool.,  vol.  44,  1904,  p.  264.  Analysis  of  rock  by  R.  E.  Swain,  of  the  corals  by  L.  R. 

Lenox. 

* Idem,  vol.  42,  1903,  pp.  53-126. 

6 See  R.  Harkness,  Quart.  Jour.  Geol.  Soc.,  vol.  15,  1859,  p.  103,  on  dolomite  near  Cork,  Ireland.  Also 
C.  Doelter  and  R.  Hoemes,  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  25,  p.  293.  These  authors  give  a bibliog- 
raphy of  dolomitization,  down  to  1875,  the  date  of  their  memoir. 


568 


THE  DATA  OF  GEOCHEMISTRY. 


The  most  striking  illustration  of  this  mode  of  transformation  is 
furnished  by  the  borings  on  the  atoll  of  Funafuti,  as  discussed  by 
J.  W.  Judd.1  The  principal  boring  was  driven  to  a depth  of  over 
1,100  feet  through  coral  and  coral  rock  all  the  way,  and  samples 
of  the  cores  were  analyzed  for  practically  every  10  feet  of  the  dis- 
tance. From  the  table  of  data  presented  by  Judd,  the  following 
figures  are  selected: 


Magnesium  carbonate  in  borings  on  atoll  of  Funafuti. 


Depth,  feet. 

Percentage 

MgCOs. 

Depth,  feet. 

Percentage 

MgC03. 

4 

4.  23 

295 

3.6 

13 

7.  62 

400 

3.1 

15 

16.4 

500 

2.7 

20 

11.  99 

598 

1.  06 

26 

16.0 

640 

26.  33 

55 

5.  85 

698 

40.  04 

110 

2. 11 

795 

38.  92 

159 

.79 

898 

39.  99 

200 

2.  7 

1,000 

40.  56 

250 

4.9 

1,114 

41.  05 

These  figures  are  very  remarkable.  They  show,  first,  an  enrich- 
ment in  magnesium  carbonate  near  the  surface,  then  an  irregular 
rising  and  falling  in  much  smaller  amounts,  while  below  700  feet  the 
approach  to  a dolomite  ratio  is  apparent.  The  surface  enrichment 
Judd  attributes  to  a possible  leaching  out  of  lime  salts,  and  the 
irregularities  may  be  due  in  part  to  differences  in  the  proportions  of 
the  various  reef-forming  organisms.  Some  of  these  are  more  soluble 
than  others,  as  we  have  already  seen.  Algae,  especially  Lithothamnium 
and  Halimeda , are  abundant  at  Funafuti,  and  Judd  suggests  that  the 
abnormally  high  magnesia  found  by  Hogbom  in  these  organisms  may 
also  be  due  to  leaching,  possibly  aided  by  carbon  dioxide  derived 
from  the  decomposition  of  the  plants  after  death.  The  replacement 
of  lime  by  magnesia  extracted  from  sea  water  probably  takes  place 
at  the  same  time,  so  that  two  distinct  processes  combine  to  produce 
the  final  result.  It  is  noticeable  that  the  lower  portions  of  the  core, 
which  were  the  earliest  deposited  and  have  therefore  been  acted 
upon  for  the  longest  time,  are  the  most  completely  changed. 

In  this  double  process  of  leaching  and  replacement,  we  find  the 
nearest  approach  to  a satisfactory  theory  of  dolomitization  in  coral 
reefs.  It  is,  however,  not  general,  as  the  following  analyses  by 


1 The  atoll  of  Funafuti,  published  by  the  Royal  Society,  London,  1904.  For  Judd’s  report  on  the  chem- 
ical examination,  see  pp.  362-389. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


569 


George  Steiger,1  of  borings  from  an  artesian  well  at  Key  West, 
Florida,  clearly  show: 


Lime  and  magnesia  in  borings  at  Key  West. 


Depth,  feet. 

Percentage 

CaO. 

Percentage 

MgO. 

Depth,  feet. 

Percentage 

CaO. 

Percentage 

MgO. 

25 

54.  03 

0.  29 

1,325 

54.  49 

0.  62 

100 

54.  01 

.77 

1,400 

55. 12 

.30 

150 

54.  38 

.86 

1,475 

54.  48 

.73 

350 

51.  46 

1.  67 

1,625 

53.  90 

1. 14 

600 

48.  87 

2.  50 

1,850 

54.  28 

1. 12 

775 

46.  53 

6.  70 

2, 000 

54.  02 

1.  06 

1,125 

53.  84 

.86 

Here  there  is  a progressive  magnesian  enrichment  down  to  775 
feet,  and  then  a falling  off,  but  no  such  thorough  alteration  appears 
as  at  Funafuti.  What  different  conditions  may  have  existed  to 
account  for  these  differences  of  composition  is  not  known. 

It  is  of  course  evident  that  dolomitization  by  replacement  need 
not  be  limited  to  the  action  of  sea  water  upon  coral  reefs.  Magnesian 
spring  waters  may  be  equally  effective,  and  are  so  locally,  as  observed 
by  J.  E.  Spurr  2 in  the  rocks  about  Aspen,  Colorado.  In  that  region 
hot  springs  containing  magnesium  are  manifestly  operative  in  trans- 
forming limestone  to  dolomite.  But  large  areas  of  dolomite  are  not 
likely  to  originate  in  that  way.  Where,  however,  limestones  are 
situated  near  magnesian  eruptive  rocks,  dolomitization  due  to  this 
cause  is  to  be  anticipated. 

The  following  analyses  of  magnesian  limestones  were  made  in  the 
laboratory  of  the  United  States  Geological  Survey.3  Other  analyses 
in  abundance  are  scattered  through  the  literature  of  limestones. 

1 Analyses  made  in  the  laboratory  of  the  United  States  Geological  Survey.  Published  in  full  in  Bull. 
No.  228, 1904,  p.  309.  Boring  described  by  E.  O.  Hovey,  Bull.  Mus.  Comp.  Zool.,  vol.  28,  1896,  p.  63. 

2 Mon.  U.  S.  Geol.  Survey,  vol.  31, 1898,  p.  206.  Spurr  (p.  216)  also  reports  an  interesting  silicification  of 
limestones,  which  is  visible  in  all  its  stages.  The  final  product  is  made  up  of  quartz  grains.  The  mag- 
nesian enrichment  of  slates  at  the  expense  of  sea  water  has  been  described  by  J.  A.  Phillips,  Quart.  Jour. 
Geol.  Soc.,  vol.  31,  1875,  p.  324.  A recent  paper  by  M.  Nahnsen  on  the  formation  of  oolite  and  dolomite  is 
in  Neues  Jahrb.,  Beil.  Band  35, 1913,  p.  277.  A study  of  the  mixed  carbonates  of  lime,  magnesia,  and  iron, 
by  K.  Griinsberg,  is  in  Zeitschr.  anorg.  Chemie,  vol.  80, 1913,  p.  337.  For  an  attempt  to  apply  the  principles 
of  physical  chemistry  to  dolomitization,  see  R..  C.  Wallace,  Compt.  rend.  XII  Cong.  geol.  internat., 
1913,  p.  875. 

3 See  Bull.  No.  591, 1915,  pp.  225-249,  for  these  analyses  and  others. 


570 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  magnesian  limestones. 

A.  Green  Peak  Quarry,  Dorset,  Vermont.  Analysis  by  George  Steiger.  Described  by  T.  N.  Dale  in 
Bull.  No.  195,  1902. 

B.  “Knox  dolomite,”  Morrisville,  Alabama.  Analysis  by  W.  F.  Hillebrand.  Described  by  I.  C.  Rus- 
sell in  Bull.  No.  52, 1889. 

C.  Penokee  district,  Wisconsin.  Analysis  by  Hillebrand.  See  R.  D.  Irving  and  C.  R.  Van  Hise,  in 
Mon.,  vol.  19, 1892. 

D.  “Niobrara  dolomite,”  Denver  Basin,  Colorado.  Analysis  by  L.  G.  Eakins.  Described  by  Emmons 
in  Mon.,  vol.  27,  1896. 

E.  Near  Red  Mountain,  Silver  Peak  district,  Nevada.  Analysis  by  Steiger. 

F.  The  theoretical  composition  of  ideally  pure  dolomite. 


A 

B 

c 

D 

E 

F 

Insoluble 

12.01 

0. 31 

Si02 

8.36 

3.24 

0.  63 

A1,0, 

1.  77 

.17 

.54 

Fe203 

.22 

.17 

.03 

.11 

FeO 

1.08 

.06 

.75 

1.89 

MnO 

.08 

.20 

MgO 

16.68 

20.84 

20.68 

18.03 

20. 19 

21.9 

CaO 

29.03 

29.58 

30. 94 

27.49 

30. 35 

30.4 

Na.,0 

.06 

K20 

1.08 

HoO- 

.03 

} .30 

} .27 

} .61 

H20-f 

.42 

C02 

41.66 

J 45.54 

46.27 

41.40 

47.21 

47.7 

PoO, 

.03 

Cl 

Trace. 

100. 39 

99.90 

99.65 

100. 42 

99.95 

100.0 

Under  ordinary  atmospheric  and  aqueous  conditions  dolomite 
alters  like  limestone,  but  less  readily.  By  volcanic  agencies,  that  is, 
the  combined  action  of  heated  or  fused  rooks  and  steam,  dolomite  is 
sometimes  transformed  into  a substance  which  was  once  thought  to 
be  a distinct  mineral  species,  and  was  named  predazzite  and  penca- 
tite  by  different  investigators.  This  substance  has  been  interpreted 
by  Damour,1  G.  Hauensohild,2  J.  Roth,3  and  J.  Lemberg 4 as  a mix- 
ture of  oalcite  and  brucite,  Mg02H2.  O.  Lene6ek,5  however,  regards 
it  as  a mixture  of  calcite  and  hydromagnesite,  the  latter  being  partly 
pseudomorphous  after  periclase  and  partly  an  infiltration.  In  either 
case  the  dolomite  has  been  altered  by  the  transformation  of  its  mag- 
nesium carbonate  into  a basic  salt  or  into  hydroxide.  The  latter 
compound,  under  some  conditions,  can  be  leached  away,  leaving 
nearly  pure  calcite;  or  it  may  be  dehydrated,  forming  periclase, 
MgO.  Predazzite  was  first  observed  at  Predazzo,  in  the  Tyrol;  and 

1 Bull.  Soc.  gdol.  France,  2d  ser.,  vol.  4,  1847,  p.  1050. 

2 Sitzungsb.  K.  Akad.  Wiss.  Wien,  vol.  60, 1870,  p.  795. 

3 See  Allgemeine  und  chemische  Geologie,  vol.  1,  pp.  422-425.  Roth  cites  many  analyses  of  altered 
dolomites  and  gives  the  data  concerning  predazzite  with  considerable  fullness. 

4 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  24,  1874,  p.  187. 

6 Min.  pet.  Mitt.,  vol.  12, 1892,  pp.  429,  447.  Lenedek  gives  a good  summary  of  the  literature  of  predazzite. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


5n 

Lemberg,  by  acting  on  normal  dolomite  from  that  locality  with 
steam,  obtained  a similar  product.  A like  alteration  of  dolomite 
from  a Russian  locality  was  also  reported  by  F.  Rosen.1 

IRON  CARBONATE. 

Another  important  rock-building  carbonate  is  siderite,  the  ferrous 
carbonate  FeC03.  Its  formation  as  bog  ore  has  already  been  con- 
sidered,2 together  with  its  transformation  into  limonite,  but  its  rela- 
tions to  limestone  and  dolomite  remain  to  be  noticed.  Between  these 
rocks  there  are  many  transitional  mixtures,  and  ankerite,  the  ferrif- 
erous dolomite,  is  one  of  them.  This  mineral  contains  iron  replacing 
magnesium,  to  use  the  ordinary  phraseology,  but  this  implies  that  the 
double  salt  CaFeC206  exists  isomorphous  with  and  equivalent  to 
the  magnesian  compound,  dolomite.  The  two  salts,  CaFeC206  and 
CaMgC206,  may  commingle  in  any  proportion,  and  varieties  contain- 
ing manganese  carbonate  are  also  known.  So,  too,  there  are  mixtures 
of  magnesite  and  siderite,  known  as  breunnerite,  mesitite,  and  pis- 
tomesite,  but  they  are  comparatively  unimportant  except  in  the 
study  of  isomorphism.  The  manganese  carbonate,  rhodochrosite, 
MnC03,  is  usually  a mineral  of  metalliferous  veins. 

As  bog  ore,  siderite  is  deposited  from  a bicarbonate  solution  in 
presence  of  organic  matter  and  out  of  contact  with  air.  But  siderite, 
like  dolomite,  may  also  be  formed  by  replacement  when  iron  solu- 
tions act  upon  limestones.  H.  C.  Sorby  3 found  that  Iceland  spar 
immersed  in  a solution  of  ferrous  chloride  was  slowly  transformed 
into  crystalline  siderite;  in  ferric  chloride,  on  the  other  hand,  ferric 
hydroxide  was  formed.  A similar  precipitation  of  limonite  was 
observed  by  G.  Keller 4 when  oalcite  was  treated  with  ferric  sulphate. 
Reactions  of  this  kind  have  often  been  invoked  in  the  interpretation 
of  sedimentary  iron  ores.  J.  P.  Kimball,5  for  example,  regards  the 
reaction  of  ferrous  solutions  upon  limestones  as  of  the  highest  impor- 
tance, and  refers  to  isolated  masses  of  coral  reef  in  Cuba  which  have 
been  so  replaced  by  iron  compounds.  Fossils,  originally  calcareous, 
but  now  composed  of  limonite,  are  not  rare.  In  the  Jurassic  lime- 
stones of  central  France  ores  of  iron,  manganese,  and  zinc  are 
widely  disseminated.  According  to  L.  Dieulafait,6  these  ores  were 
precipitated  from  solution  by  calcium  carbonate,  the  iron  first,  zinc 
and  manganese  later.  The  iron  ores  are  always  at  the  bottom  of 
the  series,  and  the  other  metals  are  found  in  the  overlying  limestones. 

1 Arch.  Naturkunde  Liv.,  Esth.  u.  Kurlands,  1st  ser.,  vol.  3,  1864,  p.  142. 

2 See  ante,  p.  530. 

* Quart.  Jour.  Geol.  Soc.,  vol.  35,  Proc.,  1879,  p.  73. 

4 Neues  Jahrb.,  1882,  Band  1,  ref.,  p.  363. 

<>  Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  231. 

6 Compt.  Rend.,  vol.  100,  1885,  p.  662. 


572 


THE  DATA  OF  GEOCHEMISTRY. 


Like  carbonate  of  lime,  iron  carbonate  may  be  removed  from  solu- 
tion by  aquatic  vegetation.  The  process,  however,  is  different  in 
one  particular.  Ferrous  carbonate  is  easily  oxidized  to  limonite,  and 
that  change,  which  takes  place  in  air  alone,  is  doubtless  accelerated 
by  the  oxygen  which  the  plants  exhale.  The  deposit  formed  is  not 
siderite  then,  but  hydroxide.  Similar  precipitation  of  limonite  may 
also  occur  from  sulphate  solutions,  as  in  or  near  a chalybeate  spring 
in  Death  Gulch,  Yellowstone  National  Park.  Here,  according  to 
W.  H.  Weed,1  the  mosses  form,  from  the  water  of  the  spring,  an  iron 
sinter,  which  was  analyzed  by  J.  E.  Whitfield  in  the  laboratory  of  the 
United  States  Geological  Survey  with  the  following  results : 

Analysis  of  iron  sinter. 


Si02 1.  37 

Fe203 63.03 

A1203 08 

S03 8.35 

H20  and  organic  matter 26.  94 


99.  77 

The  instability  of  ferrous  carbonate  is  also  shown  by  the  deposits 
of  iron  rust  around  iron-bearing  springs  in  general,  and  by  the  forma- 
tion of  stalactites  of  limonite.  Such  stalactites  were  formed  exactly 
like  calcite  stalactites,  by  carbonate  solutions,  only  the  iron  salt  has 
decomposed  and  left  residues  of  hydroxide.  According  to  T.  Sterry 
Hunt 2 the  alteratioi\  of  siderite  to  limonite  is  attended  by  a contrac- 
tion of  27.5  per  cent,  whence  limonite  ore  bodies  are  often  porous  or 
spongy. 

The  vast  deposits  of  iron  ores  in  the  Lake  Superior  region,  limo- 
nites,  hematites,  magnetites,  etc.,  are  now  regarded  as  in  great 
measure  secondary  bodies  derived  from  iron  carbonates  of  sedimen- 
tary origin.  The  process  by  which  their  concentration  was  probably 
effected  has  been  summed  up  by  C.  E.  Van  Hise  3 as  follows:  First, 
meteoric  waters  attacked  the  upper  portions  of  the  original  carbon- 
ate, oxidizing  the  latter  to  limonite.  In  so  doing  the  waters  lost 
their  dissolved  oxygen  and  became  carbonated.  In  this  condition 
the  waters  dissolve  ferrous  carbonate,  with  some  silicate,  and  transfer 
it  to  lower  levels.  Later,  the  surface  oxidation  having  been  com- 
pleted, waters  charged  with  atmospheric  oxygen  percolate  downward, 
mingle  with  the  iron  solutions  previously  formed,  and  precipitate 


1 Am.  Geologist,  vol.  7, 1891,  p.  48. 

2 Canadian  Naturalist,  vol.  9, 1881,  p.  431. 

3 Twenty-first  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3,  1900,  p.  326.  Monographs  19,  28,  36,  43,  45,  and 
46  of  the  Survey,  by  Irving,  Van  Hise,  Clements,  Smyth,  Bayley,  and  Leith,  deal  exhaustively  with  these 
“Lake  Superior”  ores.  See  also  J.  E.  Spurr,  Bull.  No.  10,  Geol.  Nat.  Hist.  Survey  Minnesota,  1894,  on 
the  Mesabi  ores;  and  S.  Weidman,  Bull.  No.  13,  Wisconsin  Geol.  Nat.  Hist.  Survey,  1904,  on  the  Baraboo 
district.  Bull.  No.  6 of  the  Minnesota  Survey,  1891,  by  N.  H.  and  H.  V.  Winchell,  is  devoted  to  a dis- 
cussion of  the  Minnesota  deposits. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


573 


limonite.  The  latter*  by  heat  and  pressure*  may  be  transformed  to 
hematite.  A similar  interpretation  is  given  by  A.  Brunlechner  1 to 
the  associated  siderite  and  limonite  at  Hiittenberg  in  Carinthia.  In 
this  case,  however,  the  waters  charged  with  ferrous  carbonate  re- 
deposit it  upon  contact  with  limestones.  Here  also  the  original  for- 
mation, the  main  ore  body,  is  sedimentary. 

The  following  analyses  represent  mixed  carbonates,  mainly 
ferriferous: 

Analyses  of  mixed  carbonates. 

A.  Iron  carbonate,  Sunday  Lake,  Michigan.  Analysis  by  W.  F.  Hillebrand. 

B.  Iron  carbonate,  Penokee  district,  Michigan.  Analysis  by  R.  B.  Riggs. 

C.  Iron  carbonate,  Gunflint  Lake,  Canada.  Analysis  by  T.  M.  Chatard. 

D.  Ferrodolomite,  Marquette  district,  Michigan.  Analysis  by  G.  Steiger.  For  analyses  A,  B,  C,  D, 
and  others,  see  Bull.  U.  S.  Geol.  Survey  No.  228, 1904,  pp.  318-320. 

E.  Cobaltiferous  siderite,  from  a mine  near  Neunkirchen,  Germany.  Analysis  by  G.  Bodlander,  Neues 
Jahrb.,  1892,  Band  2,  p.  236. 

F.  Mangandolomite,  Greiner,  Tyrol.  Analysis  by  K.  Eisenhuth,  Zeitschr.  Kryst.  Min.,  vol.  35,  1902, 
p.  582.  Other  analyses  of  dolomite,  etc.,  are  given  in  this  paper. 


A 

B 

C 

D 

E 

F 

Insoluble 

0. 16 

Si02 

28.  86 

15.  62 

23.90 

26.  97 

Ti02 

. 20 

None. 

AloOq 

1.  29 

4.  27 

. 07 

1.  30 

Fc,o! 

1.  01 

8. 14 

.44 

2.  31 

^2w3  * 

FeO'. 

37.  37 

32.  85 

10.  72 

39.  77 

45.  34 

6.  59 

MnO. 

.97 

5.  06 

.28 

.29 

23.  41 

CoO..  

3.  85 

CaO 

. 74 

.81 

22.  25 

.66 

1.21 

10.  48 

MgO 

3.  64 

2.  66 

8.  52 

1.  94 

8.  80 

14.  58 

Alkalies 

.09 

H20  - 

} .68 

} .68 

None. 

. 10 

H20+ 

. 99 

.51 

PAY 

J 

Trace. 

.03 

co2 

25.  21 

30.  32 

32.  42 

26.  20 

41.  55 

45.  59 

so3 

.17 

99.  97 

100.  41 

99.  76 

, 

100. 17 

100.  75 

100.  81 

SILICATED  IRON  ORES. 

In  addition  to  siderite,  certain  sedimentary  silicates  serve  as  sources 
for  limonite  and  hematite  ores.  Glauconite,  for  example,  was  sug- 
gested by  B.  A.  F.  Penrose 2 as  a possible  parent  of  iron  ore,  and  a 
green  silicate  from  which  the  Mesabi  ores  are  derived  was  placed 
under  glauconite  by  J.  E.  Spurr.3  C.  K.  Leith,4  however,  in  his 
report  on  the  Mesabi  district,  has  shown  that  the  green  mineral  of  the 
ferruginous  cherts  is  not  glauconite,  but  a hydrated  ferrous  or  ferroso- 


1 Zeitschr.  prakt.  Geologic,  1893,  p.  301. 

3 Ann.  Rept.  Geol.  Survey  Arkansas,  vol.  1, 1892.  This  is  a monograph  on  the  iron  ores  of  Arkansas. 

3 Bull.  No.  10,  Geol.  Nat.  Hist.  Survey  Minnesota,  1894. 

* Mon.  U.  S.  Geol.  Survey,  vol.  43,  1903,  pp.  237-279.  On  the  origin  of  these  ores  see  also  N.  H.  Winchell, 
Bull.  Geol.  Soc.  America,  vol.  23,  1912,  p.  317.  Winchell  regards  the  greenalite  granules  as  derived 
from  volcanic  sand. 


574 


THE  DATA  OF  GEOCHEMISTRY. 


ferric  silicate,  containing  no  potassium.  To  this  silicate  he  gives  the 
name  greenalite.  Its  composition,  as  shown  by  the  analyses  made  by 
G.  Steiger  1 in  the  laboratory  of  the  United  States  Geological  Survey, 
is  not  accurately  determinable,  for  the  green  granules  can  not  be 
mechanically  separated  from  the  enveloping  chert.  Three  analyses 
of  the  portion  of  the  rock  soluble  in  hydrochloric  acid  gave  the  fol- 
lowing results,  after  union  of  like  bases  and  recalculation  to  100  per 
cent.  For  comparison  with  them,  in  a fourth  column,  I give  an  analy- 
sis by  F.  Field 2 of  a green,  massive,  chloritic  mineral  associated  with 
the  cronstedtite  of  Cornwall: 


Analyses  of  greenalite , etc. 


Greenalite,  Steiger. 

Cornwall, 

1 

2 

3 

Field. 

Si02 

30.  08 

30.49 

38.  00 

31.  72 

Fe203 

34.  85 

23.  52 

8.40 

18.  51 

FeO 

25.  72 

36.  92 

46.  56 

39.  46 

HoO 

9.  35 

9.  07 

7. 04 

11.  02 

100.  00 

100.  00 

100.  00 

100.  71 

Field’s  mineral  and  the  greenalite  No.  2 are  very  similar,  and 
approach  in  composition  a hydrated  compound  of  the  garnet  type, 
Fe',/2Fe,/3(Si04)3.3H20.  The  third  greenalite  analysis,  however,  is 
of  an  almost  entirely  ferrous  compound,  a hydrous  metasilicate 
approaching  the  formula  FeSi03.aq.  It  is  evident  that  the  abso- 
lutely definite  silicate  is  yet  to  be  identified. 

In  the  analyses  cited  the  soluble  green  granules  formed  from  48  to 
82.5  per  cent  of  the  entire  greenalite  rock,  which,  according  to  Leith, 
represents  a marine  sediment  analogous  to  glauconite.  From  this  sil- 
icate, by  leaching,  the  hydrous  hematites  of  the  Mesabi  district  were 
concentrated;  but  the  reactions  proposed  by  Leith  to  account,  first, 
for  the  greenalite  and,  later,  for  its  decomposition  are  largely  hypo- 
thetical. Iron,  in  solution  as  carbonate,  was  probably  brought  into 
the  ocean  by  waters  from  the  land  and  precipitated  as  ferric  hydrox- 
ide. The  latter  compound,  partly  or  wholly  reduced  to  the  ferrous 
state  by  organic  matter  derived  from  marine  vegetation,  then  com- 
bined with  silica,  of  which  an  excess,  now  represented  by  chert,  was 
also  present.  These  processes  are  possible,  and  the  explanation  thus 
offered  to  account  for  the  iron-bearing  rocks  is  probable  enough  to  be 
provisionally  held,  at  least  until  something  better  is  offered.  We 
know  that  ferruginous  sediments  are  now  forming  in  the  ocean;  we 


1 See  C.  K.  Leith,  Mon.  U.  S.  Geol.  Survey,  vol.  43, 1903,  p.  246.  Discussion  by  F.  W.  Clarke. 

2 Philos.  Mag.,  5th  ser.,  vol.  5,  1878,  p.  52. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


575 


know  that  chert,  in  many  cases,  is  of  organic  origin;  and  these  facts 
are  consistent  with  the  suppositions  summarized  above. 

At  a number  of  European  localities  iron  ores  are  found  which  con- 
sist partly  of  silicates.  One  of  these,  thuringite,  is  a member  of  the 
chlorite  group ; but  another  chloritic  mineral,  chamosite,  which  occurs 
associated  with  magnetite,  limonite,  or  hematite  in  oolitic  aggrega- 
tions, is  more  definitely  an  ore  of  iron.  Its  composition,  as  deter- 
mined by  C.  Schmidt 1 on  Swiss  material,  and  by  E.  R.  Zalinski 2 on 
Thuringian  specimens,  is  represented  by  the  empirical  formula 
3Fe0.Al203.2Si02.3H20.  The  much  rarer  mineral  cronstedtite  has 
probably  the  same  formula,  with  ferric  oxide  in  place  of  alumina;  and 
it  differs  from  greenalite,  as  represented  by  the  second  analysis  of  the 
latter,  in  containing  one  less  molecule  of  silica.  Berthierine,  from 
Hayanges,  near  Metz,  is  essentially  a mixture  of  chamosite  and  mag- 
netite,3 and  forms  a valuable  ore. 

These  silicates  all  undergo  alteration  with  great  ease,  yielding 
oxides  or  hydroxides  of  iron.  In  most  cases  the  ores  containing  them 
are  oolitic,  and  form  beds  of  sedimentary  origin.4  In  this  respect 
they  resemble  glauconite  and  greenalite,  with  which,  chemically,  they 
are  so  closely  allied.  How  they  were  formed  is  uncertain  and  differ- 
ent authorities  interpret  the  evidence  differently.  The  latest  writer, 
E.  R.  Zalinski,5  regards  thuringite  and  chamosite  as  secondary  prod- 
ucts, derived  by  alteration  from  earlier  sediments  at  the  bottom  of  the 
Lower  Silurian  sea.  Whatever  the  final  conclusion  may  be,  it  seems 
clear  that  glauconite,  chamosite,  and  greenalite,  and  possibly  other 
allied  silicates,  were  all  formed  by  similar  reactions,  different  local 
conditions  having  determined  which  product  should  appear.6 


1 Zeitschr.  Kryst.  Min.,  vol.ll,  1886,  p.  601. 

2 Neues  Jahrb.,  Beil.  Band  19, 1904,  p.  40. 

2 See  A.  Lacroix,  Min6ralogie  de  la  France,  vol.  1,  p.  401,  for  this  and  other  French  occurrences. 

* On  the  ores,  locally  known  as  “minette,”  of  Luxemburg  and  Lorraine,  see  Bleicher,  Bull.  Soc.  indust, 
de  l’Est,  1894;  L.  Hoffman,  Verhandl.  Naturhist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  vol.  55,  1898, 
p.  109;  H.  Ansel,  Zeitschr.  prakt.  Geologie,  1901,  p.  81;  and  L.  van  Werveke,  idem,  p.  396.  On  the  Thur- 

ngian  ores  see  H.  Loretz,  Jahrb.  K.  preuss.  geol.  Landesanstalt,  1884,  p.  120.  Much  other  literature  is 
cited  in  the  memoirs  mentioned  here. 

6 Neues  Jahrb.,  Beil.  Band  19,  1904,  p.  79.  Zalinski  gives  a good  summary  of  the  various  theories  which 
have  been  framed  in  order  to  account  for  these  ores. 

6 In  addition  to  the  literature  already  cited,  the  following  American  reports  on  iron  ores  are  worth 
noticing:  W.  B.  Phillips,  Iron  making  in  Alabama,  a bulletin  issued  by  the  Alabama  Geol.  Survey  in 
1908.  S.  W.  McCallie,  Bull.  No.  10-A,  Georgia  Geol.  Survey,  1900,  on  the  brown  iron  ores  of  that  State; 
H.  B.  C.  Nitze,  Bull.  No.  1,  North  Carolina  Geol.  Survey,  1893;  F.  L.  Nason,  Report  on  iron  ores,  Mis- 
souri Geol.  Survey,  1892;  Rept.  of  Progress  F,  Second  Geol.  Survey  Pennsylvania,  1878,  on  the  ores  of 
the  Juniata  Valley;  E.  T.  Dumble,  Reports  on  the  iron-ore  district  of  East  Texas:  Second  Ann.  Rept. 
Texas  Geol.  Survey,  1891.  The  most  exhaustive  general  treatise  is  R.  Beck’s  great  monograph,  Die  Ge- 
schichte  des  Eisens.  Les  minerais  de  fer  oolitique  de  France,  by  L,  Cayeux  (Ministere  trav.  publ., 
Paris,  1909)  is  an  important  recent  monograph. 


) 


576 


THE  DATA  OF  GEOCHEMISTRY. 


GYPSUM. 

The  occurrence  of  gypsum  as  a sedimentary  rock  has  already  been 
partially  considered.1  It  may  form  on  a large  scale  during  the  con- 
centration of  oceanic  and  other  natural  brines,  and  it  is  sometimes 
deposited  from  solution  in  fresh  waters.  Acid  waters  of  volcanic 
origin,2  or  derived  from  the  oxidation  of  pyrite,  by  acting  upon 
limestones,  also  produce  gypsum.  Its  appearance  as  an  accessory 
mineral  in  dolomitization  is  due  to  double  decomposition  between 
limestone  and  solutions  containing  magnesium  sulphate;  and  other 
sulphates  may  act  in  a similar  way.  L.  Jowa,3  for  example,  prepared 
crystals  of  selenite  by  acting  upon  chalk  with  a solution  of  ferrous 
sulphate.  Gypsum  formed  by  reactions  of  this  order,  however,  is 
commonly  dissolved  by  the  waters  which  assist  in  the  process,  and  is 
carried  away,  to  be  diffused  or  deposited  elsewhere.  As  an  important 
rock  gypsum  is  generally  a saline  residue,  and  its  formation  in  the  first 
instance  is  probably  oftener  due  to  the  action  of  oxidizing  pyrite 
upon  lime-bearing  rocks  than  to  any  other  cause.4 

NATIVE  SULPHUR. 

Native  sulphur  is  a frequent  companion  of  gypsum,  and  this,  too, 
may  be  produced  in  several  ways.  It  is  known  as  a volcanic  subli- 
mate and  is  a product  of  reactions  between  sulphur  dioxide  and 
hydrogen  sulphide.  It  is  also  formed  by  the  incomplete  combustion 
of  hydrogen  sulphide,  probably  in  accordance  with  the  equation  5 
2H2S  + 02  = 2H20  + 2S.  According  to  Becker,  who  studied  the  phe- 
nomena at  Sulphur  Bank,  California,  the  oxidation  of  H2S  to  H2S04 
develops  201,500  calories.  The  oxidation  to  H20  + S develops  only 
59,100  calories.  Hence,  where  oxygen  is  in  excess,  as  at  the  surface, 
hydrogen  sulphide  is  completely  oxidized,  and  sulphuric  acid  is 
formed.  A short  distance  below  the  surface  oxygen  is  deficient,  and 
then  sulphur  is  liberated.  Probably,  however,  the  actual  conditions 
are  more  complex.  Sulphur  dioxide  must  be  produced  to  some  ex- 
tent, and  that  reacts  with  the  hydrogen  sulphide  to  form  sulphur 
also.  At  all  events,  sulphuric  acid  and  free  sulphur  both  occur  at 
Sulphur  Bank,  and  in  accordance  with  the  conditions  imposed  by 

1 See  ante,  pp.  211-232. 

2 J.  W.  Dawson  (Acadian  geology,  1891,  p.  262)  attributes  the  formation  of  gypsum  in  Nova  Scotia  to 
the  action  of  sulphuric  acid,  derived  from  volcanic  sources,  on  limestones. 

s Annales  Soc.  g6ol.  Belgique,  vol.  23, 1896,  p.  cxxvii. 

* For  data  upon  American  gypsum  see  G.  P.  Grimsley,  Michigan  Geol.  Survey,  vol.  9,  pt.  2, 1904;  Grimsley 
and  E.  H.  S.  Bailey,  Kansas  Univ.  Geol.  Survey,  vol.  5,  1899;  C.  R.  Keyes,  Iowa  Geol.  Survey,  vol.  3, 
pp.  257-304;  F.  J.  H.  Merrill,  Bull.  New  York  State  Mus.,  vol.  3,  No.  11,  1893.  Bull.  U.  S.  Geol.  Survey 
No.  223, 1904,  by  G.  I.  Adams  and  others,  describes  the  gypsum  deposits  of  the  United  States.  On  the 
genetic  relations  of  gypsum  and  anhydrite  see  R.  C.  Wallace,  Geol.  Mag.,  1914,  p.  271. 

5 See  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  254;  and  J.  Habermann,  Zeitschr.  anorg.' 
Chemie,  vol.  38,  1904,  p.  101. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


577 


theory.  The  deposition  of  sulphur  at  the  Rabbit  Hole  mines,  Ne- 
vada, is  also  ascribed  by  G.  I.  Adams  1 to  solfataric  activity. 

Sulphur  deposits  are  common  around  mineral  springs,  being  due 
to  the  imperfect  oxidation  of  hydrogen  sulphide;  and  the  latter  com- 
pound may  be  generated  either  by  the  action  of  acid  waters  upon 
sulphides  or  through  the  reduction  of  sulphates,  such  as  gypsum, 
by  micro-organisms.2  The  interpretation  of  any  given  locality  for 
sulphur  is  not  easy,  for  different  conditions  reign  in  different  places. 
In  one  deposit  the  evidence  of  thermal  reduction  may  be  clear,  while 
elsewhere  some  other  process  is  seen  to  have  been  operative.  The 
most  famous  of  all  sulphur  deposits  is  that  near  Girgenti,  in  Sicily, 
and  this  has  been  variously  interpreted.  Gypsum,  sulphur,  celestite, 
and  aragonite  are  here  intimately  associated,  in  what  is  evidently  a 
sedimentary  formation  not  far  removed  from  a center  of  great  vol- 
canic activity.  The  sulphur,  therefore,  has  been  regarded  by  some 
writers  as  volcanic,  by  others  as  a product  of  nonvolcanic  agencies, 
and  the  conditions  are  such  that  either  supposition  can  be  strongly 
supported.  Sicily  abounds  in  solfataras,  and  in  springs  charged  with 
hydrogen  sulphide;  and  these  may  well  have  brought  the  sulphur 
from  volcanic  sources  far  below  the  surface.  Its  deposition,  in  that 
case,  is  due  to  the  decomposition  of  hydrogen  sulphide,  which  has 
taken  place  under  aqueous  rather  than  igneous  conditions;  and  this 
view,  with  differences  in  detail,  has  been  adopted  by  various  author- 
ities.3 A.  von  Lasaulx,4  for  example,  has  argued  that  the  sulphur 
was  deposited  from  waters  containing  hydrogen  sulphide  and  cal- 
cium carbonate  during  concentration  in  fresh-water  basins;  and  G. 
Spezia  5 has  developed  a similar  argument  more  fully.  In  order  to 
account  for  the  association  of  sulphur  and  gypsum  without  assuming 
the  derivation  of  one  from  the  other,  Spezia  cites  an  observation  of 
A.  Bechamp,6  who  found  that  when  hydrogen  sulphide  was  passed 
into  water  containing  suspended  calcium  carbonate  the  latter  was 
partly  decomposed  and  calcium  hydrosulphide  was  formed.  This 
experiment  was  repeated  by  Spezia,7  but  with  fragments  of  marble 
and  under  a pressure  of  six  atmospheres.  The  solution  thus  obtained 
was  found  to  contain  a sulphide,  and  upon  evaporation  to  small 

1 Bull.  U.  S.  Geol.  Survey  No.  225, 1904,  p.  497.  See  also  D.  F.  Hewett  on  Sulphur  deposits  in  Wyoming, 
Bull.  U.  S.  Geol.  Survey  No.  540-R,  1913. 

2 See  especially  E.  Plauchud,  Compt.  Rend.,  vol.  84,  1877,  p.  235;  vol.  95,  1882,  p.  1363.  Also  A.  Etard 
and  L.  Olivier,  idem,  vol.  95,  1882,  p.  846. 

3 R.  Travaglia  (Bol.  Com.  geol.,  1889,  p.  110),  however,  regards  the  Sicilian  sulphur  as  having  been  formed 

through  the  reduction  of  gypsum  by  organic  matter,  the  remains  of  marine  animals. 

* Neues  Jahrb.,  1879,  p.  490. 

6 Sull’  origine  del  solfo  nei  giacimenti  solfiferi  della  Sicilia,  Torino,  1892.  The  theories  relative  to  the 
origin  of  Sicilian  sulphur  are  exhaustively  summed  up  and  discussed  in  this  memoir.  Several  Italian 
works  cited  by  Spezia  I have  not  been  able  to  consult.  For  a general  paper  on  the  origin  of  sulphur,  see 
O.  Stutzer,  Econ.  Geology,  vol.  7, 1912,  p.  732. 

* Annales  chim.  phys.,  4th  ser.,  vol.  16,  1869,  p.  234. 

7 Op.  cit.  ,p.  119. 

97270°— Bull.  616—16 37 


578 


THE  DATA  OF  GEOCHEMISTRY. 


bulk  at  ordinary  temperatures  it  deposited  microscopic  crystals  of 
calcite,  sulphur,  and  gypsum.  By  a reaction  of  this  kind,  between 
the  sedimentary  limestones  and  the  ascending  sulphureted  waters, 
the  observed  association  of  minerals  may  have  been  produced. 
Wherever  such  waters  act  slowly  upon  limestones  free  sulphur  with 
gypsum  is  likely  to  be  formed.1  It  must  be  observed,  however,  that 
the  partial  oxidation  of  hydrogen  sulphide  in  presence  of  limestone 
would  also  produce  the  same  association  of  substances.  It  is  inter- 
esting to  note  that  in  a large  crystal  of  gypsum  from  Cianciana,  H. 
Sjogren 2 found  a fluid  inclusion  which  yielded  liquid  enough  for 
analysis.  Its  composition  resembled  that  of  sea  water,  and  the  cavity 
also  contained  hydrogen  sulphide. 

The  considerable  deposits  of  sulphur  found  in  western  Texas  are 
also  associated  with  gypsum,  and  with  waters  which  contain  hydro- 
gen sulphide.  Some  waters  from  the  sulphur  beds  are  strongly  acid, 
and  E.  M.  Skeats  3 reports  one  water  which  carried  1,360  parts  per 
million,  or  79.08  grains  per  gallon,  of  free  H2S04.  The  deposits  are 
associated  with  limestones,  which  are  sometimes  bituminous,  and  at 
some  points,  as  described  by  Richardson,  gypsum  has  evidently  been 
formed  by  alteration  of  the  carbonate.  At  Cove  Creek,  in  Utah, 
sulphur  occurs  in  great  quantities  as  an  impregnation  in  rhyolitic 
tuff.4  It  is  derived  from  hydrogen  sulphide  of  volcanic  origin,  and 
is  also  accompanied  by  strongly  acid  water.  So  far  as  the  sedi- 
mentary rocks  are  concerned,  the  association  of  limestone,  gypsum, 
sulphur,  and  hydrogen  sulphide  seems  to  be  quite  general,  although 
not  absolutely  invariable.  The  association  of  sulphur  with  petroleum 
or  bituminous  matter  is  also  common. 

CELESTITE. 

Celestite,  the  sulphate  of  strontium,  SrS04,  is  another  mineral  of 
the  sedimentary  rocks,  which  also  occurs  in  Sicily  with  the  gypsum 
and  sulphur.  It  is  one  of  the  most  characteristic  minerals  of  the 
Sicilian  deposits.  In  Monroe  County,  Michigan,  according  to 
E.  H.  Kraus  and  W.  F.  Hunt,5 6  the  celestite  is  found  disseminated 
through  dolomite,  and  the  upper  layer  of  the  rock  at  the  point 
especially  studied  contained  over  14  per  cent  of  the  strontium  com- 

1 Other  examples  are  given  by  R.  Brauns,  Chemische  Mineralogie,  p.  366.  L.  Dieulafait  (Compt. 
Rend.,  vol.  97,  1883,  p.  51),  has  suggested  that  polysulphides  of  calcium  and  strontium  may  assist  in  the 
formation  of  sulphur  deposits. 

2 Bull.  Geol.  Inst.  Upsala,  vol.  1,  No.  2,  1893.  A similar  inclusion  was  earlier  described  by  O.  Silvestri, 
Gazz.  chim.  ital.,  vol.  12, 1882,  p.  2. 

3 Bull.  Univ.  Texas  Mineral  Survey  No.  2,  1902.  See  also  G.  B.  Richardson,  idem,  No.  9,  1904,  p.  68. 

The  sulphur  deposits  of  Louisiana  are  described  by  L.  Baldacci,  11  giacimento  solfifero  della  Louisiana, 
Rome,  1906. 

* See  W.  T.  Lee,  Bull.  U.  S.  Geol.  Survey  No.  315,  1907,  p.  485.  For  an  earlier  description,  see  G.  vom 
Rath,  Neues  Jahrb.,  1884,  Band  1,  p.  259. 

6 Am.  Jour.  Sci.,  4th  ser.,  vol.  21, 1906,  p.  237.  See  also  W.  H.  Sherzer,  idem,  3d  ser.,  vol.  50, 1895,  p.  246, 
and  Michigan  Geol.  Survey,  vol.  7,  pt.  1, 1900,  p.  208. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


579 


pound.  Below  this  layer  there  is  a porous  stratum,  with  cavities 
containing  celestite  and  free  sulphur.  The  latter  is  found  in  consid- 
erable quantities,  and  is  evidently  derived  by  reduction  from  the 
sulphate.  Kraus  1 has  also  reported  celestite  as  extensively  dissemi- 
nated through  dolomitic  limestone  near  Syracuse,  New  York.  At 
Put-in  Bay,  Lake  Erie,  the  limestones  contain  disseminated  celestite, 
and  caverns  exist  which  are  lined  with  crystals  of  that  mineral.2 
The  celestite  here  has  evidently  been  leached  out  from  the  surround- 
ing rocks  and  redeposited  in  the  cavities.  Although  strontium  sul- 
phate is  much  less  soluble  than  gypsum,  it  is  more  soluble  than 
calcium  carbonate,  and  therefore  it  may  be  dissolved  away  from  the 
latter.  In  Transylvania,  according  to  A.  Koch,3  celestite  and  barite 
occur  together  in  bituminous  limestone.  H.  Bauerman  and  C.  Le 
Neve  Foster 4 report  celestite  in  a nummulitic  limestone  in  Egypt,  and 
the  crystals  sometimes  inclose  fossil  remains.  It  also  appears  as 
filling  the  interior  of  fossil  shells,  especially  the  chambers  of  nautili. 
At  Condorcet,  in  France,  as  described  by  Lachat,  celestite  is  found 
associated  with  gypsum  in  limestone.5  Examples  of  this  kind  might 
be  multiplied  almost  indefinitely.  Strontium  and  calcium  are  so 
nearly  related  chemically  that  their  common  association  in  rocks  is 
something  to  be  naturally  expected. 

BARITE. 

Barite,  the  barium  sulphate,  BaS04,  is  closely  akin  mineralogically 
to  celestite,  but  is  more  characteristically  found  in  metalliferous  veins 
than  in  bedded  formations.6  Its  occurrence  as  a cement  in  sandstones 
has  already  been  noticed,7  and  it  has  also  been  observed  as  a sintery 
or  even  stalactitic  deposit  from  spring  and  mine  waters.8 

P.  P.  Bedson 9 found  barium  to  be  present  in  notable  amounts  in 
an  English  colliery  water;  and  T.  Richardson 10  has  described  a 
deposit  of  barite  from  a similar  solution.  Like  deposits  from  other 
English  collieries  have  been  reported  by  F.  Clowes,11  who  analyzed 
samples  containing  from  81.37  to  93.35  per  cent  of  BaS04.  The 
pipes  carrying  water  from  the  mines  which  yielded  these  sediments 
were  often  choked  by  them,  the  barium  sulphate  being  rarely  absent 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  18, 1904,  p.  30.  On  celestite  deposits  in  California,  see  W.  C.  Phalen,  Bull. 
U.  S.  Geol.  Survey  No.  540,  1914,  p.  521. 

2 Kraus,  Am.  Jour.  Sci.,  4th  ser.,  vol.  19,  1905,  p.  286. 

3 Min.  pet.  Mitt.,  vol.  9,  1888,  p.  416. 

4 Quart.  Jour.  Geol.  Soc.,  vol.  25, 1869,  p.  40. 

6  Annales  des  mines,  7th  ser.,  vol.  20, 1881,  p.  557. 

6 See  L.  Dieulafait,  Compt.  Rend.,  vol.  97,  1883,  p.  51. 

7 See  ante,  p.  539. 

8 For  the  distribution  of  barium  in  waters,  etc.,  see  R.  Delkeskamp,  Notizbl.  Ver.  Erdkunde,  4th  ser., 
Heft  21, 1900,  pp.  47-83.  On  the  distribution  of  barium  and  strontium  in  sedimentary  rocks,  see  L.  Collot, 
Compt.  Rend.,  vol.  141,  1905,  p.  832. 

9 Jour.  Soc.  Chem.  Ind.,  vol.  6,  1887,  p.  712. 

10  Rept.  Brit.  Assoc.,  1863,  p.  54. 

11  Proc.  Roy.  Soc.,  vol.  46, 1889,  p.  368. 


580 


THE  DATA  OF  GEOCHEMISTRY. 


and  frequently  their  chief  constituent.  At  Doughty  Springs,  in 
Delta  County,  Colorado,  according  to  W.  P.  Headden,1  large  masses 
of  sinter  have  formed,  consisting  at  some  points  of  nearly  pure 
barium  sulphate,  which  at  other  points  is  mixed  with  minor  to  domi- 
nant quantities  of  calcium  carbonate.  Barytic  sinters  are  also  formed 
by  a brine  spring  in  a mine  at  Lautenthal,  in  the  Hartz  Mountains, 
and  these  have  been  carefully  studied  by  G.  Lattermami.2  In  this 
case  they  are  precipitated  by  the  mingling  of  the  sulphate-bearing 
mine  waters  with  the  brine  from  the  spring.  Lattermann’s  analyses 
of  the  two  waters,  as  stated  by  him  in  grams  per  liter,  are  as  follows: 


Analyses  of  spring  and  mine  waters  at  Lautenthal. 


Spring. 

Mine  water. 

BaCl2  

0.318 

SrCl2  

. 899 

CaCl2  

10. 120 

1.  515 

MeCl, 

4.  360 

.023 

NaCl 

68. 168 

4.  533 

KC1 

.458 

MffSCh  

.652 

ZnS04 

.015 

The  barytic  deposits  from  these  waters  contain  strontium,  and 
appear  in  several  forms — as  stalactites,  as  mud,  and  as  incrustations. 
Analyses  of  them  by  Fernandez  and  Bragard  show  the  subjoined 
proportions  of  the  two  principal  ingredients.3 


Barium  and  strontium  sulphates  in  deposits  at  Lautenthal. 


White  stalac- 
tities. 

Brown  stalac- 
tities. 

Mud. 

Crusts. 

BaS04  

84.  81 
12.04 

83. 88 
8.  64 

82.3 

13.4 

92.  44 
4.  32 

SrS04 

Similar  mixtures  of  the  two  sulphates  intermediate  between  barite 
and  celestite  are  well  known  in  crystalline  form,  and  calcium  sulphate 
is  often  present  also.  A remarkable  banded  barite,  from  Pettis 
County,  Missouri,  described  by  C.  Luedeking  and  H.  A.  Wheeler,4 
had  the  following  composition : 

i Proc.  Colorado  Sci.  Soc.,  vol.  8,  1905,  p.  1. 

* Jahrb.  K.  preuss.  geol.  Landesanstalt,  1888,  p.  259.  A similar  deposit  of  barium  and  strontium  sulphates 
from  an  English  mine  water  is  described  by  J.  T.  Dunn,  Chem.  News,  vol.  35,  1877,  p.  140. 

a Complete  analyses  are  given  in  the  original  memoir  by  Lattermann. 

'Am.  Jour.  Sci.,  3d  ser.,  vol.  42, 1891, p.  495.  The  presence  of  ammonium  salts  was  independently  verified 
by  tests  in  the  laboratory  of  the  United  States  Geological  Survey. 


SEDIMENTARY  AND  DETRITAL  ROCKS. 


581 


Analysis  of  barite  from  Pettis  County , Missouri. 


BaS04 87.2 

SrS04 10.9 

CaS04 2 

(NH4)2S04 2 

H20 2.4 


100.9 

The  presence  of  an  ammonium  salt  in  such  a mineral  is  most 
unusual. 

Nearly  or  quite  all  of  the  occurrences  of  barite  indicate  that  it  is  a 
mineral  of  aqueous  origin.  It  may  form  as  a direct  deposit  from 
waters,  or  as  a precipitate  when  different  waters  commingle,  or,  as 
C.  W.  Dickson 1 has  shown,  by  a reaction  between  solutions  of  barium 
bicarbonate  and  gypsum.  Barium  sulphate  is  also  produced,  accord- 
ing to  Dickson,  when  the  bicarbonate  solution  is  brought  into  contact 
with  oxidizing  pyrite;  and  its  presence  in  limestones  is  attributed  to 
a possible  coincidence  of  the  two  reactions.  The  oxidizing  pyrite  is 
first  instrumental  in  transforming  calcium  carbonate  to  sulphate,  and 
the  latter  then  undergoes  double  decomposition  with  the  percolating 
barium  solutions.  The  original  source  of  the  barium  is  in  the  feld- 
spars and  micas  of  the  crystalline  rocks,  from  which  it  is  dissolved  out 
during  the  ordinary  process  of  weathering. 

One  very  different  occurrence  of  barite  remains  to  be  mentioned. 
In  the  Salem  district  of  India  T.  H.  Holland  2 found  a remarkable 
network  of  veins  consisting  of  quartz  and  barite,  with  about  70  per 
cent  of  the  first  mineral  and  30  of  the  second.  These  veins  are 
mostly  in  pyroxenic  gneiss,  and  one  cuts  a dike  of  augite  diorite, 
and  Holland,  for  structural  reasons,  regarded  the  quartz-barite  rock 
as  a segregation  from  the  original  magma.  This  supposition,  how- 
ever, is  chemically  improbable.  In  a molten  state  quartz  (or  free 
silica)  would  react  upon  barium  sulphate,  to  form  a silicate  and  set 
sulphuric  acid  or  sulphur  dioxide  free.  Quartz  and  barite  are  mag- 
matically  incompatible.3 

Various  syntheses  of  crystalline  barite  are  on  record.  One  of  the 
latest  by  Hilda  Gebhart,4  is  worth  noting.  Solid  barium  chloride 
was  covered  by  a layer  of  gelatinous  silica,  over  which  a solution  of 
a sulphate  was  placed,  and  the  apparatus  was  allowed  to  stand  undis- 
turbed for  eight  or  nine  months.  By  slow  diffusion  of  the  sulphate 
through  the  intervening  siliceous  jelly  definite  crystals  of  barite  were 
formed. 


1 School  of  Mines  Quart.,  vol.  23, 1902,  p.  366. 

2 Rec.  Geol.  Survey  India,  vol.  30, 1897,  p.  236. 

a On  the  genesis  of  barite  see  an  important  paper  by  G.  B.  Trener,  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol. 
53,  1908,  p.  387.  This  paper  contains  abundant  literature  references.  On  the  barite  deposits  of  Virginia 
see  T.  L.  Watson,  Bull.  Am.  Inst.  Min.  Eng.,  1907,  p.  953. 

4 Min.  pet.  Mitt.,  vol.  29, 1910,  p.  185. 


582 


THE  DATA  OF  GEOCHEMISTRY. 


FLUORITE. 

Fluorite  or  fluorspar,  calcium  fluoride,  CaF2,  is  also  a common 
mineral  in  dolomites  and  limestones,1  and  it  is  often  associated  with 
galena  and  zinc  blende.  Crystals  of  it  are  found  in  limestone  geodes, 
where  it  has  evidently  been  deposited  from  solution.  In  some  oases 
it  may  have  been  formed  by  fluoride  solutions  percolating  through 
and  replacing  limestone.  Its  commonest  occurrence  is  as  a filling  of 
veins.2 

1 See  ante,  p.  335,  for  an  account  of  fluorite  as  a rock-forming  mineral.  Also  p.  539  for  fluorite  as  a cement 
in  sandstones.  For  an  exhaustive  memoir  on  fluorite  in  sediments  see  K.  Andrde,  Min.  pet.  Mitt.,  vol. 
28, 1909,  p.  585. 

2 For  a description  of  the  great  fluorspar  deposits  in  Kentucky  and  southern  Illinois  see  S.  F.  Emmons, 
Trans.  Am.  Inst.  Min.  Eng.,  vol.  21, 1893,  p.  31;  H.  F.  Bain,  Bull.  U.  S.  Geol.  Survey  No.  255, 1905;  E.  O. 
Ulrich  and  W.  S.  T.  Smith,  Prof.  Paper  U.  S.  Geol.  Survey  No.  36,  1905;  and  F.  J.  Fohs,Econ.  Geology, 
vol.  5, 1910,  p.  377.  On  the  fluorspar  of  Derbyshire  see  W.  M.  Egglestone,  Trans.  Inst.  Min.  Eng.,  vol. 
35,  1908,  p.  236;  and  C.  B.  Wedd  and  G.  C.  Drabble,  idem,  p.  501.  The  latter  paper  contains  a good 
bibliography.  On  the  fluorspar  of  San  Roque,  Cordoba,  Argentina,  see  J.  Valentin,  Zeitschr.  prakt. 
Geologie,  1896,  p.  104. 


CHAPTER  XIV. 

METAMORPHIC  ROCKS. 

METAMORPHIC  PROCESSES. 

In  its  widest  sense  the  adjective  metamorphio  may  be  applied  to 
any  rook  that  has  undergone  any  sort  of  change.  Practically,  how- 
ever, it  is  used  to  describe  a well-defined  class  of  rocks  in  which  the 
transformation  from  an  original  form  has  been  nearly  complete.  A 
slightly  altered  igneous  or  sedimentary  rock  is  not  commonly  called 
metamorphic;  neither  is  a mass  of  decomposition  products  so  desig- 
nated. The  gneisses,  the  schists,  quartzite,  marble,  and  serpentine 
are  the  most  familiar  examples  of  metamorphism,  and  in  each  case 
an  antecedent  rock  has  been  changed  into  a new  rock  by  one  or  sev- 
eral among  many  different  processes.1 

Some  varieties  of  metamorphism  are  entirely  physical  or  structural, 
and  therefore  will  not  be  considered  in  this  memoir.  Metamorphoses 
which  represent  only  a development  of  slaty  or  schistose  structure 
are  of  this  kind.  In  most  oases,  however,  metamorphism  is  accom- 
panied by  chemical  changes,  which  are  indicated  by  the  production 
of  new  minerals,  and  this  sort  of  metamorphism  concerns  us  now. 
It  may  be  regional,  when  large  areas  are  affected,  or  a phenomenon 
limited  to  a contact  between  two  reacting  rocks,  but  these  distinc- 
tions are  of  little  significance  chemically.  The  chemical  phases  of 
the  process  are  all  that  we  need  to  consider  at  present. 

The  reactions  involved  in  metamorphism  are  not  difficult  to  classify. 
The  following  changes  are  probably  the  most  important: 

1.  Molecular  rearrangements,  as  in  the  process  of  uralitization, 
when  a pyroxene  rock  is  changed  into  one  characterized  by  amphibole. 

2.  Metamorphism  by  hydration.  The  conversion  of  a peridotite 
or  pyroxenite  into  serpentine  is  a case  of  this  kind,  although  some- 
thing more  than  simple  hydration  is  involved  in  the  change. 

3.  Metamorphism  by  dehydration.  The  change  of  limonite  to 
hematite  and  of  bauxite  to  emery  are  good  examples.  Alterations 
of  this  class,  however,  are  often  more  profound  than  dehydration 
alone  can  account  for,  especially  when  they  take  place  at  high  tem- 
peratures. Then  the  molecules  of  hydrous  minerals  may  be  broken 

1 On  the  application  of  physicochemical  methods  to  problems  of  metamorphism,  see  J.  Johnston  and 
P.  Niggli,  Jour.  Geology,  vol.  21,  pp.  481,  588,  1913.  The  paper  is  essentially  theoretical,  with  few  references 
to  specifically  geologic  phenomena. 


583 


584 


THE  DATA  OF  GEOCHEMISTRY. 


down,  as  when  serpentine  breaks  up  into  olivine  and  enstatite,  or  talc 
into  a metasilicate  and  quartz. 

4.  Oxidations  and  reductions,  which  affect  chiefly  the  iron  oxides 
of  the  rocks.  Ferrous  compounds  become  ferric,  and  hematite,  on 
the  other  hand,  may  be  reduced  to  magnetite. 

5.  Changes  other  than  hydration,  produced  by  percolating  solu- 
tions. Cementation  is  one  process  of  this  kind,  and  the  change  from 
sandstone  to  quartzite  is  a common  example  of  it.  In  other  processes 
the  solutions  effect  chemical  transformations,  and  develop  new  com- 
pounds. The  dolomitization  of  limestone  is  a case  in  point. 

6.  Metamorphism  by  the  action  of  gases  and  vapors,  the  so-called 
“ mineralizing  agents.”  These  agents  generate  new  minerals  within 
a rock,  and  like  solutions  introduce  new  constituents. 

7.  Metamorphism  by  igneous  intrusions.  This  heading  covers  the 
changes  due  to  the  intrusion  of  molten  matter  into  or  between  rock 
masses,  whereby  a class  of  “contact  minerals”  is  formed. 

Although  this  classification  is  simple,  it  is  only  superficially  so. 
It  is  useful  as  a matter  of  convenience,  but  its  application  to  concrete 
examples  of  metamorphism  is  not  always  easy.  Two  or  more  proc- 
esses may  operate  simultaneously,  or  they  may  shade  into  one  an- 
other, with  all  sorts  of  variations  in  detail  due  to  variations  in  tem- 
perature and  pressure.  All  of  these  considerations  must  be  borne  in 
mind  in  dealing  with  the  actual  phenomena  of  metamorphism.  The 
ideal  simplicity  is  not  often  found. 

In  the  study  of  metamorphic  phenomena  the  conceptions  developed 
by  C.  R.  Van  Hise  1 are  also  helpful.  Van  Hise  divides  the  litho- 
sphere into  two  zones — an  upper  zone  of  katamorphism  and  a lower 
of  anamorphism.  The  zone  of  katamorphism  is  furthermore  sub- 
divided into  two  belts — one  the  belt  of  weathering,  the  other  that  of 
cementation.  These  approximately  concentric  shells  are  character- 
ized by  definite  chemical  differences,  which  may  be  briefly  sum- 
marized as  follows : 

The  uppermost  shell  of  all,  the  belt  of  weathering,  extends  from 
the  surface  of  the  ground  to  the  level  of  the  ground  water,  and  its 
thickness  is  very  variable.  It  is  essentially  the  region  of  rock  decom- 
position, and  its  reactions  are  mainly  those  of  hydration,  oxidation, 
absorption  of  carbonic  acid  with  liberation  of  silica,  and  losses  of 
material  by  leaching.  It  is  also  a region  of  low  pressure,  relatively 
low  temperature,  and  great  porosity.  In  it  the  complex  silicates 
are  broken  down  into  simpler  compounds,  from  which,  within  the 
belt,  they  are  rarely  regenerated. 

The  belt  of  cementation  is  that  which  contains  the  ground  water. 
Its  rocks  are  more  or  less  porous  and  fractured,  its  temperature  is 
still  not  high,  but  the  pressure  is  great  enough  to  play  an  important 


1 A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904. 


METAMORPHIC  ROCKS. 


585 


part  in  the  reconsolidation  of  sedimentary  material.  It  is,  in  short, 
the  birthplace  of  such  rocks  as  shales  and  sandstones.  In  the  belt 
above  it  solution  is  a leading  process,  but  here,  in  the  accumulated 
ground  water,  redeposition  rules.  Hence  its  name,  the  belt  of  cemen- 
tation. 

In  the  zone  of  anamorphism,  which  lies  below  the  region  of  the 
ground  water,  the  rocks  are  no  longer  distinctly  porous.  The  pres- 
sure above  them  tends  to  close  up  all  pores  and  fractures.  The  tem- 
perature is  also  relatively  high — that  is,  below  the  melting  point  of 
the  rocks,  but  possibly  above  the  critical  temperature  of  water. 
Under  these  conditions  the  reactions  of  the  upper  zone  are  reversed. 
Instead  of  hydration,  there  is  dehydration;  reduction  is  more  com- 
mon than  oxidation;  carbonates  are  decomposed  and  silicates  are 
regenerated.  Pneumatolytic  reactions  are  characteristic  of  this 
region,  and  so  too  are  metasomatic  changes.  There  is  also  a tendency 
to  the  development,  under  pressure,  of  the  heavier  and  denser  rock- 
forming minerals,  and  of  the  species  which  contain  constitutional 
water,  fluorine,  or  boric  oxide.  Garnet,  staurolite,  muscovite,  epi- 
dote,  and  tourmaline  are,  for  example,  typical  minerals  of  the  meta- 
morphic  rocks.1 

According  to  C.  R.  Van  Hise,  the  minerals  of  the  upper  zone  are 
those  which  are  formed  with  increase  of  volume  and  evolution  of 
heat.  In  the  lower  zone,  contraction  and  absorption  of  heat  occur. 
These  distinctions,  of  course,  are  general,  not  absolute,  and  should 
only  be  accepted  in  a broad  way.  They  stand  for  prevailing  tend- 
encies, to  which  many  exceptions  are  possible.  Nor  can  the  belts 
and  zones  be  rigorously  delimited,  for  they  shade  into  and  even 
interpenetrate  one  another.  Material  formed  in  the  belt  of  weather- 
ing is  covered  up  by  sediments,  and  presently  finds  itself  within  the 
belt  of  cementation.  Still  later,  covered  more  deeply,  it  may  pass 
into  the  zone  of  anamorphism.  So  also,  by  erosion,  a part  of  the 
anamorphic  zone  may  be  uncovered  and  brought  within  the  realm 
of  weathering.  To  all  of  these  changes  chemical  changes  correspond, 
so  that  the  same  mass  of  material  can  be  metamorphosed,  in  opposite 
directions,  over  and  over  again.  A clay  becomes  a shale;  that  is 
transformed  into  a schist  or  gneiss,  and  that  again  may  pass  back 
into  clay.  The  phenomena  of  decomposition,  of  reconsolidation,  and 
of  recrystallization  form  parts  of  a cycle  of  changes  which  are  recog- 
nized mainly  by  their  interruptions.  The  definite  products  to  which 
we  give  definite  names  represent  temporary  stoppages  or  periods  of 
slow  change  in  the  progress  of  the  cycle. 

1 According  to  G.  Spezia  (Atti  Accad.  sci.  Torino,  vol.  46,  p.  682;  and  Chem.  Abstracts,  vol.  6,  p.  2587, 
1912)  the  views  of  Van  Hise  relative  to  the  influence  of  pressure  are  untenable.  For  instance,  limonite, 
held  for  8 months  under  a pressure  of  8,000  atmospheres  was  not  dehydrated.  Neither,  under  7,000  atmos- 
pheres, was  aragonite  transformed  to  calcite.  For  a general  discussion  of  the  effects  of  pressure  on  the 
physical  and  chemical  relations  of  solids,  see  J.  Johnston  and  L.  H.  Adams,  Am.  Jour.  Sci.,  4th  ser.,  vol. 
35, 1913, p.  205. 


586 


THE  DATA  OF  GEOCHEMISTRY. 


In  both  zones  of  the  lithosphere  water  is  the  chief  agent  of  chem- 
ical metamorphism.  It  is  most  abundant  in  the  zone  of  katamor- 
phism,  where  it  acts  mainly  as  a liquid  and  fills  more  or  less  com- 
pletely the  pore  spaces  of  the  rooks.  In  the  zone  of  anamorphism 
water  is  much  less  abundant  and  operates  in  the  subcapillary  and 
intermolecular  spaces,  where,  because  of  the  higher  temperatures,  it 
is  probably  present,  at  least  for  the  most  part,  as  vapor.  At  a depth 
of  about  10  kilometers  the  critical  temperature  of  water  is  likely  to 
be  reached,  and  its  chemical  activity  should  then  be  very  high.  The 
well-known  corrosive  action  of  superheated  steam  upon  glass  is  an 
illustration  of  this  point.  Even  when  the  water  is  still  liquid,  at 
temperatures  of  over  200°,  it  may  form  a fluid  or  pasty  mass  with 
some  silicates,  as  was  shown  by  C.  Barus  1 in  his  experiments  upon 
aqueo-igneous  fusion. 

In  the  zone  of  katamorphism  the  water  is  moving  freely,  percolat- 
ing from  place  to  place.  In  the  lower  zone  its  mobility  must  be 
much  diminished,  so  that  on  a given  particle  of  rock  it  acts  for  a 
longer  time.  It  may  appear  in  this  zone,  according  to  Van  Hise,  in 
three  ways — as  water  held  by  buried  sedimentaries,  as  water  liberated 
from  hydrous  compounds  by  heat  or  pressure,  and  as  magmatic  water 
contained  in  igneous  intrusions.  But  from  whatever  source  it  may 
be  derived,  its  chemical  functions  are  the  same.  It  acts  as  a solvent 
upon  practically  all  the  rock-forming  minerals;  it  therefore  trans- 
fers matter  slowly  from  point  to  point  and  in  that  way  assists  in 
bringing  about  recrystallization.  In  so  doing  the  water  is  partly 
taken  up  into  the  molecules  of  new  compounds,  such  as  staurolite, 
epidote,  mica,  and  tourmaline,  of  which  it  forms  a constitutional 
part  and  from  which  it  can  only  be  expelled  at  temperatures  ap- 
proaching or  even  exceeding  a red  heat.  Loosely  combined  water 
thus  becomes  firmly  combined  water  and  ceases  for  the  time  being  to 
be  further  active.  A reference  back  to  the  chapter  upon  rock-form- 
ing minerals  will  show  how  many  syntheses  have  depended  upon 
heating  the  constituent  substances  with  water  under  pressure.  The 
minerals  thus  formed  are  characteristic  of  the  zone  of  anamorphism, 
even  though  they  are  not  confined  to  it.2 

The  sediments,  as  a rule,  contain  organic  matter.  When  they 
reach,  by  burial,  the  high  temperatures  of  this  zone,  the  organic 
matter  is  decomposed,  yielding  free  carbon,  carbon  dioxide,  nitrogen, 
and  water.  The  free  carbon  may  appear  in  the  metamorphosed  rocks 
as  amorphous  particles  or  it  may  be  recrystallized  into  graphite;  the 

1 See  ante,  p.  297. 

2 In  addition  to  works  already  cited,  the  following  papers  which  have  appeared  during  recent  years  on 
hydrothermal  syntheses  deserve  notice:  E.  Baur,  Zeitschr.  anorg.  Chemie,  vol.  72,  1911,  p.  119.  W.  T. 
Muller  and  J.  Konigsberger,  Zeitschr.  angew.  Chemie,  vol.  25, 1912,  p.  1273.  P.  Niggli,  Zeitschr.  anorg. 
Chemie,  vol.  84,  1913,  p.  31.  G.  W.  Morey  and  P.  Niggli,  Jour.  Am.  Chem.  Soc.,  vol.  35,  1913,  p.  1086. 
M.  Schlaeppfer  and  P.  Niggli,  Zeitschr.  anorg.  Chemie,  vol.  87, 1914,  p.  52. 


METAMORPHIC  ROCKS. 


587 


carbon  dioxide  may  escape,  working  its  way  slowly  upward,  or  it  may 
be  caught  and  inclosed  within  crystals  of  quartz  or  other  minerals. 
Inclusions  of  this  kind  are  common,  and  so  also  are  inclusions  of 
free  carbon. 

In  this  process  of  decomposition  the  organic  matter  of  the  sedi- 
ments acts  as  a reducing  agent,  transforming  ferric  to  ferrous  com- 
pounds. When  magnetite  is  thus  formed  from  limonite,  the  reduction 
is  partial,  but  when  the  iron  compounds  of  a clay  are  metamorphosed 
into  staurolite  or  tourmaline,  the  change  from  ferric  to  ferrous  is 
nearly  or  quite  complete.  It  must  not  be  assumed,  however,  that 
organic  matter  is  the  only  reducing  agent  during  metamorphism. 
We  have  seen  in  a previous  chapter  that  hydrogen  may  be  either 
occluded  in  or  generated  from  heated  rocks,1  and  its  activity  as  a 
reducer  may  be  very  great.  But  on  this  point,  geologically  speaking, 
there  is  little  positive  knowledge.  We  are  compelled  to  deal,  more 
or  less,  with  reasonable  inferences. 

By  the  action  of  the  heated  waters  much  silica  is  liberated,  which 
recrystallizes  in  part  as  quartz.  Some  of  it,  however,  attacks  the 
limestones  of  the  buried  sedimentaries,  liberating  carbon  dioxide  and 
forming  silicates,  such  as  wollastonite.  When,  however,  a large  mass 
of  fairly  pure  limestone  or  dolomite  reaches  the  anamorphic  zone,  it 
is  recrystallized  into  marble.  This  change,  and  also  the  formation 
of  dolomite,  was  considered  in  detail  in  the  preceding  chapter,  where 
the  subject  was  perhaps  out  of  place.  Some  of  the  concomitant 
changes  will  be  discussed  later. 

One  great  distinction  between  the  tw’o  zones  remains  to  be  noted. 
In  the  belt  of  weathering  the  transfer  of  material  from  point  to  point, 
both  by  mechanical  and  by  chemical  means,  is  a conspicuous  feature. 
In  the  belt  of  cementation  the  mechanical  transfers  become  less  prom- 
inent, but  the  moving  waters  carry  much  matter  long  distances  in 
solution.  In  the  zone  of  anamorphism  the  mechanical  movements 
become  relatively  insignificant  and  the  chemical  changes  are  prac- 
tically effected  in  place — that  is,  the  chemical  movements  of  matter 
within  the  lower  zone  are  only  through  trifling  distances,  and  the 
transformations  are  effected  with  material  close  at  hand.  The  upper 
zone  is,  then,  emphatically  a zone  of  mobility;  while  the  material  of 
the  lower  zone,  being  under  great  pressure,  is  comparatively  immov- 
able. I speak  now,  of  course,  of  certain  kinds  of  movement;  the 
motions  of  the  earth’s  crust,  its  upheavals  and  depressions,  the  dis- 
placing influence  of  igneous  intrusions,  etc.,  are  phenomena  of  a dif- 
ferent order.  Neither  do  I use  the  terms  movable  and  immovable 
in  any  absolute  sense,  for  they  have  only  a relative  meaning.  The 
freedom  of  motion  in  the  upper  zone  is  vastly  greater  than  in  the 


See  ante,  p.  275  et  seq.,  for  the  experiments  of  Tilden,  Travers,  Gautier,  etc. 


588 


THE  DATA  OF  GEOCHEMISTRY. 


lower;  and  because  of  that  fact  the  phenomena  of  the  two  zones 
become  strongly  contrasted. 

CLASSIFICATION. 

The  classification  of  the  metamorphic  rocks  is  not  a simple  matter. 
The  criterion  of  structure  is  not  sufficiently  general,  and  that  of 
genesis  is  too  vague.  We  can  not  always  determine  the  genesis  of 
a given  rock,  and  when  we  are  able  to  do  so,  the  result,  for  purposes 
of  classification,  may  be  unsatisfactory.  A gneiss  can  be  derived 
from  an  igneous  rock  or  from  one  of  sedimentary  origin,  the  product 
being  sensibly  the  same  in  both  cases.  It  is  possible,  of  course,  to 
classify  these  rocks  on  the  basis  of  their  composition;  but  here  again 
there  are  difficulties,  even  greater,  perhaps,  than  those  which  becloud 
the  classification  of  purely  igneous  material.1  Quite  dissimilar  rocks 
may  have  very  similar  composition.  In  fact,  no  single  classifica- 
tion covers  all  the  ground;  for  the  phenomena  of  nature  do  not 
arrange  themselves  in  linear  sequence.  They  form  an  irregular  net- 
work of  interlacing  lines,  with  all  manner  of  intersections  and  fre- 
quent disturbances. 

Taking  all  of  the  difficulties  into  account,  I prefer  to  study  the 
metamorphic  rocks,  so  far  as  may  be  practicable,  with  reference  to 
the  chemical  processes  which  have  governed  their  formation.  I have 
already  stated  that  several  processes  may  take  part  in  a single 
metamorphosis;  but  in  many  cases  one  process  predominates.  The 
conspicuous  process,  then,  gives  a basis  for  classifying  our  data 
which  need  not,  however,  exclude  other  arrangements  for  other  pur- 
poses. The  method  supplements,  but  does  not  supplant  its  rivals. 
For  convenience  we  may  also  divide  the  metamorphic  rocks  into  three 
classes,  as  follows:  First,  those  derived  from  igneous  rocks;  second, 
those  of  sedimentary  origin;  third,  rocks  formed  by  contact  reac- 
tions between  the  igneous  and  the  sedimentary. 

The  metamorphism  of  the  igneous  rocks  is  commonly  a deep-seated 
phenomenon;  that  is,  its  conspicuous  examples  are  formed  in  the 
zone  of  anamorphism,  or  under  anamorphic  conditions.  Leaving 
mechanical  or  structural  changes  out  of  consideration,  its  conspicu- 
ous feature  is  of  the  order  of  a molecular  rearrangement;  in  other 
words,  the  older  minerals  are  transformed  into  new  species,  some- 
times by  simple  paramorphism  and  sometimes  with  transfer  of 
material  from  one  molecule  to  another.  In  general,  as  F.  Becke2 
has  shown,  the  rearrangements  are  attended  by  decrease  of  volume, 
the  product  of  the  change  being  denser  than  the  original  material. 

>U.  Grubenmann  (Die  Kristallinen  Schiefer,  Berlin,  vol.  1, 1904;  vol.  2, 1907)  has  attempted  to  form  a 
chemical  classification  of  the  schists,  which  resembles  Osann’s  discussion  of  the  igneous  rocks.  A second 
edition  of  Grubenmann’s  book  in  one  volume  appeared  in  1910.  The  references  in  this  work  are  to  the 
first  edition.  On  metamorphic  rock  series  see  P.  Niggli,  Min.  pet.  Mitt.,  vol.  31, 1912,  p.  477. 
s Neues  Jahrb.,  189G,  Band  2,  p.  182. 


METAMORPHIC  ROCKS. 


589 


For  example,  in  the  special  case  chosen  by  Becke,  the  plagioclase  and 
orthoclase  of  a rock  containing  a little  water  were  transformed  into 
a mixture  of  albite,  zoisite,  muscovite,  and  quartz,  the  volume  reduc- 
tion being  in  the  ratio  of  547.1:462.5,  a loss  of  over  15  per  cent. 
A number  of  similar  condensations  are  cited  by  U.  Grubenmann; 1 
and  although  the  calculations  are  necessarily  crude,  they  are  none 
the  less  conclusive.2  The  fact  that  there  are  exceptions  to  the  rule 
does  not  destroy  its  general  validity. 

From  a mineralogical  point  of  view,  the  more  noteworthy  meta- 
morphoses within  the  igneous  rocks  may  be  classified  under  the 
following  headings : 

1.  Change  of  pyroxene  to  amphibole. 

2.  Change  of  feldspar  to  mica. 

3.  Change  of  feldspar  to  zoisite. 

4.  Change  of  feldspar  to  scapolite. 

5.  Formation  of  epidote. 

6.  Formation  of  garnet. 

7.  Change  of  hornblende  to  chlorite. 

8.  Segregation  of  albite  from  plagioclase. 

9.  Formation  of  serpentine. 

10.  Alteration  of  ilmenite. 

This  schedule  is  by  no  means  exhaustive,  for  many  other  minor 
changes  are  to  be  observed  in  the  metamorphism  of  igneous  rocks. 
Every  primary  mineral  that  they  contain  may  give  rise  to  secondary 
species,  and  these  represent  all  orders  of  transformation  from  the 
slightest  modification  to  the  complete  molecular  breaking  down 
which  is  seen  in  the  processes  of  weathering.  Decompositions,  how- 
ever, are  not  now  under  discussion;  we  are  dealing  with  the  phe- 
nomena of  recrystallization  within  rock  masses,  excepting,  of  course, 
the  case  of  serpentinization,  which  is  a process  of  a different  order. 

URALITIZATION. 

The  alteration  of  pyroxene  rocks  into  hornblende  rocks  is  one  of 
the  best-established  metamorphoses.  The  hornblende  thus  produced, 
when  fibrous,  is  known  as  uralite,  and  the  change  is  called  uralitiza- 
tion.3  It  is  often  accompanied  and  complicated  by  other  changes, 
such  as  the  formation  of  epidote  or  zoisite,  and  it  may  also  be  coinci- 
dent with  the  development  of  a schistose  structure.  Mediosilicic  and 
subsilicic  rocks,  like  gabbro  and  diabase,  are  thus  metamorphosed  into 
amphibolite  or  hornblende  schist.  An  excellent  example  of  this  sort 

1 Die  Kristallinen  Schiefer,  Berlin,  1904,  pp.  34-38.  Grubenmann’s  data  are  taken  from  a paper  by 
F.  Becke,  in  Compt.  rend.  IX  Cong.  gdol.  internat.,  1903,  p.  553.  See  also  F.  Loewinson- Lessing,  Studien 
fiber  die  Eruptivgesteine:  Compt.  rend.  VII  Cong.  g&>l.  internat.,  St.  Petersburg,  1897. 

2 For  a tabulation  of  the  volume  changes  attending  tho  alteration  of  minerals,  see  C.  R.  Van  Ilise,  A 
treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  pp.  397-408. 

3 See  G.  H.  Williams,  Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  p.  52,  for  a full  discussion  of  this  subject, 
accompanied  by  abundant  references  to  literature.  See  also  L.  Duparc  and  T.  Hornung,  Compt.  Rend., 
vol.  139, 1904,  p.  223,  on  a theory  of  uralitization. 


590 


THE  DATA  OE  GEOCHEMISTRY. 


of  change  was  found  by  J.  J.  H.  Teall 1 in  a dike  at  Scourie,  Suther- 
landshire,  Scotland,  where  a dolerite  had  changed,  first  into  a mas- 
sive hornblende-bearing  rock  and  later  into  a schist.  The  following 
analyses  will  serve  to  illustrate  the  character  of  the  changes  thus 
produced : 


Analyses  of  'pyroxene  rocks  before  and  after  alteration. 

Aa.  The  plagioclase-pyroxene  rock  of  the  Scourie  dike. 

Ab.  The  derived  hornblende  schist.  Analyses  A by  Teall,  loc.  cit. 

Ba.  Pyroxene  from  the  center  of  a crystal,  Templeton,  Canada. 

Bb.  Intermediate  portion  of  the  same  crystal. 

Be.  Hornblende  forming  the  rim  of  the  crystal.  Analyses  B by  B.  7.  Harrington,  Geol.  Survey  Canada, 
Rec.  of  Progress,  1877-78,  p.  21  G. 

Ca.  Diallage  from  a gabbro,  Transvaal,  South  Africa. 

Cb.  Uralite  from  alteration  of  the  diallage.  Analyses  C by  P.  Dahms,  Neues  Jahrb.,  Beil.  Band  7, 1891, 
p.  99. 


Aa. 

Ab. 

Ba. 

Bb. 

Be. 

Ca. 

Cb. 

Si02 

47.45 

49.78 

50. 87 

50. 90 

52. 82 

53.53 

52.73 

ALOo 

14.83 

13.13 

4.57 

4.82 

3.22 

3.12 

4.70 

Fe203 

2.47 

4.35 

.97 

1.74 

2.07 

5.09 

5.26 

FeO 

14.71 

11.71 

1.96 

1.36 

2.71 

13.54 

10.21 

MnO 

.15 

.15 

.28 

MgO 

5.00 

5.40 

15.37 

15.27 

19.04 

18.77 

12.59 

CaO 

8.87 

8.92 

24.44 

24. 39 

15. 39 

6.19 

12.58 

Na20 

2.97 

2.39 

.22 

.08 

.90 

.50 

.23 

K20 

.99 

1.05 

.50 

.15 

.69 

.20 

.06 

H20 

1.00 

1. 14 

« 1.44 

a 1.20 

a 2. 40 

1.54 

Ti02 

1.47 

2.22 

CO, 

.36 

.10 

Specific  gravity 

100. 12 
3.10 

100. 19 
3.10 

100. 49 
3.181 

100.  06 
3.205 

99.52 

3.003 

101. 01 

99.90 

a Loss  on  ignition. 


That  the  change  from  pyroxene  to  uralite  or  amphibole  is  something 
more  than  a paramorphism  these  few  analyses  clearly  show.  In  A 
there  has  been  oxidation  of  ferrous  to  ferric  iron,  in  B a loss  of  lime, 
and  in  C a loss  of  magnesia.  In  many  cases  uralitization  is  accom- 
panied by  a separation  of  magnetite,2  and  the  lime  removed  reappears 
as  calcite.  Epidote  is  also  a common  product  during  the  process, 
which  must  vary  with  variations  in  the  composition  of  the  altering 
rock  and  of  the  individual  pyroxene.  Augite  thus  yields  hornblende 
or  actinolite;  diopside  may  change  into  tremolite,  and  from  the  soda 
pyroxenes  the  aluminous  glaucophane  may  be  derived.  The  com- 
position of  the  pyroxene  is  reflected  in  that  of  its  derivative,  but 
the  augite-hornblende  change  is  the  most  common.3  Between  the 


1 British  petrography,  1888,  p.  198;  also  in  Quart.  Jour.  Geol.  Soc.,  vol.  41,  1885,  p.  137. 

2 See  G.  Rose,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  16,  1864,  p.  6;  E.  Svedmark,  Neues  Jahrb.,  1877,  p.  99. 

3 See  discussion  of  the  change  by  C.  H.  Gordon,  Am.  Geologist,  vol.  34,  1904,  p.  40. 


METAMORPHIC  ROCKS. 


591 


original  igneous  rock  and  the  secondary  amphibolites  there  are  all 
possible  intermediate  gradations,  from  incipient  change  to  complete 
transformation.1 

GLAUCOPHANE  SCHISTS. 

The  glaucophane  schists  differ  from  the  amphibolites  in  that  they 
contain  the  soda  amphibole  instead  of  hornblende.  H.  S.  Wash- 
ington 2 divides  these  rocks  into  three  classes,  namely,  epidote-glau- 
cophane  schist,  mica-glaucophane  schist,  and  quartz-glaucophane 
schist;  but  he  also  recognizes  the  fact  that  there  are  many  transitional 
varieties.  W.  H.  Melville,3  for  example,  has  described  a garnet- 
glaucophane  schist  from  Mount  Diablo,  California;  and  A.  Wich- 
mann 4 an  epidote-mica-glaucophane  schist  from  Celebes.  A zoisite- 
glaucophane  schist  from  Sulphur  Bank,  California,  is  also  mentioned 
by  G.  F.  Becker.5  It  consists  chiefly  of  glaucophane  and  zoisite,  but 
quartz,  albite,  sphene,  and  muscovite  are  also  present.  Another  rock 
from  Piedmont,  containing  glaucophane,  garnet,  hornblende,  epidote, 
mica,  and  sphene,  described  by  T.  G.  Bonney,6  is  called  a glaucophane 
eclogite. 

Genetically,  the  glaucophane  rooks  differ  widely.  Some  of  them 
are  undoubtedly  derived  from  mediosilicic  or  subsilicic  igneous  rocks; 
others  from  sedimentaries.  In  Greece,  for  example,  according  to  R. 
Lepsius,7  some  glaucophane  schists  represent  gahbro,  and  others  are 
metamorphosed  Cretaceous  shales.  The  epidote-glaucophane  schist 
of  Anglesey,  Wales,  described  by  J.  F.  Blake,8  was  originally  a dio- 
rite,  and  in  this  rock  alterations  of  glaucophane  to  chlorite  occur.  In 
Piedmont,  as  described  by  S.  Franchi,9  there  are  glaucophane  rocks 
associated  with  amphibolite,  both  having  been  derived  from  diabase. 
In  Japan,  according  to  B.  Koto,10  the  metamorphosed  material  was 
formerly  a diabase  tuff,  and  the  glaucophane  was  derived  from  dial- 
lage. By  further  alteration  the  glaucophane  sometimes  passes  into 
crocidolite.  And  on  Angel  Island,  in  San  Francisco  Bay,  California, 
a glaucophane  schist  studied  by  F.  L.  Ransome  11  has  been  developed 


1 On  amphibolite  produced  by  the  intrusion  of  granite  into  limestone,  in  the  Laurentian  rocks  of  Canada, 
see  F.  D.  Adams,  Jour.  Geology,  vol.  17,  1909,  p.  1. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  11, 1901,  p.  35.  This  memoir  is  a very  complete  summary  of  our  knowledge 
of  these  rocks.  It  contains  many  analyses  and  abundant  references  to  literature.  See  also  K.  Oebbeke, 
Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  38,  1886,  p.  634;  U.  Grubenmann,  Rosenbusch  “ Festschrift,  ” 1906; 
E.  H.  Nutter  and  W.  B.  Barber,  Jour.  Geology,  vol.  10,  1902,  p.  738;  and  J.  P.  Smith,  Proc.  Am.  Philos. 
Soc.,  vol.  45,  1906,  p.  183.  The  last  two  papers  relate  to  the  glaucophane  rocks  of  California.  Other  note- 
worthy papers  are  by  E.  Murgoci,  Bull.  Dept.  Geology  Univ.  California,  vol.  4,  1906,  p.  359;  L.  Milch, 
Neues  Jahrb.,  Festband,  1907,  p.  348;  and  T.  J.  Woyno,  Neues  Jahrb.,  Beil  Band  33, 1911,  p.  136. 

3 Bull.  Geol.  Soc.  America,  vol.  2, 1890,  p.  413. 

4 Neues  Jahrb.,  1893,  Band  2,  p.  176. 

5 Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  p.  104. 

6 Mineralog.  Mag.,  vol.  7, 1887,  p.  1. 

7 Geologic  von  Attika,  Berlin,  1893,  pp.  102, 133. 

s Geol.  Mag.,  1888,  p.  125. 

9 Bol.  Com.  geol.  ital . , vol.  26, 1895,  p.  192. 

10  Jour.  Coll.  Sci.  Japan,  vol.  1, 1886,  p.  85. 

u Bull.  Dept.  Geology  Univ.  California,  vol.  1,  p.  211. 


592 


THE  DATA  OF  GEOCHEMISTRY. 


from  a radiolarian  chert,  probably  by  contact  metamorphism.  In 
many  cases  the  genesis  of  these  rocks  is  obscure;  but  Washington  sug- 
gests that  the  epidote-glaucophane  schists  represent  originally  gab- 
broid  magmas,  while  the  quartz-glaucophane  schists  are  metamor- 
phosed quartzites  or  quartzose  shales.  For  convenience,  differences 
of  origin  will  be  disregarded  here  and  the  analyses  of  this  group  of 
rocks  are  tabulated  together,  as  follows: 

Analyses  of  amphibolites  and  glaucophane  schists. a 

A.  Amphibolite  dike,  Palmer  Center,  Massachusetts. 

B.  Amphibolite  bed,  Palmer  Center.  Analyses  A and  B by  W.  F.  Hillebrand,  Bull.  U.  S.  Geol.  Survey 
No.  228,  1904,  p.  36. 

C.  Amphibolite,  Crystal  Falls  district,  Michigan.  Described  by  H.  L.  Smyth,  Mon.  U.  S.  Geol.  Survey, 
vol.  36,  1899,  p.  397.  Analysis  by  H.  N.  Stokes.  Probably  derived  from  a diabase  or  basalt.  Contains 
hornblende,  plagioclase,  biotite,  and  quartz,  with  a little  rutile  and  magnetite. 

D.  Epidote-glaucophane  schist,  Mount  Diablo,  California.  Analysis  by  W.  H.  Melville,  Bull.  Geol.  Soc. 
America,  vol.  2,  1890,  p.  413.  Contains  garnets.  Possibly  derived  from  shale. 

E.  Garnet-glaucophane  schist,  Bandon,  Oregon.  Analyzed  and  described  by  H.  S.  Washington,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  11, 1901,  p.  35.  Contains  glaucophane,  epidote  or  zoisite,  garnet,  and  white  mica. 

F.  Zoisite-glaucophane  schist,  Sulphur  Bank,  California.  Analysis  by  Melville.  Described  by  G.  F. 
Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  104. 

G.  Mica-glaucophane  schist,  Island  of  Syra,  Greece.  Analyzed  and  described  by  Washington,  loc.  cit* 

H.  Quartz-glaucophane  schist,  Fourmile  Creek,  Coos  County,  Oregon.  Analyzed  and  described  by 
Washington.  Contains  quartz,  glaucophane,  chlorite,  muscovite,  and  garnet. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

49.  57 

51.  25 

50.  36 

47.  84 

49. 15 

49.  68 

58.  26 

82.  53 

ai203 

14.  23 

16.  53 

13.  26 

16.  88 

15.  87 

13.  60 

16.  21 

6.  88 

Fe203 

3.  95 

1.  81 

6.  30 

4.  99 

4. 10 

1.  86 

3.  44 

.59 

FeO 

8.  01 

7.  67 

9.  34 

5.56 

7.  58 

8.  61 

4.  63 

4. 11 

MgO 

6. 14 

5.  87 

5.  55 

7.  89 

7.  53 

6.  26 

4.  99 

1.  86 

CaO 

10. 19 

9.  32 

7.  85 

11. 15 

9.  06 

10.  97 

3.  82 

.68 

N^O 

3.  06 

3.  35 

2. 11 

3.  20 

3.  59 

3.  09 

5.  36 

1.  21 

k20 

.95 

.78 

1. 14 

.46 

.54 

.12 

.39 

1.24 

h2o- 

. 14 

. 19 

1.  55 

.17 

.16 

l Q QA 

.22 

.07 

h20+ 

1.  33 

1.  26 

1.  55 

1.  81 

1.  07 

> O.  cv± 

.98 

1.  35 

Ti02 

2.  03 

1.  84 

1.  77 

1. 19 

J 1.31 

1.  37 

co2... 

Trace. 

None. 

PoO,... 

. 21 

. 31 

. 20 

. 14 

.21 

s.  . . 

. 02 

(?) 

VoO,.. . 

. 04 

Undet. 

Cr203 

Trace. 

Trace. 

NiO 

Trace. 

Trace. 

MnO 

.27 

.28 

Trace. 

.56 

Trace. 

.04 

Trace. 

Trace. 

SrO.. 

Trace? 

(?) 

BaO.  

Trace. 

(?) 

LioO 

Trace. 

Trace? 

. 

100. 14 

100.  46 

99.  59 

100.  65 

99.  84 

99.  59 

99.  67 

100.  52 

a A number  of  amphibolites  from  Massachusetts  are  described  by  B.  K.  Emerson  in  Mon.  U.  S.  Geol.  Sur- 
vey, vol.  29,  1898.  For  analyses  see  also  Bull.  419,  1910,  pp.  19-21.  These  amphibolites  are  regarded  as 
derived  from  argillaceous  limestones.  L.  Hezner  (Min.  pet.  Mitt., vol.  22, 1903,  p.  505)  gives  several  analyses 
of  amphibolites  from  the  Tyrol.  See  also  a table  of  analyses  in  Rosenbusch,  Elemente  der  Gesteinslehre, 
p.  532.  See  also,  on  amphibolite,  F.  Becke,  Min.  pet.  Mitt.,  vol.  4,  1882,  p.  285;  and  J.  A.  Ippen,  Mitth. 
Naturwiss.  Ver.  Steiermark,  1892,  p.  328.  Ippen  describes  “normal  amphibolite,”  and  also  zoisite,  pyrox- 
ene, feldspar,  and  garnet  amphibolite. 


METAMORPHIC  ROCKS. 


593 


SERICITIZATION. 

The  conversion  of  feldspar  into  muscovite  is  one  of  the  common- 
est processes  of  metamorphism,  whether  of  igneous  or  of  sedimentary 
rocks.  In  many  instances  the  mica  produced  is  the  compact  or  fibrous 
variety  known  as  sericite,  which,  in  former  times,  was  generally  mis- 
taken for  talc.  The  so-called  talcose  schists  of  the  earlier  geologists 
have  proved  in  most  cases  to  be  not  talcose,,  but  sericitic.1  The  iden- 
tity of  sericite  with  muscovite  was  finally  established  by  H.  Las- 
peyres  2 in  1880,  and  since  then  its  occurrence  has  been  repeatedly 
investigated.  The  alteration  is  most  conspicuous  in  regions  where 
the  dynamic  metamorphism  has  been  most  intense — high  tempera- 
ture, the  chemical  activity  of  water,  and  mechanical  stress  all  work- 
ing together  to  bring  it  about.  Any  feldspathlc  rock  may  undergo 
sericitization,  but  orthoclase  rocks  furnish  the  most  typical  exam- 
ples. The  derivation  of  sericitic  schists  and  gneisses  from  granite, 
quartz  porphyry,  and  diabase,  and  also  from  arkose  and  clay  slate, 
has  been  repeatedly  observed.3 

Sericite  is  commonly  derived  from  orthoclase  or  microcline,  as 
suggested  above,  but  may  be  generated  from  plagioclase  feldspars 
also,  the  reactions  in  the  two  cases  being  different.  In  the  forma- 
tion of  muscovite  from  orthoclase  the  necessary  potassium  is  already 
present ; but  in  order  to  produce  muscovite  from  plagioclase  a replace- 
ment of  sodium  by  extraneous  potassium  is  required.  In  either  case 
the  reaction  which  takes  place  may  be  represented  by  more  than  one 
equation,  although  it  must  be  admitted  that  the  formulation  is  purely 
hypothetical.  Until  the  processes  shall  have  been  experimentally 
reproduced  the  equations  will  remain  doubtful. 

First,  orthoclase  may  be  transformed  to  muscovite  by  the  addition 
of  colloidal  alumina  equivalent  in  composition  to  dia spore,  thus: 

KAlSi308  + 2A10.0H  = KH2Al3Si3012. 

This  reaction  is  very  simple  chemically,  but  geologically  improbable. 
It  requires  the  presence  of  solutions  containing  much  alumina,  and  it 
is  not  easy  to  see  whence  they  could  be  derived.  It  suggests,  how- 
ever, a possible  relation  between  the  formation  of  sericite  and  the 
alteration  to  bauxite,  a possibility  which  deserves  further  investi- 
gation. 

1 See  G.  H.  Williams,  Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  pp.  60-62,  for  historical  details. 

2 Zeitschr.  Kryst.  Min.,  vol.  4,  1879,  p.  245. 

3 See  J.  G.  Lehmann,  Untersuchungen  iiber  die  Entstehung  der  altkrystallinischen  Schiefergesteine, 
Bonn,  1884;  A.Wichmann,Verhandl.Naturhist.Ver.preuss.Itheinlandeu.  Westfalens,  vol. 34, 1877, p.  1;  A. 
von  Groddeck,  Neues  Jahrb.,  Beil.  Band  2, 1883,  p.  72;  C.  Schmidt,  idem,  Beil.  Band  4, 1886,  p.  428,  and 
C.  Benedicks,  Bull.  Geol.  Inst.  Upsala,  vol.  7, 1904-5,  p.  278.  In  Jahrb.  K.  preuss.  geol.  Landesanstalt, 
1885,  pt.  1,  Von  Groddeck  describes  the  derivation  of  sericite  schists  from  clay  slates. 

97270°— Bull.  616—16 38 


594 


THE  DATA  OF  GEOCHEMISTRY. 


A second,  more  probable,  and  even  simpler  reaction  is  the  following : 

3KAlSi308  + H20  = KH2Al3Si3012  + K2Si03  + 5Si02. 

In  this  case  water  alone,  acting  on  orthoclase  at  a high  temperature 
and  under  pressure,  forms  muscovite,  free  silica,  and  potassium  sili- 
cate, the  last  compound  being  leached  away.  The  liberated  silica 
may  be  partly  removed  in  solution,  or  it  can  recrystallize  as  quartz, 
a mineral  which  almost  invariably  accompanies  sericite  in  meta- 
morphic  rocks.  Furthermore,  the  analyses  of  sericite  usually  show  a 
small  excess  of  silica  over  that  contained  in  normal  muscovite.  A 
similar  reaction  with  albite  should  yield  the  soda  mica  paragonite. 

A modified  form  of  the  last  reaction  is  in  common  use,  which  in- 
volves the  introduction  into  the  equation  of  carbonated  water,  as 
follows: 

3KAlSi308  + H20  + C02  = KH2Al3Si3012  + K2C03  + 6Si02. 

In  this  case,  however,  the  potassium  carbonate  would  dissolve  one 
molecule  of  the  liberated  silica,  forming  potassium  silicate  as  before. 
The  C03  would  thus  be  set  free  again,  ready  to  assist  in  further  alter- 
ations of  feldspar.  Since  carbonated  waters,  both  of  meteoric  and 
of  deep-seated  origin,  are  very  abundant,  it  is  quite  possible  that 
this  regenerative  process  is  really  in  operation.  If  so,  the  reaction 
should  be  more  vigorous  than  when  water  acts  alone.  The  frequent 
association  of  calcite  with  sericite  is  an  indication  that  carbonated 
solutions  have  helped  to  produce  the  change.1  If  the  alteration  took 
place  in  presence  of  both  albite  and  orthoclase,  the  potassium  silicate 
would  probably  react  upon  the  former  mineral  or  upon  its  incipient 
decomposition  products,  so  that  muscovite  only,  without  paragonite, 
would  be  formed.  In  the  development  of  muscovite  from  plagio- 
clase  the  presence  of  potassium-bearing  solutions,  which  exchange 
alkalies  with  the  sodium  compounds,  must  be  assumed. 

OTHER  ALTERATIONS  OF  FELDSPAR. 

Apart  from  the  phenomenon  of  sericitization,  the  plagioclase  feld- 
spars undergo  a number  of  other  metasomatic  changes,  whose  records 
are  preserved  in  the  metamorphic  rocks.  Under  the  influence  of 
carbonated  waters  the  anorthite  molecule  may  be  decomposed,  with 
the  formation  of  calcite  and  the  separation  of  silica.  In  this  case  the 
albite  remains  as  a finely  granular  aggregate,  the  so-called  11  albite 
mosaic,”  which  outwardly  resembles  quartz  and  with  which  quartz 
is  commonly  associated.2  When  the  lime  of  the  anorthite  is  not  com- 

1 Compare  W.  Lindgren,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  30, 1900,  p.  608,  in  reference  to  the  association 
with  calcite. 

2 See  K.  A.  Lossen,  Jahrb.  K.  preuss.  geol.  Landesanstalt,  1884,  pp.  525-530.  See  also  G.H.  Williams, 
Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  p.  60. 


METAMORPHIC  ROCKS. 


595 


pletely  removed,  it  goes  to  form  other  silicates,  such  as  epidote,  zois- 
ite,  or  actinolite.  The  latter  reactions  are  by  far  the  most  frequent. 

The  alteration  of  plagioclase  to  zoisite  is  exceedingly  common,  but 
it  is  rarely  complete.  As  a rule  mixtures  of  zoisite  and  feldspar 
remain,  which  were  once  thought  to  represent  a distinct  mineral  spe- 
cies and  to  which  the  name  saussurite  was  given.  The  mechanism  of 
the  change  is  obscure,  but  it  is  probably  a double  decomposition 
between  the  albite  and  anorthite  molecules,  brought  about  by  the 
intervention  of  water.  The  feldspars,  however,  vary  in  composition; 
the  water  may  contain  other  reacting  substances  in  solution,  and  so 
the  reactions  are  complicated  in  many  ways.  The  following  equa- 
tion, which  is  plausible  but  not  proved,  represents  the  transforma- 
tion of  plagioclase  into  a mixture  of  zoisite,  paragonite,  and  quartz, 
a mixture  that  sometimes  occurs : 

NaAlSi308  + 4CaAl2Si208  + 2H20  = 

Albite.  Anorthite.  Water. 

2Ca2HAl3Si3013  + H2NaAl3Si3012  + 2Si02. 

Zoisite.  Paragonite.  Quartz. 

When  orthoclase  molecules  are  present,  muscovite  will  be  formed; 
that  is,  sericitization  and  saussuritization  may  go  on  together.  With 
albite  in  excess,  the  saussurite  mixture  appears,  but  that  again  is 
variable.  It  may  contain  epidote,  scapolite,  or  garnet;  according 
to  A.  Cathrein,1  saussurite  is  sometimes  derived  from  garnet;  and  all 
of  these  minerals  may  undergo  complete  or  partial  alterations  into 
other  compounds. 

Saussuritic  rocks  have  been  described  by  many  petrographers, 
and  there  is  abundant  literature  covering  them.  F.  Becke  2 reports 
a saussurite  gabbro  from  Greece,  consisting  of  saussurite  and  dial- 
lage, the  latter  partly  altered  to  hornblende.  P.  Michael 3 describes 
another  saussurite  gabbro  from  Germany,  in  which  garnet  is  also 
present,  derived  from  diallage  and  partly  altered  to  serpentine. 
Another  saussurite  gabbro  from  Sturgeon  Falls,  Michigan,  was  care- 
fully studied  by  G.  H.  Williams.4  It  contained  saussurite  derived 
from  the  complete  alteration  of  plagioclase,  diallage,  hornblende 
partly  secondary,  and  a little  ilmenite,  with  some  calcite,  quartz, 
and  a colorless  chlorite.  By  further  alteration  this  rock  passes  into 
a silvery  schist,  consisting  mainly  of  chlorite,  calcite,  and  secondary 
quartz,  but  with  some  feldspars  remaining,  partly  sericitized.  A 
rock  designated  as  a zoisite-hornblende  diorite,  from  the  Bradshaw 
Mountains,  Arizona,  described  by  T.  A.  Jaggar  and  C.  Palache,5 6 

1 Zeitschr.  Kryst.  Min.,  vol.  10,  1885,  p.  444. 

2 Min.  pet.  Mitt.,  vol.  1,  1878,  p.  247. 

3 Neues  Jahrb.,  1881,  Band  1,  p.  32. 

4 Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  pp.  67-76.  Another  saussuritized  gabbro  from  the  Upper 

Quinnesec  Falls  is  described  on  pp.  102-104.  On  pp.  58-60  Williams  gives  a general  discussion  of  this 
form  of  alteration,  with  historical  details.  See  also  A.  Cathrein,  Zeitschr.  Kryst.  Min.,  vol.  7,  1883,  p.  234. 

6 Bradshaw  Mountains  folio  (No.  126),  Geol.  Atlas  U.  S.,  U.  S.  Geol.  Survey,  1905,  pp.  4-5. 


596 


THE  DATA  OF  GEOCHEMISTRY. 


contained  47  per  cent  of  zoisite,  derived  from  plagioclase,  17  per 
cent  of  actinolite,  and  smaller  amounts  of  quartz,  orthoclase,  albite, 
chlorite,  kaolin,  and  magnetite.  The  following  analyses  of  zoisite 
rocks  were  made  in  the  laboratory  of  the  United  States  Geological 
Survey : 

Analyses  of  zoisite  rochs. 


A.  Sturgeon  Falls  gabbro,  freshest  form. 

B.  The  same,  altered  form. 

C.  Silvery  schist  derived  from  Sturgeon  Falls  gabbro.  Analyses  A,  B,  and  C by  B.  B.  Riggs. 

D.  Zoisite-hornblende  diorite,  Bradshaw  Mountains.  Analysis  by  George  Steiger. 


A 

B 

C 

D 

Si02 

51. 46 

38.  05 

45.  70 

45.  73 

ALOo  

14.  35 

24.  73 

16.53 

19. 45 

Fe,0,  

3.  90 

5.  65 

4.  63 

5.  28 

FeO  

5.  28 

6.  08 

3.89 

3. 18 

9.  54 

11.  58 

9.  57 

6.  24 

CaO  

9.  08 

1.  25 

4.  28 

13.  86 

Na20 

2.  92 

2.  54 

.55 

.64 

K20  

.24 

1.  94 
} 7.53 

3.82 

.32 

H20- 

1.  57 

h2o+ 

} 3.30 

j 4. 70 

3.  56 

Ti02 

) 

J 

J 

.23 

co2 

.20 

.93 

5. 95 

.28 

p9o, 

Trace. 

A 2W5 

100.  27 

100.  28 

99.  62 

100. 34 

The  sericitization  of  C is  shown  by  the  loss  of  sodium  and  great 
increase  of  potassium.  The  Sturgeon  Falls  series  is  especially  in- 
structive as  illustrating  the  occurrence  of  several  alterations,  partly 
simultaneous  and  partly  successive,  in  the  same  rock  formation. 
Saussurite,  sericite,  and  uralite  are  all  represented. 

The  transformation  of  plagioclase  into  scapolite  is  by  no  means 
rare,  but  the  nature  of  the  process  is  not  always  easy  to  trace.  Scap- 
olite is  often  formed  by  contact  reactions  between  igneous  rocks  and 
limestones,  as,  well  as  by  processes  resembling  that  of  saussuritiza- 
tion.  For  the  latter  change,  which  is  the  one  to  be  properly  con- 
sidered now,  the  classical  example  is  furnished  by  the  spotted  gabbro 
of  Oedegaarden.  In  this  case  a plagioclase-pyroxene  rock  has  been 
altered  into  a scapolite-hornblende  mixture,  a rock  which,  according 
to  Fouque  and  Levy,1  is  retransformed  on  fusion  into  pyroxene  and 
labradorite.  The  alteration,  then,  is  reversible  and  one  which  ought 
to  be  studied  quantitatively.  The  change  from  plagioclase  to  scapo- 
lite, as  investigated  by  J.  W.  Judd,2  is  probably  due  to  the  action  of 


1 Bull.  Soc.  min. , vol.  2,  1879,  p.  113. 

2 Mineralog.  Mag.,  vol.  8, 1889,  p.  186.  See  also  A.  Michel-Lgvy,  Bull.  Soc.  min.,  vol.  1, 1878,  pp.  43, 78.  A 
similar  rock  from  Bamle,  Norway,  containing  sphene,  amphibole,  and  wernerite,  is  also  described.  Other 
noteworthy  memoirs  on  the  Scandinavian  rocks  of  this  class  are  by  A.  E.  Tomebohm  and  E.  Svedmark, 
Geol.  Foren.  Forhandl.,  vol.  6, 1882,  p.  192;  vol.  7,  1884,  p.  293. 


METAMORPHIC  ROCKS. 


597 


sodium  chloride,  which  exists  in  solution  in  minute  inclusions  within 
the  original  rock.  It  must  be  noted,  however,  that  the  Oedegaarden 
gabbro  is  in  contact  with  veins  of  chlorapatite,  from  which  some  of 
the  chlorine  essential  to  the  formation  of  scapolite  may  have  been 
derived. 

In  any  case,  the  conversion  of  plagioclase  to  scapolite  requires  the 
addition  of  new  material.  The  scapolites,  as  shown  by  G.  Tscher- 
mak,1  are  mixtures  of  two  end  species — meionite,  Ca4Al6Si6025,  and 
marialite,  Na4Al3Si9024Cl.  These  may  be  derived  from  anorthite  and 
albite  in  accordance  with  the  following  empirical  equations : 

3CaAl2Si208  + CaO  = Ca4Al6Si6025. 

3NaAlSi308  + NaCl  = Na4Al3Si9024Cl. 

In  order  to  change  an  ordinary  plagioclase  into  an  ordinary  scapo- 
lite, then,  lime  and  sodium  chloride  must  be  taken  up,  and  it  is  clear 
that  these  reagents  may  come  from  quite  dissimilar  sources.  The 
change  of  pyroxene  to  amphibole  may  furnish  the  lime  in  some  cases; 
apatite  may  yield  it,  with  chlorine,  in  others;  but  no  general  rule,  no 
exclusive  group  of  reactions,  can  be  postulated.  The  widely  different 
conditions  under  which  scapolitization  may  take  place  have  been 
well  summarized  by  A.  Lacroix,2  whose  two  memoirs  upon  the  subject 
are  most  exhaustive. 

On  the  epidotization  of  plagioclase  feldspar  there  is  an  abundant 
literature.3  Since  epidote  and  zoisite  are  closely  analogous  in  chem- 
ical structure,  the  process  of  alteration  must  resemble  that  of  saus- 
suritization,  from  which  it  differs  in  detail.  Epidote  contains  iron, 
typical  zoisite  does  not;  and  that  element  seems  commonly  to  be 
furnished  by  hornblende  or  pyroxene.  Feldspar,  augite,  hornblende, 
and  biotite  all  alter  into  epidote ; and  so,  too,  in  some  cases  apparently 
does  chlorite.  The  derivation  of  epidote  from  chlorite  has  been 
observed  by  G.  F.  Becker 4 in  the  rocks  of  the  Comstock  lode,  and 
although  the  observation  is  questioned  by  some  authorities,  it  is 

1 See  the  section  on  scapolite  in  Chapter  X,  p.  404,  ante. 

2 Bull.  Soc.  min.,  vol.  12,  1889,  p.  83;  vol.  14, 1891,  p.  16.  Lacroix  states  that  wernerite  gneisses  are  very 
common.  Lacroix  and  C.  Baret  (idem,  vol.  10,  1887,  p.  288)  describe  a wernerite  pyroxenite.  Wernerite, 
it  will  he  remembered,  is  one  of  the  intermediate  scapolites.  See  also  H.  Wulf,  Min.  pet.  Mitt.,  vol.  8, 1887, 
p.  213,  on  a scapolite-augite  gneiss  from  Herero  Land,  Africa;  and  F.  Becke,  idem,  vol.  4,  1882,  p.  285,  on 
similar  rocks  from  Lower  Austria.  Scapolite  amphibolites  are  described  by  O.  Miigge,  Neues  Jahrb.,  Beil. 
Band  4,  1886,  p.  583,  from  Masai  Land;  E.  Dathe,  Jahrb.  K.  preuss.  geol.  Landesanstalt,  1884,  p.  lxxvi,  from 
Germany;  and  F.  D.  Adams  and  A.  C.  Lawson,  Canadian  Rec.  Sci.,  vol.  3,  1888,  p.  185,  from  Canada. 
.Adams  and  Lawson  also  describe  two  scapolite  diorites.  The  scapolite  rocks  of  northern  New  Jersey, 
briefly  described  by  F.  L.  Nason  (Ann.  Rept.  State  Geologist,  1890,  p.  33),  occur  as  dikes  in  crystalline 
limestone,  and  may  have  been  formed  by  contact  metamorphism.  C.  H.  Smyth  (Am.  Jour.  Sci.,  4th  ser., 
vol.  1,  1896,  p.  273),  has  described  the  transformation  of  a gabbro  into  a gneiss  containing  pyroxene,  horn- 
blende, feldspar,  and  scapolite. 

2 See  A.  Cathrein,  Zeitschr.  Kryst.  Min.,  vol.  7,  1883,  p.  247;  A.  Schenck,  Verhandl.  Naturhist.  Ver. 
preuss.  Rheinlande  u.  Westfalens,  vol.  41,  1884,  p.  53;  and  G.  H.  Williams,  Bull.  U.  S.  Geol.  Survey  No.  62, 
1890,  p.  56,  for  summaries  of  the  earlier  observations. 

* Mon.  U.  S.  Geol.  Survey,  vol.  3,  1882,  pp.  75,  76,  213.  Criticised  by  Williams,  loc.  cit.,  and  H.  Rosen- 
busch,  Neues  Jahrb.,  1884,  Band  2,  Ref.,  p.  189. 


598 


THE  DATA  OF  GEOCHEMISTRY. 


not  disproved.  Chemically,  it  is  not  improbable;  but  usually  the  two 
minerals,  chlorite  and  epidote,  form  simultaneously  from  a common 
parent.  In  the  rocks  of  Leadville,  W.  Cross  1 found  epidote  derived 
from  ortboclase,  plagioclase,  biotite,  and  hornblende.  G.  H.  Wil- 
liams 2 observed  its  formation  as  a contact  rim  between  feldspar  and 
hornblende  in  the  gabbro-diorite  near  Baltimore,  and  F.  D.  Chester 3 
described  similar  occurrences  in  Delaware.  In  some  of  Chester’s 
specimens  the  epidote  contained  cores  of  feldspar. 

Epidotization,  then,  represents  a reaction  between  the  feldspars 
and  the  ferromagnesian  minerals  of  a rock,  and  when  it  is  complete 
a mixture  of  quartz  and  epidote  remains.  Such  a rock  is  known  as 
epidosite,  and  its  formation  has  been  many  times  recorded.  J.  Lem- 
berg 4 describes  an  alteration  of  this  kind  from  augite  porphyry ; 
and  Schenck5  reports  the  derivation  of  epidosite  from  diabase. 
Unakite  is  a remarkable  rock  consisting  of  rose-colored  orthoclase 
and  green  epidote,  first  described  by  F.  H.  Bradley  6 from  western 
North  Carolina.  It  has  since  been  found  near  Milams  Gap,  Virginia. 
According  to  W.  C.  Phalen,7  who  has  studied  this  locality,  the  una- 
kite is  derived  from  a hypersthene  akerite,  or  quartz-diallage  syenite, 
and  it  contains,  in  addition  to  the  two  principal  minerals,  some 
quartz,  iron  oxides,  zircon,  and  apatite.  It  passes  into  epidosite  by 
further  alteration.  Epidote-quartz  rocks  from  New  Jersey  have  also 
been  briefly  described  by  L.  G.  Westgate.8 9  Here,  as  at  Milams  Gap, 
the  epidote  is  thought  to  be  derived  from  pyroxene. 

Garnet  is  a common  mineral  of  the  metamorphic  rocks,  and  is  often 
indicated  in  their  nomenclature.  Garnet  gneiss,  garnet-mica  schist, 
garnet  homfels,  and  garnet-olivine  rock  are  good  examples.  In 
these  rocks,  however,  garnet  is  commonly  an  accessory  mineral  rather 
than  a main  constituent.  On  the  other  hand,  rocks  are  known  con- 
sisting chiefly  or  largely  of  garnet,  and  one  of  these,  eclogite,  has 
been  the  subject  of  many  investigations.8 

Eclogite  is  essentially  a rock  composed  of  red  garnet,  with  a green 
pyroxene,  omphacite.  It  may  also  contain,  subordinately,  horn- 
blende, quartz,  zoisite,  kyanite,  and  muscovite,  with  zircon,  apatite, 
sphene,  epidote,  magnetite,  pyrite,  and  pyrrhotite  as  minor  acces- 
sories.10 According  to  J.  A.  Ippen,11  the  Styrian  eclogites  shade  into 

1 Mon.  U.  S.  Geol.  Survey,  vol.  12,  1886,  pp.  341,  357. 

2 Bull.  U.  Si  Geol.  Survey  No.  28,  1886,  p.  31. 

a Bull.  U.  S.  Geol.  Survey  No.  59,  1890,  p.  35. 

4 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  29,  1877,  p.  498. 

6  Verhandl.  Naturhist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  vol.  41,  1884,  p.  53. 

6 Am.  Jour.  Sci.,  3d  ser.,  vol.  7,  1874,  p.  519. 

7 Misc.  Coll.  Smithsonian  Inst.,  Quart.  Issue,  vol.  1,  1904,  p.  301. 

8 Ann.  Rept.  State  Geologist  New  Jersey,  1895,  p.  30. 

9 See  Zirkel’s  Lehrbuch  der  Petrographie,  2d  ed.,  vol.  3,  p.  369,  for  many  references.  The  papers  by 
Lohmann  and  Hezner,  cited  on  the  next  page,  also  contain  bibliographies. 

10  See  R.  von  Drasche,  Jahrb.  K.-k.  geol.  Reichsanstalt,  1871,  Min.  Mitt.,p.  85,  and  E.  R.  Riess,  Min.  pet. 
Mitt.,  vol.  1,  1878,  pp.  165,  181. 

11  Mitt.  Naturwiss.  Ver.  Steiermark,  1892,  p.  328. 


METAMORPHIC  KOCKS. 


599 


omphacite  rock  on  one  side  and  into  garnet  rock  on  the  other;  that 
is,  either  mineral  may  predominate  and  give  its  own  character  to 
the  mixture.  The  eclogites  of  the  lower  Loire,  according  to  A. 
Lacroix,1  sometimes  contain  feldspar  formed  as  a secondary  mineral 
during  the  uralitization  of  highly  aluminous  pyroxenes.  Lacroix 
shows  that  these  rocks  are  products  of  dynamometamorphism.  The 
crushing  and  fracturing  of  the  original  rocks  has  facilitated  the  cir- 
culation of  the  waters  to  which  their  alterations  are  due. 

L.  Hezner,2  who  studied  eclogite  from  the  Oetzthal,  in  the  Tyrolese 
Alps,  regards  it  as  a metamorphic  derivative  of  gabbroid  rocks.  By 
further  metamorphosis  it  passes  into  amphibolite,  the  eclogite  being 
the  deeper-seated  phase.  The  garnet,  he  thinks,  was  formed  by  a 
reaction  between  plagioclase  and  olivine,  or  perhaps  between  plagio- 
clase  and  pyroxene.  The  omphacite  alters  into  hornblende,  and  so, 
too,  does  the  garnet,  but  later.  First  eclogite,  then  garnet  amphib- 
olite, then  amphibolite,  is  the  order  of  these  allied  rocks.  Plagio- 
clase also  appears,  as  observed  by  Lacroix,  among  the  products  of 
alteration,  together  with  epidote,  chlorite,  magnetite,  zoisite,  and 
biotite. 

The  following  analyses  of  epidote  and  garnet  rocks  are  from  the 
memoirs  already  cited: 

Analyses  of  epidote  and  garnet  rochs. 

A,  B.  Epidosite  derived  from  diabase,  upper  Ruhrthal,  Germany.  Analyzed  and  described  by  Schenck. 

C.  Unakite,  Milam’s  Gap,  Virginia.  Analysis  by  Phalen. 

D.  Eclogite,  Sulzthal,  Styria. 

E.  Eclogite,  Burgstein,  Styria.  Analyses  D and  E by  Hezner. 


A 

B 

C 

D 

E 

SiO 

42. 13 

50.  26 

58.  32 

44.  06 

46. 26 

A1203 

19.21 

13.  72 

15.  77 

17.  63 

14. 45 

Fe203 

11. 19 

9. 18 

6.  56 

3.40 

4. 41 

FeO 

2.  52 

2.  97 

.89 

9.  96 

5.  82 

MgO 

.41 

2.  20 

. r9 

7. 19 

11.  99 

CaO 

21.  42 

16.  30 

11.  68 

11.58 

11.  66 

Na20 

.29 

.71 

.32 

2.  92 

2.  45 

K20 

.08 

1. 12 

4.  01 

.91 

1.  51 

H20- 

'j 

. 12 

h20+ 

> 2. 39 

f 1.88 

f 1. 73 

.17 

1. 10 

Ti02 

1. 40 

1.  60 

(a) 

2. 29 

.28 

Zr02 

Trace. 

PXL 

.08 

.39 

.48 

MnO 

.13 

FeS2 

.25 

.26 

101.  37 

100.  59 

99.  98 

100.  23 

99.  93 

« Not  separated  from  alumina. 


1 Bull.  Soc.  sci.  nat.  de  l’Ouest  de  la  France,  vol.  1, 1891,  p.  81. 

2 Min.  pet.  Mitt.,  vol.  22, 1903,  pp.  437, 505.  See  also  E.  Joukowsky,  Compt.  Rend.,  vol.  133, 1901,  p.  1312, 
on  alterations  of  eclogite  from  Lac  Cornu.  Other  valuable  papers  upon  eclogite  are  by  P.  Lohmann,  N eues 
Jahrb.,  1884,  Band  l,p.  83;  and  F.  Becke,  Min.pet.Mitt.,vol.4,1882,  pp.  317-322.  Eclogites  from  California 
have  been  described  by  R.  S.  Holway,  Jour.  Geology,  vol.  12,  1904,  p.  344,  and  J.  P.  Smith,  Proc.  Am. 
Philos.  Soc.,  vol.  45,  1906,  p.  183. 


600 


THE  DATA  OF  GEOCHEMISTRY. 


CHLORITIZATION. 

In  chloritization  we  find  a stage  of  metamorphism  which  is  nearly 
akin  to  decomposition.  Any  ferromagnesian  mineral  may  alter  into 
chloritic  material,  and  that,  by  further  change,  may  break  down  into 
a mixture  of  carbonates,  limonite,  and  quartz.  The  gabbros  of  Michi- 
gan, described  by  G.  H.  Williams,1  show  clearly  the  successive  steps 
of  uralitization  and  chloritization,  the  final  product  often  being  a 
chloritic  schist.  Diabase  and  diorite  are  often  chloritized,  gaining 
thereby  the  green  color  to  which  the  common  appellation  “ green- 
stone’’ is  due.  In  diabase  the  chloritic  substance  is  commonly 
derived  from  augite,  calcite  and  quartz  being  formed  at  the  same  time. 
The  alumina  needed  to  produce  the  chlorite  is  probably  furnished  by 
feldspar.2  Under  anhydrous  conditions,  as  we  have  already  seen, 
a reaction  between  feldspars  and  ferromagnesian  minerals  yields 
garnet;  possibly  the  formation  of  chlorite  is  similar,  but  effected  in 
presence  of  water.  The  alterability  of  garnet  into  chlorite  empha- 
sizes this  suggestion. 

The  chlorites  developed  in  rocks  of  igneous  origin  are  rarely  definite 
species.  They  are,  as  a rule,  variable  mixtures,  of  which  many  have 
received  specific  names.  Diabantite  and  prochlorite,  both  ferrifer- 
ous, are  perhaps  the  most  common.  Because  of  this  vagueness, 
Rosenbusch  prefers  to  use  the  collective  term  “chloritic  substance” 
in  describing  the  products  of  this  class.  The  general  names  “viri- 
dite”  and  “chloropite”  have  also  been  proposed;  the  one  by  H. 
Vogelsang,  the  other  by  C.  W.  Giimbel. 

CONSTITUTIONAL  FORMULAE. 

Although  it  is  not  yet  possible  to  write  positive  reactions  for  all 
of  the  alterations  that  we  have  so  far  been  considering,  some  of  them 
are  partly  elucidated  by  the  structural  formulae  of  several  minerals. 
A number  of  these  species  are  curiously  alike  in  constitution,  and  with 
them  other  minerals,  not  specifically  studied  in  this  chapter,  may 
also  be  compared.  Taking  the  tripled  formulae  of  orthoclase  and 
albite,  which  are  suggested  by  the  alteration  of  albite  into  marialite, 
the  following  system  of  formulae  can  be  developed:3 


Orthoclase Al3(Si308)3K3 . 

Albite Al3(Si308)3Na3. 

Marialite Al2(  Si308)3N  a4(  A1C1) . 

Nephelite Al3(Si04)3Na3. 

Paragonite Al3(Si04)3NaH2. 

Muscovite Al3(Si04)3KH2. 


1 Bull.  U.  S.  Geol.  Survey  No.  62, 1890. 

2 See  G.  W.  Hawes,  Am.  Jour.  Sci./3d  ser.,  vol.  9,  1875,  pp.  190, 454.  Also  A.  Schenck,  Verhandl.  Natur- 
hist.  Ver.  preuss.  Rheinlande  u.  Westfalens,  vol.  41, 1884,  p.  74.  Chloritization  is  fully  discussed  by  Rosen- 
busch in  his  Mikroskopische  Physiographic  der  massigen  Gesteine,  2d  ed.,  vol.  2,  pp.  180-184. 

« See  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  588,  1914,  for  an  extended  discussion  of  these  formulae. 


METAMORPHIC  ROCKS. 


601 


Topaz Al3(Si04)3(AlF2)3. 

Andalusite Al3(Si04)3(A10)3. 

Biotite A12(S  i04)3Mg2KH . 

Garnet Al2(Si04)3Ca3. 

Prehnite Al2(Si04)3Ca2H2. 

Zoisite Al2(Si04)3Ca2(A10H) . 


Epidote  resembles  zoisite,  but  with  iron  partly  replacing  aluminum, 
and  similar  replacements  occur  in  the  garnet  group. 

These  formulae,  however,  are  neither  absolute  nor  final.  They 
represent  definite  relations,  and  also  the  minimum  molecular  weights 
assignable  to  the  several  minerals,  the  true  molecular  weights  being 
unknown  and  at  present  undeterminable.  It  is  probable  that  some 
of  the  formulae  should  be  doubled,  and  when  that  is  done  some  strik- 
ing new  relations  appear.  This  is  shown  in  the  following  group  of 
structural  expressions : 


.Si04=Al2=Si04x 
Al— Si04=Al2=Si04— A1 
\si04EsCa=Si0/ 
Anorthite. 

/Si04=Ca3=Si04x 
Al— Si04=Ca3=Si04— Al 
\si04=Ca=SiO// 

Gehlenite.1 


/Si04=Ca3=Si04v 
Al— Si04=Ca3=Si04— Al 
\si04— Ca—  Sio/ 

AlOH  AlOH 

Vesuvianite. 


/Si04=Al2=Si04v 
Al— Si04=Ca=Si04— Al 
\si04=Ca3=Si04/ 

Garnet. 

xSi04=Al2=Si04x 
Al— Si04=Ca3=Si04— Al 
\siO— Ca— Sio/ 

II  II 

AlOH  AlOH 

Zoisite. 

✓Si04=Al2  =Si04x 
Al— Si04=Al2=Si04— Al 
\si04=Ca2=Si04/ 

I I 

Ca O Ca 

Meionite. 


In  the  first  group  of  formulae  the  fundamental  nucleus,  which  occurs 
in  all  of  them,2  is  Al(Si04)3.  In  the  second  group  it  is  Al2(Si04)6,  or 
double  the  other.  The  two  sets  are  identical  in  type,  and  with  their 
aid  the  observed  alterations  become  intelligible.  One  species  changes 
into  another  by  replacements  of  atoms,  the  typical  structures — the 
nuclei,  so  to  speak — remaining  undisturbed.  When  the  trisilicate 
feldspars  alter  into  orthosilicates,  silica  is  liberated;  but  the  other 
changes  are  simpler.  For  example,  nephelite,  topaz,  and  andalusite 
all  change  easily  into  muscovite;  members  of  the  garnet  group  can 
form  epidote,  biotite,  or  the  normal  chlorites,  and  so  on.  Pyroxenes 


1 More  properly  the  principal  constituent  of  the  mixed  crystals  known  as  gehlenite. 

* Except  the  trisilicate  feldspars  in  which  the  group  SisOs  is  equivalent  to  SiO<. 


602 


THE  DATA  OF  GEOCHEMISTRY. 


and  amphiboles,  however,  are  compounds  of  different  structure  from 
those  given  in  the  foregoing  table,  and  the  mechanism  of  their  alter- 
ations is  not  so  clear.  Some  of  the  phenomena  are  easily  understood; 
others  still  await  interpretation.  It  is  possible  to  write  empirical 
equations  in  all  cases,  but  they  have  slender  value.  A correlation 
between  molecular  constitution  and  the  observed  changes  must  be 
established  before  the  chemistry  of  metamorphism  can  be  completely 
described. 

TALC  AND  SERPENTINE. 

When  distinctively  magnesian  silicates  undergo  hydrous  meta- 
morphism, which  happens  chiefly  in  the  belt  of  weathering,  the 
product  is  likely  to  be  either  talc  or  serpentine.1  Other  hydrous  sili- 
cates may  be  formed  also,  together  with  carbonates  and  the  hydrox- 
ide, brucite;  but  the  two  species  just  named  are  the  most  important. 
I speak  now,  of  course,  with  reference  to  alterations  in  place;  such 
a rock  as  dolomite  falls  in  quite  another  category. 

A typical  production  of  serpentine  is  from  rocks  containing  olivine; 
and  the  probable  reaction  is  as  follows: 

2Mg2Si04  + 2H20  + C02 = Mg3H4Si209  + MgC03. 

Olivine.  Serpentine.  Magnesite. 

Peridotites  are  especially  liable  to  this  sort  of  alteration,  and 
many  serpentine  rocks  can  be  assigned  this  origin.2  The  well-known 
Lizard  serpentine  of  Cornwall,  for  instance,  has  been  shown  by 
T.  G.  Bonney  3 to  be  an  altered  Iherzolite. 

Pyroxenes,  also,  are  often  converted  into  serpentine.  The  equa- 
tion, in  the  case  of  diopside,  is  perhaps  as  follows: 

3MgCaSi206  + 3C02  + 2H20  = Mg3H4Si209  + 3CaC03  + 4Si02. 

Diopside.  Serpentine.  Calcite.  Quartz. 

This  reaction  is  sustained  by  the  fact  that  serpentine  rocks  often 
contain  quartz  and  calcite.  When  serpentine  is  formed  from  gabbro 
or  pyroxenite  the  change  is  probably  of  this  kind,  although  it  may 
have  been  preceded  by  uralitization  of  the  pyroxene.  Serpentines 
derived  from  amphibolites  have  been  repeatedly  described.4 


1 According  to  G.  P.  Merrill  (Geol.  Mag.,  1899,  p.  354)  the  formation  of  serpentine  as  a rock  is  a deep-seated 
process.  This  conception,  however,  does  not  preclude  the  generation  of  disseminated  serpentine,  regarded 
not  as  a rock  but  as  a mineral  species,  within  the  belt  of  weathering. 

2 See  F.  Sandberger,  Neues  Jahrb.,  1866,  p.  385;  idem,  1867,  p.  176;  G.  Tschermak,  Sitzungsb.  K.  Akad. 
Wiss.  Wien,  vol.  56,  1867,  p.  261;  E.  Weinschenk,  Abhandl.  K.  bayer.  Akad.,  Math.-phys.  Klasse,  vol.  18, 
p.  651;  J.  Lemberg,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  27,  1875,  p.  531;  B.  Weigand,  Jahrb.  K.-k.  geol. 
Reichsanstalt,  1875,  Min.  Mitt.,  p.  183.  F.  Zirkel  (Lehrbuch  der  Petrographie,  2d  ed.,  vol.  3,  p.  404) 
gives  an  extensive  bibliography  of  serpentine. 

3 Quart.  Jour.  Geol.  Soc.,  vol.  33,  1877,  p.  884. 

* B.  K.  Emerson  (Mon.  U.  S.  Geol.  Survey,  vol.  29, 1898,  p.  114)  assigns  this  origin  to  the  serpentines  of  the 
Connecticut  Valley.  An  Australian  amphibolite  serpentine  has  also  been  described  by  J.  B.  Jaquet,  Rec. 
Geol.  Survey  New  South  Wales,  vol.  5,  1896-1898,  p.  21. 


METAMORPHIC  ROCKS. 


603 


In  short,  serpentine  may  be  formed  from  any  silicate  which  hap- 
pens to  be  rich  in  magnesia,  such  as  olivine,  pyroxene,  amphibole, 
garnet,1  or  chondrodite.2  It  also  appears  to  be  produced  by  the 
action  of  percolating  magnesian  waters  upon  nonmagnesian  minerals, 
such  as  feldspars,  and  possibly,  even,  quartz.3  J.  Lemberg  4 has 
shown  that  solutions  of  magnesium  carbonate  will  attack  oligoclase, 
replacing  sodium  by  magnesium  to  a considerable  extent;  but  alter- 
ations of  this  sort  are  not  very  common.  Many  reported  changes  of 
minerals  to  talc  or  serpentine  have  been  erroneous,  for  compact  mus- 
covite is  easily  mistaken  for  them.  A pseudomorphous  mineral 
should  be  called  serpentine  or  steatite  only  after  thorough  chemical 
and  optical  examination.  The  mere  fact  that  a mineral  is  green, 
soft,  compact,  and  soapy  to  the  touch  is  not  enough  to  establish  its 
character. 

In  many  localities  serpentine  is  associated  with  dolomite  or  dolo- 
mitic  limestone.  In  these  cases  the  mineral  has  been  derived  from 
magnesian  silicates,  which  were  first  formed  within  the  limestone  by 
metamorphic  processes.  In  the  limestones  of  Westchester  County, 
New  York,  according  to  J.  D.  Dana,5  the  parent  minerals  were  tremo- 
lite  or  actinolite.  It  is  possible  also  that  some  dolomite  itself  may 
have  become  silicated,  yielding  serpentine  by  alteration  of  the  com- 
pounds thus  formed.  Similar  views  are  advanced  by  S.  F.  Emmons  6 
with  reference  to  serpentines  found  near  Leadville,  Colorado.  The 
serpentine  of  Montville,  New  Jersey,  which  is  also  in  dolomite,  was 
shown  by  G.  P.  Merrill 7 to  be  derived  from  pyroxene,  and  the  same 
conclusion  was  reached  regarding  the  ophiolite  or  ophicalcite  of 
Warren  County,  New  York.8  The  “verde-antique”  marbles  are 
familiar  illustrations  of  this  commingling  of  carbonates  with  serpen- 
tine. A quite  different  blending  of  serpentine  with  other  minerals  is 
that  described  by  me  from  Stephens  County,  W ashington.9  This  mix- 
ture was  apparently  a normal  serpentine;  but  upon  analysis  it  was 
found  to  contain  only  20  per  cent  of  that  species,  with  60  per  cent  of 
brucite,  14  per  cent  of  chlorite,  and  5 per  cent  of  hydromagnesite. 
Its  origin,  so  far  as  I am  aware,  has  not  been  determined. 

In  the  quicksilver  region  of  California  G.  F.  Becker  10  found  ser- 
pentines which  had  been  decomposed  by  solfataric  agencies  until 
only  the  silica  remained.  Similar  reductions  of  serpentine  to  opal, 

1 See  A.  Schrauf,  Zeitschr.  Kryst.  Min.,  vol.  6, 1882,  p.  321. 

2 See  J.  D.  Dana,  Am.  Jour.  Sci.,  3d  ser.,  vol.  8,  1874,  p.  371,  on  serpentine  pseudomorphs  from  the  Tilly 
Foster  mine. 

3 See  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  pp.  108-128. 

4 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  22, 1870,  p.  345;  vol.  24,  1872,  p.  255. 

6  Am.  Jour.  Sci.,  3d  ser.,  vol.  20, 1880,  p.  30. 

6 Mon.  U.  S.  Geol.  Survey,  vol.  12, 1886,  p.  282. 

7 Proc.  U.  S.  Nat.  Mus.,  vol.  11, 1888,  p.  105. 

8 Am.  Jour.  Sci.,  3d  ser.,  vol.  20,  1880,  p.  30. 

9 Bull.  U.  S.  Geol.  Survey  No.  262,  1905,  p.  69. 

10  Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  p.  127. 


604 


THE  DATA  OF  GEOCHEMISTRY. 


chalcedony,  and  quartz  have  been  recorded  by  A.  Lacroix.1  The 
acids  of  volcanic  fumaroles  bad  removed  the  bases  of  the  serpentine 
in  the  form  of  soluble  sulphates. 

From  what  has  been  said  so  far  it  is  evident  that  serpentine  origi- 
nates in  various  different  ways.  Some  serpentine  is  merely  altered 
peridotite,  pyroxenite,  or  gabbro;  and  some  of  it  is  derived  from 
dolomite  or  other  sedimentary  rocks.  Indeed,  the  sedimentary  origin 
of  serpentine  has  bad  many  strong  advocates,  the  chief  among  them 
having  been  the  late  T.  Sterry  Hunt.2  L.  Dieulafait 3 also  has  argued 
that  the  serpentines  of  Corsica  are  true  sedimentary  rocks.  There  is7 
in  fact,  no  valid  reason  why  siliceous  magnesian  sediments,  precipi- 
tated or  detrital,  should  not  form  beds  of  serpentine;  but  the  rock  is 
commonly  a metamorphosed  eruptive,  or  else  the  result  of  a sec- 
ondary metamorphism  of  sibceous  limestones.  In  both  of  these  gen- 
erally recognized  modes  of  formation  the  chemical  processes  are  the 
same.  The  same  magnesian  silicates  are  altered  in  the  same  way 
irrespective  of  their  igneous,  metamorpbic,  or  sedimentary  origin. 

Serpentine  is  a basic  ortbosilicate,  talc  an  acid  metasihcate.  The 
former  alters  easily,  and  is  readily  decomposed;  the  latter  is  one  of 
the  least  alterable  and  therefore  among  the  most  stable,  under 
aqueous  conditions,  of  mineral  species.  Both  minerals  are  decom- 
posed by  beat,  but  differently.  Serpentine  breaks  up  into  enstatite 
and  olivine;  talc  into  enstatite  or  antbopbyllite  and  quartz,  water 
being  eliminated  in  both  cases.  These  decompositions  may  be 
written  thus: 

Mg3H4Si209  = Mg2Si04  + MgSiOa  + 2H20. 

Mg3H2Si4012  = 3MgSi03  + Si02  + H20. 

Talc,  bke serpentine,  may  originate  in  different  ways;  but  its  com- 
monest derivation  seems  to  be  by  the  alteration  of  amphiboles  or 
pyroxenes.  C.  H.  Smyth,4  who  studied  the  talc  of  St.  Lawrence 
County,  New  York,  found  it  to  be  derived  in  that  region  from  enstatite 
and  tremobte,  accordmg  to  the  following  reactions: 

4MgSi03  + H20  + C02 = Mg3H2Si4012 + MgC03. 

MggCaSqO^  + H20  + C02  = Mg3H2Si4012  + CaC03. 

These  reactions  are  much  alike,  and  resemble  those  which  are  recog- 
nized in  the  formation  of  serpentine.  In  fact,  many  serpentines 
contain  admixtures  of  talc,  and  when  the  original  rocks  are  at  all 

1 Compt.  Rend.,  vol.  124, 1887,  p.  513. 

2 Mineral  physiology  and  physiography,  1886,  pp.  434-516.  Hunt  cites  a large  amount  of  evidence  from 
Italian  sources. 

3 Compt.  Rend.,  vol.  91, 1880,  p.  1000. 

4 School  of  Mines  Quart.,  vol.  17,  1896,  p.  333. 


METAMORPHIC  ROCKS. 


605 


aluminous,  chlorites  also  may  appear.  Soapstone  or  steatite  is 
impure,  massive  talc. 

According  to  Smyth,  the  St.  Lawrence  County  talc  is  found  asso- 
ciated with  crystalline  limestones.  J.  H.  Pratt 1 found  the  deposits 
of  North  Carolina  to  be  in  connection  with  marble,  and  capped  by 
quartzite.  In  the  same  region  pyrophyllite  occurs,  a hydrous  sili- 
cate of  aluminum,  HAlSi206,  which  much  resembles  talc  and  may 
be  mistaken  for  it.  The  talc  itself  appeared  to  be  derived  from 
tremolite.  Smyth  assumes  that  a siliceous  limestone  was  first  laid 
down,  which  became,  by  metamorphism,  a tremolite-enstatite  schist. 
The  latter,  by  hydration,  became  talc.  This,  however,  is  not  the 
only  way  in  which  steatite  has  been  formed.  A.  Gurlt 2 reports  its 
formation  from  dolomite  along  contacts  with  amphibolite;  and  C.  H. 
Hitchcock 3 regards  the  steatites  of  New  Hampshire  as  alterations 
of  what  was  originally  igneous  matter.  The  talc  of  Mautern  in 
Styria  is  traced  by  K.  A.  Kedlich  and  F.  Cornu4  to  the  action  of 
magnesian  solutions  upon  the  surrounding  schists.  Pseudomorphs 
of  talc  after  many  minerals  have  been  described,  but  not  all  of  the 
reports  are  authentic.  The  warning  given  under  serpentine  may  well 
be  recalled  here.  Pseudomorphs  of  talc  after  quartz,  however,  seem 
to  be  well  known.5  Much  work  needs  to  be  done  in  order  to  deter- 
mine the  origin  of  soapstone  generally. 

The  following  analyses  represent  talcose  and  serpentinous  rocks 
of  varied  characters. 

1 North  Carolina  Geol.  Survey,  Econ.  Paper  No.  3, 1900. 

2 Sitzungsb.  Niederrhein.  Gesell.  Natur  u.  Heilkunde,  Bonn,  1865,  p.  126. 

s Jour.  Geology,  vol.  4, 1896,  p.  58. 

?Zeitschr.  prakt.  Geologie,  1908,  p.  145. 

®E.  Weinschenk,  Zeitschr.  Kryst.  Min.,  vol.  14, 1888,  p.  305. 


606 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  talcose  and  serpentinous  rocks. 

A.  Dark-green  serpentine,  Rowe,  Massachusetts.  Described  by  B.  K.  Emerson  in  Mon.  U.  S.  Geol. 
Survey,  vol.  29, 1898.  Analysis  by  G.  Steiger. 

B . Serpentine,  Greenville,  California.  Described  by  J.  S.  Diller  in  Bull.  U.  S.  Geol.  Survey  No.  150, 1898, 
p.  372.  Derived  mainly  from  pyroxene.  Analysis  by  W.  H.  Melville. 

C.  Serpentine,  Sulphur  Bank,  California.  Described  by  G.  F.  Becker  in  Mon.  U.  S.  Geol.  Survey,  vol. 
13, 1888.  Analysis  by  Melville. 

D . Serpentine  derived  from  pyroxenite,  Mount  Diablo,  California.  Analyzed  and  described  by  Melville, 
Bull.  Geol.  Soc.  America,  vol.  2,  1890,  p.  403. 

E.  Serpentinous  rock  of  unusual  composition;  also  from  Mount  Diablo.  Analyzed  and  described  by 
Melville,  loc.  cit. 

F.  “Ovenstone”  from  Canton  Valais,  Switzerland.  Described  by  T.  G.  Bonney  (Geol.  Mag.,  1897,  p. 
110)  as  a stage  in  the  alteration  of  serpentine.  The  original  rock  was  perhaps  a basalt  or  dolerite.  Analysis 
by  Emily  Aston. 

G.  Brucite  serpentine,  Stevens  County,  Washington.  Described  by  F.  W.  Clarke,  Bull.  U.  S.  Geol. 
Survey  No.  262,  1905,  p.  69.  Analysis  by  G.  Steiger. 

H.  Steatite,  Griqualand  West,  South  Africa.  Described  by  E.  Cohen,  Neues  Jahrb.,  1887,  Band  l,p. 
119.  Analysis  by  Van  Riesen. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02 

40. 42 

39. 14 

41.86 

40.  50 

30.  98 

44.  94 

13.08 

63.  29 

A1203 

1.  86 

2.  08 

.09 

. 78 

1.  04 

5.  47 

1.  63 

1.  24 

Fe203 

2.  75 

4.  27 

4.  01 

4.  01 

4.  88 

1.  75 

1.  25 

FeO 

4.  27 

2.  04 

4. 15 

2.04 

2.  01 

3.47 

. 19 

4.  68 

MgO 

35.  95 

39.  84 

38.  63 

37. 43 

38. 44 

25.  57 

56.  44 

27. 13 

CaO 

. 66 

Trace. 

.39 

.22 

8.  76 

.33 

Trace. 

Na20 

} -16 

.28 

.40 

None. 

K20 

.16 

.16 

None. 

H20- 

.21 

}l2.  70 

}l4. 16 
) 

2.  81 

.39 

.35 

.85 

} 4.40 
) 

H20+ 

10.  51 

10.  94 

20. 43 

5.  40 

23.  94 

Ti02 

None. 

J 

C02 : 

1.  44 

1.  22 

2.  03 

P90, 

Trace. 

Trace. 

Trace. 

Cr203 

.28 

.24 

.41 

.34 

Trace. 

NiO 

.53 

Trace. 

.11 

2.  90 

CoO 

Trace. 

MnO 

Trace. 

.20 

.13 

.42 

Trace. 

S03 

Trace. 

.44 

FeS2 

.43 

Chromite 

.11 

99.  47 

100. 18 

99.  93 

99.  99 

100. 15 

99.  83 

99.  74 

100.  00 

The  presence  of  chromium  and  nickel  in  several  of  these  rocks  is  a 
good  indication  of  a relationship  with  the  pyroxenite  and  perido- 
tites.  Chromite  and  nickel  ores  are  very  generally  associated  with 
these  magnesian  eruptives. 

QUARTZITE. 

The  processes  which  operate  in  the  metamorphism  of  sedimentary 
rocks  are  partly  identical  with  those  which  we  have  just  been  consid- 
ering. This  fact  has  already  been  indicated  in  several  connections. 
A shale,  or  sandstone,  contains  fragments  of  minerals,  usually  more  or 
less  weathered,  and  these  undergo  the  normal  changes.  Feldspar 
becomes  sericite,  hornblende  alters  to  chlorite,  and  so  on,  exactly  as 
in  the  metamorphoses  of  igneous  material.  The  substances  affected 


METAMORPHIC  ROCKS. 


607 


are  the  same,  and  so  are  the  reactions.  The  formation  of  serpentine 
from  pyroxene,  for  example,  is,  as  I have  already  said,  the  same 
process,  whether  it  is  effected  upon  the  pyroxene  of  a gabbro  or  upon 
the  pyroxene  developed  by  contact  metamorphism  in  a crystalline 
limestone. 

There  is,  however,  another  set  of  changes  which  are  peculiar  to  the 
sedimentaries.  These  rocks  contain  decomposition  products,  such  as 
kaolinite,  hydroxides  of  aluminum  and  iron,  etc.,  which  give  rise  to  a 
different  group  of  reactions,  and  these  generate  another  class  of  min- 
eral species.  Kyanite,  andalusite,  sillimanite,  staurolite,  and  dumor- 
tierite  are  among  the  minerals  thus  developed  in  schists  which  once 
were  shales.  These  minerals,  again,  can  alter  into  mica,  so  that  a 
mica  schist  may  represent  the  outcome  of  a series  of  transformations, 
the  intermediate  products  having  disappeared. 

Just  as  the  sedimentary  rocks  shade  into  one  another,  so,  too,  do 
their  metamorphic  derivatives,  but  with  even  greater  complexity. 
For  the  metamorphosed  rocks  contain  not  only  the  original  minerals 
of  the  sediments,  but  also  the  new  products  formed  by  alteration. 
Perhaps  the  simplest  of  these  changes  is  that  of  a sandstone  into  a 
quartzite,  which,  in  the  first  instance,  is  brought  about  by  infiltration 
of  silica.  In  this  way  the  interstices  of  the  sandstone  are  filled  up 
and  a porous  rock  is  transformed  into  a compact  one.  But  as  sand- 
stones are  not  all  sand,  so  quartzites  are  not  all  silica.  A micaceous 
sandstone  yields  a micaceous  quartzite;  a feldspathic  sandstone  may 
form  either  an  arkose  gneiss,  or  by  sericitization  it  can  become  a mica 
schist;  and  between  these  different  rocks  there  are  all  manner  of 
gradations.  These  changes,  moreover,  are  often  complicated  by 
structural  modifications  due  to  dynamic  agencies;  so  that  from  sim- 
ilar sandstones  very  different  rocks  can  be  derived.  In  some  cases 
the  nature  and  order  of  the  changes  can  be  traced;  in  others  they 
seem  to  be  hopelessly  obscure.1 

The  following  analyses  of  quartzite  and  quartz  schist  are  useful  for 
comparison  with  the  analyses  of  sandstones  given  in  the  preceding 
chapter: 


1 For  a full  discussion  relative  to  the  formation  of  quartzite,  see  C.  R.  Van  Hise,  A treatise  on  metamor- 
phism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  pp.  865-880.  See  also  R.  D.  Irving,  Bull.  U.  S.  Geol.  Survey 
No.  8, 1884,  p.  48;  Am.  Jour.  Sci.,  3d  ser.,  vol.  25, 1883,  p.  401.  Important  papers  on  the  subject  have  been 
written  by  C.  Lossen,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  19, 1867,  p.  615,  and  W.  J.  Sollas,  Sci.  Proc.  Roy. 
Dublin  Soc.,  vol.  7, 1892,  p.  169. 


608 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  quartzite  and  quartz  schist. 

A.  Dark  vitreous  quartzite,  Pigeon  Point,  Minnesota.  Contains  quartz,  with  a little  feldspar,  chlorite, 
mica,  and  magnetite.  Described  by  W.  S.  Bayley,  Bull.  U.  S.  Geol.  Survey  No.  109, 1893.  Analysis  by 
R.  B.  Riggs. 

B.  Red  vitreous  quartzite,  Pigeon  Point.  Bayley  and  Riggs  as  above. 

C.  Quartzite,  South  Mountain,  Pennsylvania.  Described  by  F.  Bascom,  Bull.  U.  S.  Geol.  Survey  No. 
136, 1896.  Analysis  by  F.  A.  Genth,  on  p.  34. 

D.  Quartz  schist,  near  Stevenson  station,  Maryland.  Contains  quartz,  muscovite,  tourmaline,  micro- 
cline,  zircon,  and  iron  stains.  Described  by  Bayley,  Bull.  U.  S.  Geol.  Survey  No.  150, 1898,  p.  302.  Analy- 
sis by  E.  A.  Schneider. 


A 

B 

C 

D 

Si02 

74.  22 

83.  69k 

a 92.  00 

91.  65 

A1203 

10.  61 

7.  50 

4.  21 

1. 59 

Fe203 

7.  45 

1.  81 

1.  80 

3.  57 

FeO 

. 85 

. 38 

.21 

1.  48 

.35 

. 17 

CaO 

. 56 

.39 

.04 

None. 

Na20 

2. 12 

2.  46 

. 16 

. 07 

k2o 

1.  08 

2.  61 

1. 16 

1.  93 

h2o 

&1.  79 

. 72 

& . 96 

. 60 

Ti02 

.16 

Trace? 

. 14 

. 13 

PXL 

.21 

None. 

MnO 

None. 

Trace. 

Trace. 

100.  32 

99.  91 

100.  68 

99.  92 

a 84.13  per  cent  quartz,  7.87  per  cent  combined  silica.  & Loss  on  ignition. 


METAMORPHOSED  SHALES. 

Shales,  slates,  phyllites,  and  mica  schists  form  a continuous  series 
of  rocks  which  can  be  derived  from  clay,  mud,  or  silt  by  progressive 
dehydration  and  crystallization.  Some  mica  schists,  of  course,  are 
traceable  back  to  igneous  rocks,  but  they  fall  outside  of  the  present 
category.  In  order  to  study  the  development  of  schists  from  shales 
or  clays,  we  must  consider  what  compounds  the  latter  contain  capa- 
ble of  dehydration  and  what  are  produced  in  this  class  of  metamor- 
phoses. 

This  ground  has  already  been  partly  covered  in  the  two  preceding 
chapters.  The  final  products  of  rock  decomposition,  apart  from 
those  that  are  removed  in  solution,  are  hydroxides  of  iron  and 
aluminum;  free  silica,  anhydrous  or  opaline;  and  hydrous  silicates 
of  iron,  aluminum,  and  magnesium.  The  simple  hydroxides  offer 
the  least  difficulties  in  the  way  of  interpretation.  The  iron  com- 
pounds yield  hematite,  which  is  a common  mineral  in  the  metamor- 
phic  schists,  and  which,  in  presence  of  organic  matter,  may  be 
reduced  to  magnetite.1  The  aluminum  hydroxides  may  furnish  dia- 
spore  if  the  dehydration  is  partial,  or  corundum  when  the  reaction 
is  complete.  Opaline  silica  loses  water  and  becomes  converted 


1 If  a bed  of  limonite  be  regarded  as  a sedimentary  rock,  a bed  of  hematite  may  be  its  metamorphic 
equivalent. 


METAMORPHIC  ROCKS. 


609 


into  quartz.  These  changes  are  of  the  simplest  character,  but  it  is 
not  certain  that  they  always  take  place.  It  is  possible  that  the 
colloidal  silica  may  react  upon  the  colloidal  hydroxides,  and  form 
silicates  anew;  but  I am  not  sure  that  this  class  of  reactions  has  been 
proved.  They  are  conceivable,  and  therefore  can  not  be  left  out  of 
account.  The  known  changes,  as  I have  stated  them,  are  those  of 
the  compounds  themselves  when  not  commingled  with  other  sub- 
stances. Hematite,  magnetite,  corundum,  and  quartz  can  be  formed 
in  the  manner  indicated;  and  hematite  or  magnetite  schists  (schists 
containing  these  minerals  in  conspicuous  proportions)  are  not  rare. 
The  itabirite  of  Brazil  is  a rock  of  this  kind,  containing  hematite, 
magnetite,  and  quartz.1  Similar  rocks  have  been  described  by  H. 
Coquand 2 in  France,  and  O.  M.  Lieber 3 in  South  Carolina.  Co- 
quand’s  rock  is  described  as  equivalent  to  a mica  schist  containing 
specular  hematite  in  place  of  mica.  Itabirite  from  Okande  Land, 
West  Africa,  is  reported  by  O.  Lenz  4 as  containing  quartz,  hematite, 
and  magnetite,  with  quartz  predominating.  Another  example  from 
the  Gold  Coast,  described  by  C.  W.  Gumbel,5  contains  also  muscovite, 
ilmenite,  and  free  gold.  A German  schist  examined  by  C.  Lossen  6 
consisted  of  specular  hematite  and  quartz. 

FERRUGINOUS  SCHISTS. 

The  ferruginous  schists  of  the  Lake  Superior  region  may  properly 
be  mentioned  here.  According  to  C.  R.  Van  Hise,7  they  are  derived 
from  carbonate  rocks  which  he  calls  sideritic  slates.  These,  by  oxida- 
tion, pass  into  limonitic  or  hematitic  slates,  and  from  the  latter  the 
schists  are  derived.  Ferruginous  cherts  are  also  formed,  and  some 
banded  rocks  of  chert  and  hematite  which  Van  Hise  calls  jaspilite. 
The  silicification  of  the  original  siderite  is  attributed  to  the  action  of 
silica  contained  in  percolating  waters.  The  following  analyses  of  the 
schists  were  made  in  the  laboratory  of  the  United  States  Geological 
Survey : 

1 See  Zirkel,  Lehrbuch  der  Petrographie,  2d  ed.,  p.  570,  for  references. 

2 Bull.  Soc.  g6ol.  France,  2d  ser.,  vol.  6, 1849,  p.  291. 

3 Rept.  Survey  South  Carolina,  1855,  pp.  89-94;  1857,  p.  79;  1858,  p.  107. 

* Verhandl.  K.-k.  geol.  Reichsanstalt,  1878,  p.  168. 

6 Sitzungsb.  K.  Akad.  Wiss.  Munchen,  1882,  p.  183. 

6 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  19, 1867,  p.  614.  Zirkel  refers  also  to  Norwegian  examples  reported 
by  J.  H.  L.  Vogt  in  a memoir  which  I have  not  seen. 

7 A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  pp.  830-842.  See  also  the  literature 
there  cited,  and  especially  Mon.  U.  S.  Geol.  Survey,  vol.  28,  1895,  by  C.  R.  Van  Hise  and  W.  S.  Bayley. 
On  the  metamorphism  of  oil  shales  by  the  combustion  of  their  hydrocarbons,  see  R.  Arnold  and  R.  Ander- 
son, Jour.  Geology,  vol.  15,  1907,  p.  750. 

97270°— Bull.  616—16 39 


610 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  ferruginous  schists. 

A.  Grunerite-magnetite  schist,  Marquette  region,  Michigan.  Contains  griinerite,  magnetite,  and  quartz. 
Described  by  C.  R.  Van  Hise  and  W.  S.  Bayley  in  Mon.  U.  S.  Geol.  Survey,  vol.  28,  1895.  Analysis  by 
H.  N.  Stokes. 

B.  Actinolite-magnetite  schist,  Mesabi  Range,  Minnesota.  Described  by  W.  S.  Bayley,  Am.  Jour.  Sci., 
3d  ser.,  vol.  46, 1893,  p.  178.  Consists  of  actinolite  and  magnetite.  Analysis  by  W.  H.  Melville. 


A 

B 

Si02 

46.25 

12.35 

A1203 

.92 

.10 

Fe203 

30.  62 

58».  68 

FeO 

16.92 

21.34 

MrO 

2.13 

4. 08 

CaO 

1.69 

1.91 

NaaO  

None. 

Trace. 

H20 

.42 

.19 

Ti02 

None. 

.12 

p90* 

.07 

.25 

MnO 

1.01 

1.22 

CuO 

Trace. 

100. 03 

100. 24 

DEHYDRATION  OF  CLAYS. 

Rocks  like  those  just  considered,  obviously,  may  vary  from  nearly 
pure  amphibole  to  nearly  pure  iron  ore,  and  the  quartz-bematite 
schists  may  range  between  the  two  extremes  in  the  same  way.  In  all 
cases,  however,  the  final  product  represents  the  dehydration  of  hy- 
droxides, followed  by  partial  reduction  in  the  case  of  the  magnetite 
schists.  The  origin  of  the  hydroxides,  whether  from  carbonates  or 
from  silicates,  is  a separate  question. 

The  hydrous  silicates  of  the  sediments  are  chiefly  those  of  alumi- 
num. Some  iron  compounds  also  occur,  such  as  glauconite,  chloropal, 
or  nontronite,  but  their  mode  of  decomposition  when  dehydrated  is 
not  clearly  known.  In  many  cases,  probably,  they  break  down  into 
ferric  oxide  and  quartz;  but  they  also,  doubtless,  contribute  to  the 
formation  of  less  hydrous  minerals,  like  staurolite  and  chloritoid. 
Of  these  species,  more  later.  Magnesian  silicates  must  also  exist  in 
the  sediments,  as  talcose  or  serpen tinous  matter,  but  their  dehydra- 
tion products  have  already  been  discussed.1 

Many  hydrous  silicates  of  aluminum  have  been  described.  A few 
of  them  are  definite,  others  are  more  or  less  doubtful.  Some,  prob- 
ably, are  colloidal  mixtures,  which  should  not  be  formulated  as  distinct 


1 See  p.  604,  ante. 


METAMORPHIC  ROCKS. 


611 


chemical  compounds.  The  following  minerals  in  this  class  are  rec- 
ognized by  Dana  as  true  species : 


Kaolinite 

Halloysite 

Newtonite 

Cimolite 

Montmorilionite 

Pyrophyllite 

Allophane 

Collyrite 

Schrotterite . . . . 


H4Al2Si209. 

H4Al2Si209+aq. 

H8Al2Si2Ou+aq. 

H6Al4Si9027+3  aq.(?) 

.H2Al2Si4012+n  aq. 

H2Al2Si4012. 

Al2Si06.5aq. 

Al4Si08.9aq. 

Al16Si3O30.30aq. 


To  this  list  rectorite 1 and  leverrierite  2 should  probably  be  added. 
Leverrierite,  as  described  by  P.  Termier,  has  the  composition  of  mus- 
covite, with  hydrogen  replacing  potassium,  and  a little  iron  equiv- 
alent to  aluminum.  Its  formula,  then,  is  HAlSi04,  or  H3Al3Si3012, 
corresponding  to  muscovite,  H2KAl3Si3012.  Rectorite,  according  to 
R.  N.  Brackett  and  J.  F.  Williams,  has  the  same  composition,  plus 
an  excess  of  water,  which  is  driven  off  when  the  mineral  is  dried  at 
110°.  Possibly  the  mineral  kryptotile,  an  alteration  product  of 
kornerupine  or  prismatine,  may  be  a compound  of  the  same  order.3 
Silicates  of  this  type,  if  their  existence  should  be  definitely  estab- 
lished, would  probably  be  found  to  be  widely  diffused  and  to  play  an 
important  part  in  the  development  of  phyllite  or  mica  schist.  They 
should  take  up  potassium  from  percolating  solutions,  forming  musco- 
vite— a probability  which  deserves  to  be  investigated  with  great  care. 

Upon  complete  dehydration  all  of  the  silicates  in  the  list  except 
collyrite  and  schrotterite  should  break  down  into  mixtures  of 
Al2Si05  and  Si02.  Al2Si05  represents  empirically,  the  three  min- 
erals andalusite,  kyanite,  and  sillimanite,  which  are  isomeric  but  not 
identical.  No  other  anhydrous  silicate  of  aluminum  alone  is  known 
to  occur  in  nature.  These  three  species,  moreover,  are  all  character- 
istic of  the  metamorphic  schists,  and  must  have  been  formed  in  most 
cases  by  some  such  process  as  that  just  indicated.  Sometimes,  how- 
ever, other  sources  are  to  be  assumed.  For  example,  K.  Dalmer 4 has 
described  a phyllite  containing  muscovite  and  chlorite,  which,  by 
contact  metamorphism,  has  been  transformed  into  a biotite-andalusite 
schist.  In  this  instance  the  andalusite  seems  to  have  been  produced 
by  a reaction  between  the  two  antecedent  species.  On  the  other  hand, 
it  has  been  shown  by  W.  Vernadsky 5 6 that  sillimanite  is  a normal  con- 
stituent of  hard  porcelain,  in  which  it  is  derived  from  kaolinite;  and 
also  that  kyanite  and  andalusite  are  convertible  into  sillimanite  by 


1 Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  16. 

2 Bull.  Soc.  min.,  vol.  22,  1899,  p.  27. 

3 See  J.  Uhlig,  Zeitschr.  Kryst.  Min.,  vol.  47, 1910,  p.  215,  and  A.  Sauer,  Zeitschr.  Deutsch.  geol.  Gesell., 

vol.  38,  1886,  p.  705. 

* Neues  Jahrb.,  1897,  Band  2,  p.  156. 

6 Bull.  Soc.  min.,  vol.  13, 1890,  p.  256.  See  also  J.  W.  Mellor,  Jour.  Soc.  Chem.  Ind.,  vol.  26,  1907,  p.  375. 


612 


THE  DATA  OF  GEOCHEMISTRY. 


heating  to  a temperature  of  1,320°  to  1,380°.  Kyanite  often  occurs 
in  mica  schist,  and  also  in  long,  bladed  crystals  embedded  in  quartz. 
All  three  species  alter  into  mica,1  so  that  here  we  have  a group  of 
facts  which  bear  obviously  upon  the  interpretation  of  metamorphic 
processes.  We  do  not  yet  know,  however,  the  conditions  which  deter- 
mine the  formation  in  a metamorphic  rock  of  one  or  another  of  the 
three  isomers.  The  chemical  structure  of  the  particular  hydrous 
silicate  from  which  andalusite,  kyanite,  or  sillimanite  has  been 
derived  probably  has  a distinct  influence  upon  the  reaction.  Temper- 
ature, as  shown  by  Vernadsky,  must  also  be  taken  into  account,  and 
so,  too,  must  pressure.  The  three  minerals  differ  in  density,  and 
pressure  may  well  help  to  determine  which  species  shall  form.  The 
specific  gravity  of  andalusite  is  near  3.2,  that  of  sillimanite  about 
3.25,  and  that  of  kyanite  varies  little  from  3.6.  Kyanite,  then,  would 
be  likely  to  appear  under  the  greatest  pressures  and  andalusite  under 
the  least,  other  conditions  being  equal.  The  problem  is  complicated, 
however,  by  the  fact  that  the  same  rock  often  contains  more  than  one 
of  these  minerals,  together  with  products  derived  from  them.  The 
argillite  of  Harvard,  Massachusetts,  according  to  B.  K.  Emerson,2 
contains  andalusite  inclosing  sillimanite,  both  in  every  stage  of  alter- 
ation to  muscovite.  The  argilhtes  of  this  region,  modified  by  intru- 
sions of  granite,  show  a zonal  system  of  changes.  Where  the  tem- 
perature was  lowest,  andulusite  and  sillimanite  form.  With  more 
intense  heat,  staurolite  and  garnet  appear.  Influx  of  alkaline  waters 
from  the  heated  granite  changes  these  species  to  muscovite,  while 
nearest  the  granite  feldspars  develop. 

Staurolite,  HAl5FeSi2013,  specific  gravity  3.75,  is  another  mineral 
of  the  metamorphic  schists,  and  one  closely  allied  to  the  andalusite 
group.  Its  formation  evidently  requires  the  presence  of  iron  in 
the  sediments,  and  also  conditions  of  temperature  and  pressure  which 
could  permit  the  retention  of  water.  Garnet  is  one  of  its  common 
associates,  and  so,  too,  are  sillimanite  and  kyanite.  Its  most  fre- 
quent matrix  is  mica  schist;  but  its  mode  of  formation  is  not  yet 
clearly  understood.  Staurolite  is  always  contaminated  by  inclusions 
of  other  substances,  and  it  alters  readily  into  mica. 

With  more  iron  and  possible  hydration,  schists  are  formed  con- 
taining chloritoid  or  ottrelite.  Chloritoid  has  the  formula 
H2FeAl2Si07;  but  that  of  ottrelite  is  not  certain.  The  best  evi- 
dence goes  to  show  that  the  two  minerals  are  alike  in  type,  except 
that  chloritoid  is  an  orthosilicate,  and  ottrelite  a trisilicate.  On  this 
supposition  the  two  formulae  become 


A102Fe.Si04.A10H.H. 


A102Fe.Si308.A10H.H. 


Chloritoid. 


Ottrelite. 


1 The  reported  alteration  of  kyanite  into  steatite  is  most  questionable.  Probably  a compact  muscovite 
(damourite)  has  been  mistaken  for  talc. 

2 Bull.  Geol.  Soc.  America,  vol.  1,  1889,  p.  559. 


METAMOEPHIC  EOCKS. 


613 


Magnesium  may  replace  iron  to  some  extent,  and  in  the  Belgian 
ottrelites  manganese  plays  a similar  part.  By  dehydration,  chlori- 
toid  would  become  A102Mg.Si04.Al,  or  Al2MgSi06,  which  is  the 
formula  of  the  aluminous  constituent  of  augite  and  hornblende, 
and  also  of  the  imperfectly  known  mineral  kornerupine.  A relation 
between  chloritoid  and  these  silicates  is  therefore  suggested,  but 
what  its  real  significance  may  be  is  unknown.  Broadly  considered, 
chloritoid  and  ottrelite  belong  to  a group  of  silicates  intermediate 
between  the  micas  and  the  chlorites,  from  either  of  which  groups 
they  may  be  derived,  or  into  which  they  may  alter.  In  the  ottrelite 
schists  of  Vermont,  according  to  C.  L.  Whittle,1  chlorite  is  derived 
from  ottrelite,  and  the  latter  mineral  was  one  of  the  last  to  form. 
In  the  Belgian  phyllites  studied  by  J.  Gosselet2  mica  sometimes 
replaces  ottrelite.  The  formation  of  ottrelite  after  the  other  min- 
erals of  the  schists  was  also  noted  by  W.  M.  Hutchings3  in  a sericite- 
ottrelite-ilmenite  phyllite  from  Cornwall,  and  by  J.  E.  Wolff  4 in  a 
rock  found  at  Newport,  Rhode  Island.  In  a collection  of  rocks  from 
the  Transvaal,  J.  Gotz  5 found  ottrelite  schist,  andalusite  schist,  and 
an  intermediate  phase  containing  both  ottrelite  and  andalusite. 

Ottrelite  and  chloritoid  are  probably  often  confounded.  At  all 
events,  chloritoid  rocks  have  been  less  frequently  described.  C.  Bar- 
rois  6 has  reported  them  from  the  lie  de  Groix,  France;  a garnet- 
chloritoid-quartz  schist  from  Japan  has  been  described  by  B.  Koto;7 
and  a rock  from  the  province  of  Salzburg,  Austria,  studied  by 
A.  Cathrein,  contained  about  64  per  cent  of  chloritoid,  with  30  of 
quartz  and  some  rutile.  Other  occurrences  are  weH  summed  up  by 
F.  Zirkel,8  for  both  ottrelite  and  chloritoid.  The  abundant  litera- 
ture, however,  is  mainly  descriptive,  and  sheds  little  light  upon  the 
genesis  of  these  minerals.  The  following  analyses  represent  rocks 
characterized  by  the  andalusite  and  chloritoid  groups.  All  except 
one,  by  Klement,  were  made  in  the  laboratory  of  the  United  States 
Geological  Survey. 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  44,  1892,  p.  270. 

2 Annales  Soc.  gdol.  du  Nord,  vol.  15,  p.  185. 

3 Geol.  Mag.,  1889,  p.  214. 

4 Bull.  Mus.  Comp.  Zool.,  vol.  16,  1890,  p.  159. 

6  Neues  Jahrb.,  Beil.  Band  4,  1886,  p.  143. 

6 Annales  Soc.  g6ol.  du  Nord,  vol.  11, 1884,  p.  18. 

7 Jour.  Coll.  Sci.  Japan,  vol.  5,  1893,  p.  270. 

8 Lehrbuch  der  Petrographie,  2d  ed.,  vol.  3,  pp.  282,  294, 303-306. 


614 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  andalusite  and  chloritoid  rocks. 

A.  Andalusite  schist,  Mariposa  County,  California.  Analysis  by  W.  F.  Hillebrand.  Described  by  H. 
W.  Turner,  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1,  1896,  p.  691.  Contains  quartz,  biotite, 
andalusite,  sericite,  and  minor  accessories. 

B.  Chiastolite  schist,  Mariposa  County,  California.  Analysis  by  G.  Steiger.  Described  by  Turner,  Bull. 
U.  S.  Geol.  Survey  No.  150,  1898,  p.  342.  Contains  andalusite  (chiastolite),  sillimanite,  mica,  etc. 

C.  Andalusite  hornfels,  Mariposa  County.  Analysis  by  Steiger.  Described  by  Turner,  op.  cit.,  p.  342. 
Contains  quartz,  andalusite,  mica,  etc. 

D.  Andalusite  schist,  Skamania  County,  Washington.  Analyzed  and  described  by  W.  T.  Schaller,  BulL 
U.  S.  Geol.  Survey  No.  262, 1905,  p.  105.  Contains  andalusite,  35  per  cent;  quartz,  32  per  cent;  muscovite, 
27  per  cent;  and  minor  accessories. 

E.  Kyanite  schist,  Serra  do  Gigante,  Brazil.  Analysis  by  Hillebrand.  Described  by  O.  A.  Derby,  Am. 
Jour.  Sci.,  4th  ser.,  vol.  7,  1899,  p.  343.  Consists  mainly  of  kyanite,  chlorite,  sericite,  quartz,  and  rutile. 

F.  Sillimanite  schist,  San  Diego  County,  California.  Analyzed  and  described  by  Schaller,  Bull.  No.  262, 
1895,  p.  98.  Mainly  quartz,  69  per  cent,  and  sillimanite,  31  per  cent,  neglecting  water  and  minor  accessories. 

G.  Chloritoid-phyllite,  Liberty,  Maryland.  Analyzed  by  L.  G.  Eakins.  Called  * ‘ ottrelite-phyllite ’ ’ by 
G.  H.  Williams,  but  the  characteristic  mineral  is  chloritoid.  See  Bull.  U.  S.  Geol.  Survey  No.  228,  p.  59. 

H.  Ottrelite  schist,  Montherm6,  Belgium.  Analyzed  by  C.  Element,  described  by  A.  F.  Renard. 
Renard’s  memoirs  on  the  phyllites  of  the  Ardennes  (Bull.  Mus.  roy.  hist.  nat.  Belgique,  vol.  1, 1882,  p.  212; 
vol.  2,  1883,  p.  127;  vol.  3,  1884,  p.  230)  are  rich  in  data  concerning  rocks  of  this  class.  For  this  particular 
schist  see  vol.  3,  p.  255.  It  contains  ottrelite,  46.11  per  cent;  sericite,  23.35  per  cent;  and  quartz,  23.15  per 
cent. 


A 

B 

c 

D 

E 

F 

G 

H 

Si02 

64.  28 

62. 15 

65. 10 

57. 18 

38.  32 

75.  54 

34.  92 

51.  93 

A1A 

17.  28 

19.  34 

17.  77 

34. 10 

28. 16 

18.  65 

32.  31 

27.  45 

Fe203 

1. 10 

4.  23 

1.  95 

.54 

2.  24 

.35 

10.  21 

2. 01 

FeO. 

5.  34 

2.  25 

3.  29 

.28 

4.  02 

.06 

8.  46 

8. 10 

MgO 

2.  57 

1.  88 

1.  43 

.10 

12.  04 

None. 

1. 13 

1.  20 

CaO 

1. 19 

1.  50 

1.  38 

.63 

.32 

CO 

o 

.36 

.18 

Na20 

.91 

1.  60 

2.  25 

.39 

.16 

None. 

2. 12 

.79 

K20 

2.  93 

3.07 

2.  45 

2.  57 

1. 11 

None. 

1.  87 

1.60 

H20- 

.20 

.19 

.47 

.69 

.55 

1. 10 

1 c;  OQ 

1 Q QO 

H20+ 

2.  72 

1.  79 

2.  49 

2. 02 

7. 46 

3.  67 

> O. 

> O.  V4 

Ti02 

.65 

.80 

.72 

.66 

4.93 

.48 

J 3.37 

.92 

Zr02 

.02 

.09 

.06 

C 

.43 

1. 12 

1.  21 

1. 05 

so3 

. 13 

.03 

s 

Trace. 

F 

. 22 

. 12 

Trace? 

Cl 

None. 

Trace. 

PA 

.27 

. 15 

. 14 

.53 

.47 

Trace. 

.23 

MnO 

.09 

Trace. 

None. 

None. 

.16 

Trace. 

.57 

■Ra.O 

. 10 

. 04 

None. 

.04 

SrO 

Trace. 

None. 

None. 

Trace? 

Trace. 

(Ni,Co)0 

.04 

Li20 

Trace. 

None. 

None. 

None. 

Trace. 

FeS2 

.28 

.10 

100. 06 

100. 46 

100.  80 

100.  03 

100.  07 

100. 04 

100.  27 

99.  72 

MICA  SCHIST. 

A great  variety  of  other  schists,  corresponding  to  the  variations  in 
the  sediments  themselves,  have  received  special  descriptive  names. 
Graphite  schists,  derived  from  carbonaceous  shales;  tourmaline 
schists,  containing  tourmaline,  and  garnet-mica  schists  are  good 
examples.  The  commonest  type  of  all,  however,  is  the  ordinary  mica 
or  sericite  schist,  which  is  essentially  a mixture  of  quartz  and  mica, 


METAMORPHIC  ROCKS. 


615 


with  varying  accessories.  A p aragonite  schist  contains  the  soda  mica, 
p aragonite,  instead  of  the  commoner  muscovite.  A shale  passes  into 
a slate;  in  that  fine  scales  of  mica  develop,  forming  a phyllite,  and 
with  more  complete  recrystallization  a mica  schist  is  produced.  Mica 
schists  also  originate  from  the  alteration  of  a granitic  detritus  con- 
sisting of  quartz  and  feldspar,1  the  latter  mineral  changing  to  mus- 
covite, or,  under  undetermined  conditions,  to  biotite.  Chlorite,  epi- 
dote,  garnet,  tourmaline,  and  feldspars  are  common  accessory  min- 
erals in  rocks  of  this  class.  The  following  analyses  of  mica  schists 
were  made  in  the  Survey  laboratory: 

Analyses  of  mica  schists. 

A.  Quartz-sericite  schist,  Mount  Ascutney,  Vermont.  Analyzed  by  W.  F.  Hillebrand.  Described  by 
R.  A.  Daly  in  Bull.  U.  S.  Geol.  Survey  No.  209, 1903. 

B.  Sericite  schist,  Ladiesburg,  Maryland.  Analyzed  by  G.  Steiger.  Described  by  W.  S.  Bayley  in 
Bull.  U.  S.  Geol.  Survey  No.  150,  1898,  p.  317. 

C.  Sericite  schist,  Marquette  region,  Michigan.  Analysis  by  Steiger.  Described  by  C.  R.  Van  Hise 
and  W.  S.  Bayley,  Mon.  U.  S.  Geol.  Survey,  vol.  28,  1895.  Mainly  sericite  and  quartz. 

D.  Mica  schist,  Crystal  Falls  district,  Michigan.  Analyzed  by  H.  N.  Stokes.  Described  by  H.  L. 
Smyth,  Mon.  U.  S.  Geol.  Survey,  vol.  36,  1898,  p.  274.  Contains  biotite,  quartz,  some  microcline,  and 
magnetite. 

E.  Mica  schist,  near  Gunflint  Lake,  Minnesota.  Analyzed  by  T.  M.  Chatard.  Contains  biotite,  quartz, 
feldspar  (?),  and  pyrite,  as  reported  by  Van  Hise. 

F.  Feldspathic  mica  schist,  Mariposa  County,  California.  Analyzed  by  Hillebrand.  Described  by 
H.  W.  Turner,  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1,  1896,  p.  691.  Contains  quartz,  feldspar, 
biotite,  muscovite,  apatite,  and  specular  iron. 


A 

B 

c 

D 

E 

F 

Si02 

90.  91 

57.  24 

70.  76 

64.  71 

64.  77 

70.  40 

A1203 

4. 18 

23.  48 

14.  83 

16.43 

14.45 

14.  70 

Fe90o 

.22 

3. 19 

1.  46 

1.  83 

1.84 

. 65 

FeO 

1.  27 

4.  87 

3.  09 

3.  84 

4.  54 

2.  57 

MgO 

.37 

.93 

1.  99 

2.  97 

2.  34 

1.47 

CaO 

.22 

.09 

.36 

.08 

2.  33 

1.  63 

Na20 

. 77 

1. 18 

. 47 

. 11 

1.  37 

3. 17 

K20 

.58 

3.  55 

3.  50 

5.  63 

5.  03 

3.  46 

H20- 

.06 

.33 

.09 

. 31 

. 07 

. 19 

h2o+ 

. 74 

4.  65 

2.  70 

2.  79 

1.  92 

. 91 

Ti02 

.28 

.08 

.33 

.72 

.60 

.51 

Zr02 

.02 

co2 

. 18 

.41 

PXL 

.05 

.09 

.26 

.02 

.20 

.05 

S03 

None. 

.60 

F 

Trace. 

MnO 

Trace. 

None. 

Trace. 

.11 

.08 

BaO 

Trace. 

.09 

SrO 

Trace. 

LioO 

Trace. 

C 

.10 

.15 

FeS2 

.11 

100.  06 

99.  68 

99.  84 

99.  44 

100.  58 

100. 03 

i See  C.  R.  Van  Hise,  Bulk  Geol.  Soc.  America,  vol.  1, 1899,  p.  206,  on  schists  from  the  Black  Hills. 


616 


THE  DATA  OF  GEOCHEMISTRY. 


Before  leaving  the  subject  of  mica  schist  a word  of  caution  may 
not  be  superfluous.  It  is  often  assumed  that  the  mica  in  such  a 
rock  has  been  derived  from  the  alteration  of  feldspathic  particles 
contained  in  the  original  sediments,  and  this  no  doubt  is  frequently 
the  case.  The  same  process  operates  that  is  traced  in  the  sericitiza- 
tion  of  an  igneous  rock,  but  it  is  not  necessarily  general.  We  have 
seen  that  muscovite  can  be  formed  from  andalusite,  for  instance, 
and  the  latter  probably  from  clay  substance.  In  short,  micas  may 
form  in  a number  of  different  ways,  so  that  no  single  set  of  reactions 
can  account  for  all  of  its  occurrences.  Sometimes  its  source  can  be 
determined,  but  not  always. 

Many  schists  contain  tourmaline  as  an  essential  constituent. 
Dumortierite  also  occurs  in  them,  perhaps  more  often  than  is  com- 
monly supposed.  These  species  are  borosilicates,  and  their  generation 
is  usually  attributed  to  the  agency  of  boron-bearing  gases  or  vapors 
emitted  from  heated  magmas  along  their  contacts  with  sedimentary 
deposits.  Boron  compounds,  and  fluorine  compounds  also,  exist  in 
volcanic  emanations,  as  was  shown  in  Chapter  VIII,  and  they  .prob- 
ably produce,  in  many  instances,  the  effects  just  ascribed  to  them. 
But  here  again  caution  is  necessary.  We  do  not  know  how  widely 
boron  and  fluorine  may  be  disseminated  in  rock-forming  mate- 
rials, for  their  determination  in  traces  is  very  difficult  and  rarely 
attempted.  Fluorine  must  be  abundantly  diffused  as  a constituent 
of  the  ubiquitous  mineral  apatite,  and  boron  may  be  equally  com- 
mon. We  observe  its  concentration  in  tourmaline,  but  we  can  not 
be  positive  as  to  its  origin  except  in  certain  individual  cases.  One 
of  these  seems  to  be  the  contact  between  mica  schist  and  granite 
on  Mount  Willard,  in  the  White  Mountains  of  New  Hampshire,  as 
described  by  G.  W.  Hawes.1  Here  there  are  seven  well-defined  zones, 
as  follows: 

1.  Argillitic  mica  schist,  chloritic. 

2.  Argillitic  mica  schist,  biotitic. 

3.  Tourmaline  hornstone. 

4.  Tourmaline  veinstone. 

5.  Mixed  granite  and  schist. 

6.  Granite  porphyry,  biotitic. 

7.  Normal  granite,  hornblendic.  This  contains  quartz,  albite,  orthoclase,  horn- 
blende, and  some  biotite.  In  the  porphyry,  biotite  entirely  replaces  the  hornblende. 

The  remarkably  complete  series  of  analyses  by  Hawes  is  given  in 
the  next  table. 


» Am.  Jour.  Sci.,  3d  ser.,  vol.  21,-1881,  p.  21. 


METAMORPHIC  ROCKS. 


617 


Analyses  of  granite  and  mica  schist  near  contact , Mount  Willard. 


A.  The  normal  Albany  granite. 

B.  Porphyry,  3 feet  from  contact. 

C.  Porphyry,  2 inches  from  contact. 

D.  Tourmaline  veinstone,  on  contact. 


E.  Tourmaline  homstone,  1 foot  from  contact. 

F.  Schist,  15  feet  from  contact. 

G.  Schist,  50  feet  from  contact. 

H.  Schist,  100  feet  from  contact. 


A 

B 

C 

D 

E 

F 

G 

H 

Si02 

72.  26 

73. 09 

71.  07 

66. 41 

67.  88 

66.  30 

63.  35 

61.  57 

AJA 

13.  59 

12.  76 

12.  34 

16.  84 

14.  67 

16.  35 

19.  69 

20.  55 

FeA 

1. 16 

1. 07 

2.  25 

1.  97 

2.  37 

.95 

.72 

2.  02 

FeO.. 

2. 18 

4.  28 

4.  92 

5.  50 

3.  95 

5.  77 

5.  48 

4.  28 

MgO 

.06 

.09 

.19 

1.  71 

1.  29 

1.  63 

1.  77 

1.  27 

CaO 

1. 13 

.30 

.55 

.37 

.30 

.24 

Trace. 

.24 

Na20 

3.  85 

3. 16 

2.  84 

1.  76 

3.  64 

1. 11 

1. 12 

.68 

K20 

5.  58 

5. 10 

5.  53 

.56 

4.  08 

3. 40 

3. 47 

4.  71 

H20 

.47 

.73 

.72 

1.  31 

1.  01 

3.  02 

3.  73 

4.  09 

Ti02 

.45 

.40 

.27 

1.  02 

.93 

1.28 

1.  00 

1. 10 

BA. 

2.  96 

. 97 

Trace. 

■^2^3 

F . . 

.25 

Trace. 

MnO 

Trace. 

.08 

Trace. 

.12 

. 11 

Trace. 

.16 

.10 

100.  73 

101.  06 

100.  68 

100.  78 

101.  20 

100.  05' 

100. 49 

100.  61 

The  dehydration  in  passing  from  schist  to  granite  is  here  very 
obvious,  but  the  sudden  appearance  of  boric  oxide  is  more  striking. 
That  its  concentration  was  brought  about  by  pneumatolytic  processes 
is  the  most  reasonable  hypothesis  by  which  to  account  for  its  pres- 
ence at  the  line  of  contact  and  its  absence  elsewhere.  The  mineral- 
ogical  composition  of  the  rocks  D to  H,  as  given  by  Hawes,  presents 
a still  clearer  picture  to  the  mind  of  the  changes  which  have  occurred : 

Mineralogical  composition  of  tourmaline  rocks  and  mica  schist,  Mount  Willard. 


D 

E 

F 

G 

H 

Quartz 

50. 03 

50.  82 
1 29. 67 

45. 15 

30. 17 

36. 87 

Muscovite 

44.  53 

49.  30 

Biotite 

| 43. 89 

Chlorite 

) 

6.  65 

13.  70 

8.  62 

Ilmenite 

1.94 

1.  77 

2. 43 

1.  90 

2.  09 

Magnetite 

2.  86 

3.44 

1.  38 

1.  04 

2.  93 

Tourmaline 

45.  95 

14.  92 

Here  we  see  that  the  chlorite  of  the  schist  alters  to  biotite,  by  dehy- 
dration, as  the  contact  is  approached,  and  that  the  tourmaline  has 
been  formed  largely  at  the  expense  of  the  micas.  The  absence  of 
feldspar,  which  is  abundant  in  the  granite,  is  also  noticeable.  On 
the  granite  side  of  the  contact  the  rocks  are  feldspathic;  on  the  schist- 
ose side  they  are  micaceous;  at  the  contact  neither  feldspar  nor  mica 
is  shown  by  Hawes’s  figures.  Probably  both  minerals  have  contrib- 
uted to  the  generation  of  tourmaline,  which  is  related  to  both. 
Tourmaline  often  alters  to  mica,  and  tourmaline  crystals  are  known 
inclosing  cores  of  feldspar. 


618 


THE  DATA  OF  GEOCHEMISTRY. 


GNEISS.  , 

The  gneisses  form  the  largest  group  of  metamorphic  rocks,  and 
represent  both  igneous  and  sedimentary  formations.  Some  of  them 
are  plutonic  rocks,  structurally  modified;  others  are  recrystallized 
sedimentaries.  The  term  “gneiss/7  unfortunately,  has  been  used  in 
quite  different  senses.  For  present  purposes,  J.  F.  Kemp’s  defini- 
tion 1 may  perhaps  serve  as  well  as  any.  He  defines  gneiss  as  a “lam- 
inated metamorphic  rock,  which  usually  corresponds  in  mineralogy 
to  some  one  of  the  plutonic  types.”  The  gneisses  “ differ  from  schists 
in  the  coarseness  of  the  laminations,  but  as  these  become  fine  they 
pass  into  schists  by  insensible  gradations.”  Under  this  definition 
any  plutonic  rock  may  have  its  gneissoid  equivalent,  and  C.  H.  Gor- 
don 2 has  proposed  to  name  the  gneisses  accordingly.  Thus  we  may 
have  granitic  gneiss,  syenitic  gneiss,  dioritic  gneiss,  etc.,  including  in 
the  series  foliated  rocks  derived  from  pyroxenite  or  peridotite. 
The  common  usage,  however,  is  not  quite  so  extreme,  and  the  term 
gneiss  is  practically  restricted  to  granular,  laminated  rocks  analogous 
in  composition  to  granite,  syenite,  or  diorite.  Chemically  these 
gneisses  differ  very  little  from  their  igneous  equivalents,  but  those 
derived  from  sedimentary  rocks  are  likely  to  he  relatively  poor  in 
alkalies  and  to  contain  minerals  of  calcareous  origin.  In  some  cases 
gneisses  of  sedimentary  origin  contain  impurities  of  organic  deriva- 
tion, either  coaly  or  graphitic.  For  example,  in  a gneiss  from  the 
Black  Forest,  H.  Rosenbusch 3 found  coaly  particles  which  contained 
nitrogenous  matter,  undoubtedly  derived  from  organic  substances. 
A convenient  aid  to  nomenclature  is  that  offered  by  Rosenbusch,4 
who  calls  gneiss  of  igneous  origin  “orthogneiss,”  and  that  of  sedi- 
mentary origin  “paragneiss.”  There  are  also  descriptive  names  of 
the  ordinary  character,  which  indicate  mineralogical  peculiarities. 
Chlorite  gneiss,  cordierite  gneiss,  tourmaline  gneiss,  garnet  gneiss, 
epidote  gneiss,  sillimanite  gneiss,  albite  gneiss,  muscovite  gneiss,  bio- 
tite  gneiss,  two-mica  gneiss,  plagioclase  gneiss,  and  orthoclase  gneiss 
are  names  of  this  kind.  The  sedimentary  varieties  are  also  named 
genetically,  as  pelite  gneiss,  psammite  gneiss,  arkose  gneiss,  etc., 
according  to  the  derivation  of  the  rock  from  shaly,  sandy,  or  arkose 
materials. 

The  following  analyses  of  gneiss,  with  the  exception  of  the  Cana- 
dian example,  were  made  by  the  chemists  of  the  United  States 
Geological  Survey: 


1 Handbook  of  rocks,  3d  ed.,  p.  123. 

2 Bull.  Geol.  Soc.  America,  vol.  7, 1895,  p.  122. 

8 Mitth.  Gr.  badisch.  geol.  Landes anstalt,  vol.  4,  Heft  1,  1899. 

* Elemente  der  Gesteinslehre,  2d  ed.,  p.  484. 


METAMORPHIC  ROCKS. 


619 


Analyses  of  gneisses. 

A.  Sedimentary  gneiss,  St.  Jean  de  Matha,  Quebec,  Canada.  Analysis  by  N.  N.  Evans.  Described 
by  F.  D.  Adams,  Am.  Jour.  Sci.,  3d  ser.,  vol.  50, 1895,  p.  67.  Adams  gives  several  other  analyses  of  gneisses. 

B.  Quartz-biotite-gamet  gneiss,  Fort  Ann,  New  York.  Analysis  by  W.  F.  Hillebrand.  Reported  by 
J.  F.  Kemp  to  contain  quartz,  garnet,  biotite,  orthoclase,  some  plagioclase,  and  zircon. 

C.  Average  sample  of  mica  gneiss,  near  Philadelphia,  Pennsylvania.  Analysis  by  Hillebrand.  De- 
scribed by  F.  Bascom,  Maryland  Geol.  Survey,  Cecil  County  volume,  1902,  p.  116.  Contains  quartz, 
muscovite,  feldspars,  and  minor  accessories. 

D.  Gneiss  from  Dorsey’s  Run,  Maryland.  Analysis  by  Hillebrand.  Described  by  C.  R.  Keyes,  Fif- 
teenth Ann.  Rept.  U.  S.  Geol.  Survey,  1895,  p.  697.  Probably  of  sedimentary  origin. 

E.  Gneiss,  probably  sedimentary,  Great  Falls  of  the  Potomac.  Analysis  by  Hillebrand.  Described  by 
G.  H.  Williams,  Fifteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  1895,  p.  670. 

F.  Biotite  gneiss,  Upper  Quinnesee  Falls,  Menominee  River,  Michigan.  Analysis  by  R.  B.  Riggs. 
Described  by  G.  H.  Williams,  Bull.  U.  S.  Geol.  Survey  No.  62,  1890,  p.  119.  Contains  biotite,  soda  ortho- 
clase, quartz,  and  accessory  sphene,  zircon,  and  apatite. 

G.  Quartz-norite  gneiss,  Odessa,  Minnesota.  Analysis  by  H.  N.  Stokes.  Described  by  W.  S.  Bayley, 
Bull.  U.  S.  Geol.  Survey  No.  150, 1898,  p.  358.  Contains  quartz,  plagioclase,  and  pyroxene,  with  accessory 
biotite,  garnet,  pyrite,  and  magnetite. 


A 

B 

C 

D 

E 

F 

G 

Si02 

61.  96 
19.  73 

65.  09 
16.  37 
.93 
5.  64 
2. 40 
2. 40 
3.  31 
1.  93 
.13 
.58 
.93 
.01 
.07 
.11 
.03 

66. 13 
15. 11 
2.  52 
3. 19 
2. 42 

1.  87 

2.  71 
2.  86 

.24 
1.  55 
.82 
J?) 

None. 

.22 

.03 

48.  92 
16.  57 

4.  21 
9. 18 

5.  98 
9.  69 
2. 47 
1.  56 

} .68 

78.  28 
9.  96 
1.  85 

1.  78 
.95 

1.  68 

2.  73 
1.  35 

.12 

.83 

.70 

67.  77 
16.  61 
2.  06 

1.  96 
1.  26 
1.87 
4.  35 

2.  35 

} L69 

61.  04 
16.  97 

ALOo 

Feb. 

4.  60 
1.  81 
.35 
.79 
2.  50 

} 1.82 
1.  66 

5.  58 
3.  62 
5.  99 
1.  96 
.55 

} .43 

MgO 

CaO 

Na20 

K20 

H20- 

H20+ 

Ti02 

Zr02 

C02 

.19 

PAR 

.11 

S 

Fe7S8 

3.  73 

FeS2 

4.  33 

Cr90o 

Trace. 

Trace. 

.16 

.03 

Trace. 

Trace. 

NiO 

Trace. 

.20 

Trace. 

Trace. 

None. 

MnO 

Trace. 

.08 

.02 

Trace. 

Trace. 

BaO 

SrO 

Li20 

Trace. 

99.  55 

100. 12 

99.  87 

100.  26 

100. 44 

100. 11 

98.  87 

In  a broad  way  the  general  order  of  change  from  clay  to  slate, 
shale,  and  metamorphic  schists  is  well  shown  by  a series  of  averaged 
analyses  compiled  by  C.  R.  Van  Hise.1  The  analyses  chosen  for 
combination  were  all  of  pelitic  material. 

1 A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47, 1904,  pp.  890, 891, 896.  The  data  are  all 
to  be  found  in  Bull.  U.  S.  Geol.  Survey  No.  591, 1910;  the  shale  average  on  p.  23. 


620 


THE  DATA  OF  GEOCHEMISTRY. 


Average  analyses  of  clay,  shale,  slate,  and  schist. 

A.  Average  of  12  analyses  of  clays  and  soils. 

B.  Average  or  composite  analysis  of  78  shales. 

C.  Average  of  22  analyses  of  slates. 

D.  Average  of  5 analyses  of  schists. 


Si02. 

ai2o. 

Fe20 

FeO. 

MgO 

CaO. 

Na20 

K20. 

h2o. 

Ti02 

C02. 

it 

Cl... 

F.... 

MnO 

SrO. 

BaO. 

Li20 

FeS2 

C... 


A 

B 

C 

D 

54.  28 

58.  38 

61.  90 

65.74 

14.  51 

15. 47 

16.  54 

17.  35 

~ 

6.  25 

4.  03 

2.  73 

1.  90 

. 77 

2. 46 

3.  63 

3.  35 

2.  99 

2. 45 

2.  99 

1.  90 

5.04 

3. 12 

1. 07 

1.  25 

) 

1.  21 

1.  31 

2.  57 

1.  78 

2. 12 

3.  25 

3. 15 

3.  28 

8. 41 

5. 02 

3.  84 

2.  01 

.42 

.65 

.82 

.55 

3.  53 

2.  64 

.59 

None. 

.09 

. 17 

.04 

.12 

.08 

.65 

.03 

.03 

.02 

Trace. 

Trace. 

Trace. 

.07 

1 

.08 

Trace. 

Trace. 

.03 

None. 

Trace. 

Trace. 

.05 

.01 

.05 

Trace. 

Trace. 

Trace. 

. 11 

.24 

.81 

.22 

.58 

100.  04 

100. 46 

100.  24 

99.  99 

In  these  figures,  reading  from  clay  to  schist,  we  see  a steady  loss 
of  water  and  of  carbon  dioxide.  The  latter  has  been  gradually 
replaced  by  silica,  and  silica  has  also  increased  in  proportion  by  its 
assumption  as  a cementing  substance.  Ferric  iron,  furthermore,  is 
partly  reduced  to  the  ferrous  state,  and  there  is  an  apparent  gain  in 
alumina,  which  may  be  partly  real,  and  so  far  due  to  cementation. 
The  averages  represent  too  few  individual  analyses  to  warrant  any 
elaborate  discussion  of  them,  but  they  serve  to  illustrate  the  general 
tendency  of  the  metamorphic  processes. 

METAMORPHIC  LIMESTONES. 

The  metamorphism  of  limestone  is  effected  by  a variety  of  processes 
which  are  quite  distinct  in  many  particulars  from  those  outlined  in 
the  preceding  pages.  A pure  or  relatively  pure  limestone  may  re- 
crystallize into  a compact  marble,  as  shown  in  the  chapter  upon  the 
sedimentary  rocks.  If  it  contains  magnesium  carbonate,  dolo- 
mite is  produced;  and  the  presence  of  iron  may  determine  the  for- 
mation of  mixed  carbonates,  such  as  ankerite  or  mesitite.  These 
changes  are  of  the  simplest  character  and  call  for  no  further  dis- 
cussion now. 


METAMORPHIC  ROCKS. 


621 


But  pure  limestones  are  relatively  rare.  Sandy  or  argillaceous 
impurities  are  generally  present,  and  also  silicates  produced  by  reac- 
tions with  infiltrating  waters.  When  limestones  of  this  sort  are  meta- 
morphosed, either  dynamically  or  by  contact  with  igneous  injections, 
new  minerals  are  generated,  and  the  range  of  possibilities  becomes 
very  broad.  Each  impurity  exerts  its  own  peculiar  influence,  and 
operates  to  develop  certain  individual  substances.  Organic  matter, 
for  example,  furnishes  the  material  for  graphite,  which  is  very  com- 
mon in  metamorphosed  limestones.  In  the  Adirondack  region  there 
are  numerous  beds  of  white,  crystalline  limestone,  thickly  spangled 
with  brilliant  hexagonal  plates  of  graphite;  and  these  localities  are 
typical  of  many  others. 

When  silica  is  the  sole  impurity  of  importance,  it  can  crystallize  as 
quartz,  or  react  with  the  calcium  carbonate  to  form  the  silicate,  wol- 
lastonite.  No  more  limpid  crystals  of  quartz  are  known  than  those 
found  in  the  cavities  of  Carrara  marble.  As  for  wollastonite,  CaSi03, 
it  is  often  formed  at  contacts  between  limestone  and  igneous  rocks, 
and  it  is  also  found  disseminated  through  schists  and  gneisses.  It 
must  be  remembered  that  shales  and  sandstones  often  contain  cal- 
careous matter,  which  undergoes  the  same  transformations  that  the 
concentrated  limestones  experience.  Calcium  carbonate  in  a siliceous 
sedimentary  rock  may  easily  become  the  progenitor  of  wollastonite, 
garnet,  scapolite,  epidote,  and  other  calciferous  species.  Carbon 
dioxide  is  expelled,  and  sihcates  are  produced. 

The  development  of  wollastonite  at  an  igneous  contact,  or,  indeed, 
in  any  metamorphic  rock,  has  peculiar  geologic  significance.  E.  T. 
Allen  and  W.  P.  White  1 have  shown  that  this  mineral  can  be  formed 
only  at  temperatures  not  exceeding  1,180°.  Above  that  temperature 
it  passes  into  the  pseudohexagonal  modification,  which  has  often  been 
prepared  artificially,  but  is  unknown  as  a natural  species.  The 
presence  of  wollastonite,  then,  is  evidence  that  the  rock  containing  it 
had  recrystallized  at  some  temperature  below  the  transition  point. 
If  that  degree  of  heat  were  ever  exceeded  in  a contact  zone,  we  should 
expect  the  pseudohexagonal  silicate  to  appear;  since  it  does  not,  we 
are  justified  in  assuming  that  this  form  of  metamorphism  is  always 
effected  at  lower  temperatures.  We  thus  obtain  a definite  datum 
point  in  what  has  been  called  the  “ geologic  thermometer.” 

The  recrystallization  of  a sedimentary  limestone  containing  limo- 
nitic  impurities  or  hydroxides  of  aluminum  will  obviously  produce 
inclusions  of  magnetite,  hematite,  or  corundum.  Magnetite  has  often 
been  identified  in  crystalline  limestones,  and  similar  occurrences  of 
corundum  are  not  uncommon.  The  Burmese  rubies,  for  example,  are 
found  in  crystalline  limestone,  and  so,  too,  are  the  red  and  blue 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  21,  1906,  p.  89.  The  memoir  is  prefaced  by  a note  from  G.  F.  Becker,  who 
points  out  the  geologic  bearing  of  the  observations. 


622 


THE  DATA  OF  GEOCHEMISTRY. 


corundums  of  Newton,  New  Jersey.  When  alumina  and  silica  are 
present  together,  the  reaction  with  calcium  carbonate  leads  to  the 
formation  of  various  silicates,  the  conditions  which  determine  the 
appearance  of  each  one,  however,  not  being  definitely  known.  Cin- 
namon garnet,  vesuvianite,  epidote,  zoisite,  and  the  scapolites  are 
among  the  species  which  appear  most  frequently.  Gehlenite  also 
occurs,  but  more  rarely;  for  example,  in  marble,  at  the  classical 
locality  of  Monzoni  in  the  Tyrol.1  Metamorphosed  limestone  with 
inclusions  of  this  class  are  common;  for  instance,  in  a belt  extending 
from  southwestern  Maine  to  central  Massachusetts.  From  two  points 
in  this  belt,  at  Raymond  and  Phippsburg,  Maine,  crystallized 
anorthite  has  also  been  identified  by  analyses  made  in  the  laboratory 
of  the  United  States  Geological  Survey.2  The  other  feldspars  as  well, 
albite,  orthoclase,  and  the  plagioclases,  are  known  as  contact  minerals 
or  inclusions  in  crystalline  limestones,3  and  also  the  micas  muscovite, 
biotite,  and  phlogopite.  Phlogopite  is  essentially  a mineral  of  this 
group  of  rocks,  its  formation  and  that  of  biotite  requiring  the  presence 
of  magnesium  compounds.  To  form  scapolites,  sodium  chloride  is 
necessary,  but  that  may  easily  come  from  percolating  waters,  or 
from  apatite.  The  alkalies  required  by  the  feldspars  and  micas  may 
have  a similar  origin,  or  else  be  derived  from  impurities  in  the  sedi- 
ments from  which  the  limestones  were  formed. 

Nearly  all  limestones  are  more  or  less  magnesian  or  ferruginous, 
facts  which  determine  the  formation  of  many  metamorphic  minerals. 
Magnesia,  for  instance,  may  crystallize  by  itself  as  periclase,  and 
that  species  alters  into  brucite.  Magnesia  and  alumina  together  give 
rise  to  spinel.  With  silica,  magnesian  silicates,  often  ferriferous, 
may  form,  such  as  forsterite,  olivine,  enstatite,  and  hypersthene. 
With  lime  and  magnesia  together,  monticellite  is  produced,  and  also 
a wide  range  of  pyroxenes  and  amphiboles.  Augite,  hornblende, 
diallage,  diopside,  actinolite,  and  tremolite  are  common  in  meta- 
morphic limestones,  and  the  minerals  of  the  chondrodite-humite 
series  are  also  characteristic  of  these  rocks  in  many  localities.  The 
white,  yellow,  and  brown  magnesian  tourmalines  are  other  species  of 
this  class.  Furthermore,  the  oh  vines,  pyroxenes,  amphiboles,  and 
chondrodites  alter  into  serpentine  and  talc,  forming  the  ophicalcite 
marbles  or  verde  antique.4 

1 See  C.  Doelter,  Jahrb.  K.-k.  geol.  Reichsanstalt,  1875,  p.  239.  Doelter  also  reports  hematite  in  these 
marbles;  and  it  has  been  identified  by  G.  d’Achiardi  in  Carrara  marble. 

2 Bull.  U.  S.  Geol.  Survey  No.  220,  1903,  p.  27.  Anorthite  also  occurs  in  the  marble  of  Monzoni,  in  the 
Tyrol.  See  G.  vom  Rath,  Zeitschr.  Deutsche  geol.  Gesell.,  vol.  27, 1875,  p.  379. 

3 See,  for  example,  G.  Linck,  Neues  Jahrb.,  1907,  p.  21,  on  orthoclase  from  the  dolomite  of  Campolongo. 

* In  Mon.  U.  S.  Geol.  Survey,  vol.  46, 1904,  p.  221,  W.  S.  Bayley  described  a talcose  schist  from  the  Aragon 

iron  mine,  Michigan,  which  was  probably  derived  from  a dolomite.  An  analysis  of  it,  by  G.  Steiger,  is 
given,  and  also  its  mineraiogical  composition.  On  the  origin  of  secondary  silicates  in  limestones  see  W.  L. 
Uglow,  Econ.  Geology,  vol.  8,  pp.  19,  215, 1913. 


METAMORPHIC  ROCKS. 


623 


In  a Scottish  dolomitic  marble  containing  forsterite,  tremolite, 
diopside,  and  brucite,  J.  J.  H.  Teall1  has  observed  a dedolomitiza- 
tion  due  to  the  silica tion  of  the  double  carbonate.  That  changes  to 
diopside  without  change  of  ratios,  and  the  partly  altered  rock  shows 
the  two  species  in  juxtaposition.  The  metamorphosis  was  effected 
by  a plutonio  intrusion,  and  where  silica  was  deficient,  brucite 
appeared.  Probably  in  the  latter  case  magnesium  carbonate  was  first 
reduced  to  periclase,  MgO,  which  was  later  hydrated  to  brucite, 
Mg02H2.  The  mixture  of  calcite  and  brucite  is  identical  with  the 
predazzite  of  the  Tyrol.2  It  may  be  noted  here  that  certain  of  the 
Adirondack  limestones  are  regarded  by  J.  F.  Kemp  3 as  having  been 
originally  siliceous  dolomites,  in  which  the  silica  and  magnesia  have 
segregated  as  pyroxene.  In  northern  New  Jersey,  according  to  L.  G. 
Westgate,4  a quartz  rock  and  a quartz-pyroxene  rock  have  been 
formed  by  the  metamorphism  of  limestones. 

In  addition  to  the  minerals  already  named,  the  crystalline  lime- 
stones contain  many  other  less  important  species.  Apatite,  fluorite, 
rutile,  perofskite,  titanite,  dysanalyte,  and  zircon  are  among  them. 
By  the  reduction  of  sulphates,  a considerable  number  of  sulphides 
may  be  formed.  At  Carrara,  for  instance,  G.  d’Achiardi 5 found 
realgar,  orpiment,  sphalerite,  pyrite,  arsenopyrite,  galena,  chalcocite, 
and  tetrahedrite ; and  also  native  sulphur  and  gypsum.  Pyrrhotite 
and  molybdenite  have  been  identified  at  other  localities,  and  in  the 
famous  Binnenthal,  in  Switzerland,  several  rare  sulphosalts  occur 
in  a crystalline  dolomite.  In  short,  the  list  of  minerals  now  known 
as  existing  in  metamorphosed  limestones  must  comprise  at  least 
70  species,  and  possibly  more.6 

The  rocks  thus  formed  from  limestones  and  dolomites,  or  from 
mixtures  of  these  with  siliceous  material,  can  vary  from  a nearly 
pure,  recrystallized  carbonate  to  an  indefinite  aggregate  of  silicates 
alone.  Even  in  a single  bed  the  rocks  may  range  from  one  extreme 
to  the  other.  Analyses  of  such  rocks,  therefore,  have  little  signifi- 
cance and  are  not  often  made.  Three  examples  from  the  silicate  side 
of  the  group  may  serve  to  illustrate  the  variety  of  composition: 

1 Geol.  Mag.,  1903,  p.  513.  A similar  example  is  reported  by  F.  H.  Hatch  and  R.  H.  Rastall,  Quart. 
Jour.  Geol.  Soc.,  vol.  66, 1910,  p.  507.  See  also  T.  Crook,  Geol.  Mag.,  1914,  p.  339. 

2 See  ante,  p.  570. 

3 Bull.  Geol.  Soc.  America,  vol.  6, 1894,  p.  241.  In  the  same  volume,  p.  263,  C.  H.  Smyth  discusses  another 
group  of  Adirondack  limestones  which  were  metamorphosed  along  contacts  with  gabbro. 

« Am.  Geologist,  vol.  14,  1894,  p.  308. 

3 Atti  Soc.  toscana  sci.  nat.,  Pisa,  vol.  21, 1905. 

8 A list  is  given  by  F.  Zirkel  in  Lehrbuch  der  Petrographie,  2d  ed.,  vol.  3,  p.  448.  Seealso  B.  Lindemann, 
Neues  Jahrb.,  Beil.  Band  19, 1904,  p.  197.  For  the  Ceylonese  localities,  see  A.  K.  Coom&ra-Sw&my,  Quart. 
Jour.  Geol.  Soc.,  vol.  58, 1902,  p.  399.  J.  F.  Kemp  and  A.  Hollick  have  described  the  crystalline  limestones 
of  Warwick,  New  York,  in  Annals  New  York  Acad.  Sci.,  vol.  7,  1893,  p.  644. 


624 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  metamorpkic  silicate  rocks. 

A.  Wollastonite  gneiss,  Amador  County,  California.  Analysis  by  W.  F.  Hillebrand.  Described  by 
H.  W.  Turner,  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1896,  p.  521.  Consists  mainly  of  wollas- 
tonite, but  garnet,  quartz,  and  titanite  are  also  present. 

B.  Prehnite  rock,  Black  Forest,  Germany.  Analysis  by  C.  Schnarrenberger.  Described  by  H.  Rosen- 
busch,  Mitt.  Gr.  badisch.  geol.  Landesanstalt,  vol.  5,  Heft  1,  1905.  Estimated  to  contain  46.2  per  cent 
prehnite,  37.9  albite,  13.8  actinolite,  and  3.2  kaolin  and  nontronite.  Probably  formed  from  a marl  con- 
taining 34.5  per  cent  of  carbonates  with  65.5  silicates  and  quartz. 

C.  Garnet  rock,  Black  Forest.  Analysis  by  Schnarrenberger.  Described  by  Rosenbusch,  loc.  cit. 
Probably  derived  from  an  original  mixture  of  48  per  cent  carbonates  and  52  of  silicates,  chiefly  kaolin. 
Contains  about  75  per  cent  garnet,  10  per  cent  soda-potash  mica,  and  15  per  cent  hornblende. 


A 

B 

C 

Si02 

50.  67 

50.  65 

41.  01 

A120, 

6.  37 

19.  54 

18.  50 

Fe^Oj. 

.31 

3.  34 

6.  57 

FeO.. 

. 50 

None. 

11.  06 

MgO 

.58 

3.  92 

11.  02 

fkO 

40.  34 

16. 11 

10.  31 

Na.„0_  . - 

. 14 

3.  91 

.48 

k2o 

.22 

.84 

.31 

h2o 

.39 

a 3.  10 

1. 18 

Ti02 

. 20 

Trace. 

co2 

. 52 

MnO 

Trace. 

100.  24 

100.  41 

100.  44 

a Loss  on  ignition. 


DIAGNOSTIC  CRITERIA. 

It  is  generally  desirable,  but  not  always  easy,  in  the  study  of  a 
metamorphic  rock,  to  determine  whether  it  was  of  igneous  or  sedi- 
mentary parentage.  For  this  purpose  various  criteria  have  been 
proposed,  and  chemical  analysis  furnishes  some  of  them.  On  the 
chemical  side  the  problem  has  been  well  discussed  by  E.  S.  Bastin,1 
who  points  out  a number  of  possibilities. 

First,  a study  of  analyses  by  the  methods  laid  down  in  the  quan- 
titative classification  of  igneous  rocks.  In  many  cases  the  “norm” 
of  a sedimentary  rock  is  identical  with  that  of  some  igneous  rock,  as 
shown  in  Washington’s  tables.2  In  such  instances  no  definite  con- 
clusion can  be  reached  from  chemical  evidence  alone.  But  if  the 
“norm”  agrees  with  that  of  no  known  igneous  rock,  the  analysis 
probably,  but  not  certainly,  indicates  a sedimentary  origin. 

Secondly,  the  manner  in  which  the  sedimentaries  are  formed 
suggests  other  chemical  criteria.  In  most  igneous  rocks  soda  is  in 
excess  of  potash,  but  decomposition  changes  the  ratio,  which,  in 

1 Jour.  Geology,  vol.  17, 1909,  p.  445.  See  also  J.  D.  Trueman,  idem,  vol.  20,  1912,  p.  311,  and  rejoinder 
by  Bastin,  idem,  vol.  21, 1913,  p.  103. 

2 For  example,  an  amphibolite  derived  from  limestone  was  shown  by  F.  D.  Adams  (Jour.  Geology,  vol. 
17,  1909,  p.  1)  to  fall  under  the  heading  of  auvergnose. 


METAMORPHIC  ROCKS. 


625 


sedimentary  rocks,  is  often  reversed.  Dominance  of  potash  over 
soda,  then,  is  an  indication  of  sedimentary  origin.  Dominance  of 
magnesia  over  lime  is  another  similar  criterion,  and  any  excess  of 
alumina  over  the  1 : 1 ratio  necessary  to  balance  lime  and  alkalies 
is  still  another.  Unusually  high  silica  also  affords  presumptive  evi- 
dence, which  by  itself  is  not  conclusive,  that  a rock  was  derived  from 
sediments.  When  two  of  these  criteria  are  applicable  to  a meta- 
morphic  rock,  there  is  a strong  presumption  established  in  favor  of 
its  former  sedimentary  character.  When  three  apply,  the  conclu- 
sion is  almost  certain,  and  the  concurrence  of  all  amounts  to  positive 
proof.  The  analyses,  however,  must  relate  to  fresh,  unweathered 
material,  and  the  criteria  proposed  apply  only  to  silicates  which  might 
be  metamorphosed  plutonics  or  eruptives. 

97270°— Bull.  616—16 10 


CHAPTER  XV. 

METALLIC  ORES. 

DEFINITION. 

From  a strictly  scientific  point  of  view,  the  terms  metallic  ore  and 
ore  deposit  have  no  clear  significance.  They  are  purely  conventional 
expressions,  used  to  describe  those  metalliferous  minerals  or  bodies 
of  mineral  having  economic  value,  from  which  the  useful  metals 
can  be  advantageously  extracted.  In  one  sense,  rock  salt  is  an  ore  of 
sodium,  and  limestone  an  ore  of  calcium;  but  to  term  beds  of  these 
substances  ore  deposits  would  be  quite  outside  of  current  usage. 

In  the  previous  chapters  of  this  work  several  forms  of  ore  deposit 
have  been  described;  and  therefore  the  present  chapter  is  in  some 
measure  supplementary.  Its  purpose  is  to  deal  with  the  subject  more 
fully,  and  especially  to  give  details  concerning  certain  groups  of  ores 
which  have  been  left  out  of  account  hitherto.  Little  has  been  said 
so  far  of  the  sulphides,  and  these  are  among  the  most  important  of 
economic  minerals.  Their  genesis,  their  deposition  in  veins  or  pock- 
ets, their  alterations  and  transferences  are  yet  to  be  considered. 

Upon  the  classification  of  ore  deposits  there  has  been  much  contro- 
versy, and  various  systems  are  in  vogue.1  To  the  geologist  or  miner 
this  question  is  most  important;  to  the  chemist  it  is  less  fundamental. 
Regarded  from  the  genetic  side,  a large  part  of  the  field  has  been 
already  covered;  and  it  is  easy  to  see  that  many  ore  deposits,  if  not 
all,  fall  under  the  headings  of  earlier  chapters.  For  example,  cer- 
tain metallic  ores  occur  as  volcanic  sublimates;  others,  like  the  titan- 
iferous  magnetites,  are  magmatic  segregations,  or  local  developments 
of  igneous  rocks.  The  sands  and  gravels  that  yield  chromite,  tin- 
stone, gold,  platinum,  etc.,  are  detrital  in  character;  many  manganese 
and  iron  ores  are  sedimentary  rocks,  and  from  the  latter  metamorphic 
beds  of  magnetite  or  hematite  are  derived.  Some  ore  bodies  are  resi- 
dues from  the  concentration  of  limestones;  others  represent  meta- 
somatic  replacements;  others  again  are  deposited  or  precipitated 

1 For  recent  papers  and  works  on  this  subject,  see  F.  Po§epn£,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  23, 1893, 
p.  197;  J.  H.  L.  Vogt,  idem,  vol.  31, 1901,  p.  125;  L.  De  Launay,  Contribution  k l’6tude  des  gites  m^talli- 
f&res,  Paris,  1897;  J.  F.  Kemp,  Ore  deposits  of  the  United  States  and  Canada,  New  York,  1900;  W.  H. 
Weed  and  J.  E.  Spurr,  Eng.  and  Min.  Jour.,  vol.  75,  1903,  p.  256;  It.  Beck,  Lehre  von  den  Erzlagerstatten, 
Berlin,  1903,  and  its  English  translation  by  Weed,  New  York,  1905;  A.  W.  Stelzner  and  A.  Bergeat,  Dio 
Erzlagerstatten,  Leipzig,  1904;  C.  R.  Van  Hise,  A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey, 
vol-  47,  1904,  chapter  12;  W.  H.  Weed,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  33,  1903,  p.  717;  C.  R.  Keyes, 
idem,  vol.  30,  1900,  p.  323;  G.  Giirich,  Zeitschr.  prakt.  Geologie,  1899,  p.  173;  F.  Beyschlag,  P.  Krusch, 
and  J.  n.  L.  Vogt,  Die  Lagerstatten  der  nutzbaren  Mineralien  und  Gesteine,  Stuttgart,  1910.  An  English 
translation  of  vol.  1 appeared  in  1914.  On  pp.  147-158  there  is  an  elaborate  discussion  of  the  relative  abun- 
dance of  the  heavy  metals. 

626 


METALLIC  ORES. 


627 


from  solutions.  In  short,  an  ore  body  is  simply  a concentration  of 
certain  compounds  of  certain  metals  effected  by  processes  with  which 
we  are  already  familiar.  Since,  however,  each  metal  forms  its  own 
special  compounds,  and  exhibits  reactions  peculiar  to  itself,  it  is  best 
for  chemical  purposes  to  adopt  i chemical  classification,  with  which 
the  broad,  general  principles  can  be  correlated.  Each  metal,  there- 
fore, will  be  treated  by  itself  as  a chemical  individual  and  from 
a chemical  point  of  view.  Geologically  it  is  important  to  know 
whether  an  ore  deposit,  laid  down  from  solution,  occupies  the  pores 
of  a sandstone,  a limestone  cavern,  or  a fissure  in  the  rocks;  and  it  is 
also  desirable  to  ascertain  how  these  cavities  or  crevices  were  formed. 
To  the  chemist  these  considerations  are  for  the  most  part  irrelevant; 
but  the  conditions  under  which  given  compounds  can  be  dissolved  or 
precipitated  are  fundamental.  What  are  the  components  of  ore 
bodies  ? How  were  they  produced  ? In  what  way  are  they  redistrib- 
uted ? These  are  some  of  the  questions  which  the  chemist  is  expected 
to  answer.  The  details  must  be  studied  with  reference  to  the  indi- 
vidual metals;  but  some  general  considerations  require  attention  first. 

SOURCE  OF  METALS. 

Although  the  immediate  derivation  of  metallic  ores  if  often  from 
sedimentary  rocks,  the  original  source  of  the  metals  is  to  be  sought 
in  the  igneous  magmas.1  In  igneous  rocks  of  some  sort  the  metals 
were  once  diffused,  and  their  presence  in  eruptive  material  is  easily 
detected.  G.  Forchhammer  2 in  a series  of  rock  samples  found  traces 
of  silver,  copper,  lead,  bismuth,  cobalt,  nickel,  zinc,  arsenic,  anti- 
mony, and  tin,  to  say  nothing  of  the  commoner  metals,  iron  and  man- 
ganese. Some  of  the  same  elements  were  found  in  the  ashes  of  plants, 
which  had  extracted  them  from  the  soil.  From  these  experiments 
Forchhammer  concluded  that  ore  bodies  derived  their  contents  from 
the  neighboring  rocks,  a conclusion  at  which  other  investigators  have 
also  arrived.  In  an  elaborate  series  of  researches  F.  Sandberger  3 
found  that  the  dark  silicates  of  many  rocks  contained  lead,  copper, 
tin,  antimony,  arsenic,  nickel,  cobalt,  bismuth,  and  silver,  and  upon 
these  facts  he  based  his  famous  theory  of  11 lateral  secretion.”  That 
is,  Sandberger  concluded  that  metalliferous  veins  derived  their  me- 
tallic contents  by  lateral  leaching  from  adjacent  rocks.  This  theory, 
however,  was  subjected  to  much  criticism  by  A.  Stelzner,  F.  Po§epny, 
and  others,4 * *  it  being  shown  that  in  some  instances  at  least  the  country 
rocks  might  have  received  secondary  impregnations  from  the  veins. 


1 C.  R.  Keyes  (Bull.  Am.  Inst.  Min.  Eng.,  1910,  p.  527)  has  suggested  the  possible  derivation  of  heavy 
metals  from  meteoritic  matter,  especially  meteoric  dust. 

2 Pogg.  Annalen,  vol.  95,  p.  60. 

3 Untersuchungen  iiber  Erzgange,  Wiesbaden,  1882  and  1885.  See  also  Neues  Jahrb.,  1878,  p.  291,  on 

copper,  lead,  cobalt,  and  antimony  in  basalt. 

* A.  Stelzner,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  31, 1879,  p.  644,  and  rejoinder  by  F.  Sandberger,  idem, 

vol.  23, 1880,  p.  350.  F.  Posepn^,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  23, 1893,  pp.  247-254. 


628 


THE  DATA  OE  GEOCHEMISTRY. 


In  other  investigations,  some  earlier  and  some  more  recent,  the  dis- 
semination of  heavy  metals  in  igneous  rocks  is  clearly  proved.  A. 
Daubree 1 found  determinable  quantities  of  arsenic  and  antimony  in 
basalt — namely,  0.01  gram  of  As  and  0.03  of  Sb  to  the  kilogram,, 
The  same  metals,  together  with  lead  and  copper,  were  detected  by 
G.  F.  Becker 2 in  the  fresh  granites  near  Steamboat  Springs,  Nevada. 
In  the  porphyries  of  Leadville,  Colorado,  W.  F.  Hillebrand 3 was 
able  to  determine  lead.  Out  of  18  samples,  taken  at  points  distant 
from  ore  bodies,  three  contained  no  lead,  the  richest  carried  0.0064 
per  cent,  and  the  average  was  0.002  per  cent  of  PbO.  One  porphyry 
yielded  0.008  per  cent  of  zinc  oxide,  and  a rhyolite  contained  0.0043 
per  cent.  Silver  was  also  found  in  these  rocks  in  variable  quantities, 
the  best  average  giving  0.0265  ounce  per  ton.  Gold,  although  some- 
times present  in  traces,  was  generally  not  found.  Traces  of  silver 
in  diabase  and  diorite  are  reported  by  G.  F.  Becker 4 near  Washoe, 
Nevada,  and  in  the  quartz  porphyry  of  Eureka  J.  S.  Curtis  5 found 
both  gold  and  silver.  Silver,  according  to  S.  F.  Emmons,6  is  also 
present  in  the  eruptive  rocks  of  Custer  County,  Colorado,  and  J.  W. 
Mallet  found  it  in  volcanic  ash  from  two  points  in  the  Andes.  Ash 
from  Cotopaxi 7 carried  silver  to  the  extent  of  1 part  in  83,600,  and 
ash  from  Tunguragua 8 yielded  1 part  in  107,200.  The  latter  quan- 
tity is  very  near  Hillebrand’ s average  for  the  Leadville  porphyries, 
which  is  equivalent  to  1 part  in  110,000.  In  recent  volcanic  ash 
from  Vesuvius  E.  Comanducci 9 found  0.0854  per  cent  of  copper 
oxide,  with  0.0038  of  cobalt  oxide. 

In  four  rocks — granite,  porphyry,  and  diabase  from  the  Archean 
of  Missouri — J.  D.  Robertson  10  determined  the  following  percentages 
of  lead,  zinc,  and  copper: 

Pb,  0.00197  to  0.0068;  average,  0.004. 

Zn,  0.00139  to  0.0176;  average,  0.009. 

Cu,  0.00240  to  0.0104;  average,  0.006. 

The  adjacent  Silurian  and  Carboniferous  limestones  also  contained 
these  metals,  but  in  slightly  smaller  proportions. 

According  to  L.  Dieulafait,11  who  tested  hundreds  of  rocks,  zinc 
and  copper  are  always  to  be  detected,  and  they  are  also  present  in 
sea  water.  Copper  salts,  it  will  be  remembered,  are  often  found 


1 Compt.  Rend.,  vol.  32,  1851,  p.  827. 

2 Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  350. 

s Idem,  vol.  12,  1886,  pp.  591-594. 

« Idem,  vol.  3,  1882,  pp.  223-227.  Assays  by  J.  S.  Curtis. 

&  Idem,  vol.  7,  1884,  pp.  80-92. 

6 Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2,  1896,  p.  471.  Assays  by  L.  G.  Eakins. 

7 Chem.  News,  vol.  55,  1887,  p.  17. 

8 Proc.  Roy.  Soc.,  vol.  47, 1890,  p.  277. 

9 Gazz.  chim.  ital.,  vol.  36,  pt.  2, 1906,  p.  797. 

10  Missouri  Geol.  Survey,  vol.  7,  1894,  pp.  479-481. 

n Annales  chim.  phys.,  5th  ser.,  vol.  18,  1879,  p.  349;  vol.  21, 1880,  p.  256. 


METALLIC  ORES. 


629 


among  the  sublimates  of  Vesuvius,  Stromboli,  and  Etna,  and  A.  B. 
Lyons  1 observed  copper  sulphate  in  the  crater  of  Kilauea.  In  15 
Hawaiian  lavas  Lyons  found  from  0.07  to  0.48  per  cent  of  copper 
oxide;  in  average,  0.18  per  cent.  G.  Steiger,  however,  in  the  labora- 
tory of  the  United  States  Geological  Survey,  analyzed  a composite 
sample  of  71  Hawaiian  lavas  and  found  only  0.0155  per  cent  of  cop- 
per, showing  that  Lyons’s  figures  are  doubtless  much  too  high.  A 
large  series  of  igneous  and  metamorphic  rocks  of  British  Guiana, 
analyzed  by  J.  B.  Harrison,2  also  yielded  appreciable  quantities  of 
copper,  with  sometimes  other  heavy  metals.  In  36  rocks  examined 
6 contained  no  copper,  12  contained  it  in  traces,  and  one,  a feldspathic 
tuff,  carried  0.13  per  cent.  The  average  percentage  of  copper  for  the 
entire  series  was  0.025.  In  23  samples  lead  was  sought  for  and 
found  in  5 of  them,  the  maximum  percentage  being  0.02  per  cent. 
Eight  rocks  yielded  silver,  from  4 to  54  grains  per  ton  of  2,240 
pounds,  in  average,  25.5  grains;  and  out  of  29  rocks  only  1 was  free 
from  gold.  The  highest  gold  was  43  grains  per  ton;  the  mean  was 
6.5  grains. 

Even  more  positive  evidence  as  to  the  wide  distribution  of  the 
heavy  metals  was  obtained  by  F.  W.  Clarke  and  G.  Steiger.3  Large 
composite  samples  of  igneous  rocks,  clays,  and  river  silt  were  ana- 
lyzed, and  in  them  copper,  lead,  zinc,  nickel,  and  arsenic  were  deter- 
mined. The  results  obtained,  in  percentages,  appear  in  the  following 
table : 

Percentages  of  heavy  metals  in  composite  samples. 

A.  The  “red  clay”  of  the  oceanic  depths.  Composite  of  51  samples,  dredged  from  the  sea  bottom  and 
representative  of  all  the  great  oceans.  The  larger  part  of  this  material  was  collected  by  the  Challenger 
Expedition.  Determinations  (by  E.  C.  Sullivan)  of  CuO,  ZnO,  PbO,  and  AS2O5  made  on  150-gram 
portions. 

B.  “Terrigenous  clays,”  from  oceanic  depths  of  140  to  2,120  fathoms.  Composite  of  52  samples,  namely, 
4 “green  muds”  and  48  “blue  muds,”  also  mainly  from  the  Challenger  Expedition.  Determinations  made 
on  300-gram  portions. 

C.  Composite  of  235  samples  of  Mississippi  silt.  For  the  heavy  metals  200-gram  portions  were  taken. 

D.  Composite  of  329  igneous  rocks,  all  American.  Determinations  on  90-gram  portions. 


A 

B 

C 

D 

Average. 

NiO 

0. 0320 

0.  0630 

0.  0170 

0.  00655 

0.  0296 

-A.S2O5 

.0010 

Trace. 

.0004 

. 00074 

.0005 

Pbo: 

.0073 

.0004 

.0002 

. 00081 

.0022 

CuO 

.0200 

.0160 

.0043 

. 01167 

.0130 

ZnO 

.0052 

.0070 

.0010 

. 00638 

.0049 

In  the  foregoing  pages  only  a part  of  the  available  evidence  has 
been  presented,  but  it  is  enough  to  establish  the  point  at  issue.  The 
heavy  metals  are  widely  disseminated,  both  in  old  and  in  recent 


1 Am.  Jour.  Sci.,  4th  ser.,  vol.  2,  1896,  p.  424.  In  andesite  from  Lautoka,  Fiji,  H.  I.  Jensen  found  0.034 
per  cent  of  copper,  on  an  average.  Chem.  News,  vol.  96,  1907,  p.  245.  The  same  quantity  was  found  by 
R.  C.  Wells  in  a sample  of  the  Columbia  River  basalt,  which  covers  a large  area. 

2 Rept.  on  petrography  of  Cuyuni  and  Mazaruni  districts,  Georgetown,  Demerara,  1905.  On  gold  and 
silver  in  diabase,  French  Guiana,  see  E.  D.  Levat,  Annales  des  mines,  9th  ser.,  vol.  13,  1898,  p.  386;  and 
also  in  Min.  Industry,  vol.  7,  p.  315. 

* Jour.  Washington  Acad.  Sci.,  vol.  4, 1914,  p.  58.* 


630 


THE  DATA  OF  GEOCHEMISTRY. 


igneous  rocks,  from  which,  by  proper  methods,  they  can  be  concen- 
trated. In  the  laboratory  of  the  United  States  Geological  Survey 
such  metals  as  nickel  and  chromium  are  often  quantitatively  esti- 
mated, as  shown  in  the  table  on  page  32.  Copper  is  determined 
in  exceptional  cases  only,  but  indications  of  its  presence  are  fre- 
quently observed.  Of  its  wide  distribution  in  igneous  rocks  there  is 
no  shadow  of  a doubt.  From  the  rocks  all  of  these  metals  are 
leached,  and  traces  of  them  accumulate  in  the  sea.  They  also  appear 
in  many  mineral  springs,1  a fact  which  is  capable  of  more  than  one 
interpretation.  Such  a spring  may  derive  its  contents  from  dispersed 
material,  or  it  may  rise  from  a segregated  body  of  ore ; its  composi- 
tion, therefore,  merely  tells  us  that  the  metalliferous  compounds  are 
more  or  less  freely  soluble.  The  true  origin  of  the  latter  is  not  thereby 
explained. 

That  sulphides  of  the  heavy  metals  can  be  dissolved  in  or  decom- 
posed by  water  alone,  there  is  some  experimental  evidence.  P.  De 
Clermont  and  J.  Frommel2  found  that  sulphides  of  iron,  nickel, 
cobalt,  antimony,  arsenic,  silver,  and  tin  were  attacked  by  boiling 
water,  hydrogen  sulphide  being  given  off.  Some  were  acted  upon 
even  at  temperatures  below  100°;  As2S3  at  22°,  FeS  at  56°,  Ag2S  at 
89°,  and  Sb2S3  at  95°.  The  sulphides  of  copper,  zinc,  mercury,  cad- 
mium, gold,  platinum,  and  molybdenum,  treated  in  the  same  way, 
gave  no  evidence  of  decomposition. 

C.  Doelter’s  experiments  3 were  conducted  differently.  The  natural 
sulphides,  in  fine  powder,  were  heated  with  water  in  glass  tubes  to 
80°  during  periods  of  30  to  32  days.  In  a second  series  of  experiments 
lasting  24  days,  a solution  of  sodium  sulphide  was  used  instead  of 
water.  The  following  percentages  of  material  passed  into  solution: 

Material  dissolved  from  natural  sulphides  in  water  and  in  sodium  sulphide  solution. 


Water 

alone. 

With 

sodium 

sulphide. 

Galena 

1.  79 

2.3 

Stibnite 

5.  01 

All 

Pyrite 

2.  99 

10.  6 

Blende 

.025 

. 62 

Chalcopyrite 

. 1669 

. 11 

Bournonite 

2.  075 

3.  9 

Arsenopyr  ite 

1.5 

3.2 

In  most  of  these  experiments,  but  not  in  all,  the  dissolved  substance 
had  the  same  composition  as  the  original  material.  That  is,  the 
minerals  dissolved  as  such,  without  decomposition — a conclusion  that 


1 See  ante,  p.  188,  for  examples.  The  traces  of  heavy  metals  which  spring  waters  contain  are  often  more 
easily  detected  in  their  sediments:  that  is,  they  become  concentrated  in  the  insoluble  precipitates  that 
spring  waters  often  deposit. 

2 Annales  chim.  phys.,  5th  ser.,  vol.  18,  1879,  p.  189. 

8 Min.  pet.  Mitt.,  vol.  11,  1890,  p.  319.  Research  continued  by  Q.  A.  Binder,  idem,  vol.  12, 1891,  p.  332. 


METALLIC  ORES.  631 

was  strengthened  by  the  observation  that  in  most  cases  new  crystal- 
lizations were  formed.1 

According  to  Doelter,  then,  sulphides  may  be  dissolved  and  recrys- 
tallized from  water  alone.  This  is  important,  but  not  a complete 
indication  of  what  occurs  in  nature.  Natural  waters,  as  we  well 
know,  are  not  pure,  but  charged  with  various  dissolved  salts,  which 
exert  a varying  influence  upon  the  solution  of  sulphides.  They  also 
contain  carbonic  acid,  and  sometimes  also  the  stronger  mineral 
acids;  and  surface  waters  carry  dissolved  oxygen.  All  of  these 
impurities  take  part  in  the  solution,  concentration,  and  redistribu- 
tion of  metallic  ores,  and  their  effects  are  furthermore  varied  by 
differences  of  temperature.  A hot  water,  rising  from  great  depths 
and  free  from  oxygen,  produces  one  set  of  changes;  a cold  surface 
water,  highly  oxygenated,  acts  quite  differently.  Direct  solution  of 
ores  is  more  likely  to  occur  in  the  one  case,  oxidation  to  soluble  salts 
is  commonly  evident  in  the  other.  The  main  fact,  that  solution  is 
effected  in  one  way  or  another,  is  well  illustrated,  not  only  by  the 
composition  of  mineral  springs,  but  also  by  the  analyses  of  mine 
waters.  For  example,  in  a water  from  a mine  shaft  near  Broken 
Hill,  J.  C.  H.  Mingaye  2 found,  in  grains  per  gallon,  8.40  copper, 
10.67  zinc,  21.82  cobalt,  and  6.71  nickel.  The  water  was  strongly 
acid.  Two  analyses  of  mine  waters  from  the  Comstock  lode,  cited 
by  J.  A.  Reid,3  are  accompanied  by  assays  for  gold  and  silver.  The 
more  concentrated  of  these  waters  contained  188.09  milligrams  per 
ton  of  water  in  silver,  with  4.15  milligrams  in  gold.  This  water  was 
also  strongly  acid. 

An  extraordinary  water  from  a mine  tunnel  at  Idaho  Springs,  Colo- 
rado, analyzed  by  R.  C.  Wells  in  the  laboratory  of  the  United  States 
Geological  Survey,  contained  nearly  8 grams  per  liter  of  an  oxide 
of  molybdenum,  probably  the  so-called  soluble  molybdenum  blue. 
The  water  also  contained  a large  amount  of  free  sulphuric  acid,  and 
was  a dark  greenish  blue  in  color  and  only  transparent  in  very  thin 
layers.  The  molybdic  compound  formed  about  25  per  cent  of  the 
total  impurity.  Other  typical  mine  waters  are  represented  in  the  fol- 
lowing table  of  analyses,  which,  when  not  otherwise  stated,  were  made 
in  the  laboratory  of  the  United  States  Geological  Survey.  All  are 
reduced  to  the  uniform  ionic  standard  and  to  parts  per  million.4 

1 Still  more  recently  O.  Weigel  (Nachrichten  K.  Gesell.  Gottingen,  Math.-phys.  Klasse,  1906,  p.  525)  has 
determined  the  solubility  in  pure  water  of  the  sulphides  of  Pb,  Hg,  Ag,  Cu,  Cd,  Zn,  Ni,  Co,  Fe,  Mn,  Sn, 
As,  Sb,  and  Bi.  All  were  slightly  soluble.  For  an  abridgment  of  this  paper,  see  Zeitschr.  physikal.  Chemie, 
vol.  58,  1907,  p.  293. 

2 Records  Geol.  Survey  New  South  Wales,  vol.  8, 1909,  p.  292. 

3 Bull.  Dept.  Geology  Univ.  California,  vol.  4,  pp.  189, 192.  In  the  same  volume,  p.  332,  A.  C.  Lawson 
gives  an  analysis  of  water  from  the  Ruth  mine,  Robinson  district,  Nevada. 

< For  other  analyses  of  minewaters,  see  J.  A.  Phillips,  Philos.  Mag.,  4th  ser.,  vol.  42, 1871,  p.  401;  A.Schrauf, 
Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  41,  1891,  p.  35;  A.  C.  Lane,  Proc.  Lake  Superior  Min.  Inst.,  vol.  12, 
1906,  p.  97;  W.  H.  Emmons  and  G.  L.  Harrington,  Econ.  Geology,  vol.  8,  p.  653,  1913;  W.  J.  Sharwood, 
idem,  vol.  6,  p.  742, 1911;  C.  R.  Van  Hise  and  C.  K.  Leith,  Mon.  U.  S.  Geol.  Survey,  vol.  52  pp.  543, 579, 1911; 
J.  S.  Maclaurin,  45th  Ann.  Rept.  Dominion  Laboratory,  New  Zealand,  1912,  pp.  47,  48.  A few  others  have 
already  been  cited  in  the  chapter  on  mineral  springs.  F.  Posepn^  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  23, 
1893,  p.  240)  has  tabulated  the  occurrences  of  Sn,  Sb,  Cu,  and  As  in  mineral  waters. 


632 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  mine  waters. 


A.  Water  from  500-foot  level  of  Geyser  mine,  Custer  County,  Colorado. 

B.  Same  locality  as  A,  from  the  2,000-foot  level.  Contains  also  traces  of  Br,  I,  F,  and  B4O7.  Analyses 
A and  B by  W.  F.  Hillebrand.  Discussed  by  S.  F.  Emmons,  Seventeenth  Ann.  Kept.  U.  S.  Geol.  Survey, 
pt.  2,  1896,  p.  462. 

C.  Water  from  the  Stanley  mine,  Idaho  Springs,  Colorado.  Analyses  by  L.  J.  W.  Jones,  Proc.  Colorado 
Sci.  Soc.,  vol.  6, 1897,  p.  48. 

D.  Hot  water  from  a bore  hole  2,316  feet  deep,  in  the  Mizpah  mine,  Tonopah,  Nevada.  Analysis  by 
R.  C.  Wells.  Bicarbonates  here  reduced  to  normal  carbonates. 

E.  Water  from  St.  Lawrence  mine,  Butte,  Montana.  Analysis  by  Hillebrand. 

F.  Water  from  Mountain  View  mine,  Butte,  Montana.  Analysis  by  Hillebrand.  Contains  a trace  of 
arsenic. 

G.  Water  from  Alabama  Coon  mine,  Joplin  district,  Missouri.  Analysis  by  H.  N.  Stokes. 

H.  Water  from  the  Victor  mine,  Joplin  district.  Analysis  by  H.  A.  Buehler  and  V.  A.  Gottschalk, 
Econ.  Geology,  vol.  5, 1910,  p.  28.  The  authors  also  give  three  other  analyses  of  Joplin  mine  waters.  Their 
study  relates  to  the  oxidation  of  sulphide  ores,  and  they  find  that  pyrite  or  marcasite  accelerates  the  reac- 
tivity of  other  sulphides.  Two  more  analyses  of  zinc-bearing  mine  waters  from  the  Joplin  district  are 
reported  by  C.  P.  Williams,  Am.  Chemist,  vol.  7,  1877,  p.  286.  See  also  E.  S.  H.  Bailey,  Water-Supply 
Paper  U.  S.  Geol.  Survey.  No.  273,  1911,  p.  349. 

I.  Water  from  the  Burra  Burra  mine,  Ducktown,  Tennessee.  One  of  a series  of  six  analyses  of  mine 
waters  by  R.  C.  Wells. 

J.  Water  from  the  Rothschonberger  Stolln,  Freiberg,  Saxony,  at  its  point  of  discharge  into  the  Triebisch 
Valley.  Analysis  by  Frenzel.  Described  by  H.  Muller,  Jahrb.  Berg-u.  Huttenw.  Konig.  Sachsen,  1885, 
p.  185.  Discharges  479  kilograms  of  ZnO  daily,  or  175,024  kilograms  per  annum. 


Cl... 

so4.. 

C03-. 

N03.. 
P04.. 
K.... 
Na... 
Li... 
Ca... 
Sr... 
Mg... 
Al... 
Few. 
Fe".. 
Mn.  . 
Ni... 
Co... 
Cu... 
Zn... 
Cd... 
Pb... 
Sn... 
Si02. 


Total  COr 


7.9 
43.2 
110.  5 


10.  6 

36.4 
Trace. 

37.4 


12.  25 

a.  4 

. 7 

.8 


Trace. 

.2 


Trace. 
25.  9 


286.  25 


186.  40 
161.  70 
1,  513.  44 
1.  60 
Trace. 
198.  00 
719.  45 
2.  85 
146.  41 
1.  95 
177.  67 
1.  06 

[ 3.50 

.57 


.02 

.34 


1.  35 
24.42 


3, 140.  73 
2,  528.  46 


8. 16 
2, 039.  51 


70.  00 
106.  27 


187. 15 


93.  50 
3. 12 
164.  82 
3.  44 
155.  58 


77.  05 
49.  66 


43.  80 


3,  002.  06 


35.6 
327.2 
87.  9 
Trace. 


3.4 

148.8 


68.8 


6.3 

.7 

.7 


Trace. 


64.8 


13.0 
2,  672.  0 


Trace. 
13. 1 
39.6 


132.5 


61.6 

83.5 

159.8 

12.0 

.5 

59.1 
852.0 

41.1 


17.0 

47.7 


744.2 

121.2 


4,  204.  5 
23.7 


a AI2O3+P2O5,  0.8  per  million. 


METALLIC  OKES. 


633 


Analyses  of  mine  waters — Continued. 


F 

G 

H 

I 

J 

Cl 

17.  7 
71,  053.  3 
1.5 
6.8 
41.  7 
Trace. 
307.  7 
149.2 
85.2 

2.7 
6, 153.  2 

3.  65 
1,  647.  58 

0.1 
6,  664.  0 

12.4 

124.8 

so4 

PCL 

K ,4 

. 5 
49.  9 
None. 
345.3 
25.2 
142. 1 

} 474. 6 

1.  7 

3.  20 
13.  02 

19.  8 
23.4 

Na 

Li 

Ca 

260.  45 
48.  60 
11.  70 

67.6 

40.6 
433.0 
None. 

2, 178.  0 
.2 

46.4 

14.5 

Mg 

A1 

Fe7//. 

} 6.6 

Fe" 

49.8 
13.2 
3.5 
4.  6 
45,  633.  2 
411.2 

142.  80 

Mn 

Ni 

Co 

Cu 

3.7 
2, 412.  0 
9.0 
107.6 

312.1 

199.8 

Zn 

345. 10 

8.9 

Cd 

Si02 

67.4 

23.  20 
251.  70 

55.  6 
129.6 

18.0 

H2SO4,  free 

Total  C02 

117,  846.  0 
8.9 

9,  727.  5 

2,  751.  00 
87.0 

10, 123.  8 

<*231.  6 

o244.9  in  the  original. 


Analysis  A represents  vadose  or  superficial  water;  B,  water  from 
the  deep  circulation.  The  difference  in  concentration  is  remarkable. 
Water  F is  essentially  a strong  solution  of  copper  sulphate,  formed 
by  oxidation  of  sulphides.  Such  waters  are  common  in  copper  mines, 
and  from  them  the  copper  can  in  many  cases  be  profitably  recovered. 
The  Ducktown  water  is  also  noteworthy  on  account  of  its  high  pro- 
portion of  ferrous  sulphate.1 

The  phenomena  of  solution,  then,  are  evidently  of  supreme  impor- 
tance in  the  concentration  of  metallic  ores.  This  statement  can  be 
given  the  broadest  possible  construction.  A magmatic  ore  owes  its 
segregation  to  a relative  insolubihty  in  the  magma.  A residual  or 
detrital  ore  is  formed,  at  least  in  part,  by  the  removal  from  a rock 
of  the  more  soluble  constituents,  the  less  soluble  thereby  becoming 
concentrated.  Sedimentary  ores  are  deposited  from  solutions,  either 
directly  or  by  precipitation,  and  metalliferous  veins  represent  an- 
other aspect  of  the  same  processes.  The  original  magmatic  rocks 
are  separated,  by  solution  or  leaching,  into  different  fractions;  and 
then,  by  direct  deposition,  by  precipitative  reactions,  or  by  metaso- 
matic  replacements,  ore  bodies,  and  especially  vein  fillings,  are  formed. 
In  most  cases,  probably,  the  final,  workable  deposit  is  the  outcome 
of  a series  of  concentrations,  the  result  of  several  interdependent  proc- 
esses, but  the  underlying  principles  are  the  same.  By  differences  of 
solubility,  the  constituents  of  the  earth’s  crust  are  separated  from  one 


For  the  remarkable  calcium  chloride  waters  of  the  Lake  Superior  copper  region,  see  ante,  p.  185. 


634 


THE  DATA  OF  GEOCHEMISTRY. 


another,  to  be  laid  down  again  under  different  conditions  and  in 
different  places. 

The  two  fundamental  facts  with  which  we  now  have  to  deal  are 
the  dissemination  of  the  heavy  metals  in  the  igneous  rocks  and  the 
circulation  of  the  underground  waters.  Descending,  meteoric  waters 
effect  some  of  the  observed  concentrations;  lateral  secretions  bring  ' 
about  others,  and  waters  ascending  from  unknown  depths  play  their 
part  in  the  complex  of  phenomena.  Whether  these  waters  have  a 
common  origin  or  not  is  unessential  to  the  present  discussion.  It  is 
held  by  some  writers,  notably  by  Suess,  that  certain  of  the  ascending 
waters  arise  from  the  original  magma  and  now  see  the  light  of  day 
for  the  first  time.  This  conception  has  been  correlated  with  the 
notion  that  the  heavier  metals,  by  virtue  of  their  high  specific  gravity, 
are  concentrated  at  great  depths,  from  which  the  solvent  waters 
bring  them  to  the  surface.1  Speculations  of  this  sort  are  interesting, 
but  not  necessary  for  present  purposes.  The  fact  that  the  ascending, 
deep-seated  waters  are  hot,  and  therefore  more  powerful  as  agents 
of  solution,  is,  however,  most  pertinent. 

The  general  principles  governing  the  circulation  of  the  under- 
ground waters  have  been  elaborately  discussed  by  Van  Hise,2  and 
need  not  be  especially  considered  here.  The  arguments  are  mainly 
physical  and  geological,  and  have  only  partial  relation  to  chemistry. 
These  waters,  ascending,  descending,  or  lateral  secreting,  tend  to 
gather  into  trunk  channels,  in  which,  sooner  or  later,  some  of  the 
substances  held  in  solution  are  deposited.  Ore  bodies  are  thus 
formed,  but  only  in  exceptional  cases.  By  far  the  greater  number  of 
veins  are  barren  of  heavy  metals,  or  at  least  so  nearly  barren  that 
they  need  not  be  further  described.  Once  in  a while  concentrations 
of  heavy  metals  are  produced,  and  in  most  cases,  but  not  invariably, 
they  appear  in  association  with  rock  of  igneous  origin.3  This  asso- 
ciation seems  to  be  fundamentally  important,  so  far  as  the  metal- 
liferous veins  are  concerned,  and  the  problem  of  their  origin  is  the 
only  one  now  before  us.  Magmatic,  sedimentary,  and  detrital  ores 
fall  under  other  headings. 

An  igneous  effusion  forces  its  way  to  the  surface  of  the  earth, 
thereby  displacing  and  fracturing  the  rocks  which  were  in  its  path. 
As  it  cools  and  shrinks,  other  crevices  are  formed,  through  which 

1 See  L.  De  Launay,  Contribution  k l’fetude  des  gites  mfetallif feres,  1897,  p.  6;  and  F.  Posepn^,  Trans.  Am. 
Inst.  Min.  Eng.,  vol.  23,  1893,  p.  206.  J.  H.  L.  Vogt  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  31,  1901,  p.  125) 
and  also  C.  R.  Van  Hise  (A  treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904)  dissent  from 
this  view.  The  importance  of  magmatic  waters  as  vein  fillers  has  been  recently  argued  by  A.  C.  Spencer, 
Trans.  Am.  Inst.  Min.  Eng.,  vol.  36, 1906,  p.  364.  The  magmatic  waters  are  regarded  by  J.  E . Spurr  (Econ. 
Geology,  vol.  2,  1907,  p.  781)  as  residues  representing  the  last  stage  of  magmatic  differentiation;  and  in 
them  the  heavier  metals  and  other  vein-filling  materials  are  supposed  to  be  concentrated. 

2 A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  chapter  12. 

* See  Beck’s  work  on  ore  deposits.  Also  papers  by  J.  F.  Kemp,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 
1901,  p.  169;  vol.  33,  1903,  p.  699;  J.  E.  Spurr,  idem,  vol.  33,  1903,  p.  288;  W.  H.  Weed,  idem,  vol.  33,  1903, 
p.  715;  W.  Lindgren,  idem,  vol.  30,  1900,  p.  578. 


METALLIC  ORES. 


635 


also  the  mineralized  waters  can  find  a passage.  These  waters  may 
be  partly  magmatic,  brought  with  the  igneous  matter  from  the 
depths,  or  partly  gathered  from  sedimentary  material;  but  whatever 
may  have  been  their  source,  they  are  heated,  and  therefore  their 
solvent  power  is  increased.  During  solidification,  moreover,  any 
water  that  was  entangled  within  the  molten  rock  is  extruded,  carry- 
ing its  dissolved  load  into  the  open  channels.  A blend  of  waters  from 
different  sources — deep  seated,  superficial,  and  magmatic — enters 
the  crevices  of  the  rocks,  each  part  of  the  mixture  contributing  its 
share  to  their  filling.  The  solutions  thus  commingled  are,  more- 
over, not  all  alike,  and  therefore  chemical  reactions,  such  as  double 
decompositions  and  precipitations,  become  possible  between  them. 
The  frequent  concentrations  of  ores  at  points  of  intersection  between 
two  veins  may  possibly  indicate  reactions  of  this  kind.  These 
changes  are  also  complicated  by  reactions  between  intruded  rock  and 
the  formations  which  it  has  penetrated,  and  they  vary  with  varia- 
tions in  the  latter.  Some  ore  deposits  are . evidently  produced  in 
zones  of  contact  metamorphism,  especially  in  limestones,  and  the  ores 
are  then  associated  with  such  characteristic  minerals  as  garnet,  wol- 
lastonite,  pyroxene,  vesuvianite,  and  so  on.1  Aqueous  solutions  take 
part  in  some  of  these  changes,  penetrating  the  walls  of  the  contact 
and  bringing  about  metasomatic  replacements.2 

In  the  ascent  of  an  igneous  intrusion,  with  its  entangled  waters,  the 
so-called  pneumatolytic  processes  appear  to  have  some  importance. 
The  molten  magma  contains  gases  and  vapors  other  than  the  vapor 
of  water,  as  we  know  from  the  phenomena  of  volcanism.  Whether 
these  gases  are  occluded,  or  evolved  by  reactions  within  the  magma,  is 
not  material  to  the  present  discussion.  In  volcanic  craters  they  form 
sublimates  containing  copper,  iron,  and  other  heavy  metals,  which 
often  consist  of  chlorides.  Ammonium  chloride,  fluorine  compounds, 
and  boric  acid,  which  last  is  volatile  in  steam,  are  other  common  sub- 
stances in  volcanic  emanations. 

In  ore  formation  the  magmatic  chlorides  and  fluorides  probably 
have  definite  functions.  In  the  molten  rock  they  convert  some  part 
of  the  heavy  metals  into  compounds  which  are  volatile  at  high  tem- 
peratures and  which  therefore  tend  to  gather  at  the  margins  of  the 
intrusions.  There,  being  soluble  in  water,  they  pass  into  solution, 
and  so  find  their  way  into  the  open  channels  wherein  deposition  takes 
place.  With  them  other  substances  are  deposited,  forming  the 
gangue  minerals — calcite,  quartz,  barite,  fluorite,  etc. — in  even  larger 
amounts. 


1 See  W.  Lindgren,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  226. 

2 Lindgren,  idem,  vol.  30,  1900,  p.  578.  These  contact  deposits  and  metasomatic  alterations  are  fully 
described  by  Lindgren,  who  gives  excellent  summaries  of  the  earlier  literature.  Later  papers  by  Lindgren 
on  ore  deposits  are  in  Econ.  Geology,  vol.  2,  1907,  pp.  105,  743. 


636 


THE  DATA  OF  GEOCHEMISTRY. 


The  heavy  metals,  however,  are  not  laid  down  as  chlorides  or  fluor- 
ides except  in  rare  instances ; hut  in  other  forms  chlorine  and  fluorine 
have  acted  as  primary  agents  in  bringing  about  their  concentration, 
water  tends  to  hydrolyze  the  salts  thus  formed,  other  solutions 
react  with  them,  and  quite  different  compounds  are  precipitated.  In 
the  case  of  tin  the  oxide  is  commonly  produced;  the  other  metals 
tend  to  appear  as  sulphides.  Chlorine  and  fluorine  act  only  as  tem- 
porary carriers  of  the  metals,  and  when  their  work  is  done  they  enter 
into  other  combinations.  Fluorine  remains  in  a gangue  mineral, 
fluorspar;  the  chlorine  returns  into  circulation  as  a soluble  alkaline 
chloride;  that  is,  as  common  salt.  I ci.te  only  the  simplest  cases. 

The  pneumatolytic  process  thus  outlined  is  largely  inferential  and 
may  not  be  entitled  to  much  weight.  Neither  is  it  exclusive.  We 
know  that  certain  sulphides  are  magmatic  minerals,  and  we  have  seen 
that  they  can  be  either  dissolved  or  decomposed  by  heated  waters. 
In  the  depths  they  would  pass  into  solution  with  some  evolution  of 
hydrogen  sulphide,  as  shown  by  the  experiments  of  De  Clermont  and 
Frommel  and  in  the  researches  of  Doelter.  The  dissolved  sulphides 
would  be  redeposited  by  the  cooling  solutions,  and  the  hydrogen  sul- 
phide would  serve  as  a precipitant  for  the  chlorides  or  sulphates 
which  we  assume  to  have  been  otherwise  formed.  The  phenomena 
must  also  vary  as  the  magmatic  waters  happen  to  be  alkaline  or  acid, 
solution  predominating  in  the  one  case  and  decomposition  in  the 
other.  Carbonated  waters  are  to  be  regarded  as  intermediate  waters 
from  this  point  of  view,  which  decompose  sulphides  at  first  and  gen- 
erate actively  solvent  solutions  that  come  into  play  later.  That  is,  a 
water  containing  alkaline  carbonates  and  free  carbonic  acid  should 
decompose  the  sulphides  at  great  depths  under  the  conditions  there 
existing  of  high  temperature  and  pressure. 

Alkaline  sulphide  solutions  would  thus  be  formed,  in  which  the 
sulphides  of  the  heavy  metals  are  variably  soluble.  In  such  solutions 
the  sulphides  of  tin,  arsenic,  and  antimony  dissolve  freely  and  other 
sulphides  in  very  much  smaller  amounts.  A partial  separation  should 
be  thus  effected,  exactly  as  in  the  operations  of  an  analytical  labora- 
tory. These  suppositions,  however,  need  to  be  tested  by  experiment ; 
until  that  has  been  done,  they  are  only  tentative. 

We  can  not  assume  that  all  metalliferous  veins  are  alike  in  origin, 
and  it  is  therefore  unwise  to  generalize  too  sweepingly  about  them. 
We  may,  nevertheless,  imagine  a typical  case  and  follow  a series  of 
concentrations  throughout  its  probable  course,  beginning  with  the 
still  unconsolidated  magma.  But  magmas  are  different  and  yield 
very  dissimilar  rocks.  One  is  mainly  feldspathic,  another  mainly 
olivine,  and  a third  solidifies  to  a pyroxenite.  More  commonly  they 
are  complex  mixtures,  and  in  their  cooling  a certain  amount  of  differ- 
entiation, the  segregation  of  certain  parts,  takes  place. 


METALLIC  ORES. 


637 


In  order  to  form  an  ore  body  the  magma  must  probably  be  richer 
in  heavy  metals  than  is  usually  the  case.  We  know  that  several  sul- 
phides exist  as  magmatic  minerals  and  that  they  are  more  abundant 
in  some  places  than  in  others,  varying  in  this  respect  just  as  the  feld- 
spars do.  In  other  words,  the  magmatic  constituents  are  not  uni- 
formly distributed  throughout  the  crust  of  the  earth.  A magma, 
then,  with  more  than  the  average  proportion  of  sulphides,  rises  to  the 
surface  of  the  earth  and  cools  progressively.  In  so  doing  some  seg- 
regation of  sulphides  must  take  place,  and  they  become  thereby  con- 
centrated at  the  margin  of  the  cooling  mass.  The  product  of  con- 
centration may  itself  appear  as  a large  and  distinct  ore  body,  like 
the  Norwegian  pyrrhotites,  or  it  may  be  relatively  trivial;  but  in 
either  case  a first  step  has  been  taken. 

Upon  this  primary  concentration  the  circulating  waters  may  act, 
and  indeed  have  been  acting  from  the  instant  that  cooling  began. 
Obviously,  the  waters  which  first  operate  are  either  those  which  were 
occluded  in  or  generated  from  the  rising  magma  or  which  it  encoun- 
tered earliest  in  the  course  of  its  upward  movement.  These,  there- 
fore, are  ascending  waters,  whatever  their  previous  history  may  have 
been.  Their  condition  at  first  is  that  of  highly  superheated  and 
compressed  steam,  for  they  are  above  the  critical  temperature  of  water 
and  can  not  liquefy  until  they  have  partly  cooled.  Below  365°  they 
become  possibly  liquid  and  heavily  charged  with  matter  dissolved 
from  the  magma  and  the  adjacent  rocks.  Solids  and  gases  are  both 
dissolved,  and  the  ascending  solution,  slowly  cooling  and  mingling 
with  other  solutions  as  it  rises,  gradually  deposits  its  burden.  Its 
channel  becomes  filled  with  various  minerals,  ores,  and  gangues,  and 
thus  a second  stage  in  the  concentration  is  completed. 

Of  this  process  in  detail  we  cannot  form  a clear  mental  picture. 
The  superheated  solutions,  formed  at  the  beginning  of  the  ascent, 
are  something  of  which  experience  tells  us  very  little.  We  know 
that  water,  at  or  above  its  critical  temperature,  attacks  silicates 
vigorously,  and  that  it  will  even,  as  shown  by  C.  Barus,1  form  a 
mutual  solution  with  glass.  But  how  it  will  act  with  molten  rock 
under  pressure,  what  sort  of  a solution  it  will  then  develop,  we  do  not 
know.  It  is  fair  to  infer  that  the  reactions  will  be  both  energetic 
and  complex,  and  that  supersaturated  solutions  are  likely  to  be  pro- 
duced ; but  the  waters  which  ultimately  rise  to  the  surface  as  thermal 
springs  are  at  moderate  temperatures  and  have  lost  much  of  their 
load.  Furthermore,  they  have  been  modified  by  other  waters,  and 
reactions  may  have  occurred  of  which  no  certain  trace  remains.  If 
organic  matter  has  reached  the  solutions  at  any  point,  sulphates 
must  have  undergone  reduction  to  sulphides,  and  the  latter  com- 
pounds would  therefore  appear  in  more  than  one  generation  and  in 


1 See  ante,  p.  297. 


638 


THE  DATA  OF  GEOCHEMISTRY. 


larger  quantities.  A multitude  of  different  reactions  are  conceivably 
possible,  and  no  one  set  can  be  summarized  which  shall  cover  all 
conditions.  Surface  waters,  descending  and  then  diffusing  laterally, 
leach  great  areas  of  rock  in  the  belt  of  weathering,  and  so  reenforce 
the  filling  of  the  veins.  Without  the  concurrence  of  waters  from  all 
directions  and  for  long  periods  of  time,  the  development  of  large 
ore  bodies  would  be  most  difficult  to  explain.  Suppose,  now,  that 
by  a complex  of  processes,  such  as  have  been  described,  segregative, 
solvent,  pneumatolytic,  and  precipitative,  a channel  has  become 
filled  with  mineral  matter  and  transformed  into  a vein.  Suppose, 
also,  that  the  vein  is  at  first  a mixture  of  quartz  and  iron  pyrites, 
containing  in  moderate  proportions  admixtures  of  chalcopyrite, 
galena,  and  zinc  blende,  with  minute  but  perceptible  traces  of  silver 
and  gold.  The  vein  rises  from  the  zone  of  anamorphism,  through 
the  belt  of  cementation,  into  the  belt  of  weathering,  where  a third 
group  of  transformations,  a new  redistribution  of  material,  occurs. 
These  changes  can  be  followed  without  much  difficulty,  and  their 
character  is  partly  known.1 

In  the  first  place,  the  surface  waters,  charged  with  oxygen  and 
carbonic  acid,  attack  the  outcrop  of  ores,  oxidizing  them  more  or 
less  completely  to  sulphates.  Sulphuric  acid  or  acid  salts  are  formed 
at  the  same  time,  which  assist  in  the  decomposition  of  the  adjacent 
rocks.  That  decomposition  is  more  than  ordinarily  extensive  in  the 
vicinity  of  metalliferous  veins,  and  the  rocks  therefore  acquire  a 
higher  degree  of  permeability  to  the  percolating  waters. 

The  sulphates  thus  formed  differ  in  solubility  and  are  furthermore 
affected  by  other  substances  contained  in  the  waters.  Gold  is  left  in 
the  free  state,  in  which  condition  it  may  partly  dissolve  in  ferric 
solutions,  but  for  the  most  part  remains  unchanged.  Silver  is  con- 
verted into  chloride,  for  chlorine  is  rarely  absent  in  such  alterative 
processes,  and  that  compound  dissolves  with  some  difficulty.  Part 
of  the  silver,  if  much  silver  is  present,  may  be  reduced  to  the  metallic 
form  and  remain  as  native  silver  near  the  surface.  The  iron  salts, 
which  are  ferrous  at  first,  are  soon  oxidized  to  the  ferric  state,  form- 
ing basic  compounds  and  passing  finally  into  hydroxide  or  limonite. 
Some  iron  is  dissolved  and  carried  away;  in  certain  cases  this  is  done 
completely,  but  generally  a mass  of  limonite  is  left  upon  the  surface, 
the  gossan  or  iron  cap  of  mining  terminology.  At  the  surface,  then, 
there  is  a concentration  of  iron,  in  which  a large  part  of  the  gold  and 
possibly  some  silver  is  retained.  The  other  metals  have  been  washed 
away,  more  or  less  perfectly,  and  carried  down  to  lower  levels. 


1 For  a summary  of  these  alterations,  see  R.  A.  F.  Penrose,  Jour.  Geology,  vol.  2,  1894,  p.  288;  also  De 
Launay’s  memoir,  previously  cited.  An  interesting  paper  by  Penrose  on  the  causes  of  ore  shoots  is  in 
Econ.  Geology,  vol.  5, 1910,  p.  97. 


METALLIC  ORES. 


639 


The  sulphates  of  copper  and  zinc  are  very  soluble;  that  of  lead 
much  less  so.  If  the  descending  waters  contain  much  silica,  silicates 
like  chrysocolla  and  calamine  are  likely  to  be  formed.  If  carbonates 
are  abundant  in  the  solutions,  malachite,  azurite,  smithsonite,  and 
cerusite  will  appear.  Oxides  of  lead  and  copper  may  also  be  pro- 
duced, and  any  or  all  of  these  substances  are  to  be  found  in  the  oxi- 
dized zone  of  an  ore  body.  Below  this  zone  the  sulphate  solutions 
meet  the  unaltered  sulphides,  and  a secondary  enrichment  of  them 
becomes  possible.1  The  dominant  sulphide,  pyrite,  reacts  upon  solu- 
tions of  copper  and  zinc  sulphates,  precipitating  both  metals  as  sul- 
phides and  passing  into  solution  as  sulphate  of  iron.  This  reaction 
is  well  known  and  was  established  experimentally.  Thus  at  the 
upper  portion  of  the  unoxidized  ores  there  is  a concentration  of  copper, 
and  perhaps  of  zinc,  below  which  the  original  leaner  ore  continues  to 
its  limit,  whatever  that  point  may  be.  In  this  way  some  “ bonanzas’ 7 
originate.  A separation  of  the  metals  is  effected  at  or  near  the  sur- 
face, and  the  more  soluble  ones  are  concentrated  by  reprecipitation 
below. 

Although  the  broad  general  conception  of  secondary  enrichment 
is  simple  enough,  its  detailed  application  to  specific  cases  is  not  always 
easy.  Complex  solutions  are  acting  upon  complex  mixtures  of 
minerals,  and  the  reactions  which  take  place  are  very  diverse.  The 
sulphides  differ  in  solubility;  they  form  with  different  degrees  of 
facility;  and  the  conditions  of  their  precipitation  vary  with  conditions 
of  concentration  and  temperature.  There  are,  however,  several 
researches  on  record,  which  help  to  show  what  may  happen  within  an 
established  ore  body.  As  long  ago  as  1837  E.  F.  Anthon 2 studied 
the  precipitation  of  soluble  metallic  salts  by  insoluble  sulphides,  and 
a similar,  but  much  more  elaborate  series  of  experiments  was  carried 
out  much  later  by  E.  Schurmann.3  In  each  investigation  a series 
was  established  in  which  the  sulphide  of  any  one  of  the  metals  in  it 
would  be  thrown  down  at  the  expense  of  any  sulphide  lower  in  the 
series.  The  series  found  by  Schurmann  was  as  follows:  Palladium, 
mercury,  silver,  copper,  bismuth,  cadmium,  antimony,  tin,  lead, 
zinc,  nickel,  cobalt,  ferrous  iron,  arsenic,  thallium,  and  manganese. 
For  example,  if  a solution  of  copper  were  long  in  contact  with  the 

1 On  secondary  enrichment,  see  W.  H.  Weed,  Bull.  Geol.  Soc.  America,  vol.  11,  1899,  p.  179;  S.  F.  Em- 
mons, Trans.  Am.  Inst.  Min.  Eng.,  vol.  30, 1900,  p.  177,  and  Weed,  idem,  p.  424;  J.  F.  Kemp,  Econ.  Geology, 
vol.  1,  1905,  p.  11.  On  enrichment  by  ascending  waters,  see  Weed,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  33, 
1903,  p.  747.  On  downward  enrichment,  see  F.  L.  Ransome,  Econ.  Geology,  vol.  5, 1910,  p.  205.  Discus- 
sion by  several  writers  of  Ransome’s  paper  appears  in  the  same  volume,  pp.  387, 477,  678.  See  also  G.  J. 
Bancroft,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  38,  1908,  p.  245,  and  Bull.  Am.  Inst.  Min.  Eng.,  1909,  p.  581; 
E.  S.  Bastin,  Econ.  Geology,  vol.  8, 1913,  p.  51.  U.  S.  Geol.  Survey  Bull.  529,  1913,  by  W.  H.  Emmons,  is  a 
general  summary  of  the  subject.  So,  too,  is  the  paper  by  C.  F.  Tolman,  Min.  and  Sci.  Press,  vol.  106, 1913, 
pp.  38, 141, 178,  which  closes  with  a long  bibliography. 

2 Jour,  prakt.  Chemie,  vol.  10,  1837,  p.  353. 

3 Liebig’s  Annalen,  vol.  249, 1888,  p.  326. 


640 


THE  DATA  OF  GEOCHEMISTRY. 


sulphide  of  any  metal  following  it  in  the  series,  it  would  decom- 
pose the  latter  with  precipitation  of  copper  sulphide.  Starting  with 
galena  the  reaction  CuS04  + PbS  = CuS  + PbS04  has  been  actually 
studied  by  R.  C.  Wells,1  in  the  laboratory  of  the  United  States  Geo- 
logical Survey  and  the  anticipated  result  was  obtained.  Wells  has 
also  investigated  the  precipitation  of  sulphides  in  pairs,  and  has 
found  that  they  are  thrown  down  unequally.  If  to  a solution  con- 
taining iron  and  copper  an  alkaline  sulphide  is  added  in  excess,  both 
metals  are  completely  precipitated.  But  if,  in  a neutral  solution, 
there  is  a deficiency  of  the  alkaline  sulphide,  all  the  copper  is 
deposited  before  any  iron  is  thrown  down.  Attempts  to  form  double 
sulphides  by  precipitation  were  unsuccessful;  but  double  sulphides 
such  as  chalcopyrite  are  among  the  most  important  ores. 

The  series  of  precipitations  studied  by  Schurmann  is  evidently 
somewhat  analogous  to  the  well-known  electrochemical  series  of  the 
chemical  elements  and  suggests  that  the  phenomena  of  secondary 
enrichment  may  be  of  an  electrical  character.  The  problem  of  elec- 
trical activities  in  ore  bodies  was  long  ago  examined  by  R.  W.  Fox2 
and  has  since  received  attention  from  a number  of  other  investigators, 
most  recently  by  V.  H.  Gottschalk  and  H.  A.  Buehler3  and  R.  C. 
Wells.4 

Gottschalk  and  Buehler  studied  especially  the  oxidation  of  sul- 
phides, and  found  that  when  two  different  minerals  are  immersed  in 
the  same  solution  one  showed  an  increase  of  solubility  while  the  other 
was  more  or  less  protected.  They  also  found  and  measured  the 
differences  in  electrical  potential  among  the  minerals  studied  and  found 
that  when  two  of  them  were  brought  in  contact  and  moistened  they 
formed  a small  battery.  Such  a contact,  in  presence  of  the  per- 
colating solutions  of  the  earth’s  crust,  may  be  an  important  factor 
in  the  process  of  oxidation  of  natural  minerals. 

Gottschalk  and  Buehler  in  their  experiments  used  as  a solvent 
only  water.  Wells,  however,  in  a similar  research  measured  the 
electrical  potential  of  his  minerals  in  various  solutions  and  found  wide 
differences.  From  this  he  concludes  that  the  nature  of  the  solvent 
is  of  fundamental  importance  and  that  by  electrical  activity  different 
minerals  may  be  produced,  depending  upon  the  character  of  the 
solutions.  Evidently  the  application  of  theory  to  the  discussion  of 
any  specific  geological  problem  involves  variable  factors  and  may  be 
exceedingly  complex. 


1 Econ.  Geology,  vol.  5, 1910,  p.  1. 

2 Philos.  Trans.,  1830,  pt.  2,  p.  399;  idem,  1835,  pt.  1,  p.  39;  British  Assoc.  Adv.  Sci.  Rept.,  1834,  p.  572; 
idem,  1837,  p.  133;  Philos.  Mag.,  3d  ser.,  vol.  23,  1843,  pp.  457,  491.  See  also  W.  J.  Henwood,  Annales  des 
Mines,  3d  ser.,  vol.  11, 1837,  p.  585;  A.  von  Strombeck,  Karsten’s  Archiv,  vol.  6,  1833,  p.  431;  F.  Reich, 
Poggendorf’s  Annalen,  vol.  48, 1839,  p.  287;  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  3,  1871,  p.  232;  C. 
Barus,  Mon.  U.  S.  Geol.  Survey,  vol.  3,  1882,  pp.  309-367. 

s Econ.  Geology,  vol.  7, 1912,  p.  15.  An  earlier  paper  is  in  vol.  5,  p.  28, 1910. 

4 Bull.  U.  S.  Geol.  Survey  No.  548,  1914. 


METALLIC  ORES. 


641 


Analogous  to  the  process  by  which  the  sulphides  of  a vein  may  be 
enriched,  is  another  process  that  often  operates  in  the  formation  of 
quite  different  ore  bodies.  This  process  has  already  been  noted  in 
relation  to  phosphate  rock,  and  it  consists  in  the  precipitation  of 
dissolved  substances  by  limestone.  A metalliferous  solution,  con- 
taining any  of  the  heavy  metals,  percolates  through  limestone,  and 
double  decomposition  takes  place.  The  heavy  metals,  zinc,  copper, 
iron,  manganese,  etc.,  are  precipitated,  and  calcium  goes  into  solution. 
Reactions  of  this  kind  have  been  experimentally  studied  by  several 
investigators.1  The  diffused  metals,  or  rather  their  compounds,  may 
be  concentrated  by  solution  and  consequent  removal  of  the  remain- 
ing carbonate  of  lime.  In  this  connection  R.  C.  Wells 2 has  inves- 
tigated the  relative  solubilities  of  the  metallic  carbonates,  much  as 
was  done  by  Schurmann  in  the  series  of  sulphides.  The  order  found, 
beginning  with  the  least  soluble,  was  mercury,  lead,  copper,  cad- 
mium, zinc,  iron,  nickel,  manganese,  silver,  calcium,  magnesium. 
Each  of  these  carbonates,  under  equal  conditions,  would  precipitate 
those  preceding  it  from  aqueous  solution.  Wells,  however,  is  careful 
to  point  out  that  the  application  of  this  series  to  specific  cases  involves 
consideration  of  mass  effects  which  may  change  the  order  of  pre- 
cipitation. 

In  this  bare  outline  of  what  may  be  supposed  to  happen  in  the 
formation  of  a metalliferous  deposit,  details  have  been  purposely 
left  out  of  account.  Their  consideration  naturally  follows  in  the 
succeeding  pages,  in  which  the  metals  are  studied  separately.3 

GOLD.4 

Although  gold  is  one  of  the  scarcer  elements,  it  is  widely  diffused 
in  nature.  It  is  found  in  igneous  rocks,  sometimes  in  visible  particles; 
it  accumulates  in  certain  detrital  or  placer  deposits;  it  also  occurs  in 
sedimentary  and  metamorphic  formations,  in  quartz  veins,  and  in 
sea  water.5  A notable  amount  of  gold  is  now  recovered  from  copper 
ores,  during  the  electrolytic  refining  of  the  copper.  A.  Liversidge 6 
found  traces  of  gold  in  rock  salt  from  several  localities,  in  quantities 
of  about  1 to  2 grains  per  ton.  F.  Laur,7  in  Triassic  rocks  taken  from 


1 See  for  example,  R.  Irvine  and  W.  S.  Anderson,  Proc.  Roy.  Soc.  Edinburgh,  vol.  18,  1890,  p.  52;  W. 
Meigen,  Ber.  Naturforsch.  Gesell.  Freiburg,  vol.  13, 1903,  p.  40;  vol.  15,  1905,  p.  38;  and  inaugural  disserta- 
tions, Freiburg,  1906,  by  L.  Gassner  and  C.  Mahler. 

2 Bull.  U.  S.  Geol.  Survey  No.  609. 

3 The  work  of  Sullivan  on  the  precipitation  of  copper  by  shale,  feldspar,  etc.,  is  noted  later  in  the  section 
of  this  chapter  upon  the  ores  of  that  metal.  The  ores  of  iron,  manganese,  and  aluminum  have  been  suffi- 
ciently described  in  the  chapters  upon  rock-forming  minerals,  rock  decomposition,  and  the  sedimentary 
rocks. 

4 For  a list  of  the  Survey  publications  on  gold  and  silver  see  Bull.  470, 1911. 

6 See  ante,  p.  121. 

6 Jour.  Chem.  Soc.,  vol.  71, 1897,  p.  298. 

7 Compt.  Rend.,  vol.  142,  1906,  p.  1409.  Also  in  Compt.  Rend.  Soc.  ind.  minerale,  Sept.-Oct.,  1906, 

97270°— Bull.  616—16 41 


642 


THE  DATA  OF  GEOCHEMISTRY. 


deep  borings  in  the  department  of  Meurthe-et-Moselle,  France,  found 
both  gold  and  silver.  The  maximum  amount  in  a sandy  limestone, 
was  39  grams  of  gold  and  245  of  silver  per  metric  ton,  but  most  of  the 
assays  ran  much  lower. 

Gold  has  been  repeatedly  observed  as  a primary  mineral  in  igneous 
or  plutonic  rocks.  G.  P.  Merrill1  reports  it  in  a Mexican  granite, 
embedded  in  quartz  and  feldspar.  W.  Moricke 2 found  visible  gold 
in  a pitchstone  from  Chile;  and  O.  Schiebe3  discovered  it  in  an 
olivine  rock  from  Damara  Land,  South  Africa. 

In  a series  of  assays  of  rocks  collected  at  points  remote  from  known 
deposits  of  heavy  metals,  L.  Wagoner4  found  the  following  quanti- 
ties, in  milligrams  per  metric  ton,  of  gold  and  silver.  The  samples 
are  Californian,  except  when  otherwise  stated. 

Gold  and  silver  in  rocJcs  from  California , Nevada , etc . 

[Milligrams  per  metric  ton.] 


Au. 

Ag. 

Granite 

104 

7,  660 
1,  220 

Do 

137 

Do 

115 

940 

Syenite,  Nevada 

720 

15, 430 
5, 590 
540 

Granite,  Nevada 

1, 130 

Sandstone 

39 

Do 

24 

450 

Do 

21 

320 

Basalt 

26 

547 

Diabase 

76 

7, 440 
212 

Marble 

5 

Marble,  Carrara 

8.  63 

201 

In  a later  investigation  Wagoner5  determined  gold  and  silver  in 
deep  sea  (Atlantic  Ocean)  dredgings.  In  six  samples  assayed  the 
gold  ranged  from  15  to  267  milligrams  per  metric  ton,  and  the 
silver  from  304  to  1,963  milligrams. 

These  figures  suggest  a very  general  distribution  of  gold  in  rocks 
of  all  kinds.  J.  ft.  Don,6  however,  in  an  extended  investigation  of 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  1, 1896,  p.  309.  Compare  W.  P.  Blake,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  26, 
1896,  p.  290. 

2 Min.  pet.  Mitt.,  vol.  12, 1891,  p.  195. 

3Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  40,  1888,  p.  611.  For  other  examples  see  Stelzner-Bergeat,  Die 
Erzlagerstatten,  pp.  69-70.  See  also  J.  Catharinet,  Eng.  and  Min.  Jour.,  vol.  79, 1905,  p.  127,  on  gold  in  the 
pegmatite  of  Copper  Mountain,  British  Columbia.  R.  W.  Brock  (idem,  vol.  77,  1904,  p.  511)  reports  gold 
in  British  Columbia  porphyries.  On  primary  gold  in  a Colorado  granite,  see  J.  B.  Hastings,  Trans.  Am. 
Inst.  Min.  Eng.,  vol.  39, 1909,  p.  97.  An  association  of  gold  with  sillimanite  is  reported  by  T.  L.  Watson; 
Am.  Jour.  Sci.,  3d  ser.,  vol.  33,  1912,  p.  241. 

* Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  808. 

5 Idem,  vol.  38,  1907,  p.  704. 

6 Idem,  vol.  27,  1897,  p.  564.  A.  R.  Andrew  (Trans.  Inst.  Min.  Met.,  vol.  19, 1910,  p.  276)  questions  the 
trustworthiness  of  many  such  assays  of  country  rock.  He  thinks  that  gold  as  an  impurity  in  litharge 
accounts  for  most  of  the  reported  findings. 


METALLIC  ORES. 


643 


the  Australian  gold  fields,  found  that  the  deep-seated  rocks  contained 
gold  only  in  association  with  pyrite.  When  pyrite  was  absent, 
gold  was  absent  also.  The  country  rocks  of  the  vadose  region,  on 
the  other  hand,  were  generally  impregnated  with  gold,  even  at  a dis- 
tance from  the  auriferous  reefs,  and  Don  supposes  that  the  metal  was 
probably  transported  in  solution.  This  point  will  be  discussed  later. 

Gold  occurs  principally  in  the  free  state  or  alloyed  with  other 
metals,  such  as  silver,  copper,  mercury,  palladium,  rhodium,  bis- 
muth, and  tellurium.  Leaving  detrital  or  placer  gold  out  of  account, 
its  chief  mineral  associates  are  quartz  and  pyrite.  Its  connection 
with  pyrite  is  so  intimate  that  some  writers  have  argued  in  favor  of 
its  existence  as  gold  sulphide,1  but  the  evidence  in  favor  of  that 
belief  is  very  inadequate.  No  unmistakable  gold  sulphide  has  yet 
been  found  as  a definite  mineral  species,  nor  is  it  likely  to  form 
except  in  an  environment  entirely  free  from  reducing  agents.  The 
compounds  of  gold  are  exceedingly  unstable  and  the  metal  separates 
from  them  with  the  greatest  ease. 

On  the  petrologic  side  gold  is  most  commonly  associated  with 
rocks  of  the  persilicic  type,  such  as  granite  and  its  metamorphic 
derivatives.  I refer  now  to  its  primary  occurrences.  It  is  not  rare 
in  association  with  dioritic  rocks,  but  in  rocks  of  subsilicic  character 
it  is  exceedingly  uncommon.  Its  very  general  presence  in  quartz 
veins  is  testimony  in  the  same  direction,  and  suggests  the  probability 
that  gold  is  more  soluble  in  silicic  magmas  than  in  those  richer  in 
bases.  The  auriferous  quartz  veins  were  probably  formed  in  most 
instances  from  solutions;  but  J.  E.  Spurr  2 has  argued  that  in  some 
cases  they  are  true  magmatic  segregations.  This  view  was  developed 
by  Spurr  in  his  studies  of  gold-bearing  quartz  from  Alaska  and 
Nevada,  but  it  has  been  questioned  by  C.  R.  Van  Hise  3 and  others. 

The  composition  of  native  gold  is  variable.  The  purest  yet  found, 
from  Mount  Morgan,  Queensland,  according  to  A.  Leibius,4  assayed 
as  high  as  99.8  per  cent,  the  remainder  being  mainly  copper  with  a 
trace  of  iron.  Gold  commonly  ranges  from  88  to  95  per  cent,  with 
more  or  less  alloy  of  the  metals  already  mentioned.  The  following 
analyses  well  represent  the  character  of  the  variations: 

1 See,  for  example,  T.  W.  T.  Atherton,  Eng.  and  Min.  Jour.,  vol.  52,  1891,  p.  698;  and  A.  Williams,  idem, 
vol.  53,  1892,  p.  451.  Williams  cites  an  auriferous  pyrite  from  Colorado  which  yielded  no  gold  on  amal- 
gamation, but  from  which  gold  was  extracted  by  solution  in  ammonium  sulphide.  Gold  sulphide  is 
soluble  in  that  reagent,  hence  the  inference  that  it  may  have  been  present  in  the  ore.  See  also  a paper 
by  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  3, 1870,  p.  216. 

2 See  papers  in  Trans.  Am.  Inst.  Min.  Eng.,  vol.  33, 1903,  p.  288;  vol.  36, 1906,  p.  372.  Also  Econ.  Geology, 
vol.  1, 1906,  p.  369. 

a A treatise  on  metamorphism:  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904,  pp.  1048-1049.  See  also  J.  B.  Has- 
tings, Trans.  Am.  Inst.  Min.  Eng.,  vol.  36, 1906,  p.  647.  Hastings  regards  the  Silver  Peak  ores  as  deposited 
by  ascending  waters  along  lines  of  fracturing. 

4 Proc.  Roy.  Soc.  New  South  Wales,  vol.  18, 1884,  p.  37. 


644 


THE  DATA  OF  GEOCHEMISTRY, 


Analyses  of  native  gold. 

A.  Gold  from  Persia.  Analyzed  by  C.  Catlett  in  the  laboratory  of  the  United  States  Geological  Survey. 

B.  Electrum,  Montgomery  County,  Virginia.  Analysis  by  S.  Porcher,  Chem.  News,  vol.  44, 1881,  p.  189. 

C.  D,  E.  Gold  associated  with  native  platinum,  Colombia.  Analyses  by  W.  H.  Seamon,  Chem.  News, 
vol.  46,  1882,  p.  216. 

F.  Amalgam,  Mariposa  County,  California.  Analysis  by  F.  L.  Sonnenschein,  Zeitschr.  Deutsch.  geol. 
Gesell.,  vol.  6,  1854,  p.  243.  Specific  gravity,  15.47.  Near  AuHg3. 

G.  Palladium  gold.  Taguaril,  Brazil.  Analysis  by  Seamon,  Chem.  News,  vol.  46,  1882,  p.  216.  See 
Wilm,  Zeitschr.  anorg.  Chemie,  vol.  4,  1893,  p.  300,  on  palladium  gold  from  the  Caucasus.  Also  E.  Hussak, 
Zeitschr.  prakt.  Geologie,  1906,  p.  284,  on  palladium  gold  in  Brazil. 

H.  Maldonite,  or  “black  gold,”  Maldon,  Victoria.  Analysis  by  R.  W.  E.  Maclvor,  Chem.  News,  vol. 
55,  1887,  p.  191.  An  alloy  near  Au2Bi. 


A 

B 

C 

D 

E 

F 

G 

H 

Au 

93.  24 
6.  65 
None. 

65.  31 
34.  01 
.14 

84.  38 
13.  26 
1.  85 

80. 12 
2.  27 
15.  84 

84.  01 
7.  66 

39.  02 

91.06 

Trace. 

65. 12 

As  

Cu  

Hs  

7.  06 

60.  98 

8.  21 

Bi 

34.  88 

Fe  

.11 

.20 

.34 

Trace. 

Trace. 

Quartz 

100.  00 

100.  00 

99.  49 

98.  23 

98.  73 

100.  00 

99.  27 

100.  00 

The  tellurides  1 containing  gold  are  also  variable  in  composition, 
partly  because  most  of  them  contain  silver,  and  often  other  metals, 
which  may  be  only  impurities.  Kalgoorlite  and  coolgardite,  for  ex- 
ample, which  are  tellurides  of  gold,  silver,  and  mercury,  are  mixtures 
of  the  mercury  compound,  coloradoite,  with  other  species.2  Calaverite 
and  krennerite  approximate  to  gold  telluride  alone.  Sylvanite,  pet- 
zite,  muthmannite,  and  goldschmidtite  are  tellurides  of  gold  and 
silver.  The  following  analyses  are  sufficient  to  indicate  the  compo- 
sition of  the  more  important  of  these  minerals : 


1 For  a general  review  of  the  tellurides,  with  references  to  literature,  see  J.  F.  Kemp,  Min.  Industry 
vol.  6,  1898,  p.  295. 

2 L.  J.  Spencer,  Mineralog.  Mag.,  vol.  13,  p.  268, 1903.  Spencer  gives  a good  bibliography  of  the  Austra- 
lian tellurides. 


METALLIC  ORES. 


645 


Analyses  of  tellurides  containing  gold. 

A.  Calaverite,  ('AuAg)Te2,  Cripple  Creek,  Colorado.  Analysis  by  W.  F.  Hillebrand. 

B.  Krennerite,  (AuAg)Te2,  Nagyag,  Hungary.  Analysis  by  L.  Sipocz,  Zeitschr.  Kryst.  Min.,  vol.  11, 

1886,  p.  210. 

C.  Sylvanite,  (AuAg)Te2,  Grand  View  mine,  Boulder  County,  Colorado.  Analysis  by  F.  W.  Clarke, 
Am.  Jour.  Sci.,  3d  ser.,  vol.  14,  1877,  p.  286. 

D.  Petzite,  (AuAgyre,  Norwegian  mine,  Calaveras  County,  California.  Analysis  by  Hillebrand. 


A 

B 

c 

D 

Au 

38.  95 

34.  77 

29.  35 

25. 16 

As 

3.  21 

5.  87 

11.  74 

41.  87 

Cu  - 

.34 

Fe 

. 59 

Te 

57.  27 

58.  60 

58.  91 

33.  21 

Se 

Trace. 

Mo 

.08 

Sb 

.65 

Fe203 

. 12 

Insoluble 

.33 

99.  88 

100.  82 

100.  00 

100.  32 

There  has  been  much  discussion  over  the  tellurides  of  gold.  B. 
Brauner  1 asserts  that  crystalline  “ poly  tellurides”  can  be  formed, 
which  dissociate  upon  heating,  leaving  the  compound  Au2Te  as  an 
end  product.  Theoretically,  the  telluride  Au2Te3  should  also  be 
capable  of  existence.  According  to  V.  Lenher,2  the  tellurides  of  gold 
are  probably  not  definite  compounds,  but  more  in  the  nature  of  alloys. 
Attempts  at  the  synthesis  of  a distinct  compound  failed.  T.  K. 
Rose,3  however,  who  studied  the  alloys  of  gold  and  tellurium,  obtained 
a definite  compound,  AuTe2,  identical  with  the  natural  calaverite. 
The  same  result  was  also  obtained  by  G.  Pellini  and  E.  Quercigh.4 
W.  J.  Sharwood 5 has  pointed  out  the  very  general  association  of 
bismuth  with  tellurium  gold  ores. 

Although  gold  is  primarily  a magmatic  mineral,  it  is  also  trans- 
ported in  and  deposited  from  solutions.  Many  occurrences  of  gold 
indicate  this  fact  very  plainly.  O.  Dieffenbach,6  for  instance,  men- 
tions gold  incrusting  siderite  at  Eisenberg,  near  Corbach,  in  Ger- 
many. O.  A.  Derby  7 reports  films  of  gold  on  limonite,  from  Brazil. 
A.  Liversidge 8 found  it  in  recent  pyrite,  which  formed  on  twigs  in 
a hot  spring  near  Lake  Taupo,  New  Zealand.  J.  C.  Newbery  9 men- 
tions gold  in  a manganiferous  iron  ore  coating  quartz  pebbles,  the 


1 Jour.  Chem.  Soc.,  vol.  55,  1889,  p.  391. 

2 Jour.  Am.  Chem.  Soc.,  vol.  24, 1902,  p.  358.  See  also  R.  D.  Hall  and  V.  Lenher,  idem,  p.  919. 

a Trans.  Inst.  Min.  Mot.,  vol.  17,  1908,  p.  285. 

4 Rend.  R.  accad.  Lincei,  5th  ser.,  vol.  19, 1910,  p.  445. 

5 Econ.  Geology,  vol.  6, 1911,  p.  22. 

6 Neues  Jahrb.,  1854,  p.  324. 

7 Am.  Jour.  Sci.,  3d  ser.,  vol.  28, 1884,  p.  440. 

8 Jour.  Roy.  Soc.  New  South  Wales,  vol.  11,  1877,  p.  262. 

9 Trans.  Roy.  Soc.  Victoria,  vol.  9,  1868,  p.  52. 


646 


THE  DATA  OF  GEOCHEMISTRY. 


quartz  itself  being  free  from  gold.  In  the  sinter  of  Steamboat 
Springs,  Nevada,  G.  F.  Becker  1 found  both  gold  and  silver;  3,403 
grams  of  sinter  gave  0.0034  of  gold  and  0.0012  of  silver.  Gold  is 
also  reported  by  J.  M.  Maclaren  2 in  the  siliceous  sinter  of  the  hot 
springs  at  Whakarewarewa,  New  Zealand.  R.  Brauns  3 has  described 
gold  as  a cement  joining  fragments  of  quartz.  The  specimen  of 
cinnabar  from  a fissure  in  Colusa  County,  California,  mentioned  by 
J.  A.  Phillips,4  which  was  covered  by  a later  deposit  of  gold,  is  also 
suggestive.  According  to  R.  W.  Stone,5  the  coal  of  Cambria,  Wy- 
oming, contains  appreciable  quantities  of  gold.  All  of  these  occur- 
rences are  best  interpreted  on  the  assumption  that  the  gold  was 
precipitated  from  solution;  and,  indeed,  they  can  hardly  be  explained 
otherwise. 

The  natural  solvents  of  gold  appear  to  be  numerous — that  is,  if 
the  recorded  experiments  are  all  trustworthy.  G.  Bischof  6 found 
that  gold  was  held  in  solution  by  potassium  silicate,  and  Liversidge 7 
was  able  to  dissolve  the  metal  by  digesting  it  with  either  potassium 
or  sodium  silicate  under  a pressure  of  90  pounds  to  the  square  inch. 
C.  Doelter  8 claims  that  gold  is  perceptibly  soluble  in  a 10  per  cent 
sodium-carbonate  solution,  and  also  in  a mixture  of  sodium  silicate 
and  bicarbonate.  Solutions  of  alkaline  sulphides  have  been  found  by 
several  authorities,  notably  by  W.  Skey,9  T.  Egleston,10  G.  F.  Becker,11 
and  A.  Liversidge,12  to  be  effective  solvents  of  gold;  and  Skey  reports 
that  even  hydrogen  sulphide  attacks  the  metal  perceptibly.  All  of 
these  solvents  occur  in  natural  waters. 

Solutions  of  ferric  salts  are  also  capable,  under  proper  conditions, 
of  dissolving  gold.  According  to  H.  Wurtz,13  ferric  sulphate  and 
ferric  chloride  are  both  effective.  P.  C.  Mcllhiney14  found  that  the 
chloride  acted  on  the  metal  only  in  presence  of  oxygen,  which  serves 
to  render  the  ferric  salt  an  efficient  carrier  of  chlorine.  Some  experi- 
ments by  H.  N.  Stokes  15  in  the  laboratory  of  the  United  States  Geo- 
logical Survey,  showed  that  ferric  chloride  and  also  cupric  chloride 
dissolve  gold  easily  at  200°.  The  reactions  are  reversible,  and  gold 
is  redeposited  on  cooling.  Ferric  sulphate,  according  to  Stokes,  does 

i Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  344. 

* Geol.  Mag.,  1906,  p.  511. 

* Chemische  Mineralogie,  1896,  p.  406. 

4 Quart.  Jour.  Geol.  Soc.,  vol.  35,  1879,  p.  390.  On  the  natural  associations  of  gold,  see  F.  C.  Lincoln, 

Econ.  Geology,  vol.  6, 1911,  p.  247. 

6 BuU.  U.  S.  Geol.  Survey  No.  499,  1912,  p.  63. 

6 Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  3,  p.  843. 

» Proc.  Roy.  Soc.  New  South  Wales,  vol.  27, 1893,  p.  303. 

8 Min.  pet.  Mitt. , vol.  11, 1890,  p.  328. 

» Trans.  New  Zealand  Inst.,  vol.  3, 1870,  p.  216;  vol.  5, 1872,  p.  382. 

w Trans.  Am.  Inst.  Min.  Eng.,  vol.  9, 1880-81,  p.  639. 

u Am.  Jour.  Sci.,  3d  ser.,  vol.  33,  1887,  p.  207. 

12  Proc.  Roy.  Soc.  New  South  Wales,  vol.  27,  1893,  p.  303. 

13  Am.  Jour.  Sci.,  2d  ser.,  vol.  26, 1858,  p.  51. 

14  Idem,  4th  ser.,  vol.  2, 1896,  p.  293. 

15  Econ.  Geology,  vol.  1, 1906,  p.  650. 


METALLIC  ORES. 


647 


not  dissolve  gold  unless  chlorides  are  also  present.  Perhaps  the 
pseudomorph  of  gold  after  botryogen,  a basic  sulphate  of  iron, 
described  by  W.  D.  Campbell,1  may  have  originated  from  some  solu- 
tion in  ferric  salts. 

F.  P.  Dewey2  has  found  that  finely  divided  gold  is  perceptibly 
soluble  in  nitric  acid,  but  that  observation  has  little  bearing  upon 
its  natural  solution.  W.  J.  McCaughey3  has  reported  its  solubility 
in  hydrochloric  acid  solutions  of  iron  alum  and  cupric  chloride. 
With  rising  temperature  the  solubility  increases  rapidly.  N.  Awer- 
kiew  4 finds  that  gold  is  also  dissolved  by  hydrochloric  acid  in  pres- 
ence of  organic  matter. 

The  usual  laboratory  solvent  for  gold,  aqua  regia,  owes  its  efficiency 
to  the  liberation  of  free  chlorine.  T.  Egleston 5 asserts  that  traces  of 
nitrates  with  chlorides  in  natural  waters  can  slowly  dissolve  the 
metal.  J.  R.  Don  6 found  that  weak  hydrochloric  acid,  1 part  in 
1,250  of  water,  in  presence  of  manganese  dioxide,  would  take  gold 
into  solution.  R.  Pearce7  heated  gold  and  a solution  containing  40 
grains  of  common  salt  to  the  gallon,  with  a few  drops  of  sulphuric 
acid  and  some  manganese  dioxide,  and  obtained  partial  solution. 
T.  A.  Rickard  8 treated  a rich  Cripple  Creek  ore,  which  contained 
manganic  oxides,  with  a solution  of  ferric  sulphate,  sodium  chloride, 
and  a little  sulphuric  acid,  and  practically  all  of  the  gold  dissolved. 
On  immersing  in  this  solution  a fragment  of  black,  carbonaceous 
shale,  the  gold  was  reprecipitated.  How  far  solutions  of  this  kind  can 
be  produced  in  nature  is  uncertain;  but  the  extreme  dilution  of  the 
solvents  may  be  offset  by  their  prolonged  action.  The  laboratory 
processes  all  tend  to  accelerate  the  reactions.  V.  Lenher’s  observa- 
tion,9 that  strong  sulphuric  acid,  in  presence  of  oxidizing  agents,  such 
as  the  dioxides  of  manganese  and  lead,  dissolves  gold,  is  probably 
not  applicable  to  the  discussion  of  natural  phenomena.  W.  H. 
Emmons,10  however,  from  a study  of  the  experiments  already  cited, 
and  also  of  the  association  of  manganese  oxides  with  gold  in  nature, 
has  shown  that  the  manganese  plays  an  important  part  in  the  for- 
mation of  auriferous  deposits.  Its  effect  is  due  to  its  interaction  with 
acid  solutions  of  chlorides,  with  which  it  generates  chlorine;  chlorine 
being  the  actual  solvent  of  gold.  In  the  presence  of  alkaline  solutions, 


1 Trans.  New  Zealand  Inst.,  vol.  14,  1881,  p.  457.  Campbell’s  observations  need  to  be  verified.  The 
specimen  was  found  in  the  Thames  gold  field,  New  Zealand. 

2 Jour.  Am.  Chem.  Soc.,  vol.  32, 1910,  p.  318. 

3 Idem,  vol.  31, 1909,  p.  1261. 

4 Zeitschr.  anorg.  Chemie,  vol.  61, 1909,  p.  1. 

3 Trans.  Am.  Inst.  Min.  Eng.,  voi.  8, 1879-80,  p.  454. 

6 Idem,  vol.  27,  1897,  p.  564.  According  to  Don,  ferric  salts  are  not  effective  solvents  for  gold. 

1 Idem,  vol.  22,  1893,  p.  739. 

3 Idem,  vol.  26,  1896,  p.  978. 

s Jour.  Am.  Chem.  Soc.,  vol.  26, 1904,  p.  550. 

13  Bull.  Am.  Inst.  Min.  Eng.,  1910,  p.  767,  and  Jour.  Geology,  vol.  19, 1911,  p.  15.  See  also  A.  D.  Brokaw, 
Jour.  Geology,  vol.  18,  1910,  p.  321,  vol.  21, 1913,  p.  251. 


648 


THE  DATA  OF  GEOCHEMISTRY. 


or  of  calcite,  free  chlorine  can  not  appear,  and  the  manganese  oxides 
become  inoperative.1 

The  experiment  by  Rickard  just  cited  is  especially  suggestive  as 
illustrating  the  ease  with  which  gold  is  redeposited  from  its  solutions. 
So  far  as  gold  is  concerned,  the  reducing  agents  are  numberless,  and 
many  of  them  occur  in  nature.  Organic  matter  of  almost  any  kind 
will  precipitate  gold,  and  such  matter  is  rarely,  if  ever,  absent  from 
the  soil.  Gold,  therefore,  although  it  may  enter  into  solution,  is  not 
likely  to  be  carried  very  far.  On  mere  contact  with  ordinary  soils  it 
would  be  at  once  precipitated.2 

Gold  is  also  thrown  out  of  solution  by  ferrous  salts,  by  other  metals, 
and  by  many  sulphides,  especially  by  pyrite  and  galena.3  According 
to  Skey  one  part  of  pyrite  will  precipitate  over  eight  parts  of  gold. 
The  sulphides  of  copper,  zinc,  tin,  molybdenum,  mercury,  silver,  bis- 
muth, antimony,  and  arsenic,  and  several  arsenides,  all  act  in  the 
same  way.  So,  too,  does  tellurium,  according  to  V.  Lenher,4  and  also 
the  so-called  tellurides  of  gold.  If  the  latter  were  definite  com- 
pounds, they  could  hardly  behave  as  precipitants  for  one  of  their 
constituent  elements. 

SILVER.5 

Silver,  like  gold,  is  widely  diffused  in  nature.  Its  presence  in 
igneous  rocks,  together  with  gold,  has  been  shown  in  the  preceding 
pages,  and  its  existence  in  sea  water  was  noted  in  an  earlier  chapter. 
A.  Liversidge  6 found  it  in  rock  salt,  seaweed,  and  oyster  shells,  while 
W.  N.  Hartley  and  H.  Ramage  7 discovered  spectroscopic  traces  of 
silver  in  a large  number  of  minerals.  Out  of  92  iron  ores  of  all 
classes  only  four  were  free  from  silver,  and  it  was  generally  detected 
in  manganese  ores  and  bauxite.  Blende,  galena,  and  the  pyritic  ores 
almost  invariably  contain  it.  Argentiferous  galena,  silver-lead  ore, 
is  one  of  the  chief  sources  of  this  metal. 

Unlike  gold,  silver  occurs  not  only  native,  but  in  many  compounds. 
The  sulphides,  sulphosalts,  and  halogen  compounds  are  best  known; 
but  selenides,  tellurides,  arsenides,  antimonides,  and  bismuthides  also 
exist.  These  minerals  or  groups  of  minerals  are  best  considered 
separately. 


1 See  F.  T.  Eddingfield,  Philippine  Jour.  Sci.,  vol.  8A,  1913,  p.  125.  Econ.  Geology,  vol.  8, 1913,  p.  498. 

2 On  the  relations  of  vegetation  to  the  deposition  of  gold  see  E.  E.  Lunqwitz,  Zeitschr.  prakt.  Geologie, 

1900,  pp.  71, 213. 

8 See  C.  Wilkinson,  Trans.  Roy.  Soc.  Victoria,  vol.  8, 1866,  p.  11;  W.  Skey,  Trans.  New  Zealand  Inst., 
vol.  3,  1870,  p.  225;  vol.  5,  1872,  pp.  370,  382;  A.  Liversidge,  Proc.  Roy.  Soc.  New  South  Wales,  vol.  27, 
1893,  p.  303;  C.  Palmer  and  E.  S.  Bastin,  Econ.  Geology,  vol.  8, 1913,  p.  140;  F.  F.  Grout,  idem,  p.  407. 

* Jour.  Am.  Chem.  Soc.,  vol.  24, 1907,  p.  355.  See  also  R.  I).  Hall  and  V.  Lenher,  idem,  p.  919.  Later 
papers  by  Lenher  are  in  Econ.  Geology,  vol.  7, 1912,  p.  744;  vol.  9, 1914,  p.  523.  On  the  relations  of  colloidal 
gold  to  ore  deposition,  see  Bastin,  Jour.  Washington  Acad.  Sci.,  vol.  5,  p.  64, 1915. 

6 For  a list  of  the  Survey  publications  on  gold  and  silver  see  Bull.  U.  S.  Geol.  Survey  No.  470,  1911. 

6 Jour.  Chem.  Soc.,  vol.  71,  1897,  p.  298. 

i Idem,  vol.  71,  1897,  p.  533. 


METALLIC  ORES. 


049 


Native  silver,  like  native  gold,  is  rarely  if  ever  pure.  It  commonly 
contains  admixtures  of  gold,  copper,  and  other  metals  in  extremely 
variable  proportions.  Silver  amalgam,  for  instance,  ranges  from  27.5 
to  95.8  per  cent  of  silver,  with  from  72.5  to  3.6  per  cent  of  mercury. 
In  the  Lake  Superior  copper  mines  silver  is  often  embedded  in  native 
copper,  each  metal  being  nearly  pure.  Specimens  showing  this 
association  are  locally  known  as  “half-breeds.” 

In  most  cases  native  silver  is  a secondary  mineral.  It  is  often 
found  in  gossan,  and  R.  Beck  1 mentions  films  of  silver  upon  the 
scales  of  fossil  fishes  from  the  Mansfield  copper  shales.  According 
to  J.  H.  L.  Vogt 2 the  native  silver  of  Kongsberg  is  largely  formed  by 
reduction  from  argentite,  although  a derivation  from  proustite  may 
also  be  observed.  The  silver  thus  formed  is  commonly  filiform.3  In 
a subordinate  degree  crystallized  silver  appears  as  a primary  deposit 
from  solutions.  Vogt  regards  a solution  of  silver  carbonate  or  bicar- 
bonate as  the  source  of  the  metal,  probably  because  of  its  association 
with  calcite,  and  thinks  that  ferrous  compounds  or  carbonaceous  sub- 
stances are  the  precipitants. 

The  reduction  of  silver  and  its  complete  precipitation  in  the  metal- 
lic state  by  organic  matter  was  long  ago  observed  by  H.de  Senar- 
mont.4  T.  A.  Rickard  5 also  found  that  it  was  thrown  down  as  a 
metallic  coating  upon  a black,  carbonaceous  shale.  The  reduction  of 
the  sulphide  by  hydrogen  is  also  possible,  but  less  likely  to  occur 
under  natural  conditions.6  Any  reaction,  however,  which  generated 
nascent  hydrogen  in  contact  with  silver  solutions  would  precipitate 
the  metal. 

The  nature  of  the  silver  solutions  in  metalliferous  veins  is  not  posi- 
tively known.  Apart  from  Vogt’s  suppositions,  it  seems  probable  that 
silver  sulphate  may  be  formed  by  oxidation  of  the  sulphide.  That 
salt,  however,  would  almost  certainly  be  transformed  into  chloride 
by  the  chlorides  present  in  percolating  waters.  Silver  chloride, 
although  soluble  with  difficulty,  is  not  absolutely  insoluble,  and  very 
dilute  solutions  of  it  may  well  take  part  in  the  filling  of  veins.  It 
has  long  been  known,  also,  that  silver  is  dissolved  by  hot  solutions 
of  ferric  sulphate,  a reaction  which  has  been  studied  by  H.  N.  Stokes 7 
in  the  laboratory  of  the  United  States  Geological  Survey.  The  reac- 
tion, 2Ag  + Fe2(S04)3  = Ag2S04  + 2FeS04,  is  reversible,  and  crystal- 
lized silver  is  redeposited  on  cooling.  Stokes  also  found  that  a 

1 Ore  deposits,  Weed’s  translation,  p.  371. 

2 Zeitschr.  prakt.  Geologie,  1899,  pp.  113, 177. 

8 On  the  formation  of  “hair  silver”  see  V.  Kohlschiitter  and  E.  Eydmann,  Liebig’s  Annalen,  vol.  390, 
1912,  p.  340. 

4 Annales  chim.  phys.,  3d  ser.,  vol.  32, 1851,  p.  140. 

6 Trans.  Am.  Inst.  Min.  Eng.,  vol.  26,  1896,  p.  978. 

8 See  G.  Bischof,  Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  3,  p.  856.  Also  J. 
Margottet,  Compt.  Rend.,  vol.  85,  1877,  p.  1142. 

T Econ.  Geology,  vol.  1, 1906,  p.  649.  See  also  the  experiment  of  H.  C.  Cooke  relative  to  secondary  enrich- 
ment in  Jour.  Geology,  vol.  21, 1913,  p.  1. 


650 


THE  DATA  OF  GEOCHEMISTRY. 


solution  of  copper  sulphate,  at  200  °,  was  an  effective  solvent  of  silver, 
this  reaction,  like  the  other,  being  reversible.  Pseudomorphs  of 
cerargyrite,  ruby  silver,  argentite,  and  stephanite  after  native  silver 
are  mentioned  by  Dana.1 

The  natural  arsenides,  antimonides,  and  bismuthides  of  silver  are 
imperfectly  known.  An  arsenide,  Ag3As,  was  described  by  H.  Wurtz,2 
under  the  name  huntilite.  Wurtz  also  reported  an  antimonide,  ani- 
mikite,  Ag9Sb.  Both  minerals  were  found  in  the  Silver  Islet  mine, 
Lake  Superior.  The  commoner  antimonide,  dyscrasite,  varies  from 
Ag3Sb  to  Ag6Sb.3  The  bismuthide,  chilenite,  is  perhaps  Ag6Bi. 

Silver  sulphide,  Ag2S,  is  found  in  nature  in  two  forms — the  iso- 
metric argentite,  which  is  a common  ore,  and  the  rare  orthorhombic 
acanthite.  It  is  one  of  the  easiest  of  the  silver  compounds  to  prepare, 
and  is  formed  whenever  moist  hydrogen  sulphide  4 comes  into  con- 
tact with  any  other  silver  salt,  or  with  the  metal  itself.  As  crystal- 
lized argentite  it  has  been  prepared  in  several  ways.  J.  Durocher5 
obtained  it  by  the  action  of  hydrogen  sulphide  upon  silver  chloride 
at  high  temperatures.  J.  Margottet 6 prepared  argentite  by  passing 
the  vapor  of  sulphur  over  silver  at  a lowT  red  heat.  With  selenium 
or  tellurium  vapor  the  corresponding  selenide  and  telluride  of  silver 
were  formed.  J.  B.  Dumas  7 obtained  the  crystallized  sulphide  by 
the  same  process.  F.  ftoessler 8 crystallized  argentite  and  the  selenide 
from  solution  in  molten  silver,  and  the  selenide  also  from  fused  bis- 
muth. C.  Geitner,9  by  heating  silver  to  200°  with  a solution  of 
sulphurous  acid,  obtained  argentite.  Silver  sulphite,  heated  with 
water  to  the  same  temperature,  broke  down  into  argentite  and  crys- 
tallized silver.  According  to  E.  Weinschenk,10  argentite  is  produced 
when  silver  acetate  and  a solution  of  ammonium  sulphocyanate  are 
heated  together  to  180°  in  a sealed  tube.  In  this  case  the  decom- 
position of  the  sulphocyanate  yields  hydrogen  sulphide,  which  is  the 
actually  effective  reagent.  Finally,  W.  Spring 11  claims  to  have 
found  that  silver  and  sulphur  could  be  forced  to  combine  by  repeated 
compression  together  of  the  two  finely  divided  elements.  The  pres- 
sure employed  was  6,500  atmospheres.  Silver  and  arsenic  also  unite 
under  the  same  conditions.  Spring’s  experiments,  however,  or  at 


1 System  of  mineralogy,  6th  ed.,  p.  20. 

2 Eng.  and  Min.  Jour.,  vol.  27,  1879,  pp.  55,  124. 

3 The  compound  Ag3Sb  appears  to  be  the  only  definite  antimonide  of  silver, 'the  others  are  mixed  crystals. 
See  C.  T.  Heycock  and  F.  H.  Neville,  Philos.  Trans.,  vol.  189A,  1897,  p.  25;  E.  Maey,  Zeitschr.  physikal. 
Chemie,  vol.  50, 1904,  p.  200:  G.  I.  Petrenko,  Zeitschr.  anorg.  Chemie,  vol.  50, 1906,  p.  139,  and  T.  Liebisch, 
Sitzungsb.  K.  Akad.  Wiss.  Berlin,  1910,  p.  365.  Petrenko  cites  other  references. 

4 Dry  hydrogen  sulphide  does  hot  attack  silver. 

6 Compt.  Rend.,  vol.  32,  1851,  p.  825. 

e Idem,  vol.  85,  1877,  p.  1142. 

2 Annales  chim.  phys.,  3d  ser.,  vol.  55,  1859,  p.  147. 

b Zeitschr.  anorg.  Chemie,  vol.  9,  1895,  p.  31. 

9 Liebig’s  Annalen,  vol.  129,  1864,  p.  358. 

i°  Zeitschr.  Kryst.  Min.,  vol.  17, 1890,  p.  497. 

u Ber.  Deutsch.  chem.  Gesell.,  vol.  16, 1883,  pp.  324,  1002;  vol.  17,  1884,  p.  1218. 


METALLIC  ORES. 


651 


least  his  deductions  from  them,  are  of  doubtful  validity.  Later 
investigations  have  failed  to  confirm  them.1 

Some  of  these  syntheses  evidently  have  no  exact  parallel  in  nature. 
Probably  the  natural  reactions  are  of  the  simplest  kind.  Sulphur, 
sulphur  dioxide,  or  hydrogen  sulphide  acts  either  upon  metallic  silver 
or  upon  any  of  its  naturally  available  compounds,  solid  or  in  solu- 
tion, and  the  sulphide  is  formed.  Its  crystallization,  which  is  accel- 
erated by  the  laboratory  methods,  is  presumably  a question  of  time, 
aided  by  the  slight  solubility  of  the  compound.  The  last  remark, 
obviously,  applies  to  many  other  sulphides  also.  The  reduction  of 
sulphate  solutions  by  organic  matter  is  another  probable  mode  of 
generation. 

It  has  already  been  shown  that  argentite  is  easily  reduced  to  sil- 
ver. Indeed,  silver  sulphide  is  the  most  readily  reducible,  that  is, 
the  least  stable,  of  all  the  commoner  sulphides.  This  is  illustrated 
by  its  heat  of  formation,  which  is  low  compared  with  that  of  other 
sulphides.  The  following  data,  giving  heats  of  formation  from  solid 
metal  and  solid  sulphur,  are  furnished  by  Julius  Thomsen.2  The 
figures  represent  small  calories. 


Heats  of  formation  of  various  sulphides. 

PbS 

Cu2S 

HgS 

Ag2S 


20,  430 
20,  270 
16,  890 
5,  340 


On  the  other  hand,  silver  is  precipitated  from  its  solutions  by 
pyrite,  chalcopyrite,  galena,  and  other  sulphides.3  H.  N.  Stokes,4 
in  the  laboratory  of  the  United  States  Geological  Survey,  found  that 
marcasite,  heated  with  silver  carbonate  and  potassium  bicarbonate 
solution  at  180°,  precipitated  silver  sulphide.  According  to  R. 
Schneider,5  bismuth  sulphide  precipitates  silver  sulphide  from  a 
nitrate  solution.  A.  Gibb  and  R.  C.  Philip,6  also  working  with  silver 
nitrate  solutions,  found  that  cuprous  sulphide  precipitated  silver  sul- 
phide, while  copper  or  cuprous  oxide  threw  down  metallic  silver. 

In  a recent  investigation  by  Chase  Palmer  and  E.  S.  Bastin7  a 
considerable  number  of  sulphides  were  treated  with  dilute  solutions 
of  silver  sulphate  at  ordinary  room  temperatures.  Metallic  silver 


1 See  W.  Hallock,  Am.  Jour.  Sci.,  3d  ser.,  vol.  34, 1887,  p.  277;  and  Bull.  U.  S.  Geol.  Survey  No.  64,  1890, 
p.  38.  Also  the  general  discussion  of  pressure  effects  by  J.  Johnston  and  L.  H.  Adams,  Am.  Jour.  Sci., 
4th  ser.,  vol.  35, 1913,  p.  205. 

2 Thermochemische  Untersuchungen,  vol.  3, 1883,  p.  455. 

3 See  W.  Skey,  Trans.  New  Zealand  Inst.,  vol.  3, 1870,  p.  225. 

* Econ.  Geology,  vol.  2, 1907,  p.  16. 

& Jour,  prakt.  Chemie,  2d  ser.,  vol.  41, 1890,  p.  414. 

6 Trans.  Am.  Inst.  Min.  Eng.,  vol.  36, 1906,  p.  667. 

7 Econ.  Geology,  vol.  8, 1913, p.  140.  Also  Palmer,  idem,  vol.  9, 1914,  p.  664,  and  F.  F.  Grout,  idem,  vol. 
8,  p.  407.  On  the  precipitation  of  silver  by  copper  sulphides,  see  E.  Posnjak,  Jour.  Am.  Chem.  Soc.,  vol. 
36, 1914,  p.  2475. 


652 


THE  DATA  OF  GEOCHEMISTRY. 


was  precipitated  by  chalcocite,  niccolite,  covellite(?),  bornite,  ten- 
nantite,  alabandite,  smaltite,  marcasite,  pyrrhotite,  and  chalcopyrite. 
Little  or  no  reaction  was  observed  with  cinnabar,  stibnite,  pyrite, 
galena,  millerite,  sphalerite,  jamesonite,  orpiment,  and  realgar.  A 
specimen  of  niccolite  containing  much  cobaltite  gave  peculiarly 
suggestive  results.  The  niccolite  went  completely  into  solution, 
precipitating  an  equivalent  amount  of  silver,  while  the  cobaltite  was 
unattacked.  The  arsenides  generally  were  found  to  dissolve,  while 
the  sulpharsenides,  like  cobaltite  and  arsenopyrite,  failed  to  react. 
A quantitative  method  for  estimating  the  relative  proportions  of 
such  minerals  in  a mixture  is  therefore  now  available,  apart  from  the 
significance  of  the  data  in  the  study  of  secondary  enrichment.  In 
certain  details  the  results  obtained  are  apparently  inconsistent  with 
the  statements  of  previous  investigators.  This  inconsistency  is  prob- 
ably due  to  differences  in  the  experimental  conditions.  Different 
solutions,  whether  acid  or  alkaline,  different  concentrations  and 
temperatures,  and  impurities  in  the  minerals  studied  would  account 
for  much  discordance.  Pyrite,  for  example,  often  contains  admix- 
tures of  maroasite,  the  latter  being  an  active  precipitant  of  silver, 
the  former  not.  Such  impure  pyrite  would  evidently  give  an  appar- 
ently abnormal  reaction.  The  case  of  covellite  is  similarly  question- 
able. The  natural  mineral  contains  some  admixed  chalcocite,  which 
precipitates  silver  quantitatively.  Pure  cupric  sulphide  dissolves  in 
a solution  of  silver  sulphate,  precipitating  silver  sulphide.  It  is 
desirable  that  reactions  of  this  class  should  be  further  investigated 
with  pure  synthetic  minerals,  and  also  with  solutions  of  silver 
chloride.  The  nitrate  is  not  an  appropriate  solvent  to  use,  for  it 
probably  does  not  occur  in  nature,  and  it  may  give  rise  to  confusing 
secondary  reactions.  Primary  reactions  of  the  character  described  in 
the  preceding  paragraphs  doubtless  assist  in  the  secondary  enrich- 
ment of  ore  bodies,  the  silver  being  dissolved  above  and  redeposited 
below. 

The  selenide  of  silver,  naumannite,  Ag2Se,  is  a well-known  but  rare 
mineral.  A sulphoselenide,  aguilarite,  Ag4SSe,  has  also  been  de- 
scribed. Naumannite  often  contains  lead,  due  to  admixtures  of 
the  lead  selenide. 

Hessite  is  the  normal  telluride  of  silver,  Ag2Te.  Stutzite,  Ag4Te,  is 
a more  doubtful  substance.  The  synthesis  of  hessite  by  Margottet  has 
already  been  mentioned.  B.  Brauner 1 also  obtained  it  by  the  same 
method.  B.  D.  Hall  and  V.  Lenher2  prepared  the  compound  by 
reducing  silver  tellurite,  and  they  also  found  that  a telluride  was  pre- 
cipitated by  the  action  of  tellurium  upon  silver  solutions.  Two  tel- 


1 Jour.  Chem.  Soc.,  vol.  55,  1889,  p.  388. 


2 Jour.  Am.  Chem.  Soc.,  vol.  24, 1902,  p.  919. 


METALLIC  ORES. 


653 


lurides,  AgTe  and  Ag2Te  have  been  prepared  by  G.  Pellini  and 
E.  Quercigh.1 

Eucairite,  CuAgSe;  stromeyerite,  CnAgS;  sternbergite,  AgFe2S3; 
and  frieseite,  Ag2Fe5S8,  are  rare  silver-bearing  minerals. 

The  sulphosalts  formed  by  silver  with  the  sulphides  of  arsenic,  anti- 
mony, and  bismuth  are  quite  numerous.  Some  of  them  are  important 
ores;  others  are  mineralogical  rarities;  but,  on  account  of  their  inter- 
relationships, all  are  significant.  They  may  be  arranged  as  follows: 


Smithite 

Monoclinic. 

Miargyrite 

AgSbS2 

Monoclinic. 

Matildite 

AgBiS2 

(?) 

Proustite 

Ag3AsS3 

Rhombohedral. 

Xanthoconite 

Ag3AsS3 

Monoclinic. 

Pyrargyrite  2 

Ag3SbS3 

Rhombohedral. 

Pyrostilpnite 

Ag3SbS3 

Monoclinic. 

Tapalpite  3 

Ag3BiTe3 

Stephanite 

Ag5SbS4 

Orthorhombic. 

Pearceite 

Ag9AsS6 

Monoclinic. 

Polybasite 

Ag9SbS6 

Orthorhombic. 

Polyargyrite 

Isometric. 

Schapbachite. . . . 

Orthorhombic. 

Brongniardite 

Ag2PbSb2S5 

Isometric. 

Andorite 

AgPbSb3S6 

Orthorhombic. 

Schirmerite 

Massive. 

Diaphorite 

(Ag2,Pb)5Sb4Sn 

Orthorhombic. 

Freieslebenite .... 

(Ag2,Pb)5Sb4Sn 

Monoclinic. 

Several  other  sulphosalts  of  lead  and  copper  also  contain  replace- 
ments of  silver  of  considerable  importance.  Tennantite,  Cu8As2S7, 
contains  up  to  13.65  per  cent  of  silver;  and  tetrahedrite,  Cu8Sb2S7,  up 
to  31.3  per  cent.  In  cosalite,  Pb2Bi2S5,  as  much  as  15.66  per  cent  of 
silver  has  been  found.  The  tin  and  germanium  sulphosalts,  canfield- 
ite,  Ag8SnS6,  and  argyrodite,  Ag8GeS6,  are  very  rare  minerals.  Small 
admixtures  of  any  of  these  compounds  with  other  sulphides,  how- 
ever, would  render  the  latter  useful  ores  of  silver. 

Several  of  these  sulphosalts  have  been  prepared  synthetically. 
J.  Durocher 4 claims  to  have  obtained  them  by  heating  mixed  chlorides 
of  silver  and  antimony,  or  silver  and  arsenic,  in  a current  of  hydrogen 
sulphide.  Details  are  not  given.  H.  de  Senarmont,5 6  by  heating  a 
salt  of  silver  at  temperatures  ranging  from  250°  to  350°  with  a solu- 
tion of  an  alkaline  sulpharsenite  or  sulphantimonite  in  an  excess  of 
sodium  bicarbonate,  succeeded  in  producing  pyrargyrite  and  prous- 
tite.  By  precipitating  a solution  of  silver  nitrate  with  the  potassium 


1 Atti  R.  accad.  Lincei,  vol.  19,  pt.  2, 1910,  p.  415. 

2 A manganiferous  sulphantimonide  of  silver,  samsonite,  allied  to  pyrargyrite,  has  been  described  by 

Werner  and  Fraatz,  Centralbl.  Min.,  Geol.  u.  Pal.,  1910,  p.  331. 

8 Contains  some  sulphur  partly  replacing  tellurium. 

* Compt.  Rend.,  vol.  32,  1851,  p.  825. 

6 Annales  chim.  phys.,  3d  ser.,  vol.  32, 1851,  pp.  171-173. 


654 


THE  DATA  OF  GEOCHEMISTRY. 


sulphantimonate,  K3SbS3,  I.  Pouget 1 obtained  the  amorphous  com- 
pound Ag3SbS3,  equivalent  in  composition  to  pyrargyrite. 
C.  Doelter 2 prepared  miargyrite,  pyrargyrite,  and  stephanite  by  a 
modification  of  Senarmont’s  method.  Silver  chloride,  mixed  with  a 
sodium  carbonate  solution  of  potassium  sulphantimonate  in  varying 
proportions,  was  heated  with  hydrogen  sulphide  in  sealed  tubes  to 
80°-150°.  Pyrargyrite  was  most  easily  formed;  miargyrite  appeared 
only  once.  Doelter 3 also  heated  silver  chloride  with  antimony 
trichloride,  sulphide,  or  oxide  in  hydrogen  sulphide,  and  obtained 
similar  results.  H.  Sommerlad  4 prepared  pyrargyrite,  miargyrite, 
and  stephanite  by  heating  antimony  sulphide  and  silver  chloride 
together.  With  arsenic  trisulphide,  proustite  was  formed.  The 
same  species,  and  also  polyargyrite,  were  produced  when  the  com- 
ponent sulphides  were  fused  together  in  a stream  of  hydrogen  sul- 
phide. According  to  R.  Schneider,5  potassium  bismuth  sulphide, 
KBiS2,  added  to  a solution  of  silver  nitrate,  precipitates  the  compound 
AgBiS2.  This,  crystallized  by  fusion,  becomes  matildite.  Matildite 
was  also  made  by  Roessler 6 when  the  sulphides  of  silver  and  bismuth 
were  allowed  to  crystallize  together  from  solution  in  molten  bismuth. 

F.  M.  Jaeger  and  H.  S.  van  Klooster,7  by  prolonged  heating  at 
200°-240°  of  a mixture  of  antimony  trichloride  and  silver  sulphide  in 
a concentrated  solution  of  sodium  sulphide  and  sodium  bicarbonate, 
obtained  crystalline  scales  of  pyrargyrite.  By  direct  fusion  of  the 
component  sulphides  together  in  an  atmosphere  of  nitrogen  they  pre- 
pared pyrargyrite,  miargyrite,  proustite  and  “arsenomiargyrite,”  the 
last  named  being  probably  identical  with  smithite.  From  the  fusion 
diagrams  they  infer  that  some  of  Sommerlad’s  results  were  erroneous. 

From  these  syntheses  it  is  evident  that  the  sulphosalts  of  silver 
are  easily  formed,  and  by  various  methods.  Those  which  involve 
fusion  are  probably  not  operative  in  nature,  for  the  ores  under  con- 
sideration are  commonly  associated  with  gangue  minerals  which 
could  not  be  formed  in  that  way.  Quartz,  calcite,  fluorite,  barite, 
etc.,  are  vein  minerals  which  can  be  deposited  only  from  solution, 
and  the  same  rule  must  hold  for  the  accompanying  sulphides.  Solu- 
tions of  silver,  produced  by  oxidation  of  ores,  probably  react  with 
great  slowness  upon  sulphur  compounds  of  arsenic,  antimony,  or 
bismuth;  and  the  new  minerals  are  produced  under  varying  condi- 
tions. The  nature  of  the  primary  sulphides  and  of  the  infiltrating 
solutions,  together  with  conditions  of  concentration  and  temperature, 
determines  the  character  of  the  sulphosalts  to  be  formed.  These  con- 


1 Compt.  Rend.,  vol.  124,  1897,  p.  1518. 

2 Allgemeine  chemische  Mineralogie,  1890,  p.  152. 

* Zeitschr.  Kryst.  Min.,  vol.  11, 1886,  p.  29. 

* Zeitschr.  anorg.  Chemie,  vol.  15,  1897,  p.  173;  vol.  18,  1898,  p.  420. 

6 Jour,  prakt.  Chemie,  2d  ser.,  vol.  41,  1890,  p.  414. 

8 Zeitschr.  anorg.  Chemie,  vol.  9,  1895,  p.  31. 

7 Idem,  vol.  78, 1912,  p.  245. 


METALLIC  ORES. 


655 


ditions  are  imperfectly  known,  at  least  quantitatively,  and  so  far  as 
the  natural  phenomena  are  concerned;  but  the  syntheses  give  hints 
which  may  aid  in  their  future  discovery.  It  is  also  possible  that 
arsenical  or  antimonial  solutions  may  react  upon  silver  compounds, 
such  as  argentite  or  the  chlorides,  and  so  form  sulphosalts  of  different 
kinds.  The  supposable  reactions  are  many,  and  it  is  not  easy  to 
determine  which  ones  have  operated  in  any  particular  case. 

The  haloid  ores  of  silver  remain  to  be  mentioned.  These  are  repre- 
sented by  three  distinct  and  several  intermediate  mineral  species; 
the  three  being  cerargyrite,  or  horn  silver,  AgCl;  bromyrite,  AgBr, 
and  iodyrite,  Agl.  Emboli te  is  a chlorobromide;  iodobromite  is  rep- 
resented by  the  formula  2 AgC1.2AgBr. Agl ; cuproiodargyrite  is  near 
CuAgI2;  and  miersite  is  an  isometric  iodide  of  silver,  the  commoner 
iodyrite  being  hexagonal.1 

All  these  minerals  are  secondary,  and  appear  for  the  most  part 
in  the  upper  levels  of  ore  bodies.  Infiltrating  solutions  of  chlorides, 
bromides,  or  iodides  act  upon  the  oxidation  products  of  the  primary 
ores,  and  precipitate  these  relatively  insoluble  species.  They  are  not 
absolutely  insoluble,  however,  and  probably  crystallize  very  slowly 
from  extremely  dilute  solutions.  A form  of  silver  chloride  identical 
in  appearance  with  cerargyrite  was  prepared  by  F.  Kuhlmann 2 when 
a solution  of  silver  nitrate  was  allowed  to  mix  very  gradually  with 
aqueous  hydrochloric  acid.  The  two  solutions  were  separated  by  a 
porous  layer  of  asbestos,  pumice,  or  platinum  sponge,  through  which 
they  slowly  commingled.3  Such  a blending  of  solutions  may  take 
place  in  nature,  through  layers  of  decomposed  rock  substance,  such 
as  a sandy  clay  or  a gossan. 

COPPER. 

The  minerals  of  copper  are  much  more  numerous  than  those  of 
silver,  and  represent  a wider  range  of  composition.  No  oxidized  ores 
of  silver  are  known,  but  copper  is  found  not  only  as  oxide,  but  also  in 
silicates,  sulphates,  phosphates,  arsenates,  carbonates,  a basic  nitrate, 
and  an  oxychloride.  The  metal  is  easily  oxidizable,  and  is  also  easily 
reduced;  it  therefore  occurs  both  as  native  copper  and  in  its  many 
compounds.  1 

Native  copper  is  commonly,  if  not  always,  a secondary  mineral, 
either  deposited  from  solution  or  formed  by  the  reduction  of  some 
solid  compound.  Pseudomorphs  of  copper  after  the  oxide,  cuprite, 

1 See  G.  T.  Prior  and  L.  J.  Spencer,  Mineralog.  Mag.,  vol.  13,  1902,  p.  174,  for  a general  paper  on  the 
cerargyrite  group.  H.  B.  Kosmann  (Leopoldina,  vol.  30,1894,  pp.  193,  203)  has  discussed  the  formation  of 
these  ores  from  a thermochemical  point  of  view.  A mineral  having  the  formula  20NaCl+AgCl  has  been 
called  huantajayite.  Recent  papers  on  the  genesis  of  these  ores  are  by  C.  R.  Keyes,  Econ.  Geology,  vol.  2, 
1907,  p.  774;  Bull.  Am.  Inst.  Min.  Eng.,  July,  1911,  p.  541,  and  J.  A.  Burgess,  idem,  vol.  6, 1911,  p.  13. 

2Compt.  Rend.,  vol.  42, 1856,  p.  374. 

3 H.  Debray  also  crystallized  the  chloride,  bromide,  and  iodide  of  silver  from  aqueous  solutions  in  mer- 
curic nitrate,  Compt.  Rend.,  vol.  70,  1870,  p.  995.  This  process  can  hardly  be  a reproduction  of  natural 
conditions, 


656 


THE  DATA  OF  GEOCHEMISTRY. 


are  well  known;  and  remarkably  perfect  pseudomorphs  after  azurite, 
from  Grant  County,  New  Mexico,  have  been  described  by  W.  S. 
Yeates.1  According  to  W.  Lindgren,2  a vein  of  metallic  copper  at 
Clifton,  Arizona,  appears  to  have  been  formed  from  chalcocite. 
Examples  of  this  general  character  might  be  multiplied  indefinitely. 

T.  Carnelley 3 has  shown  that  metallic  copper  is  perceptibly 
attacked  and  dissolved  by  distilled  water,  and  much  more  so  by  saline 
solutions  resembling  those  existing  in  nature.  The  direct  solubility 
of  the  sulphides  was  considered  earlier  in  this  chapter,  and  also  the 
formation  of  strong  sulphate  solutions  by  oxidation  of  pyrite  ores. 
From  solutions  such  as  these,  but  very  dilute,  the  greater  deposits  of 
native  copper  appear  to  have  been  formed. 

In  the  Lake  Superior  region  the  greatest  known  deposits  of  metallic 
copper  are  found.4 *  Its  original  home,  perhaps  as  sulphide,  was  in 
the  unaltered  igneous  rocks,  but  its  concentrations  are  now  found 
in  the  sandstones,  conglomerates,  and  amygdaloids.  In  the  sand- 
stones and  conglomerates  it  acts  as  a cement,  and  it  also  replaces 
pebbles  and  even  bowlders  a foot  or  more  in  diameter.  Some  of  the 
masses  of  copper  are  enormous;  one,  for  example,  found  in  the  Min- 
nesota mine  in  1857,  weighed  about  420  tons.  It  is  associated  with 
other  minerals  of  hydrous  origin,  such  as  epidote,  datolite,  calcite, 
and  zeolites,  and  calcite  crystals  are  known  which  had  been  coated 
with  copper,  and  then  overgrown  with  more  calcite.  Lane  also  men- 
tions a quartz  crystal  which  had  been  corroded  and  mainly  replaced 
by  copper.  Frequently  the  copper  incloses  nodules  of  native  silver, 
which  were  evidently  precipitated  first  and  then  enveloped  by  the 
baser  metal.  Had  these  metals  been  deposited  from  a fused  magma 
they  would  have  formed,  not  separately,  but  as  an  alloy.  The 
reducing  agent,  according  to  Pumpelly,  was  probably  some  compound 
of  iron,  oxide  or  silicate;  and  R.  D.  Irving  substantiates  this  opinion 
by  citing  particles  of  cementing  copper  which  inclosed  cores  of 
magnetite.  Pumpelly’s  conclusion  was  based  upon  the  constant  asso- 
ciation of  the  Lake  Superior  copper  with  epidote,  delessite,  and  the 
green  earth  silicates,  all  of  which  are  ferriferous.  H.  N.  Stokes  6 
has  found  that  hornblende  and  siderite  can  precipitate  metallic  cop- 
per from  a sulphate  solution  heated  to  200°.  Under  certain  condi- 
tions, also,  ferrous  sulphate,  pyrite,  and  chalcocite  are  capable,  accord- 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  38, 1889,  p.  405. 

2 Prof.  Paper  U.  S.  Geol.  Survey  No.  43, 1905,  p.  101. 

2 Jour.  Chem.  Soc. , vol.  30, 1876,  p.  1.  See  also  R.  Meldrum,  Chem.  News,  vol.  78, 1898,  p.  209. 

«See  H.  Credner,  Neues  Jahrb.,  1869,  p.  1;  R.  Pumpelly,  Am.  Jour.  Sci.,  3d  ser.,  vol.  2,  1871,  p.  348; 
Geol.  Survey  Michigan,  vol.  1,  pt.  2,  1873,  and  Proe.  Am.  Acad.,  vol.  13,  1878,  p.  253;  M.  E.  Wadsworth, 
Bull.  Mus.  Comp.  Zool.,  vol.  7,  1880,  p.  1;  R.  D.  Irving,  Mon.  U.  S.  Geol.  Survey,  vol.  5, 1883,  chapter  10; 
A.  C.  Lane,  Rept.  State  Bd.  Geol.  Survey  Michigan,  1903,  p.  239;  Quart.  Bull.  Canadian  Min.  Inst.,  No.  13, 
1911,  p.  81;  and  two  volumes  on  the  Keweenaw  series,  published  by  the  Michigan  Survey  in  1911.  In  the 

Keweenawan  rocks  of  Minnesota  F.  F.  Grout  (Econ.  Geology,  vol.  5, 1910,  p.  471)  has  found  from  0.012 
to  0.029  per  cent  of  copper. 

6 Econ.  Geology,  vol.  1,  p.  648, 1906. 


METALLIC  ORES. 


657 


ing  to  Stokes,  of  reducing  cupric  sulphate  to  the  metallic  state.  Cop- 
per itself  reacts  with  cupric  sulphate  solutions,  reducing  them  to 
cuprous  form.  When  such  a solution  of  cuprous  sulphate  is  produced 
at  a high  temperature,  it  deposits  crystallized  metallic  copper  upon 
cooling.1  In  this  way  a hot  ascending  solution  of  cupric  sulphate 
may  dissolve  copper  and  redeposit  it  at  a higher,  cooler  level.  H.  C. 
Biddle,2  by  heating  a solution  of  ferrous  chloride,  cupric  chloride, 
and  potassium  bicarbonate  in  an  atmosphere  of  carbon  dioxide  under 
pressure,  obtained  a precipitate  containing  metallic  copper.  A. 
Gautier 3 has  shown  that  superheated  steam  will  reduce  cuprous 
sulphide,  chalcocite,  to  the  metallic  state,  according  to  the  reaction — 

Cu2S  + 2H20  = 2Cu  + S02  + 2H2. 

Some  experiments  conducted  in  the  physical  laboratory  of  the 
United  States  Geological  Survey 4 are  very  suggestive  as  regards  the 
crystallization  of  copper  and  silver.  Water,  ammonium  chloride,  and 
tremolite  were  heated  together  during  three  and  a hah  days,  at  465° 
to  540°,  in  a steel  bomb  lined  with  a silver-plated  copper  tube.  The 
tube  was  attacked  near  its  base,  and  the  two  metals  were  redeposited 
in  separate  crystals  in  the  upper  and  cooler  regions  of  the  apparatus. 
In  the  lower,  hotter  part  an  alloy  of  silver  and  copper  was  formed. 

In  some  cases  organic  matter  is  evidently  the  reducing  agent.  H. 
de  Senarmont 5 showed  that  copper  solutions  were  thus  reduced  at 
temperatures  between  150°  and  250°.  it.  Beck6  mentions  native 
copper  filling  the  marrow  cavities  of  fossil  bones  in  the  Peruvian 
sandstones  of  Corocoro,  Bolivia.  The  films  of  copper  often  found  in 
shales,  as,  for  example,  near  Enid,  Oklahoma,7  were  doubtless  pre- 
cipitated by  substances  of  organic  origin.8 

On  the  other  hand,  copper  readily  undergoes  oxidation,  yielding 
cuprite,  malachite,  and  sometimes  azurite.  All  of  these  species  are 
known  to  occur  as  coatings  upon  the  native  metal.  On  buried 
Chinese  copper  coins  of  the  seventh  century  A.  F.  Rogers  9 identified 

1 Stokes,  Econ.  Geology,  vol.  1,  1906,  p.  648.  See  also  earlier  investigations  cited  by  Stokes. 

2 Jour.  Geology,  vol.  9,  1901,  p.  430;  and  Am.  Chem.  Jour.,  vol.  26,  1901,  p.  377.  G.  Femekes  (Econ. 
Geology,  vol.  2,  1907,  p.  581)  has  also  described  the  precipitation  of  copper  from  neutral  chloride  solutions 
by  FeCl2.  See  also  C.  F.  Tolman  and  J.  D.  Clark,  idem,  vol.  9,  1914,  p.  559,  on  the  behavior  of  copper  in 
electrolytic  and  colloidal  solutions. 

3 Compt.  Rend.,  vol.  142, 1906,  p.  1465. 

* Preliminary  notice  by  F.  E.  Wright,  Science,  vol.  25,  1907,  p.  389. 

6 Annales  chim.  phys.,  3d  ser.,  vol.  32,  1851,  p.  140. 

« Ore  deposits,  Weed’s  translation,  p.  499. 

i See  E.  Haworth  and  J.  Bennett,  Bull.  Geol.  Soc.  America,  vol.  12, 1900,  p.  2. 

8 The  association  of  copper  ores,  other  than  native  copper,  with  organic  remains  is  by  no  means  rare. 
For  example,  E.  J.  Schmitz  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  26,  1896,  p.  101)  mentions  impregnations 
of  copper  in  fossil  wood  in  the  Permian  of  Texas.  Percy  (Metallurgy,  vol.  1, 1875,  p.  211)  refers  to  a cuprif- 
erous peat  in  Wales  which  had  actually  been  worked  as  an  ore.  Its  ash  contained  about  3 per  cent  of 
copper. 

9 Am.  Geologist,  vol.  31,  1903,  p.  43.  Similar  coins,  probably  from  the  same  find,  are  in  the  collections 
of  the  United  States  National  Museum.  A.  Lacroix,  Bull.  Soc.  min.,  vol.  32,  1909,  p.  334,  has  reported 
chalcocite  on  ancient  Roman  coins. 

97270°— Bull.  616—16 42 


658 


THE  DATA  OF  GEOCHEMISTRY. 


cuprite,  malachite,  azurite,  cerusite,  and  occasional  crystals  of 
metallic  copper.  In  the  last  case  the  oxidation  had  been  followed 
by  a reduction.  Other  similar  examples  are  known. 

Among  the  less  important  ores  of  copper  there  are  three  arsenides, 
an  antimonide,  some  selenides,  and  a telluride.  The  arsenides  are 
domeykite,  Cu3As;  algodonite,  Cu6As;  and  whitneyite,  Cu9As. 
Mohawkite  is  a domeykite  containing  several  per  cent  of  cobalt  and 
nickel.  Domeykite  was  produced  artificially  by  G.  A.  Koenig,1  who 
passed  the  vapor  of  arsenic  over  red-hot  copper.  Horsfordite  is  the 
antimonide,  Cu6Sb.  Two  selenides  are  known,  namely,  berzelianite, 
Cu2Se,  and  umangite,  Cu3Se2.  Crookesite  is  a selenide  of  copper, 
silver,  and  thallium,  and  rickardite  is  the  telluride,  Cu4Te3.  In  the 
electrolytic  refining  of  copper  at  Baltimore  considerable  quantities 
of  tellurium  accumulate  in  the  slimes.  It  was  probably  diffused  as 
telluride  of  copper  in  the  original  ores. 

The  sulphides  of  copper  and  its  double  sulphides  with  iron  are  the 
most  important  ores  of  this  metal.  Their  composition  is  shown  in 
the  subjoined  formulae: 


Chalcocite Cu2S. 

Covellite CuS. 

Chalcopyrite CuFeS2. 

Chalmersite 2 CuFe2S3. 

Cubanite CuFe2S4. 

Bornite 3 Cu6FeS4. 


To  this  list  the  rare  cobalt  copper  sulphide,  carrollite,  CuCo2S4,  may 
be  added. 

Several  of  these  species  have  been  found  as  furnace  products,  or 
obtained  by  intentional  syntheses.  As  a furnace  product,  chalcopy- 
rite has  been  several  times  reported;  and  A.  N.  Winchell4  found  it, 
together  with  bomite,  thus  formed,  probably  by  sublimation,  at 
Butte,  Montana.  On  another  product  from  the  same  locality,  W.  P. 
Headden  5 discovered  cubanite.  Chalcopyrite  was  first  prepared  by 
J.  Fournet,6  who  simply  fused  pyrite  and  copper  sulphide  together. 
F.  de  Marigny 7 obtained  bornite  by  fusing  pyrite  with  copper  turn- 
ings and  sulphur,  a process  essentially  identical  with  Fournet’s,  the 
difference  in  product  probably  depending  upon  the  proportions  of 
the  materials  used. 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  10,  1900,  p.  439. 

2 See  E.  Hussak,  Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  p.  332.  R.  Schneider  (Jour,  prakt.  Chemie,  2d  ser., 
vol.  52,  1895,  p.  555)  gives  the  formula  here  assigned  to  chalmersite  to  cubanite. 

3 Formula  as  established  by  B.  J.  Harrington,  Am.  Jour.  Sci.,  4th  ser.,  vol.  16, 1903,  p.  151.  The  older, 
commonly  accepted  formula  is  Cu3FeS3.  On  serial  relations  between  the  copper-iron  sulphides,  see  E.  H. 

Kraus  and  P.  Goldsberry,  Am.  Jour.  Sci.,  4th  ser.,  vol.  37, 1914,  p.  539.  An  important  preliminary  paper  on 
these  ores,  by  L.  C.  Graton  and  J.  Murdoch  is  in  Trans.  Am.  Inst.  Min.  Eng.,  vol.  45, 1914,  p.  26. 

* Am.  Geologist,  vol.  28,  1901,  p.  244. 

6 Proc.  Colorado  Sci.  Soc.,  vol.  8, 1905,  p.  39. 

« Annales  des  mines,  3d  ser.,  vol.  4,  1833,  p.  3. 

* Compt.  Rend.,  vol.  58,  1864,  p.  967. 


METALLIC  ORES. 


659 


J.  Durocher,1  by  the  action  of  hydrogen  sulphide  upon  the  vapor 
of  copper  chloride,  obtained  copper  sulphide  in  hexagonal  tables. 
H.  de  Senarmont 2 heated  a solution  containing  ferrous  and  cuprous 
chlorides,  sodium  persulphide,  and  a large  excess  of  sodium  bicar- 
bonate to  250°,  and  so  produced  an  amorphous  precipitate  having 
the  composition  of  chalcopyrite.  According  to  C.  Doelter,3  malachite, 
heated  with  hydrogen  sulphide  solution  to  80°-90°  in  a sealed  tube, 
yields  covelhte.  Cupric  oxide,  heated  to  200°  in  a stream  of  hydro- 
gen sulphide,  was  converted  into  covellite;  at  higher  temperatures 
chalcocite  formed.  By  gently  heating  a mixture  corresponding  to 
2Cu0  + Fe203  in  gaseous  hydrogen  sulphide,  Doelter  obtained  chal- 
copyrite; and  from  a mixture  of  cuprous,  cupric,  and  ferric  oxides 
in  the  same  gas  at  100°  to  200°  he  prepared  bornite.  E.  Weinschenk 4 
effected  the  synthesis  of  both  chalcocite  and  covellite  by  heating 
cuprous  or  cupric  solutions  with  ammonium  sulphocyanate  to  80° 
in  sealed  tubes.  It  must  be  remembered  in  this  connection  that  the 
sulphocyanate  serves  merely  as  a source  of  hydrogen  sulphide  under 
pressure.  A.  F.  Rogers  5 obtained  covellite  by  heating  sphalerite  in  a 
solution  of  copper  sulphate  at  150°-200°  in  a sealed  tube. 

At  several  of  the  French  thermal  springs,  Bourbonne-les-Bains, 
Plombieres,  etc.,  A.  Daubree6  found  Roman  coins  and  metals  upon 
which,  derived  from  the  bronze,  chalcocite,  chalcopyrite,  bornite,  and 
tetrahedrite  had  formed.  Similar  observations  were  made  by  C.  A. 
de  Gouvenain 7 at  Bourbon-! Archambault.  E.  Chuard 8 found  chal- 
copyrite upon  bronze  articles  from  the  Swiss  lake  dwellings.  In  all 
of  these  instances  the  copper  of  the  bronze  had  been  attacked  by 
waters  containing  either  hydrogen  sulphide  or  alkaline  sulphides. 

Of  these  sulphide  ores,  chalcopyrite,  bornite,  and  chalcocite  are  by 
far  the  most  important.  Chalcopyrite  and  bornite  are  probably  the 
primary  compounds  from  which  the  others  are  in  most  cases  derived, 
and  they  have  been  repeatedly  identified  as  of  magmatic  origin.  In 
Tuscany,  according  to  B.  Lotti,9  pyrite,  chalcopyrite,  bornite,  chalco- 
cite, and  sometimes  blende  or  galena,  occur  in  serpentinized  rocks  as 
original  segregations.  Similar  occurrences  in  Servia  are  reported  by 
R.  Beck  and  Baron  W.  von  Fircks;10  and  in  dioritic  rocks  at  Ookiep, 
Namaqualand,  by  A.  Schenck.11  In  a pegmatite  near  Princeton, 

1 Compt.  Rend.,  vol.  32,  1851,  p.  825. 

2 Annales  chim.  phys.,  3d  ser.,  vol.  32,  1851,  p.  166. 

3 Zeitschr.  Kryst.  Min.,  vol.  11, 1886,  pp.  34-36. 

4 Idem,  vol.  17, 1890,  p.  497. 

s School  of  Mines  Quart.,  vol.  32, 1911,  p.  298. 

e Annales  des  mines, 7th  ser.,  vol.  8, 1875,  p.  439;  Compt.  Rend.,  vol.  80, 1875,  p.  461;  Etudes synth&iques 
de  g6ologie  exp<5rimentale,  pp.  72-86.  See  also  A.  Lacroix,  Bull.  Soc.  min.,  vol.  32, 1909,  p.  333. 

7 Compt.  Rend.,  vol.  80, 1875,  p.  1297. 

8 Idem,  vol.  113, 1891,  p.  194. 

9 Bull.  Soc.  g6ol.  Belgique,  vol.  3,  M&n.,  1889,  p.  179. 

Zeitschr.  prakt.  Geologie,  1901,  p.  321. 

ii  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  53,  Verhandl.,  1901,  p.64.  See  also  W.  H.  Weed,  Eng.  and  Min. 
Jour.,  vol.  79,  1905,  p.  272. 


660 


THE  DATA  OE  GEOCHEMISTRY. 


British  Columbia,  J.  F.  Kemp  1 found  bornite,  which  had  all  the 
appearance  of  a primary  mineral.  To  original  sources  of  this  kind, 
segregated  or  disseminated  sulphides,  the  other  concentrations  of 
copper  ores  may  reasonably  be  attributed.  These  minerals  are  found 
also  in  veins,  in  contact  zones,  and  in  impregnations  or  replacements 
in  sedimentary  rocks,  but  the  home  of  the  copper  in  the  first  place 
must  have  been  in  rocks  of  igneous  origin.  To  these  primitive  ores 
the  syntheses  by  fusion  may  have  some  relation;  secondary  deposi- 
tions originated  by  other  methods. 

From  chalcopyrite  or  bornite,  commonly  admixed  with  pyrite,  the 
other  ores  of  this  group  are  generated.  At  a locality  in  the  Altai 
Mountains,  says  P.  Jeremeef,2  every  stage  of  transition  from  chalco- 
pyrite to  chalcocite  may  be  observed.  In  the  secondary  enrichment 
of  copper  ores,  pyrite  plays  an  important  part.  Cupric  solutions, 
formed  by  oxidation  of  ores  in  the  upper  levels  of  an  ore  body,  react 
upon  pyrite,  and  chalcocite  is  formed.  This  reaction  has  been  par- 
tially studied  by  H.  V.  Winchell,3  who  treated  cupriferous  pyrite 
with  dilute  solutions  of  copper  sulphate  and  sulphur  dioxide  and 
obtained  films  of  cuprous  sulphide.  The  sulphides  of  arsenic,  lead, 
and  zinc  precipitated  copper  sulphide  from  sulphate  in  the  same  way. 
Chalcocite  is  thus  formed  both  from  pyrite  and  zinc  blende,  accord- 
ing to  W.  Lindgren,4  at  Clifton  and  Morenci,  in  Arizona.  Chalcocite 
itself  alters  into  chalcopyrite,  bornite,  and  covellite,5  the  last  species 
being  almost  invariably  of  secondary  origin.  Covellite  heated  with 
a solution  of  sodium  bicarbonate  was  found  by  H.  N.  Stokes  6 to 
yield  chalcocite;  and  chalcocite  reacts  with  copper  sulphate  to  form 
both  covellite  and  native  copper.  The  precipitation  of  chalcocite  by 
pyrite  was  also  verified  by  Stokes.7  In  short,  these  minerals  are  quite 
generally  convertible  one  into  another  by  very  varied  reactions,  and 
their  paragenesis,  therefore,  must  be  studied  independently  for  each 
deposit  in  which  they  occur.8  No  simple  rules  can  be  formed  to  cover 
all  cases,  and  a part  of  the  difficulty  arises  from  the  fact  that  many 
of  the  reactions  are  reversible. 

1 Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  182.  See  also  J.  Catherinet,  Eng.  and  Min.  Jour.,  vol.  79, 

1905,  p.  125.  Primary  bornite  and  chalcopyrite  in  a dioriticrock  of  Plumas  County,  California,  are  reported 
by  H.  W.  Turner  and  A.  F.  Rogers,  Econ.  Geology,  vol.  9,  p.  359,  1914. 

2 Zeitschr.  Kryst.  Min.,  vol.  31,  1899,  p.  508. 

3 Bull.  Geol.  Soc.  America,  vol.  14,  1903,  p.  269.  See  also  T.  T.  Read,  Bull.  Am.  Inst.  Min.  Eng.,  March, 

1906,  p.  261,  and  E.  C.  Sullivan,  idem,  January,  1907,  p.  143. 

* Prof.  Paper  U.  S.  Geol.  Survey  No.  43, 1905,  pp.  182-186. 

5 See  Dana’s  System  of  mineralogy,  6th  ed.,  p.  56. 

6 Econ.  Geology,  vol.  2, 1907,  p.  14. 

i Bull.  U.  S.  Geol.  Survey  No.  186, 1900,  p.  44. 

8 At  Copper  Mountain,  British  Columbia,  according  to  Kemp  (Econ.  Geology,  vol.  1,  1905,  p.  11),  the 
original  ore  was  bornite;  and  from  that  mineral  covellite  with  limonite,  then  chalcocite,  and  finally  chalco- 
cite with  chalcopyrite  were  successively  derived.  See  also  J.  Catharinet,  Eng.  and  Min.  Jour.,  vol.  79, 
1905,  p.  125.  On  secondary  enrichment  of  chalcocite  ores  see  A.  C.  Spencer,  Econ.  Geology,  vol.  8, 1913, 

p.  621, 


METALLIC  ORES. 


661 


Among  the  sulphosalts  there  are  a number  containing  copper,  as 
follows: 


Chalcostibite 

CuSbS2. 

Emplectite 

Stylo  typite 1 

Cu3SbS3. 

Bournonite 

CuPbSbS3. 

Wittichenite 

Cu3BiS3. 

Aikenite 

CuPbBiS3. 

Enargite 

Cu3AsS4. 

Famatinite 

Cu3SbS4. 

Tennantite 

Tetrahedrite 

Cu8Sb2S7. 

Klaprotholite 

Cu6Bi4S9. 

Epigenite  2 

Cuprobismutite 

The  foregoing  formulae  are  typical,  and  make  no  allowance  for  the 
frequent  replacements  of  copper  by  other  metals,  or  of  bismuth, 
antimony,  and  arsenic  by  one  another.  For  example,  there  are  inter- 
mediate mixtures  between  tennantite  and  tetrahedrite,  and  bismuth, 
presumably  as  Cu8Bi2S7,  is  sometimes  present  in  them.  There  are 
also  varieties  of  these  minerals  containing  very  notable  proportions 
of  silver,  mercury,  zinc,  or  lead;  but  all  reduce  to  the  same  general 
type  of  formula.3 

R.  Schneider 4 by  passing  hydrogen  sulphide  into  a solution  con- 
taining bismuth  trichloride  and  cuprous  chloride,  obtained  a precipi- 
tate having  the  composition  of  wittichenite.  By  subsequent  fusion 
this  product  assumed  the  character  of  the  natural  mineral.  In  a 
later  investigation 5 he  treated  a solution  of  cuprous  chloride  with  the 
potassium  salt  KBiS2,  and  produced  a compound  which,  after  special 
purification  and  fusion,  resembled  emplectite.  He  also  prepared 
emplectite  by  fusing  cuprous  sulphide  and  bismuth  sulphide  together. 
The  synthesis  of  bournonite  was  effected  by  C.  Doelter  6 when  a 
proper  mixture  of  the  chlorides  or  oxycompounds  of  copper,  lead,  and 
antimony  was  heated  in  a stream  of  hydrogen  sulphide  to  a tempera- 
ture below  redness.  Above  that  temperature  the  antimony  com- 
pounds volatilize.  Evidently  the  sulphosalts  of  arsenic  and  anti- 
mony can  be  generated  only  at  relatively  low  temperatures.  By 
heating  cuprous  chloride  with  antimony  sulphide  to  300°,  H.  Som- 
merlad  7 prepared  chalcostibite.  Another  preparation,  correspond- 
ing to  Cu2Sb4S7,  was  similarly  obtained.  By  fusing  together  their 

1 Copper  partly  replaced  by  silver  and  iron. 

3 Copper  partly  replaced  by  iron. 

3 On  the  composition  of  tetrahedrite  (fahlerz)  see  A.  Kretschmer,  Zeitschr.  Kryst.  Min.,  vol.  48, 1910,  p. 

484. 

4 Pogg.  Annalen,  vol.  127, 1866,  p.  316. 

3 Jour,  prakt.  Chemie,  2d  ser.,  vol.  40, 1889,  p.  564. 

• Zeitschr.  Kryst.  Min.,  vol.  11, 1886,  p.  38. 

7 Zeitschr.  anorg.  Chemie,  vol.  18, 1898,  p.  420. 


662 


THE  DATA  OF  GEOCHEMISTRY. 


component  elements,  in  proper  proportion,  F.  Ducatte  1 obtained 
emplectite,  aikenite,  and  wittichenite. 

Of  these  sulphosalts,  only  enargite,  tetrahedrite,  tennantite,  and 
bonrnonite  are  at  all  common.  The  other  species  are  rarities.  Enar- 
gite is  an  important  ore  at  Butte,  Montana,2  and  in  the  Tintic  mines, 
Utah,  it  is  the  parent  of  a number  of  rare  copper  arsenates.  Of 
the  latter  class,  produced  by  the  oxidation  of  enargite,  W.  F.  Hille- 
brand 3 has  identified  olivenite,  erinite,  tyrolite,  chalcophyllite,  clino- 
clasite,  mixite,  conichalcite,  and  chenevixite.  Several  other  natural 
arsenates  of  copper  are  known,  and  a number  of  phosphates;  but 
they  need  no  further  consideration  here. 

The  two  oxides  of  copper,  cuprite,  Cu20,  and  tenorite,  CuO,  are 
well-known  ores  of  secondary  origin.  Cuprite,  which  is  by  far  the 
more  common,  has  been  repeatedly  observed  as  a furnace  product,4 
and  also  as  an  incrustation  upon  ancient  objects  of  copper  or  bronze.5 
Both  compounds  are  easily  prepared  synthetically.  Crednerite  is 
another  oxidized  compound,  having  the  formula  Cu2Mn409.  An 
earthy  oxide  of  manganese  containing  copper  is  known  as  lampadite. 

Cuprous  chloride,  nantokite,  CuCl,  and  the  iodide,  marshite,  Cul, 
are  rare  minerals  of  slight  importance.  The  oxychloride,  atacamite, 
Cu2Cl  (OH)3,  is  more  common,  and  in  Chile  it  has  some  significance 
as  an  ore.6  Several  syntheses  of  it  have  been  reported.  F.  Field7 
obtained  atacamite  by  the  action  of  calcium  hypochlorite  upon  a solu- 
tion of  copper  sulphate.  C.  Friedel 8 obtained  it  by  heating  a solution 
of  ferric  chloride  with  cuprous  oxide  to  250°.  Neither  of  these  syn- 
theses, however,  corresponds  to  any  probable  process  in  nature.  The 
observed  development  of  atacamite  upon  ancient  copper  and  bronze 
gives  a better  notion  of  its  genesis.  G.  Tschermak  9 reports  an  alter- 
ation of  atacamite  to  malachite,  and  has  shown  that  the  change  can 
be  artificially  reproduced  when  the  oxychloride  is  slowly  digested 
with  sodium  bicarbonate.  Pseudomorphs  of  chrysocolla  after  ata- 
camite have  been  described  by  C.  Barwald.10 

The  sulphates  of  copper,  normal,  basic,  and  double,  are  represented 
by  a number  of  mineral  species,  but  only  two  of  them  are  important. 
These  are  the  normal  salt,  chalcanthite,  CuS04.5H20;  and  the  basic 
brochantite,  Cu4S04(0H)6.  Chalcanthite  is  deposited  in  crystalline 


1 Thesis,  Univ.  Paris,  1902. 

2 On  secondary  enrichment  at  Butte  see  A.  N.  Rogers,  Econ.  Geology,  vol.  8, 1913,  p.  781.  On  the  para- 
genesis  of  the  Butte  ores  see  J.  C.  Ray,  idem,  vol.  9, 1914,  p.  463.  For  experiments  relative  to  copper 

enrichment  see  G.  S.  Nishihara,  idem,  p.  743. 

s Bull.  U.  S.  Geol.  Survey  No.  20, 1885,  and  No.  55, 1889. 

* See,  for  example,  A.  Arzruni,  Zeitschr.  Kryst.  Min.,  vol.  18, 1891,  p.  58. 

6  In  addition  to  cases  already  cited,  see  A.  Lacroix,  Bull.  Soc.  min.,  vol.  6,  p.  175. 

6 For  a description  of  an  atacamite  ore  body,  see  J.  A.  W.  Murdoch,  Trans.  Inst.  Min.  Met.,  vol.  9, 1901, 
p.  300. 

7 Philos.  Mag.,  4th  ser.,  vol.  24,  1862,  p.  123. 

8 Compt.  Rend.,  vol.  77,  1873,  p.  211. 

9 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  23,  Min.  Mitt.,  p.  41. 

10  Zeitschr.  Kryst.  Min.,  vol.  7, 1883,  p.  169. 


METALLIC  ORES. 


663 


form  by  the  evaporation  of  cupriferous  mine  waters,  and  in  some 
localities  it  is  actually  a workable  ore.  For  example,  at  Copaquire, 
Chile,  according  to  H.  Oehmichen,1  chalcanthite  is  found  in  signifi- 
cant quantities  as  an  impregnation  in  partially  decomposed  granitic 
rocks,  associated  with  some  malachite,  azurite,  and  chrysocolla. 
Pyrite  and  chalcopyrite  are  also  present,  the  oxidation  of  the  latter 
mineral  having  furnished  the  sulphate.  Brochantite,  a rarer  species, 
appears  to  be  more  common  than  is  generally  supposed.  W.  Lind- 
gren  2 has  called  attention  to  its  presence  in  the  Clifton-Morenci  mines 
of  Arizona,  where  it  occurs  in  fibrous  forms  which  might  easily  be 
mistaken  for  malachite.  F.  Field  3 prepared  brochantite  artificially 
by  boiling  a solution  of  copper  sulphate  with  a very  small  quantity 
of  caustic  potash.  S.  Meunier4  obtained  it  when  copper  sulphate 
solution  was  allowed  to  act  during  eleven  months  upon  fragments  of 
galena.  Apparently,  brochantite  is  easily  formed  by  natural 
reactions. 

Two  basic  carbonates  of  copper  are  common  secondary  ores.  They 
are  malachite,  Cu2(0H)2C03,  and  azurite,  Cu3(0H)2(C03)2.  Both 
species  are  formed  in  the  upper  portions  of  ore  deposits,  by  the 
action  of  carbonated  waters  upon  copper  compounds,  or  by  reactions 
between  cupreous  solutions  and  limestones.  They  also  are  found  in 
the  patina  of  ancient  bronzes.  A.  de  Schulten  5 prepared  malachite 
by  heating  precipitated  copper  carbonate  with  a solution  of  am- 
monium carbonate  on  a water  bath  during  eight  days.  Later,6  upon 
heating  a solution  of  copper  carbonate  in  carbonated  water,  he 
obtained  a precipitate  of  malachite.  L.  Michel 7 reproduced  azurite, 
together  with  the  basic  nitrate,  gerhardtite,  by  leaving  a solution  of 
copper  nitrate  in  contact  with  fragments  of  Iceland  spar  for  several 
years. 

Several  silicates  of  copper  are  known.  One  of  them,  chrysocolla, 
CuSi03.2H20,  is  common;  the  others,  dioptase,  CuH2Si04,  bisbeeite, 
isomeric  with  dioptase,  shattuckite,  CuH2Si207,  and  plancheite, 
H4Cu6Si5018,  are  rare.8 

A.  C.  Becquerel 9 obtained  dioptase  artificially  by  allowing  a solu- 
tion of  potassium  silicate  to  diffuse  very  slowly  into  one  of  copper 
nitrate.  Chrysocolla  is  probably  formed  by  the  action  of  percolat- 
ing waters,  carrying  silica,  upon  other  soluble  compounds  of  copper. 
Possibly,  also,  it  may  be  produced  during  processes  of  secondary 

1 Zeitschr.  prakt.  Geologic,  1902,  p.  147. 

2 Prof.  Paper  U.  S.  Geol.  Survey  No.  43,  1905,  p.  119. 

8 Philos.  Mag.,  4th  ser.,  vol.  24, 1862,  p.  123. 

* Compt.  Rend.,  vol.  86, 1878,  p.  686. 

8 Idem,  vol.  110, 1890,  p.  202. 

6 Idem,  vol.  122, 1896,  p.  1352. 

7 Bull.  Soc.  min.,  vol.  13,  1890,  p.  139. 

8 On  plancheite,  see  A.  Lacroix,  Mineralogie  de  la  France,  vol.  4,  p.  757,  1910.  On  shattuckite  and  bis- 
beeite, see  W.  T.  Schaller,  Jour.  Washington  Acad.,  vol.  6,  p.  7, 1915. 

» Compt.  Rend.,  vol.  67,  1868,  p.  1081. 


664 


THE  DATA  OF  GEOCHEMISTRY. 


enrichment.  E.  C.  Sullivan  1 has  shown  that  powdered  shale,  feld- 
spar, biotite,  etc.,  will  withdraw  copper  from  sulphate  solutions,  the 
reaction  being  one  of  double  decomposition.  The  ordinary  silicates 
lose  alkalies  or  alkaline  earths,  which  pass  into  solution  and  are 
replaced  by  copper.  The  cupriferous  product  may  be  partly  silicate 
and  partly  hydrous  oxides,  but  its  investigation  is  as  yet  incomplete. 

MERCURY. 


Unlike  gold,  silver,  and  copper,  mercury  appears  to  be  not  widely 
diffused  in  nature,  although  it  must  be  admitted  that  minute  traces 
of  the  element  are  easily  overlooked.  Very  small  quantities  of  the 
precious  metals  can  be  determined  by  fire  assay,  but  the  volatility  of 
mercury  prevents  its  detection  by  such  simple  means. 

Apart  from  the  natural  amalgams  of  silver  and  gold,  which  have 
already  been  mentioned,  mercury  occurs  in  the  following  minerals: 


Native  mercury. . 

Cinnabar 

Metacinnabarite 2 

Tiemannite 

Coloradoite 

Onofrite 

Lebrbachite 

Livingstonite 

Montroy  dite 

Calomel 

Terlinguaite. 
Eglestonite 


Hg. 

HgS. 

HgS. 

HgSe. 

HgTe. 

■Hg(S,Se). 

HgSe+PbSe. 

HgSb4S7. 

HgO. 

Hg2Cl2. 

Hg2C10. 

Hg4Cl20. 


To  these  must  be  added  kleinite,  a curious  sulphato-chloride  of 
one  of  the  mercurammonium  bases  and  also  the  allied  mosesite. 
Ammiolite  and  barcenite  are  antimonates  or  antimonites  of  mercury, 
of  uncertain  composition.  The  native  iodide  of  mercury  is  said  to 
exist,  but  its  identity  is  more  than  doubtful.  Mercury  is  also  found 
in  some  tetrahedrite,  in  proportions  ranging  as  high  as  17  per  cent. 

Very  few  of  these  minerals  have  any  economic  significance.  Cin- 
nabar is  almost  the  sole  ore  of  mercury,  although  the  native  metal  is 
sometimes  found  in  notable  quantities.  In  some  of  the  California 
mines  metacinnabarite,  the  black  sulphide,  was  once  abundant,  and 
tiemannite,  the  selenide  of  mercury,  was  commercially  worked  at  one 
time  in  the  Lucky  Boy  claim  in  Utah.3  Livingstonite  is  a workable 
ore  at  Huitzuco  in  Mexico,  and  barcenite  is  a substance  produced  by 
its  oxidation.4  Montroydite,  terlinguaite,  eglestonite,  mosesite,  and 


1 Econ.  Geology,  vol.  1, 1905,  p.  67.  Complete  report  in  Bull.  U.  S.  Geol.  Survey  No.  312, 1907. 

2 Guadalcazarite  is  metacinnabarite  containing  a little  zinc. 

8 See  G.  F.  Becker,  Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  p.  385. 

4 E.  Halse  (Trans.  North  of  England  Inst.  Min.  and  Mech.  Eng.,  vol.  45,  1895-96,  p.  72)  has  described 
this  locality.  He  ascribes  the  formation  of  the  ores  to  solfataric  action.  J.  Mactear  (Trans.  Inst.  Min. 
and  Met.,  vol.  4, 1895,  p.  69),  H.  F.  Collins  (idem,  p.  120),  and  J.  D.  Villarello  (Mem.  Soc.  cient.  Ant.  Alzate, 
vol.  19,  1902,  p.  94;  vol.  20,  1903,  p.  389;  and  vol.  23,  1906,  p.  395)  have  also  described  the  Mexican  quick- 
silver deposits.  Mactear  regards  them  all  as  of  aqueous  and  probably  of  thermal  origin. 


METALLIC  ORES. 


665 


kleinite  are  secondary  minerals,  which  occur  in  small  quantities  as 
derivatives  of  cinnabar,  in  the  mines  of  Brewster  County,  Texas.1 
Calomel  has  been  found  at  several  localities,  but  always  as  a secondary 
species. 

Mercuric  sulphide,  as  shown  in  the  list  of  mineral  species,  occurs 
in  two  forms — the  red,  rhombohedral  cinnabar  and  the  black,  iso- 
metric metacinnabarite.  To  the  one  species  the  artificial  product 
vermilion  corresponds,  while  the  ordinary  precipitated  sulphide, 
familiar  to  all  analysts,  is  amorphous  and  black.  Vermilion  is  pre- 
pared by  many  processes,  which  differ  in  detail,  but  can  be  referred 
to  two  simple  types.2  Mercury  and  sulphur,  under  the  influence  of 
heat,  unite  directly,  and  upon  subliming  the  product  the  scarlet  pig- 
ment is  obtained.  The  other  general  process  is  based  upon  the  fact 
that  the  black  sulphide,  when  acted  upon  by  solutions  of  alkaline  sul- 
phides, can  be  converted  into  the  red  form.  To  these  fundamental 
processes,  the  wet  and  the  dry,  the  various  syntheses  of  crystalline 
cinnabar  correspond,  with  the  wet  methods  predominating. 

According  to  Fouque  and  Levy,3  J.  Durocher  obtained  cinnabar  by 
the  action  of  hydrogen  sulphide  upon  mercuric  chloride  at  a red  heat. 
They  also  state  that  Deville  and  Debray  prepared  the  mineral  by 
heating  the  black  precipitated  sulphide  with  hydrochloric  acid  in  a 
sealed  tube  at  100°. 

C.  Doelter’s  experiments  4 were  also  conducted  in  sealed  tubes. 
Crystals  of  cinnabar  were  formed  when  metallic  mercury  was  heated 
with  hydrogen  sulphide  at  70°  to  90°  during  six  days.  By  heating 
mercury  with  a solution  of  hydrogen  sulphide  on  a water  bath  he 
also  produced  both  cinnabar  and  the  black  modification. 

Several  syntheses  of  cinnabar  are  based  upon  the  solubility  of  mer- 
curic sulphide  in  alkaline-sulphide  solutions.  M.  C.  Mehu  5 6 found 
that  the  mercuric  compound  was  insoluble  in  either  sodium  hydroxide 
or  sodium  sulphide,  but  soluble  in  a mixture  of  the  two.  On  dilu- 
tion, the  mixture  deposited  the  black  sulphide;  but  upon  the  passage 
of  carbon  dioxide  through  the  solution  the  red  modification,  cinnabar, 

1 See  A.  J.  Moses,  Am.  Jour.  Sci.,  4th  ser.,  vol.  16,  1903,  p.  253.  Kleinite  was  erroneously  described  by 
A.  Sachs,  Sitzungsb.  K.  Akad.  Wiss.  Berlin,  1905,  p.  1091.  Its  true  composition  was  first  indicated  by 
Hillebrand,  Am.  Jour.  Sci.,  4th  ser.,  vol.  21,  1906,  p.  85,  and  later  confirmed  by  Sachs,  Centralbl.  Min., 
Geol.  u.  Pal.,  1906,  p.  200.  For  data  concerning  the  Terlingua  and  other  deposits  of  Brewster  County, 
see  B.  F.  Hill,  Am.  Jour.  Sci.,  4th  ser.,  vol.  16,  1903,  p.  251;  E.  P.  Spalding,  Eng.  and  Min.  Jour.,  vol. 
71, 1901,  p.  749;  R.  T.  Hill,  idem,  vol.  74, 1902,  p.  305;  W.  B.  Phillips,  idem,  vol.  77, 1904,  p.  160;  vol.  18, 
1904,  p.  212;  M.  P.  Kirk  and  J.  W.  Malcolmson,  idem,  vol.  77,  1904,  p.  684;  and  W.  P.  Blake,  Trans.  Am. 
Inst.  Min.  Eng.,  vol.  25,  1896,  p.  68.  For  a full  discussion,  with  analyses,  of  the  composition  of  the  Ter- 
lingua minerals,  see  W.  F.  Hillebrand  and  W.  T.  Schaller,  Jour.  Am.  Chem.  Soc.,  vol.  29,  1907,  p.  1180, 
and  also,  in  detail,  in  Bull.  U.  S.  Geol.  Survey  No.  405,  1910.  On  mosesite,  see  Hillebrand  and  Schaller, 
Am.  Join:.  Sci.,  4th  ser.,  vol.  30, 1910,  p.  202. 

2 A good  summary  of  the  individual  methods  for  the  preparation  of  vermilion  is  given  in  Thorpe’s  Dic- 
tionary of  applied  chemistry,  vol.  3,  article  “Mercury.” 

3 Synthase  des  mineraux  et  des  roches,  p.  313.  These  data  seem  not  to  have  been  published  previously 

but  to  appear  for  the  first  time  in  the  volume  cited. 

* Zeitschr.  Kryst.  Min.,  vol.  11,  1886,  p.  33. 

6 Jahresb.  Cheraie,  1876,  p.  282. 


666 


THE  DATA  OF  GEOCHEMISTRY. 


was  formed.  According  to  S.  B.  Christy,1  amorphous  mercuric  sul- 
phide, heated  in  a sealed  tube  with  alkaline  solutions  into  which 
hydrogen  sulphide  had  been  passed,  is  converted,  at  temperatures 
between  200°  and  250°,  into  cinnabar.  This  reaction  is  retarded  by 
the  presence  of  carbon  dioxide.  The  black  sulphide,  by  five  hours  of 
heating  to  180°  with  a solution  of  potassium  sulphydrate,  was  also 
transformed  into  cinnabar.  A similar  transformation  of  vermilion 
into  cinnabar  is  also  reported  by  A.  Ditte.2  When  an  excess  of  ver- 
milion is  slowly  acted  upon  by  a solution  of  potassium  sulphide  it 
gradually  changes  into  the  crystallized  mineral.  The  reactions,  as 
interpreted  by  Ditte,  are  rather  complex,  and  involve  the  formation 
and  decomposition  of  two  double  sulphides,  K2HgS2  and  K5Hg5S6. 
The  results  are  also  modified  by  variations  in  temperature  and  in  the 
concentration  of  the  solutions  employed.  J.  A.  Ippen’s  3 observa- 
tions resemble  those  of  Christy.  The  black  precipitated  sulphide  of 
mercury,  heated  in  a sealed  tube  with  a solution  of  sodium  sulphide 
for  two  months  below  4£°,  became  crystallized  as  cinnabar.  The 
same  black  sulphide,  similarly  treated  with  hydrochloric  acid,  failed 
to  yield  the  red  form. 

L.  L.  de  Koninck 4 found  that  mercuric  sulphide  is  very  soluble  in 
concentrated  solutions  of  the  alkaline  sulphides,  and  also  in  the 
sulphides  of  calcium,  strontium,  and  barium,  but  not  in  solutions  of 
sulphydrates.  Upon  slow  dilution  of  the  mercuric  solutions  thus 
obtained,  red  crystalline  cinnabar  was  precipitated.  Upon  rapid 
dilution,  the  black  amorphous  sulphide  was  thrown  down. 

E.  Weinschenk 6 prepared  cinnabar  by  a process  remotely  akin  to 
those  employed  by  Durocher  and  Doelter.  A solution  of  mercuric 
chloride  and  ammonium  sulphocyanate  was  heated  in  a sealed  tube 
from  four  to  six  days  at  a temperature  between  230°  and  250°.  Both 
cinnabar  and  a black  sulphide  were  obtained.  In  this  case  the 
ammonium  sulphocyanate  merely  served  as  a generator  of  hydrogen 
sulphide,  which  was  the  active  reagent. 

E.  T.  Allen  and  J.  L.  Crenshaw  6 in  a thorough  study  of  mercuric 
sulphide  determined  the  conditions  of  formation  of  the  two  natural 
forms,  and  also  discovered  a third,  probably  hexagonal  modifica- 
tion, which  has  not  been  found  in  nature.  The  stable  form,  cinnabar, 
was  produced  in  the  usual  way,  by  the  action  of  an  alkaline  sulphide 
upon  the  amorphous,  precipitated  compound.  Metacinnabarite  was 
formed  by  the  action  of  an  excess  of  sodium  thiosulphate  upon  sodium 
mercuric  chloride  in  dilute  solution.  This  solution  was  rendered 
slightly  acid.  Under  alkaline  conditions  only  cinnabar  is  formed; 
acidity  is  essential  to  the  production  of  the  less  stable  meta-compound. 


1 Am  Jour.  Sci.,  3d  ser.,  vol.  17,  1879,  p.  453. 

2 Compt.  Rend.,  vol.  98,  1884,  pp.  1271,  1380. 

3 Min.  pet.  Mitt.,  vol.  14,  1894,  p.  114. 


* Annales  Soc.  gdol.  Belgique,  vol.  18,  1891,  p.  xxv. 
6 Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  498. 

6 Am.  Jour.  Sci.,  4th  ser.,  vol.  34, 1912,  p.  367 


METALLIC  ORES. 


667 


This  condition  also  holds  with  regard  to  pyrite  and  marcasite,  and  also 
with  the  two  modifications  of  zinc  sulphide.  In  each  case  acidity 
controls  the  generation  of  the  less  stable  mineral,  alkalinity  that  of 
the  more  stable.  These  facts  are  correlated  with  the  natural  occur- 
rences of  the  minerals.  Cinnabar,  the  primary  form,  is  probably 
deposited  by  ascending  solutions,  which  are  commonly  alkaline. 
Descending  solutions,  acid  from  the  oxidation  of  iron  sulphides,  con- 
trol the  formation  of  the  secondary  metacinnabarite. 

Finally,  a crystalline  mass  resembling  livingstonite  was  prepared 
by  A.  L.  Baker,1  who  fused  the  sulphides  of  mercury  and  antimony 
together  in  an  atmosphere  of  carbon  dioxide. 

It  will  be  noticed  that  several  of  the  syntheses  of  cinnabar  involve 
the  solubility  of  mercuric  sulphide  in  solutions  of  alkaline  sulphides 
or  sulphydrates.2  On  this  subject,  apart  from  synthetic  considera- 
tions, there  is  a copious  literature,  and  the  earlier  observations  are 
by  no  means  concordant.  Even  the  recent  data  appear  to  be  often 
contradictory.  De  Koninck,  for  instance,  as  already  cited,  found 
that  the  sulphide  was  insoluble  in  alkaline  sulphydrates ; but  according 
to  G.  F.  Becker 3 this  statement  is  true  only  for  cold  solutions.  Mer- 
curic sulphide,  heated  with  a solution  of  sodium  sulphydrate  on  the 
water  bath,  dissolves,  doubtless  forming  a double  salt  of  the  formula 
HgS.nNa2S.  Salts  of  this  type  must  be  produced  whenever  mer- 
curic sulphide  is  dissolved  in  an  alkaline  solution,  and  Ditte's  re- 
searches have  told  us  something  of  their  nature.4  The  solubility  of 
the  mercuric  sulphide  manifestly  depends  upon  considerations  of 
temperature,  pressure,  concentration,  and  the  nature  of  the  solutions 
employed,  whether  neutral  salts,  sulphydrates,  or  polysulphides. 
That  mercuric  sulphide  is  precipitated  again  by  dilution  has  been 
shown  by  various  observers,  and  Becker 5 reports  admixtures  of 
metallic  mercury  in  the  sulphide  thus  thrown  down.  Here,  then, 
we  have  a possible  explanation  of  the  frequent  association  of  free 
mercury  and  the  black  metacinnabarite,  although  relief  of  pressure 
may  be  in  some  cases  the  equivalent  of  dilution  as  a precipitant. 
Organic  matter,  also,  is  a probable  agent  of  reduction,  by  which  the 
metal  is  liberated.  Bituminous  substances,  such  as  idrialite,  nap- 
alite,  etc.,  are  commonly  associated  with  cinnabar;  and  at  the  Phoenix 
mine  in  California  an  inflammable  gas  issuing  from  cracks  in  the  rocks 
was  found  by  W.  H.  Melville6  to  have  the  following  composition: 

1 Chem.  News,  vol.  42,  1880,  p.  196. 

2 According  to  G.  A.  Binder  (Min.  pet.  Mitt.,  vol.  12, 1892,  p.  332),  even  distilled  water,  acting  on  cinnabar 
for  five  weeks  at  90°,  will  dissolve  traces  of  the  mineral. 

3 Am.  Jour.  Sci.,  3d  ser.,vol.  33,  1887,  p.  199.  In  detail,  with  full  summaries  of  earlier  work,  in  Mon. 
U.  S.  Geol.  Survey,  vol.  13, 1888,  chapter  15.  Also,  preliminary,  in  Eighth  Aim.  Rept.  U.  S.  Geol.  Survey, 

pt.  2,  1889,  p.  985. 

1 A compound  2Na2S.6HgS.3H2O  has  been  isolated  and  described  by  J.  Knox,  Trans.  Faraday 
80c.,  vol.  4,  p.  29, 1908. 

6 Am.  Jour.  Sci.,  3d  ser.,  vol.  33,  1887,  p.  199. 

6 Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  373. 


668 


THE  DATA  OF  GEOCHEMISTRY. 


Composition  of  gas  at  Phoenix  mine. 
C02 

ch4 

N2 

02 


0.74 
61. 49 
31.44 
6.  33 


100. 00 


The  hydrocarbon  CH4,  it  must  be  observed,  is  the  first  member  of 
the  paraffin  series,  to  which  some  bitumens  belong.  Becker  1 has 
shown  that  hydrocarbons  will  precipitate  mercuric  sulphide  from  its 
alkaline  solutions,  first,  probably,  as  metacinnabarite,  which  is  after- 
wards slowly  transformed  into  cinnabar.  Another  suggestion,  due  to 
A.  Schrauf,2  who  has  studied  the  occurrence  of  mercury  ores  in  Idria, 
is  that  the  metal  may  be  liberated  by  the  direct  dissociation  of  cin- 
nabar vapor.  He  also  ascribes  the  formation  of  some  metacinnaba- 
rite to  the  action  of  hydrogen  sulphide  upon  native  mercury.  Here 
again  we  are  reminded  that  the  same  point  may  be  reached  by  more 
than  one  road. 

According  to  Becker,3  the  chief  deposits  of  mercurial  ores  are  all 
in  the  neighborhood  of  igneous  rocks,  from  which  it  is  highly  prob- 
able they  were  originally  derived.  The  deep-seated  granites,  in 
his  opinion,  form  the  principal  source  of  the  mercury.  The  ore 
bodies  in  some  cases  fill  fissures,  fractures,  or  cavities  in  rocks,  the 
latter  being  commonly  of  sedimentary  character;  and  in  other  in- 
stances the  cinnabar  forms  impregnations  in  sandstone  or  limestone. 
The  ores  are  commonly  associated  with  pyrite  or  marcasite,  sulphur, 
calcite,  barite,  gypsum,  opal,  quartz,  and  other  secondary  minerals, 
and  show  distinct  evidence  that  they  have  been  brought  up  from 
below  in  solution.4  In  many  cases,  if  not  in  all,  the  evidence  of 
hydrous  or  solfataric  origin  is  very  clear.  A.  Liversidge,5  for  ex- 
ample, reports  mercury  and  mercuric  sulphide  in  hot-spring  deposits 
near  Ohaiawai,  New  Zealand;  and  in  3,403  grams  of  a sinter  from 


1 Mineral  Resources  U.  S.  for  1892,  U.  S.  Geol.  Survey,  1893,  p.  139. 

2 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  41,  1892,  pp.  383,  396.  Schrauf  gives  many  citations  of  litera- 
ture relative  to  mercury,  and  especially  to  the  mines  of  Idria. 

3 Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  and  also,  briefly,  in  Mineral  Resources  U.  S.  for  1892,  p.  139. 
In  the  monograph,  Becker  has  summed  up  the  conditions  at  all  important  localities  as  known  in  1887. 

4 In  addition  to  Becker’s  monograph,  see  J.  A.  Phillips,  Quart.  Jour.  Geol.  Soc.,  vol.  35,  1879,  p.  390; 
and  J.  Le  Conte  and  W.  B.  Rising,  Am.  Jour.  Sci.,  3d  ser.,  vol.  24, 1882,  p.  23,  on  Sulphur  Bank,  California. 
Le  Conte  (idem,  vol.  25, 1883,  p.  424)  has  discussed  the  deposits  at  Steamboat  Springs,  Nevada.  See  also, 
on  Californian  quicksilver  ores,  W.  Forstner,  Eng.  and  Min.  Jour.,  vol.  78, 1904,  pp.  385,426;  and  in  Bull. 
Np.  27,  California  State  Mining  Bureau.  Wendebom  (Berg-  u.  hiittenm.  Zeitung,  vol.  63, 1904,  p.  274)  has 
described  mercury  deposits  in  Oregon;  and  G.  F.  Monckton  (Trans.  Inst.  Min.  Eng.  (British),  vol.  27, 
1904,  p.  463)  those  of  British  Columbia.  For  a study  of  the  mercury  mines  at  Mount  Avala,  Serbia, 
see  H.  Fischer,  Zeitschr.  prakt.  Geologie,  vol.  14,  1906,  p.  245.  For  an  account  of  the  mines  at  Almaden, 
Spain,  see  H.  Kuss,  Annales  des  mines,  7th  ser.,  vol.  13,  1878,  p.  39.  On  Huancavelica,  Peru,  see  A.  F. 
Umlaufi,  Bol.  Cuerpo  ingen.  minas  Peru,  No.  7,  1904.  F.  Katzer  (Berg-  u.  hiittenm.  Jahrbuch,  vol.  55, 
1907,  p.  145)  has  described  the  mercury  deposits  of  Bosnia.  A list  of  the  principal  mercury  deposits  of 
the  world,  by  L.  Demaret,  is  given  in  Annales  des  mines  de  Belgique,  vol.  9,  1904,  p.  35. 

5 Jour.  Roy.  Soc.  New  South  Wales,  vol.  11,  p.  262.  See  also  J.  Park,  Trans.,  New  Zealand  Inst.,  vol.  38, 
1904,  p.  27.  Park  cites  another  memoir  by  A.  P.  Griffiths,  in  Trans.  New  Zealand  Inst.  Min.  Eng.,  vol.  2, 
p.  48.  A later  report  by  J.  M.  Bell  and  E.  de  C.  Clarke  is  in  Bull.  New  Zealand  Geol.  Survey  No.  8, 1909, 
p.  87. 


METALLIC  ORES. 


669 


Steamboat  Springs,  Nevada,  Becker  and  Melville 1 found  0.0070 
gram  of  HgS.  In  Becker’s  opinion  alkaline  solutions  containing 
sulphides  are  the  natural  solvents  of  the  mercurial  compounds ; 
although  Y.  Spirek  2 describing  the  deposits  at  Monte  Amiata,  Tus- 
cany, suggests  that  the  mercury  was  first  dissolved  as  sulphate  and 
precipitated  later  by  alkaline  polysulphides.  For  this  supposition 
there  seems  to  be  little  or  no  positive  evidence.  At  Idria  A.  Schrauf 3 
found  no  indications  of  the  existence  of  alkaline  thermal  springs — 
a bit  of  negative  testimony  which  may  or  may  not  be  important.  It 
is  not  necessary,  however,  to  assume  that  the  mercurial  solutions  have 
been  the  same  at  all  localities.  In  fact,  they  must  have  varied  both 
in  their  chemical  composition  and  in  the  physical  conditions  under 
which  they  came  to  the  surface.  Even  the  differences  in  the  rocks 
through  which  the  solutions  travel  would  modify  their  properties. 

ZINC  AND  CADMIUM. 

Zinc,  as  has  been  shown  in  the  earlier  portions  of  this  chapter, 
is  widely  diffused  in  the  rocks,  and  it  also  occurs  in  minute  propor- 
tions in  sea  water.  Cadmium  is  found  associated  with  zinc,  and 
the  very  rare  metals  gallium  and  indium  are  also  obtained  from  zinc 
ores.4  Zinc  is  about  200  times  as  abundant  as  cadmium.5 

Although  native  zinc  has  been  several  times  reported,  its  existence 
is  doubtful.  None  of  the  occurrences  is  completely  authenticated. 
The  fundamental  ore  of  zinc  is  the  sulphide,  ZnS,  known  as  sphal- 
erite, blende,  or  blackjack  when  crystallized  in  the  isometric  system, 
or  as  wurtzite  when  it  is  hexagonal.  Cadmium  is  found  almost 
exclusively  as  the  sulphide,  CdS,  or  greenockite,  which  is  also  hex- 
agonal.6 Many  massive  blendes  are  really  mixtures  of  sphalerite 
and  wurtzite.7  The  rare  mineral  voltzite  is  an  oxysulphide  of  zinc, 
4ZnS.ZnO. 

Sphalerite,  wurtzite,  and  greenockite  have  all  been  prepared  syn- 
thetically, and  wurtzite  has  been  repeatedly  observed  as  a furnace 
product.8  According  to  H.  de  Senarmont,9  sphalerite  is  formed  when 

1 Mon.  U.  S.  Geol.  Survey,  vol.  13,  1888,  p.  344. 

2 Zeitschr.  prakt.  Geologie,  1897,  p.  369;  idem,  1902,  p.  297.  Spirek  gives  references  to  other  literature 
concerning  Monte  Amiata.  See  also  R.  Rosenlecher,  Zeitschr.  prakt.  Geologie,  1894,  p.  337,  on  this  and 
other  Tuscan  deposits.  On  the  mines  of  Vallalta-Sagron,  see  A.  Rzehak,  idem,  1905,  p.  325. 

3 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  41,  1892,  p.  379. 

* On  the  occurrence  of  gallium,  indium,  germanium,  and  other  rare  metals  in  zinc  blende,  see  G.Urbain, 

Compt.  Rend.,  vol.  149, 1909,  p.  602.  Also  A.  del  Campo  y Cerdan,  Jour.  Chem.  Soc.,  vol.  106,  pt.  2,  p.  270, 
abstract. 

6  See  F.  W.  Clarke  and  G.  Steiger,  Jour.  Washington  Acad.  Sci.,  vol.  4, 1914,  p.  57. 

6 A basic  carbonate  of  cadmium  and  the  crystallized  oxide,  CdO,  are  recently  discovered  minerals.  A 
useful  summary  on  cadmium  and  its  occurrences,  by  E.  Jensch,  is  in  Ahren’s  Sammlung  chemische 
technologische  Vortrage,  vol.  3,  1899,  p.  201. 

7 See  J.  Noelting,  Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  220. 

8 See  W.  Stahl,  Berg-u.  hiittenm.  Zeitung,  1888,  p.  207;  H.  Forstner,  Zeitschr.  Kryst.  Min.,  vol.  5, 1881, 
p.  363;  and  H.  Traube,  Neues  Jahrb.,  Beil.  Band  9, 1894,  p.  151. 

8 Compt.  Rend.,  vol.  32,  1851,  p.  409.  The  description  of  the  process  is  very  vague. 


670 


THE  DATA  OF  GEOCHEMISTRY. 


zinc  solutions  are  heated  in  sealed  tubes  in  an  atmosphere  of  hydro- 
gen sulphide — a method  which  was  also  employed  by  H.  Baubigny.1 
J.  Durocher 2 prepared  sphalerite  by  heating  zinc  chloride  in  a 
stream  of  hydrogen  sulphide.  Cadmium  chloride  treated  in  the 
same  way  gave  greenockite. 

By  fusing  precipitated  cadmium  sulphide  with  potassium  carbon- 
ate and  sulphur  E.  Schuler  3 obtained  crystals  of  greenockite.  This 
observation  has  since  been  verified  by  R.  Schneider.4  H.  Sainte- 
Claire  Deville  and  H.  Troost 5 fused  zinc  sulphate,  calcium  fluoride, 
and  barium  sulphide  together,  and  produced  crystals  of  wurtzite. 
With  cadmium  sulphate  greenockite  was  formed.  They  also  obtained 
wurtzite  by  passing  hydrogen  over  red-hot  zinc  sulphide.  The  latter 
was  decomposed,  forming  zinc  vapor  and  hydrogen  sulphide,  which 
reacted  in  the  cooler  parts  of  the  apparatus  to  produce  the  crystal- 
line mineral.  Wurtzite  and  greenockite  were  prepared  by  T.  Sidot 6 
when  zinc  or  cadmium  oxide  was  heated  in  the  vapor  of  sulphur.  In 
another  paper  7 he  states  that  amorphous  zinc  sulphide,  heated  in 
an  atmosphere  of  nitrogen  or  of  sulphur  dioxide,  crystallizes  into 
wurtzite.  P.  Hautefeuille 8 heated  zinc  and  cadmium  sulphide 
under  a layer  of  powdery  alumina;  the  two  compounds  volatilized 
and  were  redeposited  on  the  surface  of  the  alumina  as  wurtzite  or 
greenockite.  He  also  found  that  blende,  heated  to  redness,  was 
transformed  into  wurtzite.  R.  Lorenz 9 obtained  wurtzite  and 
greenockite  by  acting  on  the  vapor  of  zinc  or  cadmium  with  hydro- 
gen sulphide.  This  process  recalls  that  of  Deville  and  Troost. 

Two  hydrochemical  processes  have  also  yielded  greenockite.  C. 
Geitner 10  heated  metallic  cadmium  with  sulphurous  acid  to  200°  in 
a sealed  tube.  A mixture  of  amorphous  and  crystalline  sulphide  was 
deposited.  A.  Ditte 11  found  that  amorphous  cadmium  sulphide  could 
be  dissolved  in  ammonium  sulphydrate,  especially  at  a temperature 
of  60°.  On  cooling,  crystals  of  greenockite  and  free  sulphur  were 
formed. 

E.  T.  Allen  and  J.  L.  Crenshaw12  prepared  greenockite  in  large 
crystals  by  the  method  of  Lorenz.  Only  one  modification  of  the 
sulphide  was  obtained.  Wurtzite  was  formed  by  sublimation  of 
zinc  sulphide  at  about  1,200°-1,300°,  and  also  by  the  action  of  hydro- 

1 See  L.  Bourgeois,  Reproduction  artificieUe  des  mindraux,  p.  28. 

2 Compt.  Rend.,  vol.  32,  1851,  p.  825. 

3 Liebig’s  Annalen,  vol.  87,  1853,  p.  34. 

< Poggendorf’s  Annalen,  vol.  149,  1873,  p.  391. 

6 Compt.  Rend.,  vol.  52,  1861,  p.  920. 

s Idem,  vol.  62,  1866,  p.  999. 

i Idem,  vol.  63, 1S66,  p.  188. 

s Idem,  vol.  93,  1881,  p.  824. 

s Ber.  Deutsch.  chem.  Gesell.,  vol.  24, 1891,  p.  1501. 

Liebig’s  Annalen,  vol.  129, 1864,  p.  350. 

” Compt.  Rend.,  vol.  85,  p.  402,  1877. 

I2  Am.  Jour.  Sci.,  4th  ser.,  vol.  34, 1912,  p.  341;  vol.  38, 1914,  p.  873. 


METALLIC  ORES. 


671 


gen  sulphide,  derived  from  sodium  thiosulphate,  on  acid  solutions  of 
zinc  sulphate  at  250°.  By  heating  amorphous  zinc  sulphide  in  a 
solution  of  sodium  sulphide  at  350°  in  a steel  bomb  they  obtained  good 
crystals  of  sphalerite.  Sphalerite  was  also  produced,  like  wurtzite, 
in  acid  solutions,  but  with  weaker  acid  and  at  higher  temperatures. 
In  alkaline  solutions  only  sphalerite  was  formed.  This  distinction 
between  the  two  minerals  is  like  that  already  mentioned  with  regard 
to  the  sulphides  of  mercury  and  of  iron.  Sphalerite  was  also  crys- 
tallized from  solution  in  molten  sodium  chloride  and  potassium 
polysulphide.  At  1,020°  sphalerite  is  transformed  into  wurtzite. 

For  geological  purposes  the  hydrochemical  syntheses  of  blende 
are  the  only  ones  of  much  importance;  and  they  are  paralleled  by 
certain  natural  and  recent  occurrences  of  the  mineral.  G.  Bischof,1 
for  example,  mentions  a sinter,  formed  within  historical  times  in  an 
old  lead  mine,  which  contained  37.57  per  cent  of  ZnS.  It  was  prob- 
ably produced  by  the  action  of  decaying  wood  upon  the  zinc-bearing 
mine  waters.  In  North  St.  Louis,  Missouri,  H.  A.  Wheeler  2 found 
massive  blende  embedded  in  lignite,  where  it  had  evidently  been 
formed  by  the  reducing  action  of  organic  matter  upon  other  zinc 
compounds.  C.  R.  Keyes 3 speaks  of  blende  crystals,  one-fourth 
inch  across,  which  had  grown  on  iron  nails  immersed  in  a mine  water 
during  fifteen  years.  W.  P.  Jenney 4 also  refers  to  the  deposition  of 
crystallized  blende  on  the  walls  of  a tunnel  which  had  been  closed 
and  flooded  for  ten  or  twelve  years.  Some  crystals  were  deposited 
on  the  pick  marks  left  by  the  miners. 

Zinc  sulphide  is  also  known  in  nature  as  a chemical  precipitate. 
In  workings  at  Galena,  Kansas,  large  cavities  have  been  found,  filled 
with  a white  mud  which  consisted  of  nearly  pure  zinc  sulphide 
mingled  with  acid  water.5  Evidently  the  zinc  had  been  dissolved, 
probably  by  the  oxidation  of  blende,  and  then  thrown  down  again, 
either  by  sulphureted  waters  or  by  organic  matter.  Natural  solu- 
tions of  zinc  sulphate  exist  in  the  region  around  Joplin,  and  have 
already  been  described  in  previous  portions  of  this  volume.6  An 
occurrence  of  sphalerite  as  a primary  mineral  in  granite  has  been 
reported  by  E.  Rimann.7  Such  sphalerite,  if  really  of  magmatic 
origin,  must  have  formed  below  the  transition  temperature  to  wurt- 
zite, namely,  1,020°. 

1 Lehrbuch  der  chemischen  und  physikalischen  Geologie,  2d  ed.,  vol.  1,  p.  559. 

2 Trans.  Acad.  Sci.  St.  Louis,  vol.  7,  1895,  p.  123.  Other  associations  of  sphalerite  wLh  coal,  also  in 

Missouri,  are  mentioned  by  W.  P.  Jenney,  in  Trans.  Am.  Inst.  Min.  Eng.,  vol.  33,  1903,  p.  460. 

8 Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  611. 

* Idem,  vol.  33,  1903,  p.  470. 

6 Described  by  J.  D.  Robertson,  Am.  Jour.  Sci.,  3d  ser.,  vol.  40, 1890,  p.  160;  and  by  M.  W.  lies  and  J.  D. 
Hawkins,  Eng.  and  Min.  Jour.,  vol.  49, 1890,  p.  499. 

® See  ante,  p.  188. 

7 Zeitschr.  prakt.  Geologie,  1910,  p.  123. 


672 


THE  DATA  OF  GEOCHEMISTRY. 


The  oxidized  compounds  of  zinc,  as  natural  minerals,  are  fairly 
numerous.  The  following  species  are  especially  noteworthy: 


Zincite 

Gahnite 1 

Franklinite 1 . . . 
Chalcophanite 1 

Smithsonite 

Hydrozincite. . . 

Willemite2 

Calamine 

Clinohedrite — 
Hardystonite. . . 
Hodgkinsonite. 


ZnO. 

. ZnAl204. 

.ZnFe204. 

. Zn0.2Mn02.2H20. 
ZnC03. 

ZnC03.2Zn02H2. 

.Zn2Si04. 

Zn2H2Si05. 

ZnCaH2SiOs. 

ZnCa2Si207. 

Zn2Mn(Si04)(0H)2. 


To  this  list  may  be  added  the  phosphates,  hopeite  3 and  kehoeite; 
the  arsenates,  adamite,  kottigite,  and  veszelyite;  descloizite,  a vana- 
date of  lead  and  zinc;  and  the  sulphates,  goslarite  and  zincaluminite. 
Jeffersonite  is  a zinc-bearing  pyroxene,  and  danalite  is  a silicate  plus 
sulphide,  of  zinc,  manganese,  iron,  and  glucinum.  None  of  these 
species  needs  further  mention  except  goslarite,  ZnS04.7H20,  which  is 
the  compound  of  zinc  existing  in  mine  waters  and  in  zinciferous 
springs.  When  zinc  is  removed  from  an  ore  body  by  solution,  it  is 
carried  in  this  form. 

Zincite,  the  natural  oxide  of  zinc,  is  well  known  as  a furnace  prod- 
uct, and  it  has  also  been  repeatedly  synthetized.4  According  to  A. 
Daubree,5  when  zinc  chloride  and  water  vapor  act  upon  lime  at  a red 
heat,  zincite  is  formed.  Ferrieres  and  Dupont 6 obtained  it,  at  a 
similar  temperature,  by  the  action  of  steam  upon  zinc  chloride  alone. 
By  heating  the  amorphous  oxide  in  an  atmosphere  of  oxygen,  T. 
Sidot 7 was  able  to  effect  its  crystallization.  A.  Gorgeu  8 prepared 
the  mineral  by  several  processes,  one  of  which  consisted  in  the  gradual 
calcination  of  zinc  sulphate  or  nitrate.  In  this  case  better  results 
were  obtained  when  an  alkaline  sulphate  was  mingled  with  the  zinc 
salt.  Zincite  was  also  formed  when  a mixture  of  zinc  fluoride  and 
potassium  fluoride  was  strongly  heated  in  a current  of  steam. 

The  zinc  spinels,  gahnite  and  franklinite,  have  also  been  arti- 
ficially prepared.  J.  J.  Ebelmen 9 obtained  gahnite  by  fusing  a 
mixture  of  alumina,  zinc  oxide,  and  boron  trioxide.  When  ferric  oxide 


1 The  formulae  here  given  are  ideal.  Part  of  the  zinc  is  commonly  replaced  by  manganese  or  iron. 

2 Troostite  is  a manganiferous  willemite. 

3 For  a synthesis  of  hopeite,  see  C.  Friedel  and  E.  Sarasin,  Bull.  Soc.  min.,  vol.  2, 1879,  p.  153. 

4 See  H.  Traube,  Neues  Jahrb.,  Beil.  Band  9, 1894,  p.  151;  and  H.  Ries,  Am.  Jour.  Sci.,  3d  ser.,  vol.  48, 1894, 
p.  256,  on  zincite  as  a furnace  product.  See  also  J.  T.  Cundell  and  A.  Hutchinson,  Mineralog.  Mag.,  vol.  9, 
1892,  p.  5.  L.  Bourgeois  (Reproduction  artificielle  des  min&aux)  cites  other  examples,  and  so,  too,  does 
Ries.  Bourgeois  also  mentions  syntheses  by  Becquerel  and  Regnault,  but  his  references  are  erroneous 
and  I can  not  verify  them. 

5 Compt.  Rend.,  vol.  39,  1854,  p.  135. 

6 See  Bourgeois,  op.  cit.,  p.  56. 

7 Compt.  Rend.,  vol.  69, 1869,  p.  201. 

8 Idem,  vol.  104, 1887,  p.  120. 

9 Annales  chim.  phys.,  3d  ser.,  vol.  33, 1851,  p.  34. 


METALLIC  ORES. 


673 


was  used  in  place  of  alumina,  franklinite  was  formed.  By  vapor- 
izing aluminum  chloride  and  zinc  chloride  over  lime  at  a red  heat,  A. 
Daubree1  prepared  gahnite;  and  franklinite  was  similarly  produced 
by  -using  the  chlorides  of  iron  and  zinc.  H.  Sainte-Claire  Deville 
and  H.  Caron2  obtained  gahnite  by  vaporizing  a mixture  of  zinc 
and  aluminum  fluorides  in  presence  of  boric  oxide.  A.  Stelzner  3 
found  gahnite,  with  fayalite,  in  the  walls  of  a muffle  of  a zinc  furnace 
at  Freiberg,  where  it  had  been  formed  by  the  action  of  zinc  vapors 
upon  the  clay  silicates.  In  another  similar  case,  H.  Schulze  and 
Stelzner4  report  the  formation  of  willemite  and  tridymite.  The 
occurrence  of  crystallized  willemite  in  a furnace  slag  has  also  been 
recorded  by  W.  M.  Hutchings.5 

According  to  A.  Daubree,1  willemite  can  be  prepared  by  the  action 
of  silicon  tetrachloride  upon  zinc  oxide  at  a red  heat.  This,  how- 
ever, was  denied  by  H.  Sainte-Claire  Deville,6  who  found  that  wiflem- 
ite  was  decomposed  by  silicon  chloride.  It  is  formed  when  silicon 
fluoride  acts  upon  zinc  oxide,  and  also  by  the  action  of  zinc  fluoride 
upon  heated  silica.  A.  Gorgeu  7 produced  willemite  by  two  proc- 
esses. First,  zinc  sulphate,  calcined  with  an  alkaline  sulphate  and 
silica,  yields  willemite  and  tridymite.  Secondly,  the  mineral  is  formed 
when  zinc  chloride  is  fused  with  silica  in  presence  of  steam. 

By  heating  metallic  zinc  with  seltzer  water  in  a sealed  tube  at 
100°,  L.  Bourgeois  8 obtained  crystals  of  smithsonite.  G.  Bischof  9 
cites  a number  of  instances  in  which  zinc  carbonate  has  formed  as  a 
deposit  from  natural  waters. 

In  nature,  zinc  ores  occur  under  a variety  of  conditions — in  true 
metalliferous  veins,  in  metamorphic  rocks,  and  under  circumstances 
which  indicate  a sedimentary  origin.  In  some  cases  they  form  meta- 
somatic  replacements  of  limestone.  Percolating  solutions  of  zinc, 
permeating  limestones,  would  necessarily  react  upon  the  latter,  the 
zinc  being  deposited  as  carbonate  in  place  of  the  removed  lime  com- 
pounds. Pseudomorphs  of  smithsonite  after  calcite  are  well  known. 
In  an  experiment  reported  by  G.  Piolti,10  a fragment  of  calcite, 
immersed  during  17 J years  in  a solution  of  zinc  sulphate,  became 
coated  with  smithsonite  and  gypsum. 

In  the  introduction  to  this  chapter  evidence  was  adduced  showing 
that  zinc  was  present,  albeit  in  small  amounts,  in  Archean  rocks, 
from  which  it  may  be  concentrated.  It  is  also  found  in  diffused 


1 Compt.  Rend.,  vol.  39,  1854,  p.  135. 

2 Idem,  vol.  46,  1858,  p.  766. 

3 Neues  Jahrb.,  Band  1,  1882,  p.  170. 

* Idem,  Band  1, 1881,  p.  120. 

5 Geol.  Mag.,  3d  ser.,  vol.  7, 1890,  p.  31. 

6 Compt.  Rend.,  vol.  52,  1861,  p.  1304. 

7 Idem,  vol.  104, 1887,  p.  120.  * 

8 Reproduction  artificielle  des  min4raux,  p.  144. 

9 Lehrbuch  der  chemischen  und  physikalischen  Geologic,  2d  ed.,  vol.  1,  p.  561. 

10  Jour.  Chem.  Soc.,  vol.  100,  p.  902, 1911.  Abstract. 

97270°— Bull.  616—16 43 


674 


THE  DATA  OF  GEOCHEMISTRY. 


traces  in  many  sedimentary  rocks.  L.  Dieulafait 1 detected  zinc  in 
hundreds  of  samples  of  Jurassic  limestone  from  central  France.  J.  D. 
Robertson 2 found  it,  with  lead  and  copper,  in  the  limestones  of  Mis- 
souri, and  J.  B.  Weems  3 determined  lead  and  zinc  in  the  limestones 
and  dolomites  of  the  Dubuque  region,  Iowa.  The  average  of  nine 
samples  analyzed  by  Weems  gave  0.00326  per  cent  Pb  and  0.00029 
per  cent  Zn.  Robertson’s  figures  are  as  follows  for  six  Silurian  mag- 
nesian limestones  and  seven  limestones  from  the  “ Lower”  Carbon- 
iferous; they  are  stated  in  percentages. 


Lead , zinc , and  copper  in  limestones. 


Silurian. 

Lower  Carboniferous. 

T.po.rl  

Trace  to  0.00156 

Trace  to  0.00346 
Trace  to  0.00255 

Zinc 

0.00016  to  0.01536 

C!nr>r»pr  

0.00040  to  0.00256 

Trace  to  0.00880 

Small  as  these  proportions  are,  they  are  sufficient  to  account  for 
the  formation  of  the  ore  bodies  in  the  regions  studied.  In  each  region 
a comparatively  moderate  amount  of  decomposition  of  the  country 
rocks  would  supply  the  ores  contained  in  the  known  deposits.4 

Similar  results  to  those  of  Weems  and  Robertson  were  obtained 
by  A.  M.  Finlayson  5 6 in  his  study  of  the  British  lead  and  zinc  deposits. 
These  metals  were  found  in  the  country  rocks  in  quantities  of  the 
same  order  of  magnitude,  and  were  more  abundant  in  the  granites 
than  in  the  limestones.  Finlayson  regards  the  metals  as  having  been 
brought  up  in  solution  from  below,  in  waters  which  contained  alka- 
line sulphides  and  also  fluorine.  The  order  of  deposition  of  the  vein 
minerals  was  chalcopyrite,  first,  then  fluorite,  blende,  galena,  and 
finally  pyrite. 

This  association  of  sphalerite  with  other  sulphides  is  very  general, 
so  much  so  that  economic  geologists  usually  consider  lead  and  zinc 
together.  In  the  famous  ore  bodies  of  the  Mississippi  Valley  the  two 
ores  are  rarely  found  quite  apart,  although  in  one  locality  zinc  may 
predominate,  while  lead  is  the  chief  thing  of  value  in  another.  Cal- 
cite,  dolomite,  and  sometimes  fluorite  or  barite  are  frequent  com- 
panions of  the  ores,  and  bituminous  matter  is  often  present  also.  By 
alteration  of  sphalerite,  surface  deposits  of  calamine  and  smithsonite 
are  formed,  just  as  oxidized  ores  are  developed  above  bodies  of  copper 
sulphide.  Secondary  crystallizations  of  sphalerite  are  also  common 
where  solutions  of  zinc  sulphate,  formed  near  the  top  of  an  ore  body, 

1 Compt.  Rend.,  vol.  90, 1880,  p.  1573,  and  vol.  96,  1883,  p.  70. 

2 Missouri  Geol.  Survey,  vol.  7,  1894,  pp.  479-481. 

3 Cited  by  S.  Calvin  and  H.  F.  Bain,  Iowa  Geol.  Survey,  vol.  10, 1900,  p.  566. 

-4  See  T.  C.  Chamberlin,  Geology  of  Wisconsin,  vol.  4, 1882,  pp.  367-553,  and  A.  Winslow,  Missouri  Geol. 

Survey,  vols.  6 and  7,  especially  vol.  7,  1894,  p.  467,  etc. 

6 Quart.  Jour.  Geol.  Soc.,  vol.  66, 1910,  p.  299. 


METALLIC  ORES, 


675 


have  percolated  downward,  and  been  reduced  to  sulphide  again.  It 
is  highly  probable  that  pyrite  or  marcasite  may  react  upon  the  zinc- 
bearing solutions  and  aid  in  the  regeneration  of  the  sphalerite.  Some 
experiments  by  H.  N.  Stokes/  carried  out  in  the  laboratory  of  the 
United  States  Geological  Survey,  have  shown  the  possibility  of  such 
reactions.  Pyrite  and  marcasite  heated  to  180°  with  solutions  of  zinc 
salts  and  alkaline  carbonates  actually  yield  zinc  sulphide.  Sphalerite 
sometimes  occurs  in  stalactitic  forms,  which  could  be  deposited  only 
from  solutions.  The  calamine  and  smithsonite  are  sometimes  pure 
and  crystalline,  sometimes  quite  impure  and  earthy.  The  so-called 
“ tallow  clays”  of  Missouri  and  Arkansas  are  zinc-bearing  clays,  prob- 
ably mixtures  of  aluminous  silicates  with  calamine,  and  they  contain 
from  4 or  5 per  cent  up  to  56  per  cent  of  zinc  oxide.1 2  Similar  clays, 
from  an  ore  body  at  Leadville,  Colorado,  were  analyzed  by  W.  F. 
Hillebrand.3 

On  the  sedimentary  lead  and  zinc  ores  of  the  Mississippi  Valley 
there  is  a copious  literature,  with  much  discussion  about  genetic  prob- 
lems. Some  authorities  derive  the  ores  from  ascending,  heated 
waters;  some  find  their  proximate  sources  in  the  adjacent  limestones, 
and  others  trace  them  still  further  back  to  Archean  rocks,  or  argue 
that  the  zinc  and  lead  were  deposited  with  the  sediments  from  solu- 
tion in  the  Silurian  ocean.  All  agree,  however,  that  the  ores  were 
deposited  from  solution,  which  is  the  essential  fact  for  the  geochemist 
to  consider.4 


1 Econ.  Geology,  vol.  2, 1907,  p.  17.  See  also  the  work  of  Anthon,  Schiirmann,  and  others,  already  cited 
on  p.  639,  ante. 

2 See  W.  H.  Seamon,  Am.  Jour.  Sci.,  3d  ser.,  vol.  39,  1890,  p.  38;  and  J.  C.  Branner,  Ann.  Rept.  Arkan- 
sas Geol.  Survey,  vol.  5, 1892,  pp.  9-34.  Both  authors  give  analyses,  and  other  analyses  by  T.  M.  Chatard 
and  H.  N.  Stokes  can  be  found  in  Bull.  U.  S.  Geol.  Survey  No.  228, 1904,  pp.  361, 362.  A similar  clay  from 
Bertha,  Virginia,  with  12.1  per  cent  ZnO,  was  described  by  B.  H.  Heyward,  Chem.  News,  vol.  44, 1881,  p. 
207. 

s Mon.  U.  S.  Geol.  Survey,  vol.  12, 1886,  p.  603. 

* For  data  concerning  these  deposits,  see  J.  D.  Whitney,  Rept.  Geol.  Survey  Wisconsin,  vol.  1,  chapter  6, 
1862;  T.  C.  Chamberlin,  Geology  of  Wisconsin,  vol.  4,  1882,  pp.  367-553;  W.  P.  Blake,  Bull.  Geol.  Soc. 
America,  vol.  5, 1893,  p.  25;  U.  S.  Grant,  Bull.  Wisconsin  Geol.  Nat.  Hist.  Survey  No.  9,  1903,  and  Bull. 
U.  S.  Geol.  Survey  No.  260, 1905,  p.  305;  E.  E.  Ellis,  idem,  p.  310;  A.  G.  Leonard,  Iowa  Geol.  Survey,  vol. 
6,  1897,  pp.  13-65;  and  Am.  Geologist,  vol.  16,  1905,  p.  288;  H.  F.  Bain,  Bull.  U.  S.  Geol.  Survey  No.  225, 
1904,  p.  202;  A.  Winslow,  Missouri  Geol.  Survey,  vols.  6 and  7,  1894,  and  Jour.  Geology,  vol.  1,  1893,  p.  612; 
J.  D.  Robertson,  Am.  Geologist,  vol.  15,  1895,  p.  235;  Bain,  Van  Hise,  and  Adams,  Twenty-second  Ann. 
Rept.  U.  S.  Geol.  Survey,  pt.  2, 1902,  p.  23;  W.  P.  Jenney,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  22,  1894,  pp. 
171,  642;  E.  Hedburg,  idem,  vol.  31, 1901,  p.  379;  J.  C.  Branner,  Ann.  Rept.  Arkansas  Geol.  Survey,  vol.  5, 
1892,  and  Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  572;  G.  I.  Adams,  idem,  vol.  34,  1904,  p.  163;  Bull. 
U.  S.  Geol.  Survey  No.  213, 1903,  p.  187,  and  Prof.  Paper  U.  S.  Geol.  Survey  No.  24, 1904;  W.  S.  T.  Smith, 
Bull.  U.  S.  Geol.  Survey  No.  213, 1903,  p.  196,  and  A.  Keith,  Bull.  U.  S.  Geol.  Survey  No.  225, 1904,  p.  208. 
See  also  W.  H.  Case,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  22, 1894,  p.  511,  on  the  zinc  ores  of  Bertha,  Virginia, 
S.  F.  Emmons  (Trans.  Am.  Inst.  Min.  Eng.,  vol.  22,  1894,  p.  83)  briefly  discusses  the  origin  of  zinc  ores, 
and  so  too  does  C.  R.  Van  Hise  in  his  Treatise  on  metamorphism,  Mon.  U.  S.  Geol.  Survey,  vol.  47,  1904, 
pp.  1125-1158.  A zinc  deposit  in  Nevada  is  described  by  Bain,  Bull.  U.  S.  Geol.  Survey  No.  285, 1906,  p.  166. 
Other  publications  are  by  E.  Haworth  and  others,  Kansas  Univ.  Geol.  Survey,  vol.  8,  1904;  E.  R.  Buck- 
ley  and  H.  A.  Buehler,  Missouri  Bur.  Geology  and  Mines,  2d  ser.,  vol.  4,  1906;  H.  F.  Bain,  Bull.  U.  S. 
Geol.  Survey  No.  294, 1907;  T.  L.  Watson,  Bull.  Am.  Inst.  Min.  Eng.,  March,  1906.  See  also  Bain,  Bull. 
Wisconsin  Geol.  Nat.  Hist.  Survey  No.  19,  1907;  L.  C.  Snider,  Oklahoma  Geol.  Survey,  Bull.  No.  9,  1912; 
G.  H.  Cox,  Econ.  Geology,  vol.  6,  1911,  p.  427.  On  the  genesis  of  the  Ozark  deposits,  see  C.  R.  Keyes,  Bull. 
Am.  Inst.  Min.  Eng.,  1909,  p.  119, 


676 


THE  DATA  OF  GEOCHEMISTRY. 


The  zinc  mines  at  Franklin  and  Sterling  Hill,  New  Jersey,  are  of 
a different  type  from  those  of  the  Mississippi  Valley,  being  indeed 
unique.  Here  zincite,  franklinite,  and  willemite,  ores  which  are  rare 
minerals  elsewhere,  are  most  abundant,  while  blende  is  present  only 
in  insignificant  quantities.  The  ore  bodies  occur  in  crystalline  lime- 
stone, in  contact  with  gneiss,  and  the  limestone  is  pierced  by  numer- 
ous granitic  dikes.  It  seems  probable,  from  the  character  of  the  ores 
and  their  mineralogical  associations,  that  they  were  formed  by  con- 
tact metamorphism.  A bed  of  limestone  containing  calamine  and 
smithsonite,  together  with  other  impurities,  might  be  expected  to 
change,  by  thermal  metamorphosis,  into  just  such  a formation  as  that 
at  Franklin.  The  smithsonite  would  yield  zincite,  the  willemite 
might  be  formed  from  calamine,  and  the  franklinite  and  gahnite,  with 
other  spinels,  could  develop  exactly  as  members  of  the  spinel  group 
develop  in  ordinary  limestones.  This  hypothesis  needs  verification, 
but  it  is  plausible  and  simple.  In  southwestern  New  Mexico,  accord- 
ing to  W.  P.  Blake,1  zinc  ores  occur  in  a contact-metamorphosed 
limestone;  but  blende  is  the  principal  mineral.  Blake,  however,  is 
inclined  to  correlate  this  deposit  with  that  at  Franklin,  notwith- 
standing their  differences.2 

LEAD. 

Although  lead  is  one  of  the  commoner  heavy  metals,  native  lead  is 
exceedingly  rare.  It  is  known,  however,  from  several  localities,  but 
it  is  always  of  secondary  origin,  a product  of  reduction.3 

The  principal  ore  of  lead  is  the  normal  sulphide,  galena,  PbS. 
Allied  to  this  are  the  rare  selenide,  clausthalite,  and  altaite,  the  cor- 
responding telluride.4  The  synthetic  preparation  of  galena  has  been 
effected  by  various  methods,  both  wet  and  dry.  J.  Durocher 5 
obtained  it  by  the  action  of  hydrogen  sulphide  upon  lead  chloride  at  a 
red  heat.  Any  other  salt  of  lead  would  probably  serve  the  same 
purpose.  Even  the  silicate  of  lead  contained  in  glass,  according  to 
T.  Sidot,6  when  heated  in  the  vapor  of  sulphur,  yields  galena.  F. 
Stolba 7 produced  crystals  of  the  sulphide  by  heating  the  amorphous 
compound  to  dull  redness  with  chalk.  F.  de  Marigny  8 produced 


1 Trans.  Am.  Inst.  Min.  Eng.,  vol.  24, 1895,  p.  187. 

2 For  data  regarding  the  Franklin  region,  see  F.  L.  Nason,  Ann.  Rept.  State  Geologist  New  Jersey,  1890, 
p.  25;  and  J.  F.  Kemp,  Trans.  New  York  Acad.  Sci.,  vol.  13, 1893,  p.  76.  Kemp  gives  references  to  earlier 
literature.  See  also  J.  E.  Wolff,  Bull.  U.  S.  Geol.  Survey  No.  213,  1903,  p.  214,  and  A.  C.  Spencer,  Ann. 
Rept.  State  Geologist  New  Jersey,  1908,  and  Geol.  Atlas  U.  S.,  U.  S.  Geol.  Survey,  Franklin  Furnace 
folio  (No.  161),  1908. 

3 A.  Hamberg  (Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  253)  has  suggested  that  at  Harstig,  Sweden,  the 
lead  was  reduced  by  arsenious  oxide. 

* Nagyagite  is  a sulphotelluride  of  lead,  gold,  and  antimony.  Naumannite,  lehrbachite,  and  zorgite  are 

selenides  of  lead  with  silver,  mercury,  or  copper. 

6  Compt.  Rend.,  vol.  32, 1851,  p.  825.  See  also  A.  Carnot,  cited  by  L.  Bourgeois,  Reproduction  artificielle 
des  min^raux,  p.  30. 

6 Compt.  Rend.,  vol.  62, 1866,  p.  999. 

7 Jahresb.  Chemie,  1863,  p.  242. 

8 Compt.  Rend.,  vol.  58, 1864,  p.  967. 


METALLIC  ORES. 


677 


galena  by  fusing  litharge  with  iron  pyrites  and  starch.  F.  Roessler1 
crystallized  both  galena  and  clausthalite  from  solution  in  molten 
lead.  By  distillation  of  a mixture  containing  lead  oxide,  sulphur, 
and  ammonium  chloride,  E.  Weinschenk  2 also  prepared  crystals  of 
galena.  It  is  furthermore  to  be  noted  that  galena  is  not  uncommon 
in  furnace  slags,  and  that  Mayen^on  3 has  reported  its  formation  as 
I a product  of  sublimation  in  a burning  coal  mine. 

The  foregoing  syntheses  of  galena  have  small  geological  signifi- 
cance. In  nature,  the  mineral  appears  to  be  commonly  formed  by 
hydrochemical  reactions,  and  these  can  be  imitated  in  the  laboratory. 
C.  Doelter  4 allowed  lead  chloride,  sodium  bicarbonate,  and  a solution 
of  hydrogen  sulphide  in  water  to  remain  in  a sealed  tube  at  ordinary 
room  temperature  during  five  months.  Crystals  of  galena  were  thus 
formed.  E.  Weinschenk 5 heated  a solution  of  lead  nitrate  with 
ammonium  sulphydrate  to  180°  in  a sealed  tube  and  also  obtained 
galena.  H.  N.  Stokes  6 has  found  that  pyrite  or  marcasite,  heated 
with  a solution  of  lead  chloride  to  180°,  will  precipitate  lead  sul- 
phide. A.  Daubree  7 observed  the  formation  of  galena,  together  with 
anglesite  and  phosgenite,  by  the  action  of  the  thermal  waters  of 
Bourbonne-les-Bains  on  metallic  lead.  Lead  sulphide  is  also  known 
in  spring  deposits,8  and  as  a pseudomorphous  replacement  of  other 
minerals.  W.  Lindgren  9 mentions  replacements  of  calcite,  dolomite, 
and  quartz,  and  also  of  orthoclase  and  rhodonite.  W.  H.  Hobbs 10  has 
described  secondary  galena  as  a surface  film  on  cerusite,  formed 
probably  by  the  action  of  hydrogen  sulphide  on  the  latter  mineral. 
That  galena  itself  is  slightly  soluble  in  water  and  also  in  solutions  of 
sodium  sulphide  has  been  shown  by  C.  Doelter.11  A.  Gautier  12  has 
shown  that  galena  is  dissociated  into  its  elements  by  the  action  of 
steam  at  a red  heat.  A little  galena  volatilizes  and  is  redeposited  in 
crystalline  form,  and  some  also  is  converted  into  sulphate.  The  pres- 
ence of  galena  among  the  Vesuvian  sublimates,  mentioned  in  an 
earlier  chapter  of  this  volume,  may  be  correlated  with  Gautier’s 
observations. 

1 Zeitschr.  anorg.  Chemie,  vol.  9,  1895,  p.  41.  By  passing  selenium  vapor  over  melted  lead  G.  Little 
(Liebig’s  Annalen,  vol.  112,  1859,  p.  211)  also  produced  the  selenide. 

2 Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  489. 

* Compt.  Rend.,  vol.  86, 1878,  p.  491. 

* Zeitschr.  Kryst.  Min.,  vol.  11,  1886,  p.  41.  A.  C.  Becquerel  (Compt.  Rend.,  vol.  44,1857,  p.938)  men- 
tions a hydrochemical  synthesis  of  galena,  but  too  vaguely  to  warrant  citation  above. 

s Zeitschr.  Kryst.  Min.,  vol.  17, 1890,  p.  497. 

6 Econ.  Geology,  vol.  2, 1907,  p.  22. 

7 Etudes  synthStiques  de  geologie  expdrimentale,  pp.  84,  85. 

s See,  for  example,  the  sinter  described  by  G.  F.  Becker  and  W.  H.  Melville,  Mon.  U.  S.  Geol.  Survey, 
vol.  13, 1888,  p.  344. 

9 Trans.  Am.  Inst.  Min.  Eng.,  vol.  30, 1900,  p.  578. 

10  Am.  Jour.  Sci.,  3d  ser.,  vol.  50, 1895,  p.  121. 

w Min.  pet.  Mitt.,  vol.  11,  1890,  p.  31,9.  An  iron  wedge  or  chisel  coated  with  galena  is  mentioned  in  Min- 
eralog.  Mag.,  vol.  16, 1913,  p.  340. 

u Compt.  Rend.,  vol.  142,  1906,  p.  1465. 


678 


THE  DATA  OF  GEOCHEMISTRY. 


The  sulphosalts  of  lead  are  numerous,  although,  on  account  of 
their  individual  rarity,  they  have  little  significance  as  ores.1  Sarto- 
rite,  dufrenoysite,  guitermanite,  jordanite,  rathite,  and  lengenbachite 
are  sulpharsenides.  Zinkenite,  plagionite,  jamesonite,  semseyite, 
boulangerite,  meneghinite,  geocronite,  kilbrickenite,  and  epiboulan- 
gerite  are  sulphantimonides.  Other  sulphantimonides  of  lead  and 
silver  are  brongniardite,  diaphorite,  freieslebenite,  and  andorite. 
The  sulphobismuthides  are  chiviatite,  rezbanyite,  galenobismutite, 
schirmerite,  cosalite,  schapbachite,  kobellite,  lillianite,  and  beegerite. 
Teallite,  cylindrite,  and  franckeite  are  sulphostannides,  which,  for 
present  purposes,  must  be  classified  under  tin. 

According  to  J.  Fournet,2  zinkenite,  PbSb2S4,  can  be  prepared  by 
fusing  galena  and  stibnite  together  in  proper  proportions.  C.  Doel- 
ter,3  by  heating  antimony,  antimony  trioxide,  and  lead  chloride 
together  in  gaseous  hydrogen  sulphide,  obtained  jamesonite,  PbSb2S5, 
mixed  with  stibnite  and  galena.  By  the  action  of  molten  lead  chlo- 
ride upon  antimony  trisulphide,  H.  Sommerlad  4 reproduced  boulan- 
gerite, Pb3Sb2S6;  zinkenite;  jamesonite;  warrenite5  (domingite), 
Pb3Sb4S9;  and  plagionite,  Pb5Sb8S17.  By  fusing  lead  sulphide  and 
arsenic  trisulphide  together,  he  obtained  sartorite  (scleroclase), 
PbAs2S4,  and  dufrenoysite,  Pb2As2S5. 

G.  Pelabon,6  studying  the  fusion  curve  of  the  system  PbS  + Sb2S3, 
found  that . zinkenite  crystallized  out  at  558°,  and  jamesonite  at 
610°.  F.  M.  Jaeger  and  H.  S.  van  Klooster,7  by  a similar  process, 
obtained  only  jamesonite  and  plagionite.  The  component  sulphides 
were  fused  together  in  an  atmosphere  of  nitrogen.  They  assert  that 
Sommerlad’ s syntheses  are  incorrect. 

Whether  any  of  these  syntheses  correspond  to  natural  processes  is 
questionable.  The  ore  bodies  in  which  the  minerals  occur  appear  to 
have  been  formed  in  most  cases  from  mineralized  solutions,  or  else 
by  pneumatolytic  reactions  at  temperatures  which  were  not  exces- 
sively high.  Syntheses,  to  be  geologically  significant,  should  be  con- 
ducted on  the  lines  which  nature  seems  to  have  followed.8 

By  oxidation,  carbonation,  etc.,  the  sulphur  compounds  of  lead  are 
transformed  into  other  minerals.  Among  them  are  the  three  oxides, 

1 Bournonite  and  aikinite,  which  contain  both  lead  and  copper,  have  already  been  mentioned  under  the 
latter  metal. 

2 Cited  by  L.  Bourgeois,  Reproduction  artificielle  des  minSraux,  p.  46,  from  Jour,  prakt.  Chemie,  vol.  2, 
p.  490. 

3 Zeitschr.  Kryst.  Min.,  vol.  11, 1886,  p.  40. 

* Zeitschr.  anorg.  Chemie,  vol.  18,  1898,  p.  420.  Sommerlad ’s  results  have  been  called  in  question  by 

F.  Ducatte  (Thesis,  Univ.  Paris,  1902)  and  J.  Rondet  (Thesis,  Univ.  Paris,  1904),  who  claim  that  the  reac- 
tions employed  really  produce  complex  chlorinated  sulphides,  and  not  true  sulphosalts. 

6 According  to  L.  J.  Spencer  (Mineralog.  Mag.,  vol.  14,  1907,  p.  207),  warrenite  is  identical  with  jame* 
sonite.  W.  T.  Schaller  (Zeitschr.  Kryst.  Min.,  vol.  48, 1911,  p.  562)  regards  it  as  a mixture  of  jamesonite  and 
zinkenite. 

® Compt.  Rend.,  vol.  156,  p.  706, 1913. 

7 Zeitschr.  anorg.  Chemie,  vol.  78,  p.  245,  1912. 

8 Jamesonite  forms  an  important  ore  at  La  Sirena,  near  Zimapan,  Mexico.  See  W.  Lindgren  and  W.  L. 
Whitehead,  Econ.  Geology,  vol.  9, 1914,  p.  435. 


METALLIC  ORES. 


679 


massicot,  PbO;  minium,  Pb304;  and  plattnerite,  Pb02.  All  these 
have  been  prepared  synthetically  in  crystalline  form,  but  in  most 
cases  by  methods  which  scarcely  resemble  natural  processes.  A.  C. 
Becquerel,1  by  allowing  an  alkaline  solution  of  alumina  or  silica  to  act 
slowly  upon  a plate  of  lead,  obtained  crystals  of  massicot.  The  lead 
was  surrounded  by  a coil  of  copper  wire,  and  Becquerel  attributed  the 
synthesis  to  electrical  action.  It  was  more  probably  a simple  hydro- 
chemical process. 

Lead  carbonate,  cerusite,  PbC03,  is  a common  mineral,  produced 
by  the  action  of  carbonated  waters  in  the  upper  levels  of  ore  bodies.2 
There  are  also  the  basic  hydrocerusite,  Pb3  (OH)2  (C03)2,  and  the  rare 
dundasite,  a carbonate  of  aluminum  and  lead.3  Becquerel 4 obtained 
crystals  of  cerusite  when  a solution  of  sodium  and  calcium  carbonate 
acted  gradually  upon  a plate  of  lead.  E.  Fremy 5 produced  the 
mineral  by  the  slow  diffusion  of  a carbonate  solution  into  a lead 
solution  through  a porous  membrane.  By  some  such  gradual  min- 
gling of  dilute  solutions,  the  natural  cerusite  is  probably  often  formed.6 
H.  von  Dechen 7 has  reported  the  case  of  an  old  mine  whose  walls  were 
covered  with  a thick  coating  of  cerusite,  which  had  been  deposited 
from  solution  like  sinter.  A.  Lacroix  8 has  observed  the  mineral  as 
a coating  on  old  Roman  coins.  It  is  also  produced  by  metasomatic 
replacement  in  limestones,  and  fossils,  such  as  encrinites,  have  been 
found  completely  transformed  into  cerusite.9  The  rare  chloro- 
carbonate  of  lead,  phosgenite,  Pb2Cl2C03,  was  reproduced  by  C. 
Friedel  and  E.  Sarasin  10  when  lead  chloride,  lead  carbonate,  and 
water  were  heated  together  in  a sealed  tube  to  180°.  It  was  also 
prepared  by  A.  de  Schulten,11  who  allowed  a filtered  solution  of  lead 
chloride  to  stand  in  a large  flask  while  a current  of  carbon  dioxide 
passed  slowly  through  the  vacant  space  above. 

Cotunnite,  lead  chloride,  PbCl2,  is  found  in  nature  as  a volcanic 
mineral,  produced  by  sublimation.  F.  Stober  12  reproduced  the  min- 
eral by  this  process,  and  also  obtained  it  in  minute  crystals  from 
simple  solution  in  water  or  in  aqueous  hydrochloric  acid.  It  was  also 

1 Compt.  Rend.,  vol.  34, 1852,  p.  29.  See  also,  for  other  researches,  L.  Bourgeois,  Reproduction  artificielle 
des  min6raux,  p.  56.  L.  Michel  (Bull.  Soc.  min.,  vol.  13,  1890,  p.  56)  reports  syntheses  of  minium  and 
plattnerite. 

2 A large  deposit  of  cerusite  in  the  Terrible  mine,  at  Ilse,  Colorado,  has  been  described  by  R.  B.  Brins- 
made,  Eng.  and  Min.  Jour.,  vol.  83,  1907,  p.  844.  Its  formation  is  ascribed  to  the  action  of  descending 
waters. 

3 See  G.  T.  Prior,  Mineralog.  Mag.,  vol.  14,  1906,  p.  167. 

* Loc.  cit. 

5 Compt.  Rend.,  vol.  63, 1866,  p.  714. 

« The  syntheses  of  cerusite,  by  J.  Riban  (Compt.  Rend.,  vol.  93, 1881,  p.  1026),  and  of  hydrocerusite,  by 
L.  Bourgeois  (Bull.  Soc.  min.,  vol.  11,  1888,  p.  221),  have  no  relation  to  natural  processes. 

i Neues  Jahrb.,  1858,  p.  216. 

s Bull.  Soc.  min.,  vol.  6,  1883,  p.  175. 

9 See  Blode,  Neues  Jahrb.,  1834,  p.  638. 

w Bull.  Soc.  min.,  vol.  4, 1881,  p.  175. 

11  Idem,  vol.  20,  1897,  p.  194. 

12  Bull.  Acad.  roy.  sci.  Belgique,  3d  ser.,  vol.  30,  1895,  p.  345. 


680 


THE  DATA  OF  GEOCHEMISTRY. 


formed  by  A.  C.  Becquerel,1  much  earlier,  by  allowing  a solution  of 
copper  sulphate  and  sodium  chloride  to  act  upon  galena  during  a 
period  of  seven  years.  The  sulphate,  anglesite,  was  obtained  at  the 
same  time.  The  great  rarity  of  cotunnite  as  a natural  mineral  is  due 
to  the  strong  tendency  on  the  part  of  lead  to  form  basic  salts,  and  the 
basic  chlorides  are  much  more  frequently  found.  Matlockite,  Pb2OCl2, 
and  mendipite,  Pb302Cl2,  have  long  been  known.  Schwartzembergite 
is  like  mendipite  in  composition,  but  with  iodine  largely  replacing 
chlorine.  Laurionite,2  paralaurionite,  penfieldite,  daviesite,  and  fied- 
lerite  are  oxychlorides  of  lead  which  have  formed  on  ancient  slags  at 
Laurium,  in  Greece.  Caracolite  is  a double  salt  of  the  composition 
Pb0HCl  + Na2S04.  Percylite,  cumengeite,  and  pseudoboleite  are 
oxychlorides  of  lead  and  copper,  and  boleite  is  similar  in  composition, 
but  with  silver  chloride  as  an  additional  component.3 

Lead  sulphate,  PbS04,  as  the  crystallized  mineral  anglesite,  is  a 
common  oxidation  derivative  of  galena.  According  to  E.  Jannetaz  4 
galena  is  easily  attacked  by  acid  solutions  of  ferrous  sulphate  such  as 
are  generated  by  the  oxidation  of  pyrite  or  marcasite.  The  associa- 
tion of  galena  with  pyrite,  therefore,  is  favorable  to  the  formation 
of  anglesite.  Its  synthesis  by  Becquerel  has  already  been  mentioned, 
and  it  has  also  been  prepared  by  Mace,5  who  added  a solution  of  fer- 
rous sulphate  very  slowly  to  one  of  lead  nitrate.  Essentially  the 
same  process  was  successfully  followed  by  E.  Fremy  6 and  by  E. 
Masing,7  a soluble  sulphate  being  allowed  to  diffuse  very  slowly  into 
one  of  a lead  salt — in  Masing’s  case  lead  nitrate.  Lead  sulphate, 
although  relatively  insoluble,  is  not  absolutely  so;  it  therefore  can 
be  crystallized,  as  the  syntheses  show,  when  it  is  formed  with  extreme 
slowness  in  very  dilute  solutions.  Conditions  of  this  sort  probably 
attend  the  formation  of  anglesite  in  bodies  of  lead  ore;  but  when  car- 
bonates are  present  in  the  percolating  waters,  cerusite  is  produced 
instead.  The  synthesis  of  anglesite  by  N.  S.  Manross,8  who  obtained 
it  by  fusing  lead  chloride  with  potassium  sulphate,  does  not  seem  to 
correspond  with  any  natural  mode  of  formation. 

Lanarkite  is  a rare,  basic  sulphate  of  lead,  Pb2S05.9  Caledonite 
and  linarite  are  basic  sulphates  of  lead  and  copper,  and  plumbojaro- 

1 Compt.  Rend.,  vol.  34, 1852,  p.  29. 

2 For  a synthesis  of  laurionite,  PbOHCl,  see  A.  de  Schulten,  Bull.  Soc.  min.,  vol.  20, 1897,  p.  186.  On  the 
rare  minerals  of  Laurium,  see  A.  Lacroix  and  De  Schulten,  Bull.  Soc.  min.,  vol.  31, 1908,  p.  79.  Georgiaddsite, 
a phosphate  and  chloride  of  lead,  should  be  added  to  the  list. 

3 Percylite,  cumengeite,  and  boleite  have  been  made  artificially  by  C.  Friedel,  Bull.  Soc.  min.,  vol.  15, 
1892,  p.  96;  vol.  16,  1893,  p.  187;  and  vol.  17,  1894,  p.  6.  See  also,  in  reference  to  these  minerals,  E.  Mallard, 
Bull.  Soc.  min.,  vol.  16,  1893,  p.  184,  and  G.  Friedel,  idem,  vol.  29, 1906,  p.  14. 

* Bull.  Soc.  g6ol.  France,  3d  ser.,  vol.  3,  1875,  p.  310.  G.  Piolti  (Jour.  Chem.  Soc.,  vol.  100, 1911,  p.  902, 
abstract)  obtained  crystals  of  anglesite  by  the  prolonged  immersion  of  galena  in  a solution  of  potassium 
nitrate. 

b Compt.  Rend.,  vol.  36, 1853,  p.  825. 

« Idem,  vol.  63,  1866,  p.  714. 

7 Jahresb.  Chemie,  1889,  p.  4. 

8 Liebig’s  Annalen,  vol.  82, 1852,  p.  348. 

9 For  a synthesis  of  lanarkite,  see  A.  de  Schulten,  Bull.  Soc.  min.,  vol.  21, 1898,  p.  142. 


METALLIC  ORES. 


681 


site  and  beaverite  basic  sulphates  of  lead  and  ferric  iron.  Leadhillite 
is  a complex  salt  of  the  formula  PbS04.2PbC03.Pb(0H)2.  At  Granby, 
Missouri,  according  to  W.  M.  Foote,1  it  occurs  as  a pseudomorph 
after  calcite  and  galena.  In  composition  it  suggests  a double  salt 
formed  by  the  union  of  hydrocerusite  and  anglesite,  in  equimolecular 
proportions.2  Plumbojarosite,  a highly  hydrated  sulphate  of  lead 
and  iron,  is  abundant  in  some  mines  in  Utah.3 

Lead  salts  analogous  to  anglesite  are  the  chromate,  crocoite, 
PbCr04 ; the  molybdate,  wulfenite,  PbMo04 ; and  the  tungstate,  stol- 
zite,  PbW04.  The  rare  phoenicochroite 4 is  a basic  chromate, 
Pb3Cr209;  vauquelinite  is  a chromate  and  phosphate,  and  beresovite 
is  described  as  a chromate  and  carbonate  of  lead,  which  is  not,  how- 
ever, the  equivalent  of  leadhillite,  for  it  contains  no  water. 

When  sodium  tungstate  is  fused  with  lead  chloride,  according  to 
N.  S.  Manross,5  stolzite  is  formed;  with  sodium  molybdate,  wulfen- 
ite is  produced;  and  by  fusing  together  potassium  chromate  and 
lead  chloride  he  obtained  crocoite.  The  formation  of  wulfenite  as 
a furnace  product 6 is  probably  due  to  some  reaction  of  this  kind. 
By  slow  diffusion  of  solutions  of  potassium  chromate  and  lead  nitrate 
into  one  another  A.  Drevermann  7 obtained  both  crocoite  and  phceni- 
cochroite.  Cerusite  and  anglesite  were  formed  at  the  same  time 
from  impurities  in  the  reagents.  A.  C.  Becquerel 8 allowed  a gal- 
vanic couple  of  lead  and  platinum  to  act  for  several  years  upon  a 
solution  of  chromic  chloride  and  obtained  crystals  which  appeared 
to  be  crocoite.  S.  Meunier  9 found  that  phoenicochroite  was  formed 
when  fragments  of  galena  were  immersed  during  six  months  in  a 
solution  of  potassium  dichromate.  L.  Bourgeois  10  boiled  precipitated 
lead  chromate  with  dilute  nitric  acid.  From  the  hot,  filtered  solu- 
tion crystals  of  crocoite  were  deposited.  Better  results  were  obtained 
when  the  operation  was  conducted  in  a sealed  tube  at  130°.  Lachaud 
and  Lepierre  11  state  that  when  amorphous  lead  chromate  is  boiled 
with  a solution  of  chromic  acid  it  crystallizes  into  crocoite.  Phoeni- 
cochroite was  formed  when  lead  chromate  and  sodium  chloride  were 
fused  together.  Both  chromates  were  obtained  by  Ludeking  12  upon 

1 Am.  Jour.  Sci.,  3d  ser.,  vol.  50,  1895,  p.  99. 

2 Palmierite,  a double  sulphate  of  lead  and  potassium,  is  found  among  the  recent  products  of  fumarole 

action  at  Vesuvius. 

a In  certain  of  the  mines  of  Beaver  County,  plumbojarosite  is  abundant  enough  to  be  treated  as  an  ore 
of  lead.  See  B.  S.  Butler,  Econ.  Geology,  vol.  8, 1913,  p.  311. 

* Also  called  melanochroite. 

6 Liebig’s  Armalen,  vol.  82,  1852,  p.  348.  H.  Schultze  (idem,  vol.  126,  1863,  p.  51)  prepared  wulfenite  in 
the  same  way. 

e See  J.  F.  L.  Hausmann,  idem,  vol.  81, 1852,  p.  224. 

7 Idem,  vol.  87, 1853,  p.  120;  vol.  89,  1854,  p.  11. 

8 Compt.  Rend.,  vol.  63, 1866,  p.  1. 

8 Idem,  vol.  87, 1878,  p.  656. 

10  Bull.  Soc.  min.,  vol.  10, 1887,  p.  187. 

11  Bull.  Soc.  chim.,  3d  ser.,  vol.  6, 1891,  p.  230. 

12  Am.  Jour.  Sci.,  3d  ser.,  vol.  44,  p.  57. 


682 


THE  DATA  OF  GEOCHEMISTRY. 


exposing  to  the  air  during  several  months  a solution  of  lead  chromate 
in  caustic  potash.  G.  Cesaro  1 prepared  crocoite  by  the  same  process, 
and  with  lead  molybdate  crystalline  wulfenite  was  formed.  E. 
Dittler2  added  a hot,  concentrated  solution  of  lead  chloride  to  a 
dilute  solution  of  ammonium  molybdate,  and  obtained  an  amor- 
phous precipitate.  This,  dissolved  in  a solution  of  sodium  carbonate, 
was  gradually  redeposited  as  wulfenite.  Natural  wulfenite,  digested 
with  sodium  bicarbonate,  yielded  hydrocerusite.  Of  all  these  syn- 
theses, that  by  Meunier  seems  best  to  represent  the  probable  natural 
processes. 

Three  lead  minerals,  the  chlorophosphate,  pyromorphite, 
Pb5P3012Cl;  the  corresponding  arsenate,  mimetite,  Pb5As3012Cl;  and 
the  vanadium  salt,  vanadinite,  Pb3V3012Cl,  occur  both  independently 
and  in  a great  variety  of  isomorphous  mixtures.  Endlichite,  for 
example,  is  a mixture  of  the  arsenic  and  vanadium  compounds,  and 
minerals  intermediate  between  mimetite  and  pyromorphite  are 
common. 

All  these  species  have  been  prepared  synthetically,  and  pyromor- 
phite is  also  known  as  a furnace  product  in  slag.3  N.  S.  Manross4 
obtained  pyromorphite  by  fusing  lead  chloride  with  tribasic  sodium 
phosphate.  H.  Sainte-Claire  Deville  and  H.  Caron 5 fused  lead  phos- 
phate, lead  chloride,  and  sodium  chloride  together  to  produce  pyro- 
morphite, and  L.  Michel 6 accomplished  the  same  purpose  by  the 
same  process,  only  omitting  the  common  salt.  From  fusions  of  lead 
arsenate  with  lead  chloride  G.  Lechartier 7 and  also  Michel  succeeded 
in  reproducing  mimetite.  Vanadinite  was  obtained  by  P.  Haute- 
feuille8  when  vanadic  ’ oxide  was  fused  with  lead  oxide  and  lead 
chloride.  All  of  these  syntheses,  it  will  be  seen,  are  similar  and  were 
effected  by  fusion,  while  the  natural  occurrences  of  the  minerals  indi- 
cate hydrochemical  reactions.  In  the  case  of  pyromorphite  this 
natural  process  was  simulated  by  H.  Debray,9  who  prepared  pyro- 
morphite by  digesting  lead  pyrophosphate  with  a solution  of  lead 
chloride  at  250°. 

Other  phosphates,  arsenates,  and  vanadates  containing  lead  and 
sometimes  zinc,  iron,  or  copper  also,  are  plumbogummite,  caryinite, 
carminite,  lossenite,  bayldonite,  ecdemite,  beudantite,10  svanhergite, 
hinsdalite,  descloizite,  cuprodescloizite,  brackebuschite,  and  psittaci- 

1 Bull.  Acad.  roy.  sci.  Belgique,  1905,  p.  327. 

2 Zeitschr.  Kryst.  Min.,  vol.  53, 1914,  p.  158. 

s J.  J.  Noggerath,  Neues  Jahrb.,  1847,  p.  37. 

< Liebig’s  Annalen,  vol.  82, 1852,  p.  348. 

6 Annales  chim.  phys.,  3d  ser.,  vol.  67, 1863,  p.  451. 

6 Bull.  Soc.  min.,  vol.  10, 1887,  p.  133. 

i Compt.  Rend.,  vol.  65, 1867,  p.  172. 

8 Idem,  vol.  77,  1873,  p.  896. 

• Annales  chim.  phys.,  3d  ser.,  vol.  61, 1861,  p.  443. 

Phosphate,  arsenate,  and  sulphate  of  lead.  Svanbergite,  hinsdalite,  and  the  sulphate,  beaverite.  are 
allied  to  beudantite. 


metallic;  ores. 


683 


nite.  Bindheimite  is  a lead  antimonate,  formed  by  oxidation  from 
sulphosalts  of  lead.  Nadorite,  PbClSb02,  and  ochrolite,  Pb6Cl2Sb207, 
are  perhaps  of  similar  origin.  All  of  these  species  are  rare  minerals 
and  need  not  be  considered  further.  The  same  may  be  said  of  the 
lead-bearing  silicates,  barysilite,  ganomalite,  hyalotekite,  kentrolite, 
melanotekite,  nasonite,  roeblingite,  and  molybdophyllite.  The 
roeblingite,  however,  from  the  zinc  mines  at  Franklin,  New  Jersey, 
is  unique  in  containing  a sulphite  molecule  combined  with  the  silicate. 
An  artificial  lead  silicate  from  furnace  slag  has  been  described  by 
E.  S.  Dana  and  S.  L.  Penfield,1  and  also  by  H.  A.  Wheeler.2 

The  common  association  of  lead  ores  with  those  of  zinc  was  pointed 
out  in  the  preceding  section  of  this  chapter.  Blende  and  galena  are 
both  formed  from  solutions,  but  not  always  in  the  same  manner.  By 
differences  in  the  solubility  of  their  oxidation  products  the  two 
metals  are  often  separated  from  each  other,  for  lead  sulphate  is 
slightly  soluble,  while  zinc  sulphate  is  easily  so.  Zinc,  therefore, 
disappears  from  the  upper  portions  of  ore  bodies  much  more  rapidly 
than  lead,  and,  for  the  same  reason,  so  does  copper.  The  lead  ores 
of  Eureka,  Nevada,  are  regarded  by  J.  S.  Curtis  3 as  the  product  of 
solfataric  action;  those  of  Leadville,  Colorado,  according  to  S.  F. 
Emmons,4  were  deposited  from  descending  solutions,  which  had  gath- 
ered their  metallic  burden  from  neighboring  eruptive  rocks.  In  both 
cases  the  ore  bodies  are  interpreted  as  replacements  in  country  rock. 

TIN.5 

Tin  is  one  of  the  rarer  metals  and  its  ores  are  not  numerous. 
Native  tin  is  occasionally  found,  but  never  in  more  than  trifling  quan- 
tities and  in  small  grains.6  The  ore  of  chief  importance  is  the 
dioxide,  cassiterite,  Sn02,  but  several  sulphosalts  are  also  known. 
They  are — 


Stannite Cu2FeSnS4. 

Teallite  7 PbSnS2. 

Cylindrite Pb3FeSn4Sb2S14. 

Franckeite Pb5FeSn3Sb2S14. 


1 Am.  Jour.  Soi.,  3d  ser.,  vol.  30, 1885,  p.  138. 

2 Idem,  vol.  32, 1886,  p.  272. 

3 Mon.  U.  S.  Geol.  Survey,  vol.  7,  1884,  chapters  7,  8. 

4 Idem,  vol.  12, 1886,  p.  378. 

& For  a paper  on  the  occurrence  and  distribution  of  tin,  with  a bibliography,  see  F.  L.  Hess  and  L.  C. 
Graton,  Bull.  U.  S.  Geol.  Survey  No.  260, 1904,  p.  160.  A summary  of  tin  localities  is  also  given  by  W.  P. 
Blake,  in  Mineral  Resources  U.  S.  for  1883-84,  U.  S.  Geol.  Survey,  1885,  pp.  592  et  seq. 

6 A recent  discovery  of  native  tin  is  noted  by  E.  S.  Simpson  in  Ann.  Rept.  Geol.  Survey  West  Australia, 
1899,  p.  52. 

7 See  G.  T.  Prior,  Mineralog.  Mag.,  vol.  14,  1904,  p.  21,  on  the  composition  of  teallite,  cylindrite,  and 
franckeite.  See  also  A.  Stelzner,  Neues  Jahrb.,  Band  2, 1893,  p.  114,  and  A.  Frenzel,  idem,  p.  125.  On 
stannite  and  its  alteration  products  from  the  Black  Hills,  see  W.  P.  Headden,  Am.  Jour.  Sci.,  3d  ser., 
vol.  45,  1893,  p.  105. 


684 


THE  DATA  OF  GEOCHEMISTRY. 


There  is  also  a very  rare  borate  of  calcium  and  tin,  nordenskiol- 
dine,1  CaSnB206,  which  is  interesting  because  it  directly  connects  tin 
with  boron.  The  same  is  true  of  hulsite  and  paigeite,  two  iron-tin 
borates  found  in  Alaska.2  Other  minerals,  especially  those  of  the 
rare  earths,  sometimes  contain  small  amounts  of  tin  as  an  impurity, 
and  the  metal  has  also  been  found  in  zinc  blende.3 

Cassiterite  has  been  repeatedly  observed  as  a furnace  product, 
formed  by  the  direct  oxidation  of  tin.  Recent  occurrences  of  this 
kind  are  recorded  by  A.  Arzruni 4 and  J.  H.  L.  Vogt,5  and  L.  Bour- 
geois 6 has  identified  the  mineral  in  scoria  from  a bronze  foundry. 
The  first  synthesis  of  cassiterite  was  performed  by  A.  Daubree 7 when 
the  vapor  of  stannic  chloride  was  mixed  with  steam  in  a red-hot 
porcelain  tube.  Later  the  same  chemist 8 prepared  the  mineral  by 
passing  the  vapor  of  stannic  chloride  over  heated  lime.  The  crystal- 
lized oxide  was  obtained  by  H.  Sainte-Claire  Deville  and  H.  Caron  9 
when  stannic  fluoride  and  boric  oxide  were  heated  together  to  white- 
ness. H.  Sainte-Claire  Deville  10  also  obtained  it  by  heating  the 
amorphous  oxide  in  a slow  current  of  hydrochloric  acid  gas  and 
again  by  a repetition  of  Daubree’s  first  process.  A.  Ditte  11  noticed 
the  formation  of  crystalline  stannic  oxide  when  the  amorphous  com- 
pound, mixed  with  calcium  chloride  and  ammonium  chloride,  was 
subjected  to  a white  heat. 

According  to  C.  Doelter,12  cassiterite  is  perceptibly  soluble  in  water 
at  80°,  and  more  so  in  presence  of  sodium  fluoride.  Some  recrystal- 
lization from  the  solution  was  observed.  This  solubility  is  also 
indicated  by  several  natural  occurrences  of  tin.  S.  Meunier  13  found 
0.5  per  cent  of  Sn02  in  an  opaline  deposit,  resembling  geyserite,  from 
a thermal  spring  in  Selangor.  J.  H.  Collins  14  reports  tinstone  as  a 
cement  in  certain  Cornish  conglomerates,  as  an  impregnation  in  long- 
buried  horns  of  deer,  as  pseudomorphs  after  feldspar,15  and  as  cap- 


1 Described  by  W.  C.  Brogger,  Zeitschr.  Kryst.  Min.,  vol.  16, 1890,  p.  61. 

2 See  A.  Knopf  and  W.  T.  Schaller,  Am.  Jour.  Sci.,  4th  ser.,  vol.  25,  1908,  p.  323.  Also  Schaller,  idem, 
vol.  29, 1910,  p.  543. 

3 See  A.  Stelzner  and  A.  Schertel,  Jahrb.  Berg-  u.  Hiittenw.  Konig.  Sachsen,  1886,  p.  52,  on  tin  in  black 

blende  from  Freiberg.  It  has  also  been  found  in  the  zinc  ores  of  the  Slocan  district,  British  Columbia. 
See  Kept.  Comm,  on  Zinc  Resources,  etc.,  of  British  Columbia,  Mines  Branch,  Dept.  Interior,  Ottawa, 
1906, p.  15. 

* Zeitschr.  Kryst.  Min.,  vol.  25,  1896,  p.  467. 

& Idem,  vol.  31, 1899,  p.  279. 

6 Bull.  Soc.  min.,  vol.  11,  1888,  p.  58. 

7 Compt.  Rend.,  vol.  29, 1849,  p.  227. 

3 Idem,  vol.  39,  1854,  p.  135. 

9 Idem,  vol.  46,  1858,  p.  764.  Details  not  given. 

w Idem,  vol.  53,  1861,  p.  161. 

a Idem,  vol.  96, 1883,  p.  701. 

12  Min.  pet.  Mitt.,  vol.  11,  1890,  p.  325. 

is  Compt.  Rend.,  vol.  110,  1890,  p.  1083. 

h Mineralog.  Mag.,  vol.  4, 1880,  pp.  1, 103,  and  vol.  5, 1883,  p.  121. 

10  According  to  C.  Reid  and  J.  B.  Scrivenor  (Mem.  Geol.  Survey  Eng.  and  Wales,  Geology  of  country 

near  Newquay,  1906,  p.  39),  the  so-called  pseudomorphs  are  replacements  of  orthoclase  by  an  aggregate  of 

cassiterite,  muscovite,  and  quartz.  On  the  genesis  of  the  Cornish  ores,  see  also  J.  B.  Hill  and  D.  A.  Mae- 

Alister,  idem,  Geology  of  Falmouth,  Truro,  etc.,  p.  167. 


METALLIC  ORES. 


685 


pings  on  crystals  of  quartz.  He  also  notes  that  cassiterite  crystals 
often  line  fissures  in  quartz,  the  latter  containing  numerous  fluid 
inclusions.  An  incrustation  resembling  “wood  tin”  was  found  by 
Collins  on  an  ingot  of  ancient  tin,  having  been  formed  by  slow  oxi- 
dation of  the  metal.  Furthermore,  Collins  reports  secondary  crystal- 
lizations of  cassiterite  on  reniform  masses  of  “wood  tin,”  and  all  of 
this  evidence  he  regards  as  proof  that  the  Cornish  ores  are  of  aqueous 
origin.  Pseudomorphs  of  cassiterite  after  hematite  were  found  by 
F.  A.  Genth  1 in  tin  ores  from  Durango,  Mexico,  and  he  also  cites 
an  observation  by  W.  Semmons,  who  described  specimens  of  bis- 
muthinite  coated  with  concentric  layers  of  tinstone.  It  is  possible 
in  some  of  these  cases  that  the  tin-bearing  solutions  may  have  been 
derived  from  the  oxidation  of  stannite,  but  this  point  seems  to  have 
received  little  or  no  consideration.  Stalactitic  cassiterite,  from  the 
Sierra  de  Guanajuato,  Mexico,  has  been  described  by  E.  Wittich.2 

Cassiterite  has  been  noted  as  an  original  constituent  of  igneous 
rocks,3  but  it  more  commonly  occurs  in  veins  or  stringers  of  quartz 
under  conditions  which  indicate  a secondary  deposition.  As  a rule, 
tin-bearing  veins  are  found  in  or  near  persilicic  rocks,  such  as  pegma- 
tites and  altered  granites.  Sometimes  the  association  is  with  quartz 
porphyry,  as  at  Mount  Bischoff,  in  Tasmania,4  and  at  certain  Mexican 
mines;  but  at  other  localities  of  tin  in  Mexico  the  prevailing  rock  is 
rhyolite  or  rhyolite  tuff.  In  these  instances,  as  at  the  Potrillos  mine, 
in  Durango,  the  ore  is  found  along  fault  planes  in  the  rhyolite.5 
The  Cacaria  mine,  also  in  Durango,  is  in  quartz  porphyry.  In  the 
Malay  Peninsula,  according  to  R.  A.  F.  Penrose,6  the  prevalent 
stanniferous  rocks  are  granitic,  or  detrital  matter  derived  from 
granite;  but  at  Chongkat  Pari,  in  Perak,  cassiterite  is  extracted 
from  limestone,  and  at  Bruseh,  Perak,  it  is  found  in  seams  in  sand- 
stone. These  abnormal  occurrences  are  perhaps  due,  as  Penrose 
suggests,  to  infiltration  of  tin-bearing  solutions — a supposition 
which  becomes  probable  in  the  light  of  evidence  already  cited. 

The  typical  mode  of  occurrence  of  tin  ores  is  in  quartz  veins  cut- 
ting granite,  the  walls  of  the  latter  rock  being  altered  into  greisen. 
Greisen  is  essentially  a granite  in  which  the  feldspars  have  been 

1 Proc.  Am.  Philos.  Soc.,  vol.  24,  1887,  p.  23.  L.  V.  Pirsson  (Am.  Jour.  Sci.,  3d  ser.,  vol.  42,  1891,  p.  407) 
has  described  crystals  of  hematite  inclosing  cassiterite,  from  the  same  locality. 

2 Zeitschr.  prakt.  Geologie,  1910,  p.  121. 

2 See  ante,  p.  353,  in  chapter  on  rock-forming  minerals. 

4 On  Tasmanian  tin  deposits  see  L.  K.  Ward,  Bull.  Geol.  Survey  Tasmania,  No.  6, 1909.  Earlier  separate 
papers  by  G.  A.  Waller  and  W.  H.  Twelvetrees  were  issued  by  the  same  office.  On  the  Mount  Bischoff 
mines,  see  W.  von  Fircks,  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  51,  1899,  p.  431. 

5 See  C.  W.  Kempton,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  25,  1896,  p.  997,  and  W.  R.  Ingalls,  idem,  p.  147. 
On  the  Sain  Alto  mines,  Zacatecas,  see  E.  Halse,  idem,  vol.  29, 1900,  p.  502,  and  J.  N.  Nevius,  Eng.  and  Min. 
Jour.,  vol.  75,  1903,  p.  920.  This  locality  is  also  rhyolitic.  On  the  tin  deposits  of  Guanajuato,  see  A.  H. 
Bromly,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  36,  1906,  p.  227. 

6 Jour.  Geology,  vol.  11,  1903,  p.  135.  On  the  ores  of  Banca  and  Billiton,  see  R.  Beck,  Zeitschr.  prakt. 
Geologie,  1898,  p.  121.  W.  R.  Rumbold  (Bull.  Am.  Inst.  Min.  Eng.,  September,  1906)  has  described 
the  tin  deposits  of  the  Kinta  Valley,  Malay  States.  He  mentions  deposits  in  limestone. 


686 


THE  DATA  OF  GEOCHEMISTRY. 


transformed  into  mica  and  of  which  topaz  and  tourmaline  are  fre- 
quent constituents.  The  mica  is  often,  but  not  invariably,  lithia 
hearing,  either  ordinary  lepidolite  or  zinnwaldite.  Bismuth  ores, 
wolfram,  and  arsenopyrite  are  common  associates  of  the  tinstone. 

These  mineralogical  data,  the  usual  presence  in  stanniferous  veins 
of  species  containing  fluorine  and  boron,  and  also  the  alteration  of  the 
granite  walls,  have  led  to  the  very  general  belief  that  tin  deposits  of 
the  ordinary  type  have  been  formed  by  the  injection  of  vapors  carry- 
ing the  two  elements  above  named  and  also  the  tin.  This  belief  is 
strengthened  by  the  various  syntheses  of  cassiterite,  in  which  boric 
oxide  and  chloride  or  fluoride  of  tin  have  taken  part.  The  signifi- 
cance of  the  very  rare  mineral  nordenskioldine,  with  its  tin  and  boron 
together,  here  becomes  apparent,  although  the  species  has  not  been 
found  in  any  vein  or  deposit  of  the  usual  stanniferous  type,  but  only 
in  a dike  of  elseolite  syenite.  Ordinarily  the  two  elements  are  sepa- 
rated, the  boron  going  to  the  tourmaline  molecules  and  the  tin  to 
form  cassiterite.  Fluorine  is  represented  by  topaz,  fluorite,  or  apa- 
tite, and  sometimes  by  the  lithia-bearing  phosphates  triphylite  and 
amblygonite.1  In  some  localities  formerly  worked  for  tin  the  lithia 
minerals,  especially  amblygonite  and  lepidolite,  are  now  the  species 
of  chief  commercial  value. 

American  deposits  of  tin,  more  or  less  resembling  those  of  Cornwall 
and  Saxony,  are  found  in  the  York  region,  Alaska;  in  Rockbridge 
County,  Virginia,  and  near  El  Paso,  Texas.  The  Alaskan  field  has 
been  well  studied  by  A.  J.  Collier  2 and  A.  Knopf,3  who  describe  both 
lodes  and  placers.  The  typical  cassiterite  is  disseminated  in  more  or 
less  altered  granitic  dikes,  essentially  greisen,  consisting  of  quartz, 
zinnwaldite,  calcite,  and  fluorspar.  In  one  case  the  ore  is  intimately 
associated  with  tourmaline,  and  other  borates  and  borosilicates, 
including  the  rare  minerals  hulsite  and  paigeite,  are  also  found.  It 
also  occurs  in  veins  which  cut  through  metamorphic  slates — a 
rather  unusual  development.  At  the  Cash  mine,  in  Virginia,  accord- 
ing to  L.  C.  Graton,4  the  ore  is  in  quartz  veins  in  granite,  the  walls 
of  the  veins  being  converted  into  greisen.  W.  H.  Weed  5 and  G.  B. 
Richardson  6 have  studied  the  tin  deposits  of  the  Franklin  Mountains 

1 For  discussions  on  the  genesis  of  cassiterite  veins,  see  A.  Daubree,  Etudes  synthetiques  de  geologic 
experimentale,  pp.  28-71;  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1895,  p.  145,  and  Trans.  Am.  Inst.  Min. 
Eng.,  vol.  31, 1901,  p.  125;  and  W.  Lindgren,  idem,  vol.  30, 1900,  p.  578.  See  also  F.  Gautier,  Actes  Soc.  sci. 
Chili,  vol.  5, 1895,  p.  92.  R.  Recknagel  (Trans.  Geol.  Soc.  South  Africa,  vol.  12, 1910,  p.  128)  attributes  the 
South  African  tin  deposits  to  magmatic  differentiation,  and  in  part  to  concentration  by  lateral  secretion. 

2 Bull.  U.  S.  Geol.  Survey  No.  229, 1904;  and  also  in  Bull.  No.  225, 1903,  p.  154;  Bull.  No.  259, 1905,  p.  120; 
and  Eng.  and  Min.  Jour.,  vol.  76, 1903,  p.  999. 

s Bull.  U.  S.  Geol.  Survey  No.  345,  1908,  p.  251;  No.  358,  1908,  and  Econ.  Geology,  vol.  4,  1909,  p.  214. 
See  also  A.  H.  Brooks,  Mineral  Resources  U.  S.  for  1900,  U.  S.  Geol.  Survey,  1901,  p.  267,  and  Bull.  No.  213, 
1902,  p.  92;  and  E.  Rickard,  Eng.  and  Min.  Jour.,  vol.  75, 1903,  p.  30. 

* Bull.  U.  S.  Geol.  Survey  No.  293, 19Q6,  p.  44.  See  also  T.  Ulke,  Mineral  Resources  U.  S.  for  1893,  U.  S. 

Geol.  Survey,  1894,  p.  178. 

6 Bull.  U.  S.  Geol.  Survey  No.  178, 1901,  and  also  in  Bull.  No.  213. 1902,  p.  170. 

6 Bull.  U.  S.  Geol.  Survey  No.  285, 1905,  p.  146, 


METALLIC  ORES. 


687 


near  El  Paso,  where  the  ore  is  found  in  quartz  under  conditions  which 
Weed  thinks  resemble  those  of  Cornwall.  The  Temescal  deposit,  in 
southern  California,  as  described  by  H.  W.  Fairbanks,1  may  also  be- 
long to  the  class.  The  vein  material  consists  almost  wholly  of  tour- 
maline and  quartz,  formed  by  gradual  replacement  of  the  granite  walls. 

Another  mode  in  which  cassiterite  occurs  is  as  an  original  con- 
stituent in  pegmatite.  It  is  thus  found,  although  scantily,  in  the 
famous  localities  in  Maine  for  lithia  tourmalines  and  lepidolite. 
The  workable  cassiterite  of  the  Carolina  tin  belt,  according  to  L.  C. 
Graton,2  is  also  in  pegmatite,  none  being  found  in  the  wall  rock. 
Here  again  lithia  minerals  are  found,  namely,  lithiophilite  and 
spodumene.  The  tin  ores  of  the  Black  Hills,  in  South  Dakota,  seem 
to  belong  under  this  heading,  and  the  Etta  mine  especially  is  noted 
for  its  enormous  crystals  of  spodumene  and  columbite.  In  this 
locality  crystalline  faces  of  spodumene  are  exposed  which  are  from 
30  to  40  feet  long;  and  in  the  Ingersoll  claim  a single  mass  of  colum- 
bite is  said  to  have  weighed  more  than  2,000  pounds.3  Cassiterite 
in  pegmatite,  accompanied  by  corundum,  is  reported  by  P.  F. 
Molengraaf 4 from  Swazieland,  South  Africa. 

The  tin  ores  of  Bolivia  represent  still  another  class  of  associations. 
Cassiterite  in  masses  resembling  hematite,  and  the  four  sulphosalts 
of  tin,  are  here  found  in  veins  carrying  ores  of  silver,  lead,  and 
bismuth  in  rocks  of  recent  volcanic  origin.  According  to  A.  W. 
Stelzner  5 the  rock  is  commonly  dacite  or  trachyte;  but  at  Potosi, 
as  described  by  A.  F.  Wendt,6  the  matrix  is  rhyolite.  The  vein 
matter  is  quartz,  with  carbonates  and  barite.  In  these  deposits  we 
evidently  have  a transition  between  the  ordinary  tin-bearing  vein 
and  the  type  of  vein  characterized  by  silver-lead  ores.  W.  R.  Rum- 
bold,7  who  has  studied  the  Bolivian  deposits,  regards  them  as  of 
pneumatolytic  origin. 

ARSENIC,  ANTIMONY,  AND  BISMUTH. 

Arsenic,  antimony,  and  bismuth  are  three  closely  related  elements. 
Arsenic,  from  a purely  chemical  point  of  view,  is  a nonmetal;  for, 
despite  its  metallic  appearance,  it  is  an  acid-forming  element,  and 
only  in  exceptional  cases  does  it  play  the  part  of  a base.  Antimony 

1 Am.  Jour.  Sci.,  4th  ser.,  vol.  4,  1897,  p.  39. 

2 Bull.  U.  S.  Geol.  Survey  No.  293,  1906,  and  also  in  Bull.  No.  260,  1904,  p.  188.  Other  papers  on  the 
Carolina  belt  are  by  J.  H.  Pratt,  Mineral  Resources  U.  S.  for  1903,  U.  S.  Geol.  Survey,  1904,  p.  337,  and 
Pratt  and  I).  B.  Sterrett,  Bull.  North  Carolina  Geol.  Survey  No.  19, 1904. 

2 See  W.  P.  Blake,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  13, 1885,  p.  691.  On  the  Black  Hills  mines,  see  also 
E.  W.  Claypole,  Am.  Geologist,  vol.  9, 1892,  p.  228,  and  J.  D.  Irving,  Prof.  Paper  U.  S.  Geol.  Survey  No.  26, 
1904,  p.  95. 

4 See  abstract  in  Zeitschr.  prakt.  Geologie,  1900,  p.  146. 

5 Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  49, 1897,  p.  51.  See  also  M.  Frochot,  Annales  des  mines,  9th  ser., 
vol.  19, 1901,  p.  186. 

6 Trans.  Am.  Inst.  Min.  Eng.,  vol.  19,  1890,  p.  90. 

7 Econ.  Geology,  vol.  4, 1909,  p.  321. 


688 


THE  DATA  OF  GEOCHEMISTRY. 


is  more  commonly  acid  than  basic,  but  in  bismuth  the  basic  character 
is  strongly  predominant,  except  in  its  sulphosalts. 

All  three  elements  &re  found  native,  and  also  in  many  closely 
related  compounds.  Among  the  latter  the  sulphosalts  of  silver, 
lead,  copper,  and  tin  have  already  been  mentioned,  and  few  others 
remain  to  be  named.  Berthierite  is  a sulphantimonite  of  iron, 
FeSb2S4,  and  lorandite  is  a sulpharsenite  of  thallium,  T1AsS2. 
There  are  also  a number  of  arsenides,  antimonides,  and  bismuthides 
of  silver,  copper,  nickel,  cobalt,  platinum,  etc.,  which  are  best  con- 
sidered under  the  several  metals  that  characterize  them.  For 
present  purposes  it  is  enough  to  mention  the  iron  arsenides,  loHingite, 
FeAs2,  and  leucopyrite,  Fe3As4,  and  also  the  sulpharsenide,  arseno- 
pyrite,  FeAsS.  Arsenopyrite  or  mispickel  is  the  most  important 
ore  of  arsenic. 

Native  arsenic,  native  antimony,  and  native  bismuth  are  all  rather 
common  minerals,  and  with  them  the  arsenide  of  antimony,  allemon- 
tite,  SbAs3,  may  be  grouped.  There  are  also  natural  sulphides, 
selenides,  and  tellurides,  as  follows : 


Realgar AsS. 

Orpiment As2S3. 

Stibnite Sb2S3. 

Metastibnite Sb2S3. 

Bismuthinite Bi2S3. 

Guanajuatite Bi2Se3. 

Tetradymite Bi2Te3. 

Joseite1 Bi2Te. 

Wehrlite1 Bi3Te2. 

Griinlingite Bi4TeS3. 

Kermesite Sb2S20 . 


Several  of  these  minerals  have  been  produced  artificially.  J. 
Durocher2  prepared  stibnite  and  bismuthinite  by  the  action  of 
hydrogen  sulphide  upon  the  volatilized  chlorides  of  antimony  and 
bismuth.  H.  de  Senarmont3  found  that  when  pulverized  realgar  or 
orpiment  was  heated  to  150°  with  a solution  of  sodium  bicarbonate 
in  a sealed  tube  they  dissolved  and  were  later  redeposited  as  crystal- 
lized realgar.  Amorphous  antimony  sulphide,  treated  in  the  same 
way  at  250°,  also  dissolved  and  crystallized  as  stibnite.  The  pre- 
cipitated sulphide  of  bismuth,  similarly  heated  to  200°  with  a solu- 
tion of  an  alkaline  sulphide,  gave  crystals  of  bismuthinite.  E.  Wein- 
schenk4  obtained  orpiment  and  stibnite  by  heating  solutions  of  arsenic 
or  antimony  with  ammonium  sulphocyanate  to  180°  in  a sealed 
tube.  According  to  A.  Carnot,5  stibnite  and  bismuthinite  are  easily 

1 Formula  approximate  only.  Sulphur  or  selenium  partly  replaces  tellurium. 

2 Compt.  Rend.,  vol.  32, 1851,  p.  825. 

2 Annales  chim.  phys.,  3d  ser.,  vol.  32, 1851,  p.  129. 

4 Zeitschr.  Kryst.  Min.,  vol.  17,  1890,  p.  497. 

5 See  L.  Bourgeois,  Reproduction  artificielle  des  mineraux,  pp.  41,42. 


METALLIC  ORES. 


689 


formed  by  passing  hydrogen  sulphide  at  a dull  red  heat  over  other 
compounds  of  antimony  or  bismuth.  Kealgar,  orpiment,  stibnite, 
and  bismuthinite  are  all  reported  by  Mayen^on1  as  found  among  the 
sublimation  products  of  a burning  coal  mine.2 

C.  Doelter3  states  that  stibnite  at  80°  is  slightly  soluble  in  water 
and  that  recrystallization  from  the  solution  is  also  perceptible.  The 
same  statement  holds  for  arsenopyrite,  FeAsS.  In  several  localities 
the  deposition  of  arsenical  or  antimonial  sulphides  from  hot  springs 
has  been  observed.  W.  H.  Weed  and  L.  V.  Pirsson4  report  both 
realgar  and  orpiment  from  a hot  spring  in  the  Yellowstone  National 
Park,  and  G.  F.  Becker5  found  sulphides  of  arsenic  and  antimony 
in  a sinter  at  Steamboat  Springs,  Nevada.  In  3,403  grams  of  this 
sinter,  as  analyzed  by  W.  H.  Melville,  were  found  the  following  sub- 


stances : 

Sulphides,  etc.,  found  in  sinter.  Grams. 

Au 0.0034 

A g 0012 

HgS 0070 

PbS 0720 

CuS 0424 

Sb2S3+As2S3 78.0308 

Fe203 3.5924 


The  antimony  sulphide  was  in  the  amorphous,  orange-colored  form, 
to  which  Becker  gave  the  name  of  metastibnite.  Crystals  of  ordinary 
stibnite  have  since  been  discovered  by  W.  Lindgren6  in  the  same 
sinter,  apparently  of  quite  recent  formation.  The  locality,  it  must 
be  observed,  is  one  which  yields  mercury,  and  G.  F.  Becker7  has 
reported  stibnite  from  several  quicksilver  mines  in  California.  A 
similar  association  of  stibnite  and  cinnabar  is  found  at  Monte  Amiata 
in  Tuscany;8  and  at  Huitzuco,  Mexico,  stibnite  occurs  with  living- 
stonite,  kermesite,  baroenite,  and  some  cinnabar  in  a matrix  of  gyp- 
sum.9 Cinnabar  has  also  been  noted  in  the  antimony  mines  of  Cor- 
sica.10 According  to  Coquand,11  the  antimonyores  at  Pereta,  Tuscany, 
are  of  solfataric  origin.  This  mode  of  deposition,  which  genetically 
connects  antimony  and  mercury,  may  be  ascribed  to  the  fact  that 


1 Compt.  Rend.,  vol.  86, 1878,  p.  491;  vol.  92, 1881,  p.  854. 

2 On  the  conditions  governing  the  formation  of  orpiment  and  realgar,  see  W.  Borodowsky,  Sitzungsb. 
Naturf.  Gesell.  Univ.  Dorpat,  vol.  14,  p.  159.  Also  in  Chem.  Abstracts,  vol.  1, 1907,  p.  1106. 

3 Min.  pet.  Mitt.,  vol.  11, 1890,  p.  322. 

* Am.  Jour.  Sci.,  3d  ser.,  vol.  42, 1891,  p.  401.  At  another  spring  in  the  Park,  Arnold  Hague  (idem,  vol. 
34,  1887,  p.  171)  found  a deposit  of  scorodite,  an  arsenate  of  iron. 

5 Mon.  U.  S.  Geol.  Survey,  vol.  13, 1888,  p.  344. 

e Trans.  Am.  Inst.  Min.  Eng.,  vol.  36, 1906,  p.  27. 

7 Op.  cit.,  p.  3890 

s B.  Lotti,  Zeitschr.  prakt.  Geologie,  1901,  p.  43. 

9 J.  G.  Aguilera,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  32,  1902,  p.  307. 

10  Nentien,  Annales  des  mines,  9th  ser.,  vol.  12,  1897,  p.  251. 

11  Bull.  Soc.  geol.  France,  2d  ser.,  vol.  6, 1848-49,  p.  91. 

97270°— Bull.  616—16 44 


690 


THE  DATA  OF  GEOCHEMISTRY. 


both  metals  form  easily  volatile  compounds.  The  same  property  is 
shared  by  arsenic,  but  deposits  of  other  than  solfataric  nature  are 
known.  At  least  there  are  deposits  in  which  no  indication  of  sol- 
fataric action  can  now  be  discerned.  The  sulphides  of  arsenic  and 
antimony  are  easily  soluble  in  alkaline  solutions,  and  in  that  way 
may  be  transported  to  points  far  distant  from  their  original  ore 
bodies.  The  sulphide  of  bismuth  is  much  less  soluble. 

Stibnite  is  the  most  important  ore  of  antimony.  Its  deposition 
from  solution  is  in  most  cases  evident,  and  its  alkaline  solutions, 
which  also  dissolve  silica,  seem  to  have  formed  the  typical  occur- 
rences, in  which  stibnite  is  intimately  associated  with  quartz.  It  is 
so  found  in  the  mines  of  Sevier  County,  Arkansas; 1 in  Mexico,  and  in 
Corsica,  where  the  ore  bodies  occur  in  sericitic  schists.  At  Kostainik, 
in  Serbia,  according  to  R.  Beck  and  W.  von  Fircks,2  the  stibnite  is 
found  in  trachyte,  in  graywacke,  and  also  as  replacements  in  lime- 
stone. Arsenopyrite  also  occurs  most  commonly  with  quartz,  oftenest 
in  metamorphic  schists  and  sometimes  in  serpentine.3  When  either 
arsenic,  antimony,  or  bismuth  is  found  in  a metalliferous  vein,  asso- 
ciated with  silver,  copper,  or  lead,  it  is  usually  combined  with  those 
metals  in  the  form  of  sulphosalts. 

By  oxidation  of  the  sulphides,  a large  number  of  secondary  min- 
erals can  be  formed.  First  of  all  are  the  oxides,  as  follows: 


Arsenolite  4 5 

Claud  etite  4 

Senarmontite 

Valentjnite 

Cervantite 

Bismite,  or  bismuth  ocher 
Stibiconite 


As203,  isometric. 
As203,  monoclimc. 
Sb203,  isometric. 
Sb203,  orthorhombic. 
. Sb204. 

Bi203.3H20. 

H2Sb205. 


Bismuth  also  forms  two  basic  carbonates,  bismutite  and  bismuto- 
sphserite,  and  a rare  oxychloride,  daubreeite.  The  oxides  of  antimony 
form  important  ore  bodies  at  Altar,  Sonora,  Mexico,6  and  in  Neoco- 
mian  limestone  at  Mount  Hamimat,  Province  of  Constantine,  Algeria.7 

From  oxidation  of  the  sulphosalts,  a large  number  of  arsenates, 
antimonates,  and  various  compounds  of  bismuth  have  been  derived. 


1 SeeC.  E.  Wait,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  8,  1879,  p.  42;  J.  C.  Branner,  Ann.  Rept.  Arkansas 
Geol.  Survey,  1888,  vol.  1,  p.  136;  and  G.  H.  Ashley,  Proc.  Am.  Philos.  Soc.,  vol.  36, 1897,  p.  306. 

2 Zeitschr.  prakt.  Geologie,  1900,  p.  33. 

3 On  the  arsenic  mines  of  Hastings  County,  Ontario,  see  J.  W.  Wells,  Rept.  Bur.  Mines  Ontario,  1902, 
p.  101.  J.  L.  Cowan  (Eng.  and  Min.  Jour.,  vol.  78, 1904,  p.  105)  has  described  an  arsenic  mine  at  Brinton, 
Virginia.  For  the  antimony  mines  of  Nova  Scotia,  see  W.  R.  Askwith,  Canadian  Min.  Rev.,  vol.  20, 1901, 
p.  173. 

4 The  true  molecular  weight,  as  shown  by  the  vapor  density,  is  more  probably  represented  by  the 
formula  AS4O6.  A similar  doubling  may  be  proper  for  the  other  oxides  and  sulphides  of  this  group. 

5 On  the  composition  of  bismuth  ocher,  see  W.  T.  Schaller,  Jour.  Am.  Chem.  Soc.,  vol.  33, 1911,  p.  162. 

6 E.  T.  Cox,  Am.  Jour.  Sci.,  3d  ser.,  vol.  20, 1880,  p.  421. 

7 Coquand,  Bull.  Soc.  g6ol.  France,  2d  ser.,  vol.  9,  1851-52,  p.  342. 


METALLIC  ORES. 


691 


Some  of  these  were  mentioned  in  the  preceding  sections  of  this  chap- 
ter; others  are  salts  of  calcium,  magnesium,  iron,  or  manganese.  For 
example,  pharmacolite  is  an  arsenate  of  lime,  pharmacosiderite  an 
arsenate  of  iron,  and  sarkinite  an  arsenate  of  manganese.  Atopite, 
schneebergite,  and  romeite  are  antimonates  of  lime.  Some  of  these 
compounds,  and  there  are  many  others,  may  have  been  formed  by  the 
action  of  percolating  arsenical  or  antimonial  solutions  upon  carbo- 
nates of  lime,  magnesia,  manganese,  or  iron,  or  upon  hydroxides  of  the 
two  metals  last  named.  There  are  also  arsenates  of  bismuth,  and  a 
tellurate,  a vanadate,  a molybdate,  and  a silicate  of  the  same  base. 
The  strange  mineral  longbanite  is  an  antimonio-silicate  of  manganese 
and  iron;  derbylite  and  lewisite  are  antimonio-titanates  of  iron  and 
lime,  respectively;  and  mauzeliite  is  a similar  salt  of  calcium  and  lead. 
Derbylite,  lewisite,  and  tripuhyite,  Fe2Sb207,  are  found  in  the  cinna- 
bar-bearing gravels  of  Tripuhy,  Brazil.1  They  were  derived  from 
mica  schists,  but  their  association  with  cinnabar  is  suggestive. 

NICKEL  AND  COBALT.2 

Among  the  minor  constituents  of  igneous  rocks,  nickel  is  one  of 
the  commonest.  Cobalt  also  is  widely  diffused,  but  in  much  smaller 
proportions.3  In  262  analyses  of  igneous  rocks  made  in  the  labora- 
tory of  the  United  States  Geological  Survey  an  average  of  0.0274 
per  cent  of  nickel  oxide  was  found.  Had  it  been  sought  for  in  all 
cases,  this  figure  might  have  been  slightly  reduced,  but  perhaps  not 
materially. 

Nickel  and  cobalt  are  characteristic  elements  in  meteoric  irons, 
and  also  in  terrestrial  irons  of  similar  character.  Indeed,  some  of 
the  “irons”  of  which  analyses  are  given  in  another  chapter  of  this 
book 4 are  more  truly  described  as  native  nickel,  that  being  the 
metal  which  predominates  in  them.  Awaruite  and  josephinite  are 
nickel  irons  of  this  kind,  in  which  the  percentage  of  nickel  reaches  * 
60  or  even  more, 

1 See  E.  Hussak  and  G.  T.  Prior,  Mineralog.  Mag.,  vol.  11, 1895,  pp.  80, 176, 302. 

2 For  a general  paper  upon  nickel  and  its  occurrences,  see  P.  Argali,  Proc.  Colorado  Sci.  Soc.,  vol.  4, 1893, 
p.  395.  A note  by  A.  G.  Charlton  follows  (p.  420)  on  Colorado  nickel  ores.  On  nickel  in  the  Mansfeld 
copper  shales,  see  Baeumler,  Zeitschr.  Deutsch.  geol.  Gesell. , vol.  9, 1857,  p.  25.  On  cobalt  ores  at  Schweina, 
Thuringia,  see  F.  Beyschlag,  Zeitschr.  prakt.  Geologie,  1898,  p.  1.  On  cobalt  in  Mexico,  G.  de  J.  Caballero, 
Mem.  Soc.  cient.  Ant.  Alzate,  vol.  18, 1902,  p.  197.  O.  Stutzer  (Zeitschr.  prakt.  Geologie,  1906,  p.  291)  has 
described  tourmaline-bearing  cobalt  veins  at  San  Juan,  Atacama,  Chile.  The  ore  is  cobaltite. 

3 On  the  wide  diffusion  of  cobalt  and  nickel  in  nature,  see  K.  Kraut,  Zeitschr.  angew.  Chemie,  1906,  p.  1793, 

4 See  ante,  p.  331. 


692 


THE  DATA  OF  GEOCHEMISTRY. 


The  ores  of  these  metals  fall  into  three  principal  classes,  namely, 
sulphides  or  arsenides,  oxides,  and  silicates.  In  the  first  case  the 
chief  minerals  are  as  follows: 


Millerite NiS. 

Beyrichite Ni3S4. 

Polydymite  1 Ni4S5. 

Niccolite NiAs. 

Chloanthite NiAs2. 

Kammelsbergite NiAs2. 


Gersdorffite NiAsS. 

Pentlandite  3 (Fe,Ni)S. 


Jaipurite 

CoS. 

Linnaeite 

Co3S4. 

Smaltite 

CoAs2. 

Safflorite 

Skutterudite  2 

Cobaltite 

CoAsS. 

Carrollite 

.Co2CuS4. 

Two  other  arsenides  of  nickel  have  recently  been  described ; 4 
maucherite  and  temiskamite.  A careful  study  of  the  two  by  Chase 
Palmer,  however,  has  shown  that  they  are  identical,  and  that  the 
true  formula  is  Ni4As3. 

With  these  minerals  we  may  include  the  nickel  telluride,  melonite, 
and  the  antimonide,  breithauptite,  NiSb.  Ullmannite  is  a sulphide 
of  antimony  and  nickel,5  NiSbS.  Corynite  and  wolfachite  are  mix- 
tures of  a salt  of  the  last  type  with  the  corresponding  salt  NiAsS. 
Glaucodot  is  sulpharsenide  of  cobalt  and  iron,  and  alloclasite  is  sim- 
ilar, but  with  bismuth  partly  replacing  arsenic.  Another  mineral  of 
the  formula  NiCoS2Sb2  has  been  named  willyamite. 

Arsenides  and  antimonides  of  nickel  are  known  as  accidental  fur- 
nace products.6  The  crystalline  sulphides  of  cobalt  and  nickel  have 
also  been  repeatedly  prepared  artificially.  H.  de  Senarmont7  heated 
solutions  of  potassium  sulphide  with  nickel  or  cobalt  chloride  to  tem- 
peratures between  160°  and  180°  in  a sealed  tube,  and  obtained  the 
compounds  NiS,  Ni3S4,  and  Co3S4,  corresponding  to  the  natural  min- 
erals. C.  Geitner  8 also  produced  crystals  of  Ni3S4  by  heating  metal- 
lic nickel  with  sulphurous  acid  or  a solution  of  nickel  sulphite  under 
pressure  to  200°.  E.  Weinschenk9  heated  solutions  of  cobalt  or 
nickel  salts  with  ammonium  sulphocyanate  to  180°  in  a sealed  tube 
and  so  produced  crystalline  NiS  or  CoS,  respectively.  T.  Hiortdahl 10 


1 The  Sudbury  polydymite  is  very  nearly  N^FeSs. 

2 There  is  also  a variety  containing  much  nickel  replacing  cobalt.  Bismutosmaltite,  Co(AsBi)3,  is  a 
related  mineral. 

3 Another  nickel-iron  sulphide  has  been  called  gunnarite.  Its  formula  is  near  FezNisSg.  Still  another, 
akin  to  pentlandite,  is  the  incompletely  described  heazlewoodite. 

4 On  maucherite,  see  F.  Grinding,  Centralbl.  Min.,  Geol.  u.  Pal.,  1913,  p.  225.  On  temiskamite,  T.  L. 

Walker,  Am.  Jour.  Sci.,  4th  ser.,  vol.  37,  1914,  p.  170.  Palmer’s  work  is  in  Econ.  Geology,  vol.  9,  1914, 
p. 664. 

6 A similar  sulphide,  with  bismuth  partly  replacing  antimony,  has  been  named  kallilite. 

6 See  L.  Bourgeois,  Reproduction  artificielle  des  mindraux,  p.  35,  for  old  instances.  Also  A.  Brand, 
Zeitschr.  Kryst.  Min.,  vol.  12,  1887,  p.  234,  on  breithauptite. 

i Annales  chim.  phys.,  3d  ser.,  vol.  32, 1851,  p.  129. 

3 Liebig’s  Annalen,  vol.  129, 1864,  p.  350. 

9 Zeitschr.  Kryst.  Min.,  vol.  17, 1890,  p.  497. 

10  Compt.  Rend.,  vol.  65, 1867,  p.  75.  Jaipurite  is  also  known  as  syepoorite. 


METALLIC  ORES.  693 

also  produced  jaipurite  by  fusing  cobalt  sulphate  with  barium  sul- 
phide and  common  salt. 

These  scanty  data  show  that  the  minerals  of  this  group  may  be 
produced  in  either  the  wet  or  the  dry  way,  and  their  natural  occur- 
rences point  to  the  same  conclusion.  Millerite,  for  instance,  forms 
beautiful  tufts  of  slender,  hairlike  needles  in  geodes  lined  with  crys- 
tals of  dolomite.  Specimens  of  this  kind  are  familiar  objects  to  col- 
lectors of  minerals.  Millerite  is  also  reported  by  Des  Cloizeaux  1 as 
found  in  the  coal  measures  of  Belgium,  and  he  mentions  linnseite  in 
coal  from  Glamorganshire,  Wales.  On  the  other  hand,  as  J.  H.  L. 
Vogt2  has  shown,  the  nickeliferous  pyrrho tites  are  often,  if  not 
always,  distinct  segregations  from  molten  magmas.  On  this  subject, 
however,  controversy  still  reigns,  and  especially  with  reference  to  the 
nickel  ores  of  Sudbury,  Canada.  Here  the  ores  are  chiefly  pyrrho- 
tite  with  admixtures  of  pentlandite,  a certain  amount  of  chalcopyrite 
being  also  present.  The  matrix  is  norite,  although  the  earlier 
observers  termed  it  diorite.  Their  magmatic  origin  has  been  advo- 
cated by  R.  Bell,3  H.  B.  von  Foullon,4  T.  L.  Walker,5  A.  P.  Coleman,6 
D.  H.  Browne,7  and  others.  A.  E.  Barlow,8  for  example,  repeatedly 
speaks  of  the  “nickel-bearing  eruptive.”  Browne  compares  the 
occurrences  at  Sudbury  with  the  phenomena  observed  in  cooling  a 
copper-nickel  matte,  in  which  the  copper  sulphides  concentrate  along 
the  margins  of  the  mass,  and  the  nickel  sulphides  at  the  center. 
This  arrangement  of  ores,  chalcopyrite  near  the  wall  rock,  then  pyr- 
rhotite  carrying  nickel,  and  finally  nickel  sulphide,  is  the  order 
observed  at  Sudbury. 

R.  Beck,9  C.  W.  Dickson,10  and  W.  Campbell  and  C.  W.  Knight,11 
on  the  other  hand,  have  argued  strongly  in  favor  of  a secondary 
origin  of  these  ores — a deposition  from  circulating  solutions.12  A 
similar  view  is  expressed  by  F.  W.  Voit 13  concerning  the  nickel  ores 


1 Bull.  Soc.  min.,  vol.  3,  1880,  p.  170. 

2 Zeitschr.  prakt.  Geologie,  1893,  pp.  125, 357. 

3 Bull.  Geol.  Soc.  America,  vol.  2, 1890,  p.  125.  Another  paper  by  Bell,  on  Sudbury,  appears  in  Ann. 
Rept.  Geol.  Survey  Canada,  2d  ser.,  vol.  5,  F,  1890-91. 

4 Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  42,  1892,  p.  223.  The  nickel  ores  of  Schweiderich,  Bohemia,  are 
described  as  analogous  to  those  of  Sudbury. 

e Quart.  Jour.  Geol.  Soc.,  vol.  53,  1897,  p.  40. 

e Bull.  Geol.  Soc.  America,  vol.  15, 1904,  p.  551.  In  Rept.  Ontario  Bur.  Mines,  1904,  pt.  1,  p.  192,  Coleman 
has  a long  paper  on  the  “Northern  Nickel  Range.”  The  report  of  the  same  bureau  for  1905,  pt.  3,  contains 
a monograph  by  Coleman  on  the  Sudbury  ores.  A later  paper  by  Coleman  is  in  Jour.  Geology,  vol.  51, 
1907,  p.  759. 

7 School  of  Mines  Quart.,  vol.  16, 1895,  p.  297;  and  Econ.  Geology,  vol.  1,  1906,  p.  487. 

8 Econ.  Geology,  vol.  1,  1906,  pp.  454,  545. 

8 The  nature  of  ore  deposits,  Weed’s  translation,  p.  41. 

w Trans.  Am.  Inst.  Min.  Eng.,  vol.  34,  p.  3, 1904.  See  also  Jour.  Canadian  Min.  Inst.,  vol.  9, 1906,  p.  236. 

11  Eng.  and  Min.  Jour.,  vol.  82,  1906,  p.  909.  These  authors  base  their  opinions  on  the  microscopic  struc- 
ture of  the  pyrrhotite. 

12  Other  memoirs  upon  Sudbury  and  its  ores  are  by  J.  EL  Collins,  Quart.  Jour.  Geol.  Soc.,  vol.  44, 1888, 
p.  834;  J.  Gamier,  M&n.  Soc.  ing6n.  civils  (France),  vol.  44,  p.  239;  E.  R.  Bush,  Eng.  and  Min.  Jour.,  vol. 
57,  1904,  p.  245;  T.  L.  Walker,  Am.  Jour.  Sci.,  3d  ser.,  vol.  47,  1894,  p.  312;  F.  W.  Clarke  and  C.  Catlett, 
Bull.  U.  S.  Geol.  Survey  No.  64,  1890,  p.  20;  S St.  Clair,  Min.  and  Sci.  Press,  vol.  109, 1914,  p.  248;  and  L.  P. 
Silver,  Canadian  Min.  Rev.,  vol.  21,  1902,  p.  207. 

13  Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  50,  1900,  p.  717. 


694 


THE  DATA  OF  GEOCHEMISTRY. 


of  Dobschau,  Hungary.  Here  the  arsenides  of  nickel  occur  in  a 
carbonate  gangue  at  or  near  contacts  of  diorite.  At  Mine  La  Motte, 
Missouri,  linnseite  is  found  with  lead  and  copper  ores  in  bodies  which 
C.  R.  Keyes  1 describes  as  metasomatic  replacements  in  limestone. 
Small  quantities  of  nickel  are  shown  in  analyses  of  the  adjacent 
granites. 

At  the  Gap  mine,  in  Lancaster  County,  Pennsylvania,  pyrrho tite 
and  chalcopyrite  occur  with  secondary  millerite  in  an  amphibolite, 
which  J.  F.  Kemp  2 thinks  is  an  altered  gabbro  or  norite.  This 
deposit  Kemp  regards  as  originally  magmatic.  In  the  serpentines 
of  Malaga,  Spain,  according  to  F.  Gillman,3  niccolite  is  found, 
altered  to  silicates  of  nickel  at  the  surface,  but  associated  with  chro- 
mite and  augite  in  the  norites  below.  Here  again  a magmatic  origin 
is  indicated.  The  nickeliferous  pyrrhotites  of  the  southern  Schwarz- 
wald  are  regarded  by  E.  Weinschenk 4 * as  not  magmatic. 

Near  Lake  Temiskaming,  Ontario,  an  extraordinary  group  of 
deposits  of  associated  cobalt,  nickel,  arsenic,  and  silver  ores  was 
discovered  in  19 03. 5 In  this  district  native  silver  and  native  bis- 
muth are  found,  together  with  niccolite,  chloanthite,  smaltite,  miHer- 
ite,  cobaltite,  argentite,  dysorasite,  pyrargyrite,  tetrahedrite,  arseno- 
pyrite,  etc.,  in  relations  which  are  interpreted  by  Miller  as  suggesting 
a deposition  from  heated  waters,  which  latter  were  “ probably 
associated  with  the  post-Middle  Huronian  diabase  and  gabbro 
eruption.’ ’ According  to  Miller,  the  deposits  are  analogous  to 
those  of  Annaberg,  Saxony,  and  Joachimsthal,  Bohemia,  which  are 
classical  localities  for  cobalt  and  nickel  minerals.  The  original 
source  of  the  Temiskaming  ores  has  not  yet  been  clearly  determined. 
They  may  represent  a leaching  of  the  accompanying  eruptive  rocks, 
or  they  may  have  been  brought  from  below;  at  all  events,  they  are 
not  igneous  segregations.6 

By  oxidation  or  carbonation  the  sulphides  and  arsenides  of  nickel 
and  cobalt  are  transformed  into  sulphates,  arsenates,  carbonates, 
oxides,  etc.  Morenosite,  NiS04.7H20;  bieberite,  CoS04.7H20;  the 
arsenates,  roselite,  erythrite,  annabergite,  forbesite,  and  cabrerite; 
the  carbonates  sphserocobaltite,  zaratite,  and  remingtonite ; the  oxide 
bunsenite;  and  the  hydroxides  asbolite,  heubachite,  heterogenite, 
transvaalite,  etc.,  are  among  these  products  of  alteration.  Bunsenite, 
NiO,  was  prepared  artificially  by  J.  J.  Ebelmen,7  through  the  action 

1 Missouri  Geol.  Survey,  vol.  9,  pt.  4, 1896,  p.  82. 

2 Trans.  Am.  Inst.  Min.  Eng.,  vol.  24,  1894,  p.  620. 

3 Trans.  Inst.  Min.  and  Met.  (London),  vol.  4, 1896,  p.  159. 

4 Zeitschr.  prakt.  Geologie,  1907,  p.  73. 

6 See  the  reports  by  W.  G.  Miller,  Kept.  Ontario  Bur.  Mines,  1904,  pt.  1,  p.  96;  1905,  pt.  2.  Also  in  Eng. 
and  Min.  Jour.,  vol.  76,  1903,  p.  888. 

6 These  ores  have  recently  been  studied  microscopically  by  W.  Campbell  and  C.  W.  Knight  (Econ. 
Geology,  vol.  1,  1906,  p.  767),  who  find  that  smaltite  was  first  formed,  then  niccolite,  then  calcite,  with 
argentite,  native  silver,  and  native  bismuth  later. 

7 Compt.  Rend.,  vol.  33, 1851,  p.  525. 


METALLIC  ORES. 


695 


of  lime  on  fused  nickel  borate.  Ferrieres  and  Dupont1  also  ob- 
tained it  by  heating  nickel  chloride  to  redness  in  a current  of  steam. 
Neither  process  seems  to  bear  any  close  relation  to  the  observed 
occurrences  of  bunsenite  in  nature.  Asbolite,  or  earthy  cobalt,  is 
an  indefinite  mixture  of  manganese  and  cobalt  hydroxides,  and  has 
some  significance  as  a workable  ore.2  This  association  of  cobalt  and 
manganese  is  not  uncommon,  and  many  manganese  ores  contain  more 
or  less  cobalt. 

The  hydrous  silicates  of  nickel  form  a distinct  class  of  ores,  differ- 
ing genetically  from  the  sulphides.  They  are  found  in  connection 
with  serpentine  or  other  hydromagnesian  rocks,  and  in  some  instances, 
if  not  always,  they  represent  concentrations  from  peridotitic  magmas, 
and  especially  from  nickeliferous  olivine.  At  Riddles,  Oregon,  for 
example,  the  parent  rock  is  a saxonite  or  harzburgite,  containing, 
as  shown  by  my  own  analysis,3  0.10  per  cent  of  NiO.  The  olivine 
separated  from  the  rock  contained  0.26  per  cent;  and  from  this  min- 
eral the  nickel  silicates  were  doubtless  formed.  Similar  silicate  ores 
are  found  in  North  Carolina;4  at  Revda  in  the  Urals;  at  Franken- 
stein, Prussian  Silesia,  in  serpentine;  and  at  Mount  Avala,  Servia, 
with  mercurial  minerals.  The  most  important  deposits,  however, 
are  in  New  Caledonia,5  where  asbolite  also  occurs.  Chromite  and  vari- 
ous hydromagnesian  minerals  are  generally  associated  with  the  nickel 
ores. 

These  silicates  are  rarely,  if  ever,  found  as  definite  mineral  species, 
although  they  have  been  described  as  such.  Genthite  appears  to  be 
H4Mg2Ni2(Si04)3.4H20,  and  connarite  is  near  H4Ni2Si3O10.  An- 
other silicate  from  New  Caledonia,  called  nepouite,6  has  been  given 
the  formula  (NiMg)3Si207.2H20.  Alipite,  desaulesite,  garnierite,  nou- 
meite,  pimelite,  refdanskite,  and  rottisite  are  uncertain  substances, 
mixtures  of  nickel  silicates  with  magnesian  compounds  and  free 
silica.  The  following  analyses  will  serve  to  illustrate  the  variable 
composition  of  these  ores: 

1 See  L.  Bourgeois,  Reproduction  artiflcielle  des  mindraux,  p.  51. 

2 As  at  Mine  Lamotte,  Missouri,  and  in  New  Caledonia.  On  the  New  Caledonia  cobalt  ores,  see  G.  M. 
Colvocoresses,  Eng.  and  Min.  Jour.,  vol.  76,  1903,  p.  816,  and  A.  Liversidge,  Minerals  of  New  South  Wales, 
pp.  275  et  seq. 

3 F.  W.  Clarke  and  J.  S.  Diller,  Bull.  U.  S.  Geol.  Survey  No.  60, 1890,  p.  21.  See  also,  with  regard  to 
this  locality,  A.  R.  Ledoux,  Canadian  Min.  Rev.,  vol.  2^,  1901,  p.  84;  W.  L.  Austin,  Proc.  Colorado  Sci. 
Soc.,  vol.  5,  1898,  p.  173;  and  H.  B.  von  Foullon,  Jahrb.  K.-k.  geoi.  Reichsanstalt,  vol.  42, 1892,  p.  223. 
Von  Foullon  also  describes  the  deposits  at  Revda,  Frankenstein,  and  Mount  Avala.  A later  report  on 
the  Riddles  ores,  by  G.  F.  Kay,  appears  in  Bull.  U.  S.  Geol.  Survey  No.  315, 1907,  p.  120. 

4 See  H.  J.  Biddle,  Mineral  Resources  U.  S.  for  1886,  U.  S.  Geol.  Survey,  1887,  p.  170.  The  mother  rock 
here  is  dunite.  See  also  A.  E . Barlow,  Jour.  Canadian  Min.  Inst. , vol.  9, 1906,  p.  303.  Barlow  regards  these 

ores  as  formed  by  the  leaching  of  the  peridotite. 

6 See  A.  Liversidge,  Minerals  of  New  South  Wales,  p.  275;  J.  Gamier,  Compt.  Rend.,  vol.  86,  1878,  p. 
684;  D.  Levat,  M6m.  Assoc,  frang.  av.  sci.,  1887,  p.  534;  and  F.  D.  Power,  Trans.  Inst.  Min.  Met.,  vol.  8, 
1900,  p.  427.  Liversidge  gives  several  analyses  of  garnierite  and  noumeite.  See  also  J.  S.  Leckie,  Jour. 
Canadian  Min.  Inst.,  vol.  6, 1903,  p.  169. 

6 E.  Glasser,  Compt.  Rend.,  vol.  143, 1906,  p.  1173.  Also  Annales  des  mines,  10th  ser.,  vol.  4, 1904, p.  448. 


696 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  nickel  silicates. 

A.  From  Riddles,  Oregon.  Analysis  by  F.  W.  Clarke,  Bull.  U.  S.  Geol.  Survey  No.  60, 1890,  p.  21. 

B.  From  Riddles.  Analysis  by  Hood,  Mineral  Resources  U.  S.  for  1882  ,U.  S.  Geol.  Survey,  1883,  p.  404. 
Probably  this  sample  was  dried  at  or  near  100°  before  analyzing. 

C.  D,  E.  From  New  Caledonia.  Analyses  by  A.  Liversidge,  Minerals  of  New  South  Wales,  pp.  275-280. 
Liversidge  gives  19  analyses  in  all,  including  several  by  Leibius. 


A 

B 

c 

D 

E 

Si02 

44.  73 
} 1.18 

27.  57 
10.  56 
8.  87 
6.  99 

40.  55 
} 1.33 

29.  66 
21.  70 

} 7.00 

48.  25 
} .55 

J 14.60 
16.  40 
10.  95 
8.  82 

38.  35 
.40 
.15 
32.  52 
10.  61 
6.  44 
11.  53 

50. 15 
.57 
Trace. 
10.  20 
17.  43 
11.  28 
10.  37 

A120, 

Fe203 

NiO 

MgO 

H20  at  100° 

H20  redness 

99.  90 

100.  24 

99.  57 

100.  00 

100.  00 

In  one  respect  all  the  ores  of  nickel  seem  to  agree.  Their  magmatic 
associate  is  always  a subsilicic  rock,  such  as  norite,  peridotite,  or 
sometimes  diabase  or  diorite.  In  no  case  are  they  clearly  shown  to 
have  originated  from  persilicic  magmas. 

CHROMIUM. 

Like  nickel,  chromium  is  widely  diffused  in  the  subsilicic  rocks, 
the  average  proportion  found  in  256  analyses  of  igneous  rocks  in  the 
laboratory  of  the  United  States  Geological  Survey  being  0.05  per 
cent  of  Cr203.  The  native  metal  has  not  been  found,  nor  are  any  ter- 
restrial sulphides  of  chromium  known,  although  the  mineral  daubree- 
lite,  FeCr2S4  occurs  in  some  meteoric  irons.  The  one  important  ore 
of  chromium  is  chromite,  or  chromic  iron.  There  are  also  the  lead 
chromates,  mentioned  in  a previous  section  of  this  chapter;  the  two 
sulphates  knoxvillite  and  redingtonite;  and  the  silicates  represented 
by  chromiferous  garnet,  diopside,  mica,  and  tourmaline.  The  clay- 
like silicates  avalite,  milosin,  and  alexandrolite  also  contain  chromium 
as  an  essential  constituent.1  Dietzeite,  from  the  Chilean  niter  beds, 
is  an  iodate  and  chromate  of  calcium.  Of  all  these  species  chromite 
alone  needs  any  further  consideration. 

In  the  chapter  upon  rock-forming  minerals  chromite  was  described 
as  a member  of  the  spinel  group.  Its  ideal  formula  is  FeCr204,  but  it 
rarely,  if  ever,  is  found  in  a state  of  even  approximate  purity.  It 
commonly  contains  isomorphous  admixtures  of  other  spinels,  whose 
presence  is  revealed  in  the  analyses.  The  following  examples  will 
serve  to  illustrate  its  variations : 2 

1 See  S.  M.  Losanitsch,  Ber.  Deutsch.  chem.  Gesell.,  vol.  28, 1895,  p.  2631. 

2 See  also  table  in  Chapter  X,  on  rock-forming  minerals,  p.  344.  Two  of  the  analyses  there  given  are  re- 
peated here. 


METALLIC  ORES. 


697 


Analyses  of  chromite. 

A.  From  Price  Creek,  North  Carolina.  Analysis  by  C.  Baskerville. 

B.  From  Corundum  Hill,  North  Carolina.  Baskerville. 

C.  From  Corundum  Hill.  Analysis  by  T.  M.  Chatard,  in  the  laboratory  of  the  United  States  Geological 
Survey. 

D.  From  Webster,  North  Carolina.  Analysis  by  H.  W.  Foote.  Variety  named  mitchellite.  For  A,  B, 
and  D,  see  J.  H.  Pratt  and  J.  V.  Lewis,  North  Carolina  Geol.  Survey,  vol.  1,  p.  369,  1905.  Magnochromite 
is  another  name  for  a magnesian  chromite. 

E.  From  Tampadel,  lower  Silesia.  Analysis  by  Laszczynski.  Described  by  H.  Traube,  Zeitschr. 
Deutsch.  geol.  Gesell.,  vol.  46,  p.  50, 1894. 


A 

B 

c 

D 

E 

Cr203 

59.  20 

57.  20 

45.  94 

39.  95 

41.  23 

ALO,  . 

7. 15 

7.  82 

2.  51 

29.  28 

24.  58 

FeO 

25.  02 

25.  68 

42.  90 

13.  90 

19.04 

MnO  

.92 

.69 

.84 

.58 

CoO,NiO 

. 16 

CuO  

.40 

MgO 

4.  42 

5.  22 

2.  81 

17.  31 

14.  77 

CaO  

1.  40 

Si02  

3.  20 

2.  80 

3.  20 

TiOo  

.36 

p„o! 

.12 

A 2W5*  • • • 

99.  91 

99.  41 

100.  64 

100. 44 

100.  20 

Chromite  was  first  produced  artificially  by  J.  J.  Ebelmen,1  who 
fused  chromic  oxide,  ferric  oxide,  and  boric  oxide  together,  with  a 
little  tartaric  acid  added  to  reduce  the  iron  to  the  ferrous  state.  By 
adding  small  amounts  of  alumina  and  magnesia  the  composition 
of  the  product  was  made  to  vary,  like  that  of  the  natural  mineral. 
J.  Clouet2  also  prepared  chromite  by  essentially  the  same  process, 
only  with  trifling  differences  in  detail.  S.  Meunier 3 obtained 
chromite  by  oxidizing  an  alloy  of  iron  and  chromium,  and  suggested 
that  such  an  alloy  might  be  brought  up  from  great  depths  and 
oxidized  by  vapors  near  the  surface  of  the  earth.  There  is  no  direct 
evidence,  however,  to  show  that  such  an  alloy  exists  in  nature,  and 
the  common  presence  of  chromite  in  meteorites  indicates  a different 
origin  for  the  mineral. 

Chromite  is  almost  exclusively  found  in  subsilicic  rocks,  such  as 
peridotites  and  the  serpentines  derived  from  them.  Its  occurrence 
in  placers  as  a detrital  mineral  is  of  course  not  excluded  by  this 
statement.  It  is  distinctly  a magmatic  mineral,  as  Vogt  and  others 
have  shown.4 


1 Annales  chim.  phys.,  3d  ser.,  vol.  22, 1848,  p.  228. 

2 Idem,  4th  ser.,  vcl.  16, 1869,  p.  90. 

s Compt.  Rend.,  vol.  110, 1890,  p.  424. 

* See  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1894,  with  special  reference  to  Norwegian  deposits.  On 
chromite  at  Kraubath,  Styria,  see  F.  Ryba,  idem,  1900,  p.  337;  and  in  Asia  Minor,  K.  E.  Weiss,  idem,  1901, 
p.  250.  R.  Helmhacker  (Min.  Industry,  1895,  p.  94)  describes  Austrian  localities.  On  chromite  in  Mary- 
land, see  W.  Glenn,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  25, 1896,  p.  481;  and  on  Canadian  ores,  the  same  author, 
in  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3, 1896,  p.  261.  M.  Penhale  (Min.  Industry,  1895,  p.  92) 
also  describes  Canadian  chromite.  The  chromite  of  North  Carolina  is  discussed  by  J.  H.  Pratt  in  Am. 
Jour.  Sci.,  4th  ser.,  vol.  7,  p.  281 ; and  Trans.  Am.  Inst.  Min.  Eng.,  vol.  29,  1899,  p.  17.  See  also  J.  H.  Pratt 
and  J.  V.  Lewis,  North  Carolina  Geol.  Survey,  vol.  1,  1905,  p.  369. 


698 


THE  DATA  OF  GEOCHEMISTRY. 


MOLYBDENUM  AND  TUNGSTEN. 

Although,  molybdenum  and  tungsten  are  members  of  the  same 
elementary  group  with  chromium,  their  geologic  affinities  are  not 
the  same.  Chromium,  as  we  have  seen,  is  found  characteristically  in 
subsilicic  rocks,  while  molybdenum  and  tungsten  are  commonly  asso- 
ciated with  granite.  Neither  metal  is  found  free  in  nature,  nor  is 
either  one  widely  diffused. 

The  principal  ore  of  molybdenum  is  the  sulphide,  molybdenite, 
MoS2.  The  molybdate  of  lead,  wulfenite,  has  already  been  described. 
Calcium  molybdate,  powellite,  is  a rare  mineral,  and  natural  molyb- 
dates of  cobalt  and  magnesium  are  imperfectly  known.  Molybdic 
ocher  is  a common  oxidation  product  of  molybdenite.  It  is,  as  shown 
by  W.  T.  Schaller,1  a hydrous  ferric  molybdate,  Fe2(Mo04)3.7§H20. 

Artificial  molybdenite  has  been  prepared  by  A.  de  Schulten.2 
Potassium  carbonate  was  fused  with  sulphur,  and  molybdic  oxide  was 
gradually  added,  in  successive  portions,  to  the  melt.  Crystals  of 
molybdenite  were  thus  formed.  Powellite,  also,  has  been  made  by 
L.  Michel,3  who  heated  sodium  molybdate,  calcium  chloride,  and 
sodium  chloride  together.  A little  sodium  tungstate  was  added  to 
the  mixture,  in  order  to  reproduce  more  exactly  the  natural  mineral, 
in  which  some  tungsten  is  found. 

As  a rule,  molybdenite  is  a fairly  pure  compound,  although 
Michel 4 has  described  a variety  containing  28.37  per  cent  of  bismuth. 
It  was  evidently  a mixture  of  molybdenite  with  bismuthinite.  Bis- 
muth is  a not  infrequent  associate  both  of  molybdenite  and  of 
wolfram. 

At  Crown  Point,  Washington,  according  to  A.  R.  Crook,5  large 
quantities  of  molybdenite  are  found  in  a quartz  vein  in  granite.  At 
Cooper,  Maine,  as  described  by  G.  O.  Smith,6  the  molybdenite  is 
found  in  pegmatite  dikes  and  also  in  the  adjacent  granite.  It  may 
be  either  an  original  mineral  or  an  impregnation;  probably,  says 
Smith,  the  latter.  In  Canada  molybdenite  occurs  under  a variety 
of  conditions,  often  in  granite,  but  also,  according  to  J.  W.  Wells,7 
in  veins  cutting  limestone,  and  associated  with  pyroxene,  calcite, 
quartz,  mica,  pyrite,  etc.  The  mineral  was  found  embedded  some- 
times in  pyroxene  and  sometimes  in  pyrrho tite,  and  Wells  further- 
more reports  it  in  veins  through  pyroxenite.  The  nature  and  origin 
of  these  unusual  associations  remain , to  be  determined.  They 
probably  represent  contact  metamorphism. 

1 Am.  Jour.  Sci.,4th  ser.,  vol.  23,  1907,  p.  297.  Work  done  in  the  laboratory  of  the  United  States  Geo- 
logical Survey. 

2 Geol.  Foren.  Forhandl.,  vol.  11, 1889,  p.  401. 

3 Bull.  Soc.  min.,  vol.  17, 1894,  p.  612. 

4 Idem,  vol.  22,  1899,  p.  29. 

6 Bull.  Geol.  Soc.  America,  vol.  15,  1904,  p.  283. 

6 Bull.  U.  S.  Geol.  Survey  No.  260, 1905,  p.  197. 

7 Canadian  Min.  Rev.,  vol.  22, 1903,  p.  113. 


METALLIC  ORES. 


699 


The  ores  of  tungsten  are  by  no  means  numerous.  In  addition  to 
stolzite,  which  was  mentioned  among  the  ores  of  lead,  there  are  the 
tungstate  of  iron,  wolframite,  or  ferberite  when  the  compound  is 
entirely  free  from  manganese;  the  tungstate  of  manganese,  hubner- 
ite;  calcium  tungstate,  scheelite;  the  copper  salt,  cuprotungstite ; and 
an  alteration  product,  tungstic  ocher.  Of  these,  wolframite,  hub- 
nerite,  and  scheelite  are  economically  important,  and  all  three  have 
been  prepared  artificially. 

N.  S.  Manross  1 obtained  scheelite  by  fusing  sodium  tungstate  with 
calcium  chloride.  A.  Cossa  2 also  prepared  it  by  fusing  the  amor- 
phous compound,  CaW04,  with  common  salt.  H.  Debray  3 heated 
amorphous  calcium  tungstate  with  lime  in  a current  of  gaseous  hydro- 
chloric acid,  and  so  effected  its  crystallization.  He  also  heated  a mix- 
ture of  tungstic  oxide  and  ferric  oxide  in  the  same  gas,  forming  in 
that  way  both  wolframite  and  magnetite.  Some  of  the  tungstic  acid 
crystallized  at  the  same  time.  A.  Geuther  and  E.  Forsberg4  pro- 
duced wolframite  and  its  manganesian  varieties  by  fusing  sodium 
tungstate  with  ferrous  chloride,  or  with  the  mixed  chlorides  of  iron 
and  manganese.  L.  Michel,5  by  fusing  sodium  tungstate  and  sodium 
chloride  with  the  chlorides  of  calcium,  manganese,  iron,  or  lead, 
obtained  scheelite,  hlibnerite,  wolframite,  and  stolzite,  respectively. 

Wolframite  is  a frequent  companion  of  tin  ores,  especially  in 
greisen,  the  cassiterite  and  the  tungsten  minerals  having  developed 
in  much  the  same  way.  In  the  Cornish  tin  mines  wolframite  is  an 
annoying  impurity,  and  it  also  occurs,  according  to  J.  D.  Irving,6  in 
the  Etta  tin  district  of  the  Black  Hills.  Near  Lead  City,  in  the  same 
region,  however,  Irving  found  wolframite  in  magnesian  limestone, 
where  it  had  apparently  been  formed  by  metasomatic  replacement. 
This  occurrence  was  secondary,  the  primary  wolframite  being  found 
in  quartz  veins  cutting  granite  rocks.  At  Osceola,  Nevada,  hubnerite 
is  abundant,  with  some  scheelite,  in  veins  of  white  quartz  in  a porphy- 
ritic  granite.7  The  Tungsten  deposits  of  the  Dragoon  Mountains, 
Arizona,  are  of  the  same  character,8  the  ore  being  principally  hiib- 
nerite,  with  scheelite  and  some  wolfram.  The  tungsten  mine  at  Trum- 
bull, Connecticut,  where  wolframite,  scheelite,  and  tungstic  ocher  are 
found,  has  been  described  by  A.  Gurlt 9 and  W.  H.  Hobbs.10  In  the 


1 Liebig’s  Annalen,  vol.  81,  1852,  p.  243. 

2 Cited  by  L.  Bourgeois,  Reproduction  artiflcielle  des  mineraux,  p.  172. 

3 Compt.  Rend.,  vol.  55,  1862,  p.  287. 

* Liebig’s  Annalen,  vol.  120, 1861,  p.  270. 

6  Bull.  Soc.  min.,  vol.  2, 1879,  p.  142. 

6 Trans.  Am.  Inst.  Min.  Eng.,  vol.  31, 1901,  p.  683.  See  also  J.  D.  Irving  and  S.  F.  Emmons,  Prof.  Paper 
U.  S.  Geol.  Survey  No.  26,  1904,  p.  163. 

7 See  F.  B.  Weeks,  Twenty-first  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  6,  1901,  p.  319;  and  F.  D.  Smith, 
Eng.  and  Min.  Jour.,  vol.  73,  1902,  p.  304. 

8 See  W.  P.  Blake,  Trans.  Am.  List.  Min.  Eng.,  vol.  28, 1898,  p.  543,  and  F.  Rickard,  Eng.  and  Min.  Jour., 
vol.  78,  1904,  p.  263. 

9 Trans.  Am.  Inst.  Min.  Eng.,  vol.  22, 1893,  p.  236. 

10  Twenty-second  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2,  1902,  p.  13. 


700 


THE  DATA  OF  GEOCHEMISTRY. 


Sierra  de  Cordoba,  Argentina,  according  to  G.  Bodenbender,1  the 
wolframite  is  again  in  quartz  veins  in  granite,  and  molybdenite  is 
sometimes  present  also.  These  illustrations  of  tungsten  occurrences 
are  ample  for  present  purposes. 

THE  PLATINUM  METALS. 

The  metals  platinum,  iridium,  osmium,  palladium,  rhodium,  and 
ruthenium  form  a well-defined  natural  group  of  elements,  which  are 
found  associated  with  one  another,  and  in  less  degree  with  iron, 
nickel,  chromium,  etc.  With  two  exceptions  the  platinum  metals 
occur  native,  or  in  alloys,  which  vary  much  in  composition,  and  have 
received  many  specific  names.  The  two  exceptions  are  laurite, 
ruthenium  sulphide,  RuS2;  and  sperrylite,  platinum  arsenide,  PtAs2. 
The  native  metals  and  recognized  alloys  are  as  follows: 

Native  platinum. 

Native  iridium  and  platiniridium. 

Native  palladium,  isometric. 

Allopalladium,  rhombohedral. 

T . . . fNevyanskite,  over  40  per  cent  Ir. 

IndosmmeL.  J . ..  ’ AT  , 

[Siserskite,  30  per  cent  Ir,  or  less. 

Palladium  gold.2 

Rhodium  gold.2 

The  list  might  be  extended  by  subdivision,  but  the  increase  in 
names  would  be  meaningless.  The  following  selected  analyses  fairly 
represent  the  great  variations  in  native  platinum:3 


1 Zeitschr.  prakt.  Geologie,  1894,  p.  409.  On  the  tungsten  ores  of  Colorado,  see  W.  Lindgren,  Econ. 
Geology,  vol.  2, 1907,  p.  453,  and  R.  D.  George,  First  Kept.  Colorado  Geol.  Survey,  1908,  p.  7.  On  tungsten 
deposits  in  the  Cceur  d’Alene  region,  Idaho,  see  H.  S.  Auerbach,  Eng.  and  Min.  Jour.,  vol.  86,  1908,  p.  1146. 

2 See  section  on  gold,  ante,  p.  644. 

s See  J.  F.  Kemp,  Bull.  U.  S.  Geol.  Survey  No.  193, 1902,  for  a full  collection  of  analyses,  both  of  platinum 
and  iridosmine.  Other  analyses  by  W.  J.  Martin,  jr.,  appear  in  Sixteenth  Arm.  Rept.  U.  S.  Geol.  Survey, 
pt.  3,  1895,  p.  633.  See  also  Dana’s  System  of  mineralogy,  6th  ed.,  pp.  26,  27.  Recent  analyses  of  Uralian 
platinum  by  L.  Duparc  and  H.  C.  Holtz  are  in  Min.  pet.  Mitt.,  vol.  29, 1910,  p.  498.  G.  P.  Merrill  (Proc. 
Nat.  Acad.,  vol.  1, 1915,  p.  429)  reports  the  presence  of  Pt,  Pd,  Ir,  and  Ru  in  meteorites. 


METALLIC  ORES. 


701 


Analyses  of  native  platinum. 

A.  From  Choco,  Colombia.  Analysis  by  H.  Sainte-Claire  Deville  and  H.  Debray,  Annales  chim.  phys., 
3d  ser.,  vol.  56,  1859,  p.  449. 

B.  From  California.  Deville  and  Debray. 

C.  Nugget  found  near  Plattsburg,  New  York,  of  54  per  cent  chromite  and  46  per  cent  metallic  platinum. 
Analysis  of  the  platinum  by  P.  Collier,  Am.  Jour  Sci.,  3d  ser.,  vol.  21, 1881,  p.  123. 

D.  From  Nizhni  Tagilsk,  Urals,  Deville  and  Debray. 

E.  From  Nizhni  Tagilsk,  blackish  magnetic  grains.  Analysis  by  J.  von  Muchin  (commonly  but  erro- 
neously quoted  as  Minchin),  cited,  with  other  analyses,  by  N.  von  Kokscharof,  Materialien  zur  Mineralogie 
Russlands,  vol.  5, 1866,  p.  186. 

F.  Granite  Creek,  British  Columbia.  Nonmagnetic  portion  of  sample.  Analysis  by  G.  C.  Hoffmann, 
Trans.  Roy.  Soc.  Canada,  vol.  5,  sec.  3,  p.  17. 

G.  Magnetic  portion  of  F.  Analysis  by  Hoffmann. 

H.  From  Condado,  Minas  Geraes,  Brazil.  Analysis  by  E.  Hussak,  Zeitschr.  prakt.  Geologie,  1906,  p. 
284.  For  a paper  by  Hussak  on  platinum  and  palladium  in  Brazil,  see  Sitzungsb.  Akad.  Wien,  vol.  113, 
Abth.  1,  1904,  p.  379. 


A 

B 

c 

D 

E 

F 

G 

H 

Pt 

86.  20 
.85 

85.  50 
1.  05 

82.  81 
.63 

76.  40 
4.  30 

68.  95 
1.  34 
Trace. 
.21 
3.  30 

68. 19 
1.  21 

78.  43 
1.04 

72.  96 
.88 
Undet. 
21.  82 
Undet. 

Ir 

Os 

Pd 

.50 
1.40 
1.00 
.60 
7.  80 
.95 

.60 
1.  00 
.80 
1.  40 
6.  75 
1. 10 

3. 10 
.29 

1.40 
.30 
.40 
4. 10 
11.  70 
.50 

.26 
3. 10 

.09 
1.  70 

Rh 

Au 

Cu 

.40 

11.04 

1.59 
18.  93 
3.  75 

3.  09 
7.  87 
14.  62 

3.  89 
9.  78 
3.  77 

Fe 

Trace. 

Iridosmine 

AIoOq 

1.  95 
.07 
.03 

CaO 

MgO 

Insoluble 

.42 

Sand 

.95 

2.  95 

1.  40 

Chromite 

1.  95 

1.  27 

100.  25 

101. 15 

100.  32 

100.  50 

98.  07 

100.  29 

99.  97 

96.  08 

In  another  sample  of  Uralian  platinum,  A.  Terreil 1 found  0.75 
per  cent  of  nickel.  A remarkable  nugget  from  the  river  Approuague, 
French  Guiana,  gave  A.  Damour2  41.96  Pt,  18.18  Au,  18.39  Ag,  and 
20.56  per  cent  Cu.  This  sample  is  altogether  exceptional. 

The  subjoined  analyses  are  of  native  iridium,  platiniridium,  and 
iridosmine. 


1 Compt.  Rend.,  vol.  82,  1876,  p.  1116. 


2 Idem,  vol.  52,  1861,  p.  688. 


702 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  native  iridium,  etc. 

A.  Native  iridium.  Nizhni  Tagilsk,  Urals. 

B.  Platiniridium,  probably  from  Brazil.  Analyses  A and  B by  Svanberg,  Berzelius’s  Jahresb.,  vol- 
16, 1834,  p.  205. 

C.  Iridosmine  from  Colombia. 

D.  Iridosmine  from  the  Urals. 

E.  iridosmine  from  the  Urals.  Analyses  C,  D,  and  E by  Deville  and  Debray,  Annales  chim.  phys.,  3d 
ser.,  vol.  56,  1859,  pp.  481,  482. 


A 

B 

C 

D 

E 

Ir 

76.  80 
19.  64 

27.  79 
55.44 
Trace. 
.49 
6.  86 

70.  40 
.10 
17.  20 

77.  20 
1. 10 
21.  00 

43.  94 
.14 
48.  85 

Pt 

Os 

Pd 

.89 

Rh 

12.  30 
None. 

.50 

.20 

Trace. 

1.  65 
4.  68 
.11 
.63 

Ru 

Cu 

1.  78 

3.30 
4. 14 

Fe 

99. 11 

98.  02 

100.  00 

100.  00 

100.  00 

The  indefinite  character  of  these  natural  alloys  seems  to  be  per- 
fectly evident. 

The  platinum  and  iridosmine  of  commerce  are  almost  entirely  from 
detrital  or  placer  deposits,  but  their  primary  geologic  affinities  are 
subsilicic.  That  is,  the  ores  are  associated  with  chromite  and  other 
products  of  the  decomposition  of  peridotic  rocks,  from  which  they 
were  undoubtedly  derived.  Chromite  has  been  repeatedly  observed 
adherent  to  or  interpenetrating  platinum  nuggets,  and  A.  Inostran- 
zeff  1 has  reported  platinum  in  place  in  the  dunite,  or  rather  serpen- 
tine, of  Mount  Solovief  in  the  Urals.  On  the  Tulameen  River, 
British  Columbia,  according  to  J.  F.  Kemp,2  the  mother  rock  is  also 
dunite,  and  grains  of  platinum  are  found  with  both  chromite  and 
olivine  adhering  to  them.  Even  the  serpentine  of  this  region  yields 
traces  of  platinum  upon  careful  assay.  The  black  sands  of  the 
Pacific  coast,  from  British  Columbia  southward  to  California,  contain 
platinum,  and  also  iridosmine,  and  their  origin  is  peridotic.3  Accord- 
ing to  H.  Bancroft,4  platinum  is  found  in  certain  peridotite  dikes  in 
Clark  County,  Nevada.  On  the  other  hand,  L.  Duparc,5 6  who  has 
devoted  much  study  to  Uralian  platinum,  reports  its  association 
with  pyroxenite  and  gabbro. 

1 See  English  translation  from  the  Russian  in  Bull.  U.  S.  Geol.  Survey  No.  193, 1902,  p.  76. 

2 Bull.  U.  S.  Geol.  Survey  No.  193,  1902.  A brief  monograph  on  the  geologic  relations  and  distribution  of 
platinum. 

a See  D.  T.  Day,  Nineteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  6,  1899,  p.  265.  Also  Day  and  R.  H. 

Richards,  Bull.  U.  S.  Geol.  Survey  No.  285,  1906,  p.  150.  In  Trans.  Am.  Inst.  Min.  Eng.,  vol.  30,  1900,  p. 
702,  Day  has  a memoir  on  platinum  in  North  America. 

* Bull.  U.  S.  Geol.  Survey  No.  430,  1910,  p.  192. 

6 Arch.  Sci.  phys.  nat.,  4th  ser.,  vol.  30,  1910,  p.  379;  and  vol.  31,  1911,  p.  211.  An  earlier  memoir  by 
Duparc  is  in  vol.  15,  1903,  pp.  287,  377,  which  includes  a bibliography  of  Uralian  platinum.  See  also  A. 
Saytzeff,  Zeitschr.  prakt.  Geologie,  1898,  p.  395;  C.  W.  Purington,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  29, 1899, 
p.  3;  and  R.  Spring,  Zeitschr.  prakt.  Geologie,  1905,  p.  49. 


METALLIC  ORES. 


703 


A.  Daubree,1  many  years  ago,  commenting  upon  the  constant 
association  of  platinum  with  olivine  rocks  and  chromite,  pointed  out 
the  similarity  of  these  rocks  to  meteorites.  Much  later,  J.  M.  Davi- 
son 2 announced  the  presence  of  platinum  and  iridium  in  the  meteoric 
iron  of  Coahuila.  Still  more  recently,  S.  Meunier3  has  discussed 
this  relationship  at  some  length,  and  argued  that,  contrary  to  the 
usual  view,  the  native  platinum  and  iron  of  these  rocks  are  not  mag- 
matic, but  are  introduced  as  vaporized  chlorides  and  subsequently 
reduced  by  heated  hydrogen.  This  mode  of  introduction  and  depo- 
sition Meunier  reproduced  artificially,  but  the  application  of  the 
experiments  to  meteorites  is  not  quite  clear. 

In  a number  of  cases  platinum  has  been  detected  in  sedimentary 
or  metamorphic  rocks.  Kemp  4 mentions  its  occurrence  in  certain 
Pennsylvanian  shales,  and  states  also  that  the  palladium  gold  of 
Brazil  is  sometimes  associated  with  itabirite.  E.  Hussak5  found 
palladium  gold  in  a contact  limestone,  and  reports  the  platinum  of 
Brazil  not  only  from  olivine  rocks,  but  also  from  a conglomeritic 
quartzite.  According  to  J.  B.  Jaquet,6  platinum  occurs  near  Broken 
Hill,  Australia,  in  ironstone,  ferruginous  claystone,  and  decomposed 
gneiss.  It  is  also  said  to  be  present  in  the  ash  of  certain  Australian 
coals.7  F.  Sandberger  8 identified  platinum  in  limonite  nodules  from 
Mexico.  In  an  altered  limestone  lens  in  Sumatra,  L.  Hundeshagen  9 
found  platinum  up  to  6 grams  per  metric  ton.  The  metal  was  in 
wollastonite,  which  formed  from  85  to  88  per  cent  of  the  rock,  with 
12  to  14  per  cent  of  grossularite.  Hundeshagen  regards  this  occur- 
rence as  due  to  the  introduction  of  hot  solutions  containing  gold, 
silver,  and  platinum  into  the  metal-bearing  rock.  Natural  solutions 
of  platinum,  however,  do  not  appear  to  have  been  observed;  and  its 
solubility  in  natural  solvents  is  undetermined.  Possibly  the  plati- 
niferous  quartz  from  the  south  island  of  New  Zealand,  recently  de- 
scribed by  J.  B.  Bell,10  had  a similar  origin.  The  quartz  veins,  how- 
ever, were  near  altered  magnesian  eruptives,  in  which  no  platinum 
was  found. 

The  occasional  presence  of  platinum  in  sulphide  ores  has  long  been 
known,  although  it  has  attracted  serious  attention  only  within  recent 

1 Compt.  Rend.,  vol.  80,  1875,  p.  707. 

2 Am.  Jour.  Sci.,  4th  ser.,  vol.  7, 1899,  p.  4. 

3 Compt.  rend.  VII  Cong.  geol.  intemat.,  1897,  p.  157. 

4 Bull.  U.  S.  Geol.  Survey  No.  193,  1902. 

6 Zeitschr.  Kryst.  Min.,  vol.  42, 1906,  p.  399. 

G Rec.  Geol.  Survey,  New  South  Wales,  vol.  5, 1896-1898,  p.  33.  See  also  J.  C.  H.  Mingaye,  Ann.  Rept. 
Dept.  Mines,  New  South  Wales,  1889,  p.  249. 

7 See  Seventeenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3, 1896,  p.  282. 

8 Neues  Jahrb.,  1875,  p.  625. 

9 Trans.  Inst.  Min.  and  Met.,  vol.  13, 1903-4,  p.  550. 

19  Econ.  Geology,  vol.  1,  1906,  p.  749. 


704 


THE  DATA  OF  GEOCHEMISTRY. 


years.  E.  Gueymard1  found  it  in  tetrahedrite,  in  a gangue  of  dolo- 
mite, quartz,  and  barite,  at  Chapeau  Mountain,  in  the  French  Alps. 
The  country  rock  was  a metamorphic  limestone.  H.  Rossler2  de- 
tected both  platinum  and  palladium  in  silver  bullion;  and  H.  Vogel3 
reports  its  presence  in  the  metallic  ores  of  Boitza,  Transylvania. 
Much  more  striking,  however,  is  the  presence  of  platinum  in  the 
sulphide  ores  of  Sudbury,  Canada.  Here  it  is  found  as  the  arsenide, 
sperrylite,4  associated  with  nickeliferous  pyrrhotite  and  chalcopyrite, 
but  most  intimately  with  the  latter.  F.  W.  Clarke  and  C.  Catlett,5 
however,  showed  its  presence  in  massive  polydymite.  At  the  Ram- 
bler mine,  in  Wyoming,  both  platinum  and  palladium  are  found  in 
covellite,  in  ores  derived  from  diorite.6  Here,  also,  sperrylite  has 
been  identified.7  At  this  locality  palladium  appears  to  be  more 
abundant  than  platinum,  but  its  mode  of  combination  is  as  yet  unde- 
termined. Sperrylite  has  furthermore  been  found  by  J.  Catharinet 8 
in  the  pegmatite  of  Copper  Mountain,  British  Columbia.  One  small 
crystal  was  embedded  in  biotite.  Platinum  is  also  present,  according 
to  C.  W.  Dickson,9  in  chalcopyrite  from  the  Key  West  mine,  Bunker- 
ville,  Nevada;  but  sperrylite  could  not  be  detected.  J.  H.  L.  Vogt 10 
found  platinum  to  be  present  in  the  nickeliferous  pyrrhotites  of  Nor- 
way, and  R.  W.  Brock 11  discovered  traces,  of  it  in  sulphide-bearing 
quartz  at  the  Mother  Lode  claim,  Yale  district,  British  Columbia. 
These  occurrences  have  led  to  much  searching  after  platinum  in 
copper  and  nickel  ores,  and  the  search  is  likely  to  be  occasionally 
fruitful.12  The  presence  of  platinum  in  sulphide  ores  near  Broken  Hill 
has  been  reported  by  J.  C.  H.  Mingaye.13  In  plumb ojarosite  from 
Goodsprings,  Nevada,  R.  C.  Wells  14  found  up  to  0.2  per  cent  of 
palladium,  with  a trace  of  platinum. 

1 Compt.  Rend.,  vol.  29, 1849,  p.  814.  See  also  Gueymard,  Bull.  Soc.  gdol.  France,  2d  ser.,  vol.  12, 
1854-55,  p.  429,  on  other  occurrences  of  platinum  in  the  Alps. 

2 Liebig’s  Annalen,  vol.  180,  1875,  p.  240. 

2 Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  vol.  39,  p.  32. 

* See  H.  L.  Wells,  Am.  Jour.  Sci,  3d  ser.,  vol.  37,  1889,  p.  67.  Sperrylite  has  since  been  found  by  W.  E. 
Hidden  (idem,  4th  ser.,  vol.  6, 1898,  p.  381),  and  by  Hidden  and  J.  H.  Pratt  (idem,  vol.  6, 1898,  p.  467),  at 
two  localities  in  North  Carolina,  associated  with  rhodolite  garnet.  For  details  concerning  Sudbury,  see 
the  section  on  nickel  and  cobalt,  ante,  p.  693. 

5 Bull.  U.  S.  Geol.  Survey  No.  64,  1890,  p.  20. 

6 See  W.  C.  Knight,  Eng.  and  Min.  Jour.,  vol.  72,  1901,  p.  845;  vol.  73,  1902,  p.  696;  J.  F.  Kemp,  Cont. 
Geol.  Dept.  Columbia  Univ.,  vol.  11,  No.  93, 1903;  S.  F.  Emmons,  Bull.  U.  S.  Geol.  Survey  No.  213, 1903, 
p.  94;  and  T.  T.  Read,  Eng.  and  Min.  Jour.,  vol.  79, 1905,  p.  985. 

i H.  L.  Wells  and  S.  L.  Penfield,  Am.  Jour.  Sci.,  4th  ser.,  vol.  13, 1902,  p.  95. 

s Eng.  and  Min.  Jour.,  vol.  79, 1905,  p.  127. 

9 Jour.  Canadian  Min.  Inst.,  vol.  8,  1905,  p.  192.  Memoir  on  the  distribution  of  the  platinum  metals 
in  other  sources  than  placers.  On  platinum  and  palladium  in  blister  copper,  see  A.  Eilers,  Bull.  Am. 
Inst.  Min.  Eng.,  No.  78, 1913,  p.  999.  In  graywacke,  P.  Krusch,  Metall  u.  Erz,  vol.  11, 1914,  p.  545. 

19  Zeitschr.  prakt.  Geologie,  1902,  p.  258. 

“ Eng.  and  Min.  Jour.,  vol.  77,  1904,  p.  280. 

i2  According  to  W.  Baragwanath  (Bull.  Geol.  Survey  Victoria,  No.  20,  1906),  platinum  is  found  in  the 
Thomson  River  copper  mine  in  a hornblende  rock  rich  in  chalcopyrite. 

I®  Rec.  Geol.  Survey  New  South  Wales,  vol.  8, 1909,  p.  287. 

14  Work  done  in  the  laboratory  of  the  U.  S.  Geological  Survey.  On  the  Goodsprings  deposit,  see  A. 
Knopf,  Bull.  U.  S.  Geol.  Survey  No.  620-A,  1915. 


METALLIC  OEES. 


705 


VANADIUM  AND  URANIUM. 

Although  vanadium  and  uranium  are  chemically  unlike,  they  occur 
together  in  one  of  their  important  ores,  and  are  therefore  considered 
together  in  this  section.  Vanadium  is  a member  of  the  phosphorus 
group  of  elements;  uranium  is  more  akin  to  molybdenum  and  tung- 
sten, and  the  two  metals  are  also  magmatically  opposed.  Vanadium 
is  most  common  in  ferromagnesian  rocks,  while  uranium  minerals 
occur  more  frequently  in  granites  and  pegmatites. 

Vanadium  is  reckoned  among  the  rarer  elements,  and  yet  it  is 
widely  diffused.  Traces  of  it  are  common  in  iron  ores,  especially  in 
the  titaniferous  magnetites,  and  it  is  found,  when  sought  for,  in  rocks 
of  nearly  every  class.1  W.  F.  Hillebrand,2  in  a special  investigation, 
examined  57  igneous  rocks,  and  found  vanadium,  in  most  cases,  in 
weighable  proportions.  The  smallest  traces  were  in  persilicic  rocks, 
but  in  subsilicic  varieties  the  amount,  reckoned  as  V203,  frequently 
ran  as  high  as  0.03  to  0.05  per  cent.  In  the  ferromagnesian  minerals 
separated  from  some  of  the  rocks  the  proportion  of  vanadium  was 
even  higher,  in  one  biotite,  for  example,  reaching  0.127  per  cent  of 
V203.  Hillebrand  also  found  vanadium  in  slates  and  in  other  sedi- 
mentary rocks.  A composite  of  253  sandstones  gave  0.003,  and 
another  of  498  limestones  gave  0.004  per  cent  of  vanadious  oxide. 

H.  Sainte-Claire  Deville  3 found  vanadium  in  French  bauxite,  in 
cryolite,  and  in  rutile.  P.  Beauvallet 4 detected  it  in  a French  clay. 
In  bricks  made  from  a clay  found  near  Sydney,  Australia,  according 
to  E.  H.  Bennie,5  vanadium  is  present  to  a perceptible  amount. 
Other  Australian  clays  and  shales  gave  J.  C.  H.  Mingaye  6 similar 
results.  He  also  found  vanadium  in  the  ash  of  coals  and  in  the  oil- 
bearing shales  of  Scotland.  E.  Bechi 7 reports  vanadium  in  clays, 
schists,  and  the  ashes  of  plants,8  and  C.  Baskerville  9 found  it  in  the 
ashes  of  peat  from  North  Carolina.  A.  Jorissen  10  discovered  it  in 
delvauxite,  which  is  a hydrous  phosphate  of  iron. 


1 See  A.  A.  Hayes,  Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  10,  1875,  p.  294.  Hayes  found  vanadium  in 
many  rocks,  and  also  in  the  waters  of  Brookline,  Massachusetts.  For  determinations  of  vanadium  in 
lavas  of  Vesuvius  and  Etna,  see  L.  Ricciardi,  Gazz.  chim.  ital.,  vol.  13,  1883,  p.  259.  Scattered  deter- 
minations are  numerous. 

2 Bull.  U.  S.  Geol.  Survey  No.  167, 1900,  p.  49.  See  also  J.  H.  L.  Vogt,  Zeitschr.  prakt.  Geologie,  1899, 
p.  274,  on  the  distribution  of  vanadium  in  rocks.  W.  Pollard  (Summ.  Prog.  Geol.  Survey  Great  Britain, 
1902,  p.  60)  has  found  vanadium  in  a number  of  rocks.  On  vanadium  in  the  Stassfurt  salt  clay  see  E . Marcus 
and  W.  Biltz,  Zeitschr.  anorg.  Chemie,  vol.  68, 1910,  p.  91. 

3 Annales  chim.  phys.,  3d  ser.,  vol.  61, 1861,  pp.  309, 342.  See  also  L.  Dieulafait,  Compt.  Rend.,  vol.  93, 
1881,  p.  804. 

< Compt.  Rend.,  vol.  49, 1859,  p.  301. 

6 Proc.  Roy.  Soc.  New  South  Wales,  vol.  17,  1883,  p.  133.  He  cites  similar  examples  from  other  authori- 
ties. 

c Rec.  Geol.  Survey  New  South  Wales,  vol.  7,  1903,  p.  219. 

v Atti  R.  accad.  Lincei,  3d  ser.,  vol.  3,  1879,  p.  403. 

c See  also  E.  Demargay,  Compt.  Rend.,  vol.  130,  1900,  p.  91. 

o Jour.  Am.  Chem.  Soc.,  vol.  21, 1899,  p.  706. 

w Annales  Soc.  gdol.  Belgique,  vol.  6,  1878-9,  p.  41. 

97270°— Bull.  616—16 45 


706 


THE  DATA  OF  GEOCHEMISTRY. 


A still  more  remarkable  occurrence  of  vanadium  was  noted  by  J.  J. 
Kyle 1 in  a lignite  from  San  Rafael,  Province  of  Mendoza,  Argentina. 
The  coal  yielded  only  0.63  per  cent  of  ash,  but  the  latter,  upon  analy- 
sis, was  found  to  contain  38.22  per  cent  of  V205,  together  with  sili- 
cates and  sulphates  of  other  metals.  In  a similar  coal,  probably 
from  the  same  region,  A.  Mourlot2  obtained  38.5  per  cent  of  V205 
from  the  ash;  and  in  another,  from  Yauli,  Peru,  Torrico  y Meca3 
discovered  38  per  cent.  The  ash  of  a grahamite  from  near  Page, 
Oklahoma,  analyzed  in  the  laboratory  of  the  United  States  Geo- 
logical Survey  by  R.  C.  Wells,  contained  12.2  per  cent  of  V205. 
In  the  ash  of  an  asphalt  from  Nevada  the  same  chemist  found  nearly 
30  per  cent.  These  ash  analyses,  taken  together  with  the  finding  of 
vanadium  in  the  ashes  of  wood  and  peat,  suggest  that  plants  have 
played  some  part  in  the  concentration  of  vanadium.  Other  evidence 
of  similar  purport  will  be  cited  later. 

The  definite  minerals  containing  vanadium  as  an  essential  con- 
stituent are  not  very  numerous.  Some  of  them,  vanadates  of  lead, 
such  as  vanadinite  and  descloizite,  were  mentioned  in  a previous 
section  of  this  chapter.  Volborthite  and  calciovolborthite  are  vana- 
dates of  copper,  with  other  bases,  and  pucherite  is  a vanadate  of  bis- 
muth. Mottramite,  a vanadate  of  copper  and  lead,  found  at  Alderley 
Edge,  in  England,  has  had  some  significance  as  a workable  ore.  It 
occurs  as  an  impregnation  in  Keuper  sandstone.4  A Mexican  variety 
of  descloizite,  ramirite,5  has  also  been  commercially  exploited.  These 
vanadates,  with  the  exception  of  mottramite,  occur  principally  in 
metalliferous  veins;  and  A.  Ditte 6 attributes  their  formation  to 
percolating  vanadiferous  waters  acting  on  other  compounds,  most 
commonly  the  compounds  of  lead.  The  so-called  vanadic  ocher  is 
doubtful. 

A sulphovanadate  of  copper,  sulvanite,  Cu3VS4,  is  found  in  South 
Australia.7  At  Minasragra,  near  Cerro  de  Pasco,  Peru,  another  sul- 
phide of  vanadium,  patronite,  is  found,  associated  with  pyrite,  in  a 
carbonaceous  substance  resembling  a coal  but  abnormally  rich  in 
sulphur.8  This  occurrence  may  well  be  correlated  with  the  other 

1 Chem.  News,  vol.  66,  1892,  p.  211. 

2 Compt.  Rend.,  vol.  117,  1893,  p.  *46. 

3 Abstract  from  a Peruvian  original,  in  Jour.  Chem.  Soc.,  vol.  70,  pt.  2, 1896,  p.  252.  For  more  details, 

see  D.  F.  Hewett,  Bull.  Am.  Inst.  Min.  Eng.,  1909,  p.  291. 

* See  H.  E.  Roscoe,  Proc.  Roy.  Soc.,  vol.  25,  1876,  p.  111. 

6  See  G.  de  J.  Caballero,  Mem.  Soc.  cient.  Ant.  Alzate,  vol.  20,  1903,  p.  87. 

6 Compt.  Rend.,  vol.  138,  1904,  p.  1303. 

7 See  G.  A.  Goyder,  Jour.  Chem.  Soc.,  vol.  77,  1900,  p.  1094. 

8 See  D.  F.  Hewett,  Eng.  and  Min.  Jour.,  vol.  82,  1906,  p.  385;  and  J.  J.  Bravo,  Inform,  y Mem.  Bol. 
Soc.  ingen.  minas,  Lima,  vol.  8,  1906,  p.  171.  For  a later  and  much  more  complete  description  of  the 
sulphide,  patronite,  and  its  associated  minerals,  see  W.  F.  Hillebrand,  Am.  Jour.  Sci.,  4th  ser.,  vol.  24, 
1907,  p.  141.  The  bituminous  matrix  he  names  quisqueite.  A still  later  memoir  on  vanadium  deposits 
in  Peru,  by  Hewett,  is  in  Bull.  Am.  Inst.  Min.  Eng.,  1909,  p.  291. 


METALLIC  ORES. 


707 


discoveries  of  vanadium  in  the  ash  of  coal;  and  the  sulphates,  equiva- 
lent to  13.70  per  cent  of  S03,  found  by  Kyle  in  his  analysis,  may  show 
that  he  too  had  originally  a sulphide  to  deal  with  which  was  oxidized 
during  combustion.  Associated  with  and  derived  from  patronite  are 
the  calcium  vanadates  hewettite,  pascoite,  and  fernandinite,  a vana- 
dium sulphate,  minasragrite,  and  other  alteration  products.1 

The  rare  mineral  ardennite  is  a vanadio-silicate  of  manganese  and 
aluminum.  Roscoelite  appears  to  be  essentially  a muscovite  in  which 
vanadium  has  partly  replaced  aluminum.2  It  contains  about  24 
per  cent  of  V203.  In  a green  sandstone  from  Placerville,  Colorado, 
W.  F.  Hillebrand  3 found  3.50  per  cent  of  V2Q3,  which  was  present  in 
a replacement  of  the  original  calcareous  cement.  The  green  mineral, 
isolated,  contained  12.84  per  cent  of  V203  and  was  apparently  a 
variety  of  roscoelite,  or  else  a closely  related  compound. 

The  metal  uranium  is  much  less  abundantly  diffused  than  vana- 
dium. It  is  found  in  a number  of  rare  minerals — phosphates,  arse- 
nates, sulphates,  carbonates,  and  silicates — which  are  all  of  secondary 
origin.  Autunite,  a phosphate  of  uranium  and  lime,  is  not  uncom- 
mon in  the  form  of  yellow  scales  on  granite  or  gneiss,  but  the  other 
species  are  much  less  frequently  seen.  A number  of  other  minerals, 
samarskite,  euxenite,  etc.,  are  columbates  or  tantalates  containing 
uranium,  and  these  are  primary  constituents  of  pegmatite. 

The  only  uranium  ores  of  any  importance  are  uraninite  or  pitch- 
blende and  carnotite.  Uraninite  is  found  crystallized  in  pegmatites, 
and  also  massive  in  metalliferous  veins,  as  at  Joachims thal, 4 in 
Bohemia,  and  Johanngeorgenstadt,  in  Saxony.  It  varies  much  in  com- 
position, so  much  so  that  different  modifications  of  it  have  received 
different  names,  such  as  cleveite,  nivenite,  broggerite,  etc.  The  fol- 
lowing analyses,  by  W.  F.  Hillebrand,5 6  will  serve  to  illustrate  the 
variations. 

1 On  hewettite  and  pascoite  see  W.  F.  Hillebrand,  H.  E.Merwin,  and  F.  E.  Wright,  Proc.  Am.  Philos. 
Soc.,  vol.  53, 1914,  p.  31.  The  two  other  species  are  described  by  W.  T.  Schaller,  Jour.  Washington  Acad. 
Sci.,  vol.  5, 1915,  p.  7. 

2 Bull.  U.  S.  Geol.  Survey  No.  167,  1900,  p.  73. 

a Bull.  U.  S.  Geol.  Survey  No.  262, 1905,  p.  18. 

* On  the  Joachimsthal  ores,  see  Janda,  Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  vol.  50,  p.  283;  also  J.  St8p 
and  F.  Becke,  Zeitschr.  prakt.  Geologie,  1905,  p.  148.  R.  Pearce  (Proc.  Colorado  Sci.  Soc.,  vol.  5,  1895, 
p.  156)  has  described  the  occurrence  of  uraninite  in  a mine  near  Central  City,  Colorado.  On  uranium  ores 

in  German  East  Africa,  see  W.  Marckwald,  Centralbl.  Min.,  Geol.  u.  Pal.,  1906,  p.  761. 

6 See  Bull.  U.  S.  Geol.  Survey  No.  78,  1891,  p.  43,  and  No.  90,  1892,  p.  23,  for  details;  also  Bull.  No,  220, 
1903,  pp.  111-114.  22  analyses  inall  aregiven.  On  the  pitchblende  of  Joachimsthal  see  R.  Jafle,  Zeitschr. 
prakt.  Geologie,  1912,  p.  425. 


708 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  uraninite. 


A.  Hale’s  quarry,  Glastonbury,  Connecticut. 

B.  Near  Central  City  or  Blackhawk,  Colorado. 

C.  Johanngeorgenstadt,  Saxony. 


D.  Nivenite,  Llano  Comity,  Texas. 

E.  Broggerite,  Annerod,  Norway. 

F.  Cleveite,  Arendal,  Norway. 


A 

B 

C 

D 

E 

F 

UO, 

26.  48 

25.  26 

22.  33 

20.  89 

30.  63 

41.  71 

uo2 

57.  43 

58. 51 

59.  30 

44. 17 

46. 13 

24. 18 

Th02  

9.  79 

None. 

6.  69 

6.  00 

Ce02. 

.25 

.22 

None. 

.34 

.18 

\ 3.66 

Zr02 

7.  59 

None. 

.34 

.06 

(La,  DiLOo 

. 13 

None. 

2.  36 

.27 

J 

(Y,  Er)90, 

.20 

None. 

9.46 

1. 11 

9.  76 

A1203 *... 

.20 

Fe203 

.40 

.21 

.14 

.25 

.03 

FeO  ° 

.32 

PbO 

3.  26 

.70 

6.  39 

10. 08 

9.04 

10.  54 

ZnO  

.44 

CuO 

.17 

MnO 

Trace. 

. 16 

.09 

CaO 

.08 

.84 

1.  00 

.32 

.37 

1.06 

MgO 

Trace? 

.17 

Trace. 

.10 

Bi203 

.75 

VoO*,  Mo03,  W03 

.75 

Alkalies 

Trace. 

Trace? 

.31 

Traces. 

.23 

so, 

.19 

. 22 

.06 

.02 

As206 

.43 

2.  34 

He 

Undet. 

.02 

Trace. 

.08 

. 17 

Undet. 

H20 

.61 

1.  96 

3. 17 

1.  48 

.74 

1.  23 

Si02 

.16 

2.  79 

.50 

.46 

.22 

.90 

CuFeS2 

. 12 

FeS2 

.24 

Insoluble 

.70 

1.  47 

4.  42 

1. 10 

99. 49 

99.  82 

97.  93 

98.  28 

99.  61 

94.  50 

From  these  analyses  no  single  definite  formula  can  be  deduced. 
The  uranium,  it  is  clearly  seen,  exercises  a double  function,  acid  and 
basic,  the  latter  being  represented  by  the  radicle  uranyl,  U02.  With 
this  base  other  bases  are  variably  present — tboria,  zirconia,  the  rare 
earths,  and  oxide  of  lead,  sometimes  one  and  sometimes  another  pre- 
dominating. There  are  also  impurities  of  several  kinds  which  can 
not  be  clearly  distinguished  from  essential  constituents,  and  some  of 
the  variations  may  be  due  to  incipient  alterations.  For  example,  the 
varying  ratios  between  U02  and  U03  may  be  ascribed  to  oxidation, 
the  increase  in  U03  marking  stages  in  the  process  of  transformation 
of  uraninite  into  gummite,  a well-known  alteration  product  of  pitch- 
blende. In  gummite,  which  is  a hydrous  oxide  of  uranium  1 plus 
other  bases,  with  from  61  to  75  per  cent  of  U03,  the  final  transforma- 
tion of  uraninite  is  seen. 

From  a physical  point  of  view  uraninite  is  an  extraordinary  min- 
eral. In  it  helium  was  first  discovered,  and  later  the  radioactive 
elements  polonium  and  radium.  Uranium  and  its  compounds  are 


1 For  analyses  of  gummite,  see  H.  von  Foullon,  Neues  Jahrb.,  1885,  pt.  1,  Ref.,  p.  21,  and  F.  A.  Genth, 
Am.  Chem.  Jour.,  vol.  1, 1879,  p.  89. 


METALLIC  ORES. 


709 


themselves  radioactive,  but  radium  is  vastly  more  so ; and  the  latter, 
while  distinctly  an  element  so  far  as  its  chemical  characteristics  are 
concerned,  undergoes  disintegration,  yielding  a series  of  emanations 
which  seems  to  end  in  the  production  of  helium.  Radioactivity,  then, 
appears  to  be  a phenomenon  of  atomic  decay;  but  the  subject  is  one 
which  hardly  falls  within  the  scope  of  this  treatise.  For  the  present 
it  is  enough  to  say  that  the  chief  sources  of  radium  to-day  are  in  the 
uraninite  of  Joachimsthal  and  in  carnotite,  and  that  uranium  itself 
is  the  progenitor  of  its  more  highly  active  companion. 

Carnotite,  which  is  essentially  a vanadate  of  uranium  and  potas- 
sium, but  with  other  bases  present  also,  was  first  described  by  C. 
Friedel  and  E.  Cumenge.1  It  is  found  as  a canary-yellow  impregna- 
tion in  sandstone  in  western  Colorado  and  eastern  Utah.  The  former 
field  has  been  studied  by  W.  F.  Hillebrand  and  F.  L.  Ransome,2 
the  latter  by  J.  M.  Boutwell.3  An  outlying  region  for  carnotite  in 
Rio  Blanco  County,  Colorado,  has  also  been  described  by  H.  S.  Gale.4 

The  following  analyses  of  carnotite,  by  Hillebrand,  will  show  its 
general  character: 

Analyses  of  carnotite. 


A.  Copper  Prince  claim,  Roc  Creek,  Montrose  County,  Colorado. 

B.  Yellow  Boy  claim,  La  Sal  Creek,  Montrose  County. 


A 

B 

uo3 

54.  89 

54.00 

v2os 

18.  49 

18.  05 

P205 

.80 

.05 

As205 

Trace. 

None. 

ALO, 

.09 

.29 

.21 

.42 

3.  34 

1.  86 

SrO 

.02 

Trace. 

BaO 

.90 

2.  83 

MgO 

.22 

.14 

k2o 

6.  52 

5.  46 

Na20 

.14 

.13 

Li20 

Trace. 

Trace. 

H20- 

2.  43 

3. 16 

H20+ 

2. 11 

2.  21 

PbO 

.13 

.07 

CuO . 

. 15 

Trace. 

Mo03 

.18 

.05 

Si02 

. 15 

.20 

p 

None. 

Ti02 

.03 

C02 

.56 

Insoluble 

7. 10 

10.  33 

98.  46 

99.  25 

1 Compt.  Rend.,  vol.  128, 1899,  p.  532.  Tyuyamunite,  a recently  described  mineral,  is  a calcium  carnotite, 
originally  from  Siberia  but  also  found  in  Utah. 

1 Bull.  U.  S.  Geol.  Survey  No.  262,  1905,  p.  9. 

3 Bull.  U.  S.  Geol.  Survey  No.  260,  1904,  p.  200. 

* Bull.  U.S.  Geol.  Survey  No.  315, 1907,  p.  110.  Gale  (Bull.  340, 1908,  p.  258)  has  also  described  carnotite 
from  Routt  County,  Colorado.  See  also  H.  Fleck  and  W.  G.  Haldane  (Rept.  State  Bur.  Mines,  1905-6,  p. 
47)  on  the  uranium  and  vanadium  deposits  of  southern  Colorado.  Bull.  U.  S.  Bureau  of  Mines  No.  70,  by 
R.  B.  Moore  and  K.  L.  Kithil,  is  essentially  a monograph  on  the  ores  of  vanadium  and  uranium.  The 
Colorado  ores  are  now  being  worked  as  a source  of  radium.  On  carnotite  from  Mauch  Chunk,  Pennsyl- 
vania, see  E.  T.  Wherry,  Am.  Jour.  Sci.,  4th  ser.,  vol.  33, 1912,  p.  574. 


710 


THE  DATA  OF  GEOCHEMISTRY. 


With  the  carnotite  a vanadiferous  silicate  also  occurs,  which  may 
be  akin  to  roscoelite.  Two  calcium  vanadates,  metahewettite  and 
pintadoite,  and  a vanadate  of  uranium,  uvanite  are  also  present.1 

In  the  Utah  field,  as  described  by  Boutwell,  not  only  carnotite,  but 
other  vanadates,  such  as  calciovolborthite,  are  found.  In  Wildhorse 
Canyon  a black,  carbonaceous  sandstone  also  occurs,  in  which  vana- 
dium is  present.  This  recalls  the  occurrences  of  vanadium  in  coals 
elsewhere.  In  the  San  Rafael  Swell  the  carnotite  is  found  principally 
on  or  near  the  fossil  remains  of  plants,  whose  organic  matter,  Bout- 
well  suggests,  may  have  acted  as  precipitants  of  vanadium.  The 
same  association  with  fossil  wood  was  also  noted  by  Gale.  No  sul- 
phide of  vanadium,  however,  like  that  of  Peru,  has  yet  been  identified 
in  this  region.  Carnotite  has  also  been  reported  by  D.  Mawson  2 in 
the  pegmatite  of  “ Radium  Hill,”  South  Australia. 

Uranium,  like  vanadium,  has  been  found  in  coal.  In  an  anthra- 
citic bitumen  from  Sweden,  described  by  A.  E.  Nordenskiold,3  the 
ash  contained  about  3 per  cent  of  U308,  with  some  nickel  oxide  and 
rare  earths.  In  the  ash  of  Swedish  “kolm,”  a bituminous  coal,  H. 
Liebert,4 *  working  in  C.  Winkler’s  laboratory,  found  from  1.68  to  2.87 
per  cent  of  U308.  An  anthracitic  mineral  from  a pegmatite  vein  in 
the  Saguenay  district,  Canada,  yielded  J.  Obalski 6 2.56  per  cent  of 
uranium,  equivalent  to  35.43  per  cent  in  the  ash.  The  significance 
of  these  occurrences  remains  to  be  determined. 

COLUMBIUM,  TANTALUM,  AND  THE  RARE  EARTHS. 

A striking  feature  in  the  recent  development  of  chemical  indus- 
tries has  been  the  utilization  of  rare  elements  which  previously  had 
only  scientific  interest.  The  invention  of  incandescent  gas  lighting 
has  created  a demand  for  several  of  these  substances,  and  that  reason 
alone  is  enough  to  justify  their  brief  consideration  here. 

Columbium 6 and  tantalum  are  acid-forming  elements,  whose 
typical  oxides  have  the  formulae  Cb205  and  Ta205.  They  enter  into 
the  composition  of  a considerable  number  of  minerals,  which  are 
found  principally  in  pegmatites.  Among  these,  columbite,  tantalite, 
samarskite,  and  euxenite  are  by  far  the  most  important.  Columbite 
and  tantalite  are  salts  of  iron,  FeCb206  and  FeTa206,  which  com- 
monly occur  more  or  less  isomorphously  commingled,  often  with 

1 On  metahewettite  see  Hillebrand,  Merwin,  and  Wright,  loc.  cit.  The  two  other  species  are  described 
by  F.  L.  Hess  and  W.  T.  Schaller,  Jour.  Washington  Acad.  Sci.,  vol.  4,1914,  p.576.  On  the  origin  of 
carnotite  see  Hess,  Econ.  Geology,  vol.  9, 1914,  p.  675. 

2 Trans.  Roy.  Soc.  South  Australia,  vol.  30, 1906,  p.  188. 

3 Compt.  Rend.,  vol.  116, 1893,  p.  677. 

* See  C.  Winkler,  Zeitschr.  Kryst.  Min.,  vol.  37, 1903,  p.  287. 

6 Jour.  Canadian  Min.  Inst.,  vol.  7,  1904,  p.  245. 

6 Known  in  Germany  as  niobium.  The  name  columbium  has  more  than  40  years’  priority  and  refers  to 
the  original  discovery  of  the  element  in  a mineral  from  America.  Niobium  is  etymologically  meaningless. 


METALLIC  ORES. 


711 


manganese  partly  replacing  the  iron.  Metallic  tantalum  1 has  recently 
been  utilized  as  a substitute  for  the  carbon  filament  in  incandescent 
electric  lights,  and  tantalite  is  the  chief  source  from  which  it  can  be 
obtained.2  The  supply  so  far  is  mainly  from  Scandinavian  localities. 

Zirconium  and  thorium  are  tetrad  metals  forming  oxides  of  the 
type  R02.  They  also  are  found  in  granitic  rocks,  and  zirconium 
compounds  are  almost  always  present  in  nepheline  syenites.  The 
chief  zirconium  mineral,  zircon,  ZrSi04,  has  already  been  described 
in  the  chapter  upon  rock-forming  minerals.  The  mineral  baddeley- 
ite,  found  in  Ceylon  and  Brazil,  is  the  oxide,  Zr02.  Eudialyte,  cata- 
pleiite,  and  the  zircon-pyroxenes  are  complex  silicates  containing 
zirconia.  Zircon  syenite  and  eudialyte  syenite  are  rare  but  well- 
known  rocks,  and  zircon  also  occurs,  though  not  commonly,  in  con- 
tact limestones.  The  most  remarkable  American  locality  for  zircon 
is  near  Green  River,  in  Henderson  County,  North  Carolina,  where 
it  is  found  abundantly  in  a decomposed  pegmatite  dike.  From  this 
source  many  tons  of  zircon  have  been  obtained. 

The  typical  thorium  mineral  is  also  a silicate,  thorite,  ThSi04. 
The  ideal  species,  however,  has  not  been  found,  for  the  actual  speci- 
mens are  always  more  or  less  altered.  The  chief  source  of  thoria, 
which  is  used  in  the  manufacture  of  mantles  for  incandescent  gas- 
burners,  is  from  monazite  sand,  in  which  the  thorium  compounds 
exist  as  variable  impurities.  Thorianite,  a thorium-uranium  oxide 
from  Ceylon,  is  noteworthy  for  being  richer  in  helium  than  any 
other  known  mineral.  Like  uranium,  thorium  is  strongly  radio- 
active, and  so  are  its  compounds.3 

In  the  group  of  elements  known  as  the  metals  of  the  rare  earths, 
the  following  members  have  been  identified:  Scandium,  yttrium, 
lanthanum,  cerium,  praseodymium,  neodymium,  samarium,  euro- 
pium, gadolinium,  terbium,  dysprosium,  erbium,  thulium,  holmium, 
lutecium,  and  ytterbium.  Among  these  yttrium  and  cerium  may  be 
regarded  as  the  type  elements,  and  they  are,  moreover,  the  most 
important.  In  the  mineral  kingdom  these  substances  occur  in  a 
large  number  of  compounds — fluorides,  carbonates,  silicates,  phos- 
phates, columbates,  and  tantalates,  minerals  which  are  found,  like 
the  other  species  mentioned  in  this  section,  principally  in  granites, 
gneisses,  and  pegmatites. 

Cerium,  which  is  always  accompanied  by  lanthanum,  neodymium, 
and  praseodymium,  is  obtainable  principally  from  three  minerals 
which  are  found  in  reasonably  large  quantities.  Cerite,  a hydrous 
silicate  of  these  elements,  forms  a bed  in  gneiss  at  Bastnas,  Sweden. 

1 Native  tantalum  has  been  reported  from  two  localities  in  Siberia  by  P.  Walther,  Nature,  1909,  p.  335, 
and  W.  von  John,  idem,  1910,  p.  398. 

2 See  Werner  von  Bolton,  Zeitschr.  angew.  Chemie,  1906,  p.  1537. 

3 For  an  elaborate  paper  on  the  occurrence  of  thorium  in  the  mineral  kingdom,  see  J.  Schilling,  Zeitschr. 
angew.  Chemie,  1902,  p.  869. 


712 


THE  DATA  OF  GEOCHEMISTRY. 


It  was  for  a long  time  the  only  commercial  source  of  cerium  com- 
pounds. Allanite,  a more  complex  silicate  of  cerium,  aluminum,  and 
other  bases,  is  also  abundant  enough  to  be  an  available  ore.  It  is 
not  a very  rare  mineral,  and  a notable  locality  for  it  is  on  Little 
Friar  Mountain,  Amherst  County,  Virginia.1  Allanite  has  also  been 
found  associated  with  iron  ores,  as,  for  example,  with  the  magnetite 
of  Moriah,  near  Lake  Champlain. 

Monazite,  the  phosphate  of  cerium,  which  is  normally  CeP04,  is, 
however,  the  chief  source  of  the  cerium  earths  at  the  present  day. 
It  is  obtained  for  commercial  purposes  from  detrital  deposits  of 
monazite  sand,2  and  yields  both  cerium  and  thorium  compounds. 
Monazite,  the  allied  yttrium  phosphate,  xenotime,  and  allanite  have 
all  been  adequately  considered  in  the  chapter  upon  rock-forming 
minerals.  The  following  analyses  of  monazite  are  by  S.  L.  Penfield: 3 

Analyses  of  monazite. 


A.  From  Portland,  Connecticut.  B.  From  the  sands  ofBrindletown,  North  Carolina.  C.  From  Amelia 
Court  House,  Virginia. 


A, 

B 

C 

p„(X 

28. 18 

29.  28 

26. 12 

Ce203 

38.  54 

31.  38 

29.  89 

(La  Di)oOo 

28.  33 

30.  88 

26.  66 

Th02 

8.  25 

6.  49 

14.  23 

Si02 

1.  67 

1.  40 

2.  85 

Ignition 

.37 

.20 

.67 

100.  34 

99.  63 

100.  42 

Yttria  and  its  companions,  erbia,  terbia,  ytterbia,  etc.,  are  obtained 
for  the  most  part  from  gadolinite,  Gl2FeYt2Si2O10.  These  oxides, 
therefore,  are  sometimes  called  the  “gadolinite  earths.”  The  type 
locality  for  this  species  is  Ytterby,  in  Sweden,  and  other  Swedish 
localities  have  yielded  the  mineral.  A more  remarkable  occurrence 
of  gadolinite  and  other  allied  minerals  is  at  Baringer  Hill,  Llano 
County,  Texas.  Here,  in  a giant  pegmatite  containing  enormous 
crystals  of  quartz  and  feldspar,  gadolinite  is  found  in  large  crystals, 
together  with  yttrialite,  thorogummite,  nivenite,  fergusonite,  allanite, 
tengerite,  cyrtolite,  rowlandite,  mackintoshite,  and  yttrocrasite. 
Several  of  these  species  and  varieties  are  peculiar  to  this  locality.4 

1 See  J.  W.  Mallet,  Am.  Jour.  Sci.,  3d  ser.,  vol.  14, 1877,  p.  397. 

2 On  the  monazite  sand  of  North  Carolina,  see  H.  B.  C.  Nitze,  Bull.  North  Carolina  Geol.  Survey  No.  9, 
1898.  Also  the  references  on  p.  356,  ante.  Nitze  cites  37  analyses  of  monazite.  On  monazite  sand  in  the 
tin-bearing  alluvium  of  the  Malay  Peninsula,  see  Bull.  Imp.  Inst.,  vol.  4, 1906,  p.  301. 

3 Am.  Jour.  Sci.,  3d  ser.,  vol.  24,  1882,  p.  250.  The  symbol  Di  represents  the  old  didymium,  which  is 
now  known  to  be  a mixture  of  neodymium,  praseodymium,  samarium,  etc. 

4 See  W.  E.  Hidden  and  J.  B.  Mackintosh,  Am.  Jour.  Sci.,  3d  ser.,  vol.  38,  1889,  p.  474;  Hidden,  idem, 
vol.  42,  1891,  p.  430;  Hidden  and  W.  F.  Hillebrand,  idem,  vol.  46,  1893,  pp.  98,  208;  Ilillebrand,  idem,  4th 
ser.,  vol.  13, 1902,  p.  145;  Hidden,  idem,  vol.  19,  1905,  p.  425;  Hidden  and  C.  H.  Warren,  idem,  vol.  22,  1906, 
p.  515. 


CHAPTER  XVI. 

THE  NATURAL  HYDROCARBONS. 
COMPOSITION. 


Natural  gas,  petroleum,  bitumen,  and  asphaltum  are  all  essentially 
compounds  of  carbon  and  hydrogen,  or,  more  precisely,  mixtures  of 
such  compounds  in  bewildering  variety.  They  contain,  moreover, 
many  impurities — sulphur  compounds,  oxidized  and  nitrogenous  sub- 
stances, etc. — whose  exact  nature  is  not  always  clearly  defined.  The 
proximate  analysis  of  a petroleum  or  bitumen  consists  in  separat- 
ing its  components  from  one  another,  and  in  their  identification  as 
compounds  of  definite  constitution. 

All  the  hydrocarbons  fall  primarily  into  a number  of  regular  series, 
to  each  of  which  a generalized  formula  may  be  assigned,  in  accordance 
with  the  following  scheme: 


1.  CnH2n+2. 

2.  CnH2n. 

3.  CnH2n_2. 

4.  CnH2n_4. 

5.  CnH2D_6. 


6.  CnH2n_8. 

7.  CnH2n_10. 

8.  CnH2n_12. 

18.  CnH2n_32. 


Members  of  the  first  eight  series  have  been  discovered  in  petroleum. 

These  expressions,  however,  have  only  a preliminary  value, 
although  they  are  often  used  in  the  classification  of  petroleums.  Each 
one  represents  a group  of  series — homologous,  isomeric,  or  polymeric, 
as  the  case  may  be — and  for  precise  work  these  must  be  taken  sepa- 
rately. The  first  formula,  for  example,  represents  what  are  known 
as  the  paraffin  hydrocarbons,  which  begin  with  marsh  gas  or  methane, 
CH4,  and  range  at  least  as  high  as  the  compound  C35H72.  Even  these 
are  again  subdivided  into  a number  of  isomeric  series — the  primary, 
secondary,  and  tertiary  paraffins — which,  with  equal  percentage  com- 
position, differ  in  physical  properties  by  virtue  of  differences  of 
atomic  arrangement  within  the  molecules.  Each  member  of  the 
series  differs  from  tho  preceding  member  by  the  addition  of  the 
group  CH2,  and  also  by  the  physical  characteristics  of  greater  con- 
densation. Methane,  CH4,  for  example,  is  gaseous;  the  middle  mem- 
bers of  the  series  are  liquids,  with  regularly  increasing  boiling  points ; 
the  higher  members  are  solids,  like  ordinary  paraffin.  These  hydro- 
carbons are  especially  characteristic  of  the  Pennsylvania  petroleums, 
from  which  the  following  members  of  the  series  have  been  separated.1 


i The  table  is  condensed  from  H.  Hofer’s  valuable  work,  Das  Erdol,  2d  ed.,  Braunschweig,  1906,  pp.  58-59. 
A third  edition  appeared  in  1912. 


713 


714 


THE  DATA  OF  GEOCHEMISTRY, 


Paraffins  from  Pennsylvania  petroleum. 


Name. 

Formula. 

Melting  point. 

Boiling  point. 

1.  Gaseous: 

°C. 

°C. 

Methane 

ch4 

—186 

—164 

Ethane 

c2h6 

—172. 1 

— 84.1 

Propane 

CoHo 

— 37 

Butane 

C,H10 

+ 1 

2.  Liquid: 

Pentane 

CvH19 

37 

Hexane 

^5  12"  - - - - 

c«h14 

69 

Heptane 

c7h16 

98 

Octane 

CoH-io ..... 

125 

Nonane 

c9h20 

— 51 

150 

Decane 

CiqH-22-  - - - - 

— 31 

173 

Endecane 

c„h94 

— 26 

195 

Dodecane 

----- 

^12^26 

— 12 

214 

Tridecane 

C13U28  ----- 

Tetradecane 

OiJT,n 

+ 4 

252 

Pentadecane 

ClvHo9 

Hexadecane 

C1f!Ho4 

18 

3.  Solid: 

Octodecane 

C18Hoo 

Eicosane 

v18  3o  ----- 
^20^42  ----- 

37 

Tricosane 

^23^48  ----- 

48 

Tetracosane 

c9,hw 

50-51 

Pentacosane 

C9JL9 

53-54 

Hexacosane 

CrJEL. 

55-56 

Octocosane 

''20  54 

60 

Nonocosane 

28  58 

62-63 

Hentriacontane 

P29tt60 

\ Jet  1 1 I r»  1 _ 

66 

Dotriacontane 

p TT 

67-68 

Tetratriacontane 

P32tt66 

71-72 

Pentatriacontane  a 

P34tt70 

\ Jet  r 1 I nn  _ _ 

76 

v35  72 

a For  a description  of  these  higher,  solid  paraffins,  see  C.  F.  Mabery , Am.  Chem.  Jour.,  vol.  33,  1905,  p.  251. 
The  literature  of  these  substances  is  so  voluminous  that  I can  not  attempt  to  give  exhaustive  references. 
C.  Hell  and  C.  Hagele  (Ber.  Deutsch.  chem.  Gesell.,  vol.  22, 1889,  p.  504)  have  described  an  artificial  hydro- 
carbon, C60H122. 

To  this  list  the  isomeric  secondary  paraffins  isobutane,  isopentane, 
isohexane,  isoheptane,  and  isooctane  must  be  added,  and  even  then 
the  list  is  probably  not  complete.  For  instance,  the  solid  paraffins 
C27H56  and  C30H62  have  been  found  in  petroleum. 

Natural  gas  consists  almost  entirely  of  paraffins,  mainly  of  methane, 
with  quite  subordinate  impurities.  In  six  samples  from  West  Vir- 
ginia, analyzed  by  C.  D.  Howard,1  the  total  paraffins  varied  between 
94.13  and  95.73  per  cent.  Methane  ran  from  79.95  to  86.48  per  cent 
and  ethane  from  7.65  to  15.09.  The  following  analyses  from  other 
sources  may  be  cited  more  in  detail: 2 


1 West  Virginia  Geol.  Survey,  vol.  1 A,  1904,  p.  556. 

2 See  also  Mabery,  Am.  Chem.  Jour.,  vol.  18, 1896,  p.  215,  for  analyses  of  gas,  largely  methane,  from  south- 
ern Ohio.  Hofer  (Das  Erdol,  pp.  100-103)  gives  many  other  data.  In  Boverton  Redwood’s  Petroleum  and 
its  products,  2d  ed.,  vol.  1,  1906,  pp.  24&-250,  full  tables  of  analyses  are  given,  with  excellent  references  to 
literature.  An  unusual  analysis  is  cited  by  G.  B.  Richardson  in  Bull.  U.  S.  Geol.  Survey  No.  260,  1905, 
p.  481.  Many  other  analyses  are  published  in  Trans.  Am.  Inst.  Min.  Eng.,  vol.  15,  pp.  529  et  seq.  Many 
analyses  of  Kansas  gases  are  given  by  H.  P.  Cady  and  D.  F.  McFarland,  Kansas  Univ.  Geol.  Survey, 
vol.  9, 1908,  p.  228.  They  found  in  nearly  all  samples  appreciable  quantities  of  helium,  and  also  argon  and 
neon.  See  also  Trans.  Kansas  Acad.  Sci.,  vol.  20, 1907,  p.  80;  vol.  21, 1908,  p.  64.  See  also  E.  Czakd,  Zeitschr. 
anorg.  Chemie,  vol.  82,  1913,  p.  249.  For  analyses  of  Californian  gas  see  G.  A.  Burrell,  Bull.  U.  S.  Bur. 
Mines  No.  19,  1911,  p.  47.  On  liquefaction  of  natural  gas,  see  L.  C.  Allen  and  G.  A.  Burrell,  Tech.  Paper 
U.  S.  Bur.  Mines  No.  10,  1912. 


THE  NATURAL  HYDROCARBONS. 


715 


Analyses  of  natural  gas. 


A.  From  Creighton,  Pennsylvania. 

B.  From  Pittsburgh,  Pennsylvania. 

C.  From  Baden,  Pennsylvania. 

D.  From  Vancouver,  British  Columbia.  Analyses  A to  D by  F.  C.  Phillips,  Am.  Chem.  Jour.,  vol.  16, 
1894,  p.  406.  Selected  from  a table  of  seventeen  analyses  to  show  extreme  variations. 

E.  Mean  of  four  gases  from  Indiana  and  three  from  Ohio,  analyzed  by  C.  C.  Howard  for  the  United  States 
Geological  Survey.  Cited  by  W J McGee,  Eleventh  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1891,  p.  592. 

F.  From  Osawatamie,  Kansas.  From  a table  of  seven  analyses  by  E.  H.  S.  Bailey,  Kansas  Univ. 
Quart.,  vol.  4,  1895,  p.  1. 


> 

A 

B 

c 

D 

E 

F 

ch4 

93.  36 

97.  63 

Paraffins  a 

96. 36 

98.  90 

87. 27 

93. 56 

C2H4,  etc 

.28 

.22 

CO 

.53 

1.  32 

co2 

3.  64 

.40 

.41 

.14 

.25 

.22 

h2 

None. 

None. 

None. 

None. 

1.  76 

None. 

n2 

None. 

.70 

12.  32 

6. 30 

3. 28 

.60 

h2s 

None. 

None. 

None. 

None. 

.18 

None. 

None. 

None. 

None. 

.29 

Trace. 

100. 00 

100. 00 

100. 00 

100. 00 

99.  93 

100. 00 

a Largely  CH*,  with  more  or  less  ethane.  CO  not  found  by  Phillips. 


The  analyses  of  Pennsylvania  gases  by  S.  P.  Sadtler  1 gave  some- 
what different  results.  In  gas  from  four  different  wells  he  found, 
in  percentages,  CH4,  60.27  to  89.65;  C2H6,  4.39  to  18.39;  and  H2,  4.79 
to  22.50.  These  high  figures  for  hydrogen  are  unusual  and  suggest 
a resemblance  to  coal  gas.  In  all  cases,  however,  methane  is  the  pre- 
ponderating constituent,  the  characteristic  hydrocarbon  of  natural 
gas.  In  the  natural  gas  of  Point  Abino,  Canada,  F.  C.  Phillips  2 
found  96.57  per  cent  of  paraffins  and  0.74  of  H2S. 

Hydrocarbons  of  the  form  CnH2n  are,  as  constituents  of  petroleum, 
of  equal  importance  to  the  paraffins.  These  again  fall  into  several 
independent  series,  which  vary  in  physical  properties  and  in  their 
chemical  relations,  but  are  identical  in  percentage  composition.  One 
series,  the  olefines,  is  parallel  to  the  paraffin  series,  and  the  following 
members  of  it  are  said  to  have  been  isolated  from  petroleum.3 


1 Second  Geol.  Survey  Pennsylvania,  Rept.  1,  1876,  pp.  146-160.  Sadtler  cites  some  analyses  by  other 
chemists. 

2 Jour.  Am.  Chem.  Soc.,  vol.  20,  1898,  p.  696. 

3 See  H.  Hofer,  Das  Erdol,  p.  65. 


716 


THE  DATA  OF  GEOCHEMISTRY. 


So-called  “ olefines ” isolated  from  petroleum. 


Name. 

Formula. 

Melting  point. 

Boiling  point. 

1.  Gaseous: 

Ethyl  fin  ft  

CJL 

-103 

Propyl  fin  fi  

CJL 

- 18 

Pntylfinfi  

CJL 

- 5 

2.  Liquid: 

Amylene 

C5H10 

+ 35 
68 

Hexylene 

CJL  9 

Heptylene  

C7H14 

98 

Octylene  

C8H1r 

124 

Nonylene  

CqH18 

153 

Decylene  

CioH2o  - - - - * 

172 

Undecylene  

Ci  i H99 

195 

Duodecylene 

GJL, 

216 

Tridecy  lene 

O13H26-  - - - - 

232.7 

Cetene 

Ci6H32-  - - - - 

275 

^20^-40  ----- 

3.  Solid: 

Cerotene 

C97H  KA 

65-66 

Melene 

27  54  * 

^30^60  ----- 

62 

This  table  is  probably  exact  in  an  empirical  sense,  but  not  so  con- 
stitutionally. Hydrocarbons  of  the  indicated  composition  have  un- 
doubtedly been  found,  and  some  of  them  are  certainly  olefines. 
According  to  C.  F.  Mabery,1  however,  the  true  olefines,  the  “ open- 
chain”  series,  are  present  in  petroleum  at  most  in  very  small  amounts. 
In  Canadian  petroleum  Mabery  and  W.  O.  Quayle  2 identified  hexyl- 
ene, heptylene,  octylene,  and  nonylene.  In  other  cases,  and  notably 
in  the  Russian  petroleums,  the  compounds  CnH2n  are  not  olefines,  but 
cyclic  hydrocarbons  of  the  polymethylene  series,  which  were  origi- 
nally called  naphtenes.  They  were  at  first  supposed  to  be  derivatives 
of  the  benzene  series,  and  it  is  only  within  recent  years  that  their  true 
constitution  has  been  determined.  In  Russian  oils  they  are  the  prin- 
cipal constituents,  and  according  to  C.  F.  Mabery  and  E.  J.  Hudson 3 
they  also  predominate  in  California  petroleum. 

Members  of  the  series  from  C7H14  to  C15H30  were  isolated  from  the 
California  material.  Mabery  and  S.  Takano  4 also  found  that  Japa- 
nese petroleum  consisted  largely  of  CnH2n  hydrocarbons.  Other  sim- 
ilar occurrences  are  recorded  in  the  treatises  of  Hofer  and  Redwood.5 6 

The  series  CnH2Q_2  is  often  called  the  acetylene  series,  after  its 
first  member,  acetylene,  C2H2.  The  lower  members  of  this  series 


1 Jour.  Am.  Chem.  Soc.,  vol.  28,  1906,  p.  415.  An  important  summary  of  our  knowledge  relative  to  the 

composition  of  American  petroleums. 

3 Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  41,  1905,  p.  89. 

a Idem,  vol.  36,  1901,  p.  255. 

« Idem,  p.  295. 

6 In  vol.  2 of  Redwood’s  great  work,  there  is  a bibliography  of  petroleum  covering  nearly  6,000  titles. 
In  the  text  Redwood  gives  a full  discussion  of  the  composition  of  various  petroleums,  and  so  too  does  Hofer. 
Only  the  barest  outline  of  the  subject  can  be  given  here,  and  that  must  presuppose  a knowledge  on  the 
part  of  the  reader  of  elementary  organic  chemistry. 


THE  NATURAL  HYDROCARBONS. 


717 


seem  not  to  have  been  found  in  petroleum;  but  several  of  its  higher 
members  are  characteristic  of  oils  from  Texas,  Louisiana,  and  Ohio. 
In  oil  from  the  Trenton  limestone  of  Ohio,  Mabery  and  O.  H.  Palm  1 
found  hydrocarbons  having  the  composition  C19H36,  C21H40,  C22H42, 
and  C24H46.  With  these  compounds  were  members  of  the  CnH2n 
series  as  high  as  C17H34.  There  were  also  members  of  the  next  series, 
CnH2n_4 — namely,  C23H42,  C24H44,  and  C25H46.  In  petroleum  from 
Louisiana,  C.  E.  Coates  and  A.  Best 2 found  the  hydrocarbons  C12H22 
and  C14H26.  These,  together  with  C16H30,  were  also  separated  by 
Mabery 3 from  Texas  oils.  These  oils  are  furthermore  peculiar  in 
containing  free  sulphur,  which  separates  out  in  crystalline  form.4  In 
petroleum  from  Santa  Barbara,  California,  Mabery 5 discovered 
hydrocarbons  of  the  three  series  CnH2n_2,  CnH2n_4,  and  CnH2n_8,  rep- 
resented by  the  formulae  C13H24,  C16H30,  C17H30,  C18H32,  C24H44,  C27H46, 
and  C29H50.  A remarkable  oil  from  the  Mahoning  Valley,  Ohio, 
according  to  Mabery,6  consists  almost  entirely  of  hydrocarbons  of 
the  series  CnH2U_2  and  CnH2n_4.  Paraffins  are  entirely  absent. 

Hydrocarbons  of  the  series  CnH2n-6,  the  “ aromatic”  or  benzene 
series,  occur  in  nearly  all  petroleums,  but  in  usually  subordinate 
amounts.  Their  empirical  formulae,  ignoring  the  existence  of  iso- 
meric compounds,  are  as  follows : 


Benzene 
Toluene. 
Xylene. . 
Cumene. 
Cymene. 
Etc. 


c6h6 

c7h8 

c8h10 

c9h12 


According  to  Mabery,7  Pennsylvania  petroleum  contains  small  pro- 
portions of  the  lower  members  of  this  series,  and  Mabery  and  Hudson  8 
found  larger  amounts  of  them,  especially  of  the  xylenes,  in  California 
oil.  Numerous  other  examples  are  cited  by  Hofer  and  Redwood,  but 
they  need  not  be  multiplied  here.9  Naphthalene,  C10H8,  is  the  only 
compound  of  the  series  CnH2n_12  which  has  been  certainly  identified 


1 Am.  Chem.  Jour.,  vol.  33,  1905,  p.  251. 

2 Jour.  Am.  Chem.  Soc.,  vol.  25, 1903,  p.  1153. 

3 Idem,  vol.  23,  1901,  p.  264.  See  also  on  Texas  oils,  C.  Richardson  and  E.  C.  Wallace,  Jour.  Soc.  Chem. 
Ind.,  vol.  20,  1901,  p.  690;  F.  C.  Thiele,  Am.  Chem.  Jour.,  vol.  22, 1899,  p.  489;  W.  B.  Phillips,  Bull.  Univ. 
Texas  No.  5,  1902;  C.  W.  Hayes  and  W.  Kennedy,  Bull.  U.  S.  Geol.  Survey  No.  212,  1903;  R.  T.  Hill, 
Trans.  Am.  Inst.  Min.  Eng.,  vol.  33, 1903,  p.  363;  and  N.  M.  Fexmeman,  Bull.  U.  S.  Geol.  Survey  No.  282, 
1906.  Fenneman  describes  both  Texas  and  Louisiana  petroleums.  On  the  composition  of  Kansas  oils, 
see  F.  W.  Bushong,  Kansas  Univ.  Geol.  Survey,  vol.  9,  1908,  p.  303.  In  the  same  volume,  p.  187, 
E.  Haworth  discusses  the  origin  of  oil  and  gas. 

* See  C.  Richardson  and  E.  C.  Wallace,  Jour.  Soc.  Chem.  Ind.,  vol.  21,  1902,  p.  316;  and  Thiele,  Chem. 
Zeitung,  vol.  26,  1902,  p.  896. 

5 Am.  Chem.  Jour.,  vol.  33, 1905,  p.  270. 

6 Jour.  Ind.  Eng.  Chem.,  vol.  6, 1914,  p.  101. 

7 Jour.  Am.  Chem.  Soc.,  vol.  28, 1906,  p.  418. 

3 Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  36, 1890,  p.  255. 

9 R.  Zaloziecki  and  J.  Hausmann  (Zeitschr.  angew.  Chemie,  1907,  p.  1761)  have  called  attention  to  the 
richness  of  Roumanian  petroleum  in  aromatic  hydrocarbons. 


718 


THE  DATA  OF  GEOCHEMISTRY. 


in  petroleum.  It  was  found  by  C.  M.  Warren  and  F.  H.  Storer1  in 
Rangoon  oil,  and  also  by  Mabery  and  Hudson  in  oil  from  California. 
In  one  of  Mabery  and  Hudson’s  distillations  of  crude  oil  so  much 
naphthalene  was  present  that  the  distillate  became  solid  on  slight 
cooling.  Still  more  complex  hydrocarbons  have  been  found  in  petro- 
leum residues,  but  it  is  possible  that  they  were  formed  during  the 
process  of  refining.  It  is  not  certain  that  they  were  present  in  the 
natural  oil.2 

In  many  petroleums  small  quantities  of  oxidized  bodies  are  con- 
tained, sometimes  complex  acids,  sometimes  phenols.  According  to 
Mabery,3  the  phenols  are  found  in  notable  proportions  in  some  Cali- 
fornia oils  but  not  in  petroleum  from  the  eastern  part  of  the  United 
States. 

Nearly  all  petroleums  contain  nitrogen,  from  a trace  up  to  1 per 
cent  and  over.  It  appears  to  exist  in  most  cases,  if  not  in  all,  in  the 
form  of  complex  organic  bases,  but  their  constitution  is  yet  to  be 
determined.  They  are  peculiarly  abundant  in  California  oil,  in  which 
they  were  discovered  by  S.  F.  Peckham,4  and  Mabery 5 * has  shown 
that  in  some  cases  they  constitute  from  10  to  20  per  cent  of  the  crude 
petroleum.  Mabery  isolated  compounds  of  this  class  ranging  from 
Cj2H17N  to  C17H21N,  although  these  formulae  are  subject  to  some 
uncertainty. 

Petroleum  free  from  sulphur  is  extremely  rare,  but  the  amount 
of  this  constituent  is  commonly  very  small.  In  some  instances,  how- 
ever, the  sulphur  compounds  are  annoyingly  abundant,  as,  for  exam- 
ple, in  the  Lima  oil  of  Ohio.  In  this  oil  Mabery  and  A.  W.  Smith  0 
found  normal  sulphides  of  the  paraffin  series,  and  isolated  ten  com- 
pounds ranging  from  methyl  sulphide,  C2H6S,  to  hexyl  sulphide, 
C12H26S.  In  Canadian  petroleum  Mabery  and  Quayle 7 discovered 
another  series  of  sulphur  compounds,  of  the  general  formula  CnH2nS, 
which  they  named  thiophanes.  Eight  members  of  this  series  were 
described,  between  C7H14S  and  C18H36S.  Other  sulphur  compounds 
have  been  mentioned  as  occasional  admixtures  in  petroleum,  and  the 
occurrence  of  free  sulphur  in  Texas  oil  has  already  been  noted.8 


» Mem.  Am.  Acad.  Arts  and  Sci.,  2d  ser.,  vol.  9, 1865,  p.  208. 

2 For  data  and  references,  see  Hofer,  Das  Erdol,  p.  74. 

2 Jour.  Am.  Chem.  Soc.,  vol.  28,  1906,  p.  596. 

* Am.  Join.  Sci.,  3d  ser.,  vol.  48,  1894,  p.  250. 

s Jour.  Soc.  Chem.  Ind.,  vol.  19, 1900,  p.  505.  F.  X.  Bandrowsky  (Monatsh.  Chemie,  vol.  8, 1887,  p.  224) 
and  A.  Weller  (Ber.  Deutsch.  chem.  Gesell.,  vol.  20, 1887,  p.  2097)  have  detected  nitrogenous  bases  in  Euro- 
pean oils. 

s Am.  Chem.  Jour.,  vol.  13, 1891,  p.  233. 

7 Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  41,  1905,  p.  89.  A paper  by  R.  Kayser,  published  in  1897,  con- 
tains data  relative  to  sulphur  compounds  in  Syrian  asphalt  oils.  I have  not  been  able  to  consult  his 
original  memoir.  Cited  by  W.  C.  Day  in  Jour.  Franklin  Inst.,  vol.  140,  1895,  p.  221,  and  also  in  Kohler’s 
treatise  on  asphalt. 

8 On  sulphur  in  California  petroleum,  see  S.  F.  Peckham,  Proc.  Am.  Philos.  Soc.,  vol.  36,  1897,  p.  108. 
Also  S.  F.  and  H.  E.  Peckham,  Jour.  Soc.  Chem.  Ind.,  vol.  16,  1897,  p.  996,  on  the  sulphur  content  of 
bitumens. 


THE  NATURAL  HYDROCARBONS. 


719 


Between  liquid  petroleum  and  solid  asphalt  there  are  numberless 
intermediate  substances.  Indeed,  there  is  no  distinct  break  in  the 
continuity  of  the  series  from  natural  gas  to  bituminous  coal.1  The 
latter  contains  solid  hydrocarbons  of  undetermined  character,  which 
break  up  under  the  influence  of  heat,  yielding  coal  gas  and  various 
tarry  products.  Some  of  the  heavier  hydrocarbon  mixtures  are  vis- 
cous, pasty  semifluids;  others  are  black,  brittle  solids,  which  resem- 
ble coal  in  their  outward  appearance.  Albertite,  grahamite,  uintaite, 
and  the  so-called  “ pitch  coal”  of  Oregon  are  familiar  examples  of 
these  solid  forms. 

Many  of  the  solid  hydrocarbons  have  been  described  as  mineral 
species  and  given  specific  names.2  Scheererite,  fichtelite,  konlite, 
hatchettite,  ozokerite,  zietrisikite,  elaterite,  hartite,  napalite,  tab- 
byite,  etc.,  are  among  the  substances.  They  vary  widely  in  compo- 
sition, being  commonly,  if  not  in  all  cases,  mixtures,  and  they  repre- 
sent different  series  of  hydrocarbons.  They  also  occur  under  widely 
differing  conditions,  indicating  genetic  distinctions.  Some  are  found 
in  coal  in  such  a way  as  to  show  their  derivation  from  vegetable 
resins;  others  appear  to  be  inspissated  petroleums;  others  again  are 
associated  with  metallic  ores,  and  are  seemingly  of  solfataric  origin. 
Napalite,  for  example,  is  found  with  ores  of  mercury  in  California, 
and  the  oxygenated  compound  idrialite  occurs  under  similar  condi- 
tions in  the  quicksilver  mine  of  Idria.3  Most  of  these  substances  are 
found  in  small  quantities,  and  are  so  imperfectly  described  that  they 
need  no  detailed  consideration  here.  Others,  like  ozokerite,  alber- 
tite, grahamite,  uintaite,  and  the  various  asphaltums  and  bitumens, 
occur  in  large  deposits  and  are  of  commercial  significance. 

Ozokerite,  for  instance,  is  an  important  source  of  paraffin.  In 
fact,  it  appears  to  consist  largely  of  the  higher  hydrocarbons  of  the 
paraffin  series,  although  some  varieties  probably  contain  compounds 
of  the  form  CnH2n.  In  Caucasian  ozokerite  F.  Beilstein  and  E. 
Wiegand  4 found  a hydrocarbon  to  which  they  gave  the  name  lekene, 
and  which  appears  to  be  a polymer  of  CH2.  In  the  ozokerite  of 
Utah5 6  paraffin  predominates,  of  composition  between  C18H38  and 
C25H52. 


1 This  continuity,  and  the  probable  community  of  origin  is  emphasized  by  Mabery,  Jour.  Ind.  Eng. 
Chem.,  vol.  6, 1914,  p.  101. 

2 See  Dana,  System  of  mineralogy,  6th  ed.,  pp.  996-1024. 

s Bitumen  is  also  common  in  the  New  Almaden  mines.  Its  association  with  the  lead  and  zinc  ores  of 

Missouri  and  with  the  copper-bearing  shales  of  Mansfeld,  Germany,  is  an  occurrence  of  a different  order, 
with  which  solfataric  action  has  nothing  to  do. 

* Ber.  Deutsch.  chem.  Gesell.,  vol.  16, 1883,  p.  1547. 

6 On  Utah  ozokerite,  see  J.  S.  Newberry,  Am.  Jour.  Sci.,  3d  ser.,  vol.  17,  1879,  p.  340;  and  A.  N.  Seal, 
Jour.  Franklin  Inst.,  vol.  130,  1890,  p.  402.  A monographic  paper  on  ozokerite  by  E.  B.  Gosling  (School 
of  Mines  Quart.,  vol.  16,  1894,  p.  41)  contains  a bibliography  of  the  mineral.  Der  Erdwachsbergbau  in 
Boryslaw,  by  J.  Muck,  Berlin,  1903,  is  an  important  monograph  on  ozokerite. 


720 


THE  DATA  OF  GEOCHEMISTRY. 


Uintaite,  or  gilsonite,1  is  another  black,  brittle,  lustrous  mixture 
of  hydrocarbons  found  in  the  Uinta  Mountains,  Utah.  Another 
similar  mineral  from  Utah  was  named  wurtzilite  by  W.  P.  Blake.2 
The  exact  nature  of  these  hydrocarbons  is  yet  to  be  determined.  The 
same  remark  may  be  applied  to  the  albertite  3 of  New  Brunswick, 
the  grahamite4  of  West  Virginia,  the  “ pitch  coal”  5 of  Coos  Bay, 
Oregon,  and  other  like  substances.  The  albertite  and  grahamite 
fill  veinlike  fissures  in  the  country  rock,  into  which  they  were  pos- 
sibly injected  when  fluid.  These  hydrocarbons,  it  should  be  observed, 
are  fusible,  therein  differing  from  coal.  They  are  also  variably 
soluble  in  organic  solvents.  Their  origin  is  obscure.  Some  authors 
attribute  them  to  the  oxidation  of  lighter  oils;  others,  like  S.  F. 
Peckham  6 regard  them  as  residues  from  a natural  distillation  of 
petroleum.  The  oxidation  theory  is  borne  out  by  the  fact  that 
grahamite,  according  to  White,  contains  13.5  to  14.7  per  cent  of 
oxygen,  while  W.  C.  Day  found  14.61  per  cent  in  the  Oregon  mineral. 
Furthermore,  W.  P,  Jenney,7  by  aspirating  heated  air  through  Penn- 
sylvania petroleum  for  several  hours,  partially  converted  the  oil 
into  a substance  resembling  grahamite.  In  this  experiment,  obvi- 
ously, the  more  volatile  hydrocarbons  were  distilled  away.  The  two 
processes,  oxidation  and  distillation,  went  on  simultaneously  0 

In  most  cases  the  solid  hydrocarbons  found  in  nature  are  not  given 
specific  names,  but  are  known  generically  as  asphalt  or  bitumen. 
The  pasty,  viscid  varieties  are  called  maltha.  There  are  also  mix- 
tures of  these  substances  with  the  material  of  sandstones,  shales,  and 
limestones,  forming  the  so-called  asphalt  rocks,  from  which  oils  or 
tars  can  be  separated  by  distillation  or  melting. 

Asphalt  and  asphalt  rock  are  widely  diffused  in  nature,  being 
found  in  all  parts  of  the  world.  Probably  the  most  remarkable 
occurrence  of  asphalt  is  that  of  the  famous  “ Pitch  Lake”  in  Trini- 
dad, which  has  been  many  times  described — best,  so  far  as  chemical 

lUintaite  has  priority,  but  gilsonite  is  the  name  most  commonly  used.  On  this  bitumen  see  J.  M. 
Locke,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  17, 1887, p.  162;  R.  W. Raymond,  idem,  vol.  18, 1888,  p.  113;  W.  P. 
Blake,  idem,  vol.  18,  1890,  p.  563;  G.  H.  Stone,  on  Utah  and  Colorado  asphalts,  Am.  Jour.  Sci.,3d  ser., 
vol.  42, 1891,  p.  148;  and  G.  H.  Eldridge,  Seventeenth  Arm.  Rept.  U.  S.  Geol.  Survey,  pt.  1,  1896,  p.  915, 
and  also  Bull.  No.  213,  1903,  p.  296.  A chemical  investigation  of  gilsonite  by  W.  C.  Day  is  reported  in 
Join*.  Franklin  Inst.,  vol.  140,  1895,  p.  221. 

2 Trans.  Am.  Inst.  Min.  Eng.,  vol.  18,  1890,  p.  497;  Eng.  and  Min.  Jour.,  vol.  48,  1889,  p.  542;  vol.  49, 
1890,  p.  106. 

s C.  H.  Hitchcock,  Am.  Jour.  Sci.,  2d  ser.,  vol.  39,  1865,  p.  267;  and  S.  F.  Peckham,  idem,  vol.  48,  1869, 
p.  362. 

4 J.  P.  Lesley,  Proc.  Am.  Philos.  Soc.,  vol.  9, 1863,  p.  183;  and  I.  C.  White,  Bull.  Geol.  Soc.  America,  vol. 

10, 1898,  p.  277.  J.  P.  Kimball  (Am.  Jour.  Sci.,  3d  ser.,  vol.  12, 1876,  p.  277)  has  described  a ‘'grahamite” 
from  Mexico.  See  also  B.  Doss,  Centralbl.  Min.,  Geol.  u.  Pal.,  1914,  p.  609. 

& W.  C.  Day,  Nineteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  3, 1898,  p.  370. 

6 Peckham, loc.  cit.,  and  also  Am.  Jour.  Sci.,  3d  ser.,  vol.  48, 1894,  p.  389. 

7 Am.  Chemist,  vol.  5, 1875,  p.  359.  For  analyses  of  Texas  grahamite  see  E.  T.  Dumble,  Trans.  Am.  Inst. 
Min.  Eng.,  vol.  21,  p.  601. 


THE  NATURAL  HYDROCARBONS. 


721 


questions  are  concerned,  in  three  papers  by  Clifford  Richardson.1  Ac- 
cording to  Richardson,  the  “lake”  occupies  the  crater  of  an  old  mud 
volcano  or  geyser,  which  has  become  filled  with  “pitch.”  This  is  an 
emulsion  of  water,  gas,  bitumen,  with  some  other  organic  substances, 
and  mineral  matter.  The  gas,  which  is  continually  evolved,  consists 
principally  of  hydrogen  sulphide  and  carbon  dioxide.  The  water 
which  permeates  the  pitch  is  rich  in  saline  matter,  mainly  sodium 
chloride,  but  it  also  contains  small  quantities  of  borates  and  of 
ammoniacal  salts,  which  indicate  that  it  is  probably  of  volcanic  ori- 
gin. An  analysis  of  the  purified  bitumen  gave  the  following  results: 

Analysis  of  Trinidad  bitumen. 


C 82.33 

H 10.69 

S 6.16 

N 81 


99.  99 

The  sulphur  content  of  this  material  led  to  an  investigation  of 
other  asphalts.  In  eighteen  hard  asphalts  the  sulphur  ran  from  3.28 
to  9.76  per  cent,  while  in  soft  asphalts  or  malthas  only  0.60  to  2.29 
per  cent  was  found.  This  leads  to  the  suggestion  that  sulphur  has 
been  active  in  hardening  the  bitumen;  that  is,  in  effecting  the  con- 
densation and  polymerization  #of  the  hydrocarbons.2  Oxygen  may 
act  in  the  same  way,  but  is  eliminated,  after  union  with  hydrogen,  as 
water.  Richardson  concludes  that  the  bitumen  consists  in  great 
part  of  unsaturated  hydrocarbons,  but  their  exact  nature  remains 
undetermined.3  He  also  describes  the  Bermudez,  Venezuela,  locality. 


1 Jour.  Soc.  Chem.  Ind.,  vol.  17,  1898,  p.  13;  Rept.  Inspector  Asphalts  and  Cements,  Washington,  D.  C., 
year  ending  June  30, 1892;  Proc.  Am.  Soc.  Testing  Materials,  vol.  6,  1906,  p.  509.  See  also  N.  S.  Manross, 
Am.  Jour.  Sci.,  2d  ser.,  vol.  20, 1855,  p.  153.  W.  Merivale  (Trans.  North  of  England  Inst.  Mech.  and  Min. 
Eng. , vol.  47, 1898,  p.  119,  has  described  the  “ manjak”  of  Barbadoes,  an  asphalt  resembling  that  of  Trinidad. 
See  also  R.  W.  Ells,  Ottawa  Naturalist,  vol.  23,  1907,  p.  73.  A recent  paper  by  Richardson  is  in  Jour. 
Phys.  Chem.,  vol.  19, 1915,  p.  241. 

2 A well-known  method  for  preparing  H2S  is  to  fuse  paraffin  with  sulphur.  The  reaction  doubtless 
involves  a union  of  the  residues  from  which  hydrogen  has  been  partially  withdrawn— that  is,  the  forma- 
tion of  a more  condensed  hydrocarbon  molecule.  The  reaction  does  not  seem  to  have  been  exhaustively 
studied.  Some  artificial  “asphalts”  have  been  prepared  by  heating  petroleum  residues  with  sulphur, 
and  a similar  substance,  “byerlite,”  is  made  by  the  slow  distillation  of  such  residues  in  presence  of  air. 
The  latter  product  resembles  gilsonite.  See  C.  F.  Mabery  and  J.  H.  Byerly,  Am.  Chem.  Jour.,  vol.  18, 
1896,  p.  141.  See  also  references  to  the  sulphur  processes  in  Kohler’s  monograph,  p.  119. 

s On  the  composition  of  asphalt,  see  also  H.  Endemann,  Jour.  Soc.  Chem.  Ind.,  vol.  16, 1897,  p.  121.  For 
analyses  of  Texas  asphalts  see  H.  W.  Harper,  Bull.  Texas  Univ.  Min.  Survey  No.  3, 1902,  p.  108.  Elaborate 
data  are  also  given  by  G.  H.  Eldridge,  Twenty-second  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1901,  p.  209, 
in  a long  paper  on  the  asphalts  and  bituminous  rocks  of  the  United  States.  Important  monographs  on 
asphalt  are  by  H.  Kohler,  Die  Chemie  und  Technologic  der  naturlichen  und  kiinstlichen  Asphalte,  Braun- 
schweig, 1904;  and  P.  Narcy,  Les  bitumes,  Paris,  1898.  See  also  T.  Posewitz,  Mitt.  K.  ungar.  geol.  Anstalt, 
vol.  15,  Heft  4, 1907,  pp.  235-463,  on  petroleum  and  asphalt  in  Hungary.  Memoirs  on  the  proximate  com- 
position of  petroleum  are  innumerable.  I have  cited,  principally,  those  of  Mabery,  because  they  relate 
specifically  to  American  oils.  The  limited  scope  of  this  volume  prevents  me  from  going  into  details,  and 
a vast  literature  must  be  passed  over.  The  fundamental  labors  of  Pelouze  and  Cahours  in  France,  of  Schor- 
lemmer  in  England,  of  Markownikoff  in  Russia,  and  of  others  in  nearly  every  country  of  Europe,  can  not 
be  given  the  consideration  here  which  is  properly  due  them. 


97270°— Bull.  616—16 16 


722 


THE  DATA  OF  GEOCHEMISTRY. 


In  a recent  article  Richardson  1 has  also  studied  at  length  the 
nature  of  grahamite,  and  given  many  analyses  of  samples  from 
different  localities.  It  is  mainly  derived  from  the  condensation  of 
paraffin  oils,  and  so  differs  from  gilsonite  and  manjak,  which  were 
formed  by  unsaturated  hydrocarbons.  Grahamite  differs  from 
albertite  in  being  soluble  in  carbon  bisulphide;  a distinction  which 
leads  to  the  designation  of  albertite  as  a pyrobitumen,  or  more  com- 
pletely metamorphosed  petroleum.  Richardson  also  gives  examples 
of  the  presence  of  vanadium  in  the  ash  of  grahamite,  a fact  already 
noticed  in  the  preceding  chapter. 

SYNTHESES  OF  PETROLEUM. 

Hydrocarbons,  notably  methane,  ethane,  acetylene,  and  benzene, 
have  been  repeatedly  prepared  by  laboratory  methods  from  inorganic 
sources,  and  also  by  the  breaking  down  of  more  complex  organic 
matter.  Some  of  the  methods  employed  have  led  to  the  production 
of  substances  resembling  petroleum,  and  these  alone  demand  con- 
sideration here.  Let  us  begin  with  the  inorganic  material. 

When  cast  iron  is  dissolved  in  an  acid,  hydrogen  is  evolved,  hut 
with  contaminations  that  were  long  ago  recognized  as  akin  to  hydro- 
carbons. In  1864  H.  Hahn 2 attempted  to  determine  their  exact 
nature  by  passing  the  gas  through  bromine.  Organic  bromides  were 
thus  formed,  corresponding  to  the  olefines  from  C2H4  to  C7H14,  the 
general  formula  being  CnH2nBr2.  In  hydrogen  evolved  from  spiegel- 
eisen  Hahn  found  still  higher  hydrocarbons,  up  to  C16H32.  These 
were  collected  by  direct  condensation  in  wash  bottles  without  the 
use  of  bromine. 

In  1873  similar  experiments  were  reported  by  F.  H.  Williams,3 
who  dissolved  spiegeleisen  in  hydrochloric  acid.  The  gas  evolved 
was  passed  through  tubes  immersed  in  a freezing  mixture,  and 
afterward  through  bromine.  In  one  experiment  7,430  grams  of 
iron  gave  49  grams  of  directly  condensible  hydrocarbons,  with  325.5 
grams  of  bromides;  and  other  experiments  yielded  similar  results. 
The  nature  of  the  hydrocarbons  was  not  further  investigated. 

Much  more  elaborate  researches  were  those  conducted  by 
S.  Cloez,4  in  the  years  1874  to  1878.  Hydrochloric  or  sulphuric  acid 
was  allowed  to  act  on  large  quantities  of  spiegeleisen,  and  the  hydro- 
gen, partly  by  direct  condensation  and  partly  by  absorption  in  bro- 
mine, yielded  abundant  hydrocarbons  and  their  bromides,  which  were 
separated  by  fractional  distillation  and  identified.  Ferromanganese 
gave  a particularly  large  product  of  hydrocarbons,  and  a cast  man- 
ganese, containing  85.4  per  cent  of  metal,  was  even  attacked  by  water 

1 Jour.  Am.  Chem.  Soc.,  vol.  32, 1910,  p.  1032. 

2 Liebig’s  Annalen,  vol.  129, 1864,  p.  57.  Hahn  gives  references  to  the  earlier  investigations. 

2 Am.  Jour.  Sci.,  3d  ser.,  vol.  6, 1873,  p.  363. 

* Compt.  Rend.,  vol.  78, 1874,  p.  1565;  vol.  85, 1877,  p.  1003;  vol.  86,  1878,  p.  1248. 


THE  NATURAL  HYDROCARBONS. 


723 


alone,  with  evolution  of  similarly  carburized  hydrogen.  In  his  first 
paper  Cloez  reports  that  he  obtained  octylene,  C8H16,  by  direct  con- 
densation, with  bromheptylene,  C7H13Br,  and  bromoctylene,  C8II15Br, 
from  the  bromine  solution.  In  his  second  paper  he  described  the 
products  obtained  during  the  solution  of  600  kilograms  of  white  cast 
iron,  which  yielded  640  grams  of  oily  hydrocarbons,  2,780  grams  of 
bromolefines,  and  532  grams  of  paraffins.  Seven  of  the  latter  were 
identified,  from  C10H22  up  to  C16H34,  hydrocarbons  identical  with 
those  which  occur  in  petroleum;  that  is,  from  the  carbides  con- 
tained in  cast  iron,  a mixture  of  hydrocarbons  chemically  resembling 
petroleum  can  be  prepared. 

In  recent  years,  through  the  development  of  the  electric  furnace 
by  Moissan,  many  carbides  have  been  made  and  investigated.  The 
greater  number  of  these  compounds  react  with  water,  yielding  hydro- 
carbons, and  the  production  of  acetylene,  as  an  iUuminating  gas,  from 
calcium  carbide,  has  become  an  important  industry.  The  metallic 
carbides,  however,  differ  in  their  yield  of  hydrocarbons,  and  the 
results  obtained  may  be  summarized  as  follows:1 

The  carbides  of  lithium,  sodium,  potassium,  calcium,  strontium, 
and  barium,  treated  with  water,  yield  acetylene,  C2H2. 

The  carbides  of  aluminum  and  glucinum  yield  principally  methane, 

CH4. 

The  carbide  of  manganese  yields  a mixture  of  methane  and 
hydrogen. 

The  carbides  of  yttrium,  lanthanum,  cerium,  thorium,  and  ura- 
nium yield  mixtures  of  acetylene,  methane,  ethylene,  and  hydrogen. 
The  cerium,  lanthanum,  and  uranium  compounds  also  yield  some 
liquid  and  solid  hydrocarbons.  From  4 kilograms  of  uranium  car- 
bide Moissan  obtained  100  grams  of  liquid  hydrocarbons,  consisting 
largely  of  olefines,  with  some  members  of  the  acetylene  series  and 
some  saturated  compounds. 

According  to  R.  Salvadori,2  hydrocarbons  can  be  generated  by 
heating  together  calcium  carbide  and  ammonium  chloride,  an 
observation  which  has  been  confirmed  by  A.  Brun.3  Furthermore 
G.  Steiger,  in  the  laboratory  of  the  United  States  Geological  Survey, 
obtained  both  saturated  and  unsaturated  hydrocarbons  by  the  simi- 
lar action  of  ammonium  chloride  upon  the  native  iron  of  Ovifak. 
Ammonium  chloride,  it  must  be  remembered,  is  one  of  the  most  char- 
acteristic of  volcanic  emanations.  The  bearing  of  these  observations 
upon  theories  of  petroleum  formation  will  be  discussed  later. 

1 See  H.  Moissan,  Compt.  Rend.,  vol.  122, 1896,  p.  1462.  Also  a summary  by  J.  A.  Mathews,  Jour.  Am. 
Chem.  Soc.,  vol.  21, 1899,  p.  647.  Berthelot  (Compt.  Rend.,  vol.  132,  1901,  p.  281)  has  discussed  the  reac- 
tions thermochemically. 

2Gazz.  chim.  ital.,  vol.  32, 1902,  p.  496. 

3 Arch,  sci.  phys.  nat.,  4th  ser.,  vol.  27, 1909,  p.  113. 


724 


THE  DATA  OF  GEOCHEMISTRY. 


It  will  be  observed  that  acetylene  is  a common  product  of  these 
reactions.  But  acetylene  is  not  a constituent  of  petroleum.  P. 
Sabatier  and  J.  B.  Senderens,1  however,  have  found  that  when  a mix- 
ture of  hydrogen  and  acetylene  is  brought  into  contact  with  finely 
divided  metallic  nickel  at  a temperature  of  200°  a mixture  of  paraffins 
is  formed  which  resembles  Pennsylvania  petroleum.  Acetylene  alone, 
in  presence  of  nickel,  also  yields  aromatic  hydrocarbons,  and  a mix- 
ture is  produced  resembling  Russian  oil.  In  this  connection  it 
should  be  noted  that  M.  Berthelot 2 long  ago  proved  that  acetylene, 
when  heated  to  the  temperature  at  which  glass  begins  to  soften,  poly- 
merizes into  benzene.  Three  molecules  of  C2H2  yield  one  of  C6H6. 
Benzene  itself,  when  heated  under  suitable  conditions,  loses  hydrogen, 
and  the  residues  combine  to  form  diphenyl,  C12H10: 

2C6H6-2H  = C12H10  + H2 

From  acetylene,  then,  as  a starting  point,  higher  hydrocarbons  may 
be  generated.  These,  again,  at  high  temperatures,  act  upon  one 
another,  and  the  complexity  of  the  final  product  may  be  very  great. 
Furthermore,  carbon  and  hydrogen  can  unite  directly.  When  the 
electric  arc  is  formed  between  carbon  terminals  in  an  atmosphere  of 
hydrogen,  acetylene  is  produced — a reaction  discovered  by  Berthelot.3 
According  to  W.  A.  Bone  and  D.  S.  Jerdan,4  methane  and  ethane  are 
formed  at  the  same  time,  but  at  a lower  temperature  (about  1,200°) 
methane  is  the  sole  product  of  the  union.  Even  by  passing  hydro- 
gen over  charcoal  at  1,200°  methane  may  be  formed. 

So  much  for  the  inorganic  syntheses  of  hydrocarbons.  On  the 
other  side  of  the  question  it  has  long  been  known  that  the  destructive 
distillation  of  organic  matter,  animal  or  vegetable,  under  conditions 
which  preclude  the  free  access  of  air,  will  produce  hydrocarbons  and 
nitrogenous  bases.  This  fact  was  first  applied  to  the  production  of 
an  artificial  petroleum  by  C.  M.  Warren  and  F.  H.  Storer5  as  far 
back  as  1865.  They  prepared  a lime  soap  from  menhaden  (fish)  oil, 
which,  on  destructive  distillation,  yielded  a mixture  of  hydrocarbons 
hardly  distinguishable  from  coal  oil6  or  kerosene.  From  this  mix- 
ture they  isolated  and  identified  the  paraffins  pentane,  hexane,  hep- 
tane, and  octane;  the  olefines  amylene,  hexylene,  heptylene,  octylene, 


1 Compt.  Rend.,  vol.  134, 1903,  p.  1185.  Similar  results  to  those  of  Sabatier  and  Senderens  have  also  been 
obtained  by  K.  Charitschkoff,  Chem.  Zentralbl.,  1907,  p.  294.  A paper  by  Charitschkoff  on  the  origin  of 
petroleum  is  abstracted  in  Jour.  Chem.  Soc.,  vol.  102,  pt.  1, 1912,  p.  329. 

2 Annales  chim.  phys.,  4th  ser.,  vol.  12, 1867,  p.*52.  According  to  E.  Briner  and  A.  Wroczynski  (Arch. 
Sci.  Phys.  Nat.,  4th  ser.,  vol.  32, 1911,  p.  389),  the  polymerization  of  acetylene  is  much  aided  by  pressure. 

3 Annales  chim.  phys.,  3d  ser.,  vol.  67,  1863,  p.  64. 

4 Jour.  Chem.  Soc.,  vol.  71,  1897,  p.  41;  vol.  79,  1901,  p.  1042.  See  also  J.  N.  Pring  and  R.  S.  Hutton, 

idem,  vol.  89, 1906,  p.  1591.  Also  W.  A.  Bone  and  H.  F.  Coward,  Jour.  Chem.  Soc.,  vol.  93,  1908,  p.  1975; 
vol.  97, 1910,  p.  1219. 

6 Mem.  Am.  Acad.  Arts  and  Sci.,  2d  ser.,  vol.  9, 1865,  p.  177. 

6 Coal  oil  is  oil  distilled  from  shale  or  coal.  The  term  is  not  synonymous  with  petroleum,  although  it 
is  often,  loosely,  so  used. 


THE  NATURAL  HYDROCARBONS. 


725 


nonylene,  decylene,  undecylene,  and  duodecylene ; together  with  ben- 
zene, toluene,  xylene,  and  isocumene,  members  of  the  aromatic  series. 
A true  artificial  petroleum  had  been  prepared. 

In  1888  C.  Engler’ s famous  investigations1  were  announced.  He 
distilled  menhaden  oil,  unsaponified,  at  a temperature  between  320° 
and  400°,  and  under  a pressure  of  ten  atmospheres.  The  distillate 
resembled  petroleum,  and  contained  the  paraffins  from  C5H12  up  to 
C7II16.  In  a later  memoir2  he  mentions  the  isolation  of  normal 
octane  and  nonane,  with  secondary  hexane,  heptane,  and  octane.  In 
a still  later  research  with  T.  Lehmann3  he  also  obtained  olefines  from 
C6H12  up  to  C9H18  and  some  derivatives  of  the  benzene  series.  These 
experiments  upon  fish  oil  confirmed  those  of  Warren  and  Storer,  but 
differed  from  theirs  in  the  direct  use  of  the  oil  instead  of  its  fatty 
acids  alone.  The  lime  soap  of  the  American  chemists  contained  only 
the  acids  of  the  oil,  separated  from  its  glycerine;  the  entire  oil  was 
used  by  Engler.  From  his  crude  product  Engler  also  prepared 
an  illuminating  oil,  practically  indistinguishable  from  commercial 
kerosene.4 

Analogous  experiments,  but  with  a somewhat  different  purpose, 
were  carried  out  by  W.  C.  Day.5  A mixture  of  fish  (fresh  herring) 
and  resinous  pine  wood  was  distilled  from  an  iron  retort,  the  process 
being  continued  to  complete  carbonization  of  the  residual  material. 
The  distillate  consisted  of  a mixture  of  oil  and  water,  and  the  oil, 
upon  redistillation,  yielded  a residue  closely  resembling  gilsonite. 
When  fish  alone  was  distilled,  the  final  product  was  more  like  elater- 
ite.  Wood  alone  gave  a similar  oil,  with  a similar  residue  on  redis- 
tillation.  In  this  research,  then,  artificial  asphalts  were  obtained, 
curiously  resembling  the  natural  substances.  They  also,  like  ordi- 
nary asphalt,  contained  some  nitrogen. 

Vegetable  oils  likewise  yield  hydrocarbons  upon  destructive  dis- 
tillation. S.  P.  Sadtler,6  for  example,  established  this  fact  with 
regard  to  linseed  oil,  but  the  nature  of  the  product  was  not  completely 
determined.  Engler  7 obtained  hydrocarbons  by  the  distillation  of 
colza  and  olive  oils,  as  well  as  from  fish  oil,  butter,  and  beeswax. 
Furthermore,  J.  Marcusson  8 cites  an  experiment  in  which  pure  oleic 
acid  was  heated  for  several  hours  to  330°  in  a sealed  tube.  On  open- 
ing the  tube  there  was  a strong  evolution  of  gas,  and  in  the  residue  a 

1 Ber.  Deutsch.  chem.  Gesell.,  vol.  21, 1888,  p.  1816. 

a Idem,  vol.  22, 1889,  p.  592. 

3 Idem,  vol.  30, 1897,  p.  2365.  A paper  by  C.  Engler  and  E.  Severin  on  artificial  petroleum  is  in  Zeitschr. 
angew.  Chemie,  vol.  25, 1912,  p.  153. 

4 Observations  confirmed  by  Redwood,  Petroleum  and  its  products,  2d  ed.,  vol.  1,  p.  259. 

6 Am.  Chem.  Jour.,  vol.  21, 1899,  p.  478. 

« Proc.  Am.  Philos.  Soc.,  vol.  36, 1897,  p.  93. 

7 Cong,  intomat.  du  pgtrole,  Paris,  1900,  p.  20. 

s Chem.  Zeitung,  vol.  30, 1906,  p.  789. 


726 


THE  DATA  OF  GEOCHEMISTRY. 


product  was  found  which,  completely  resembled  a lubricating  oil  from 
petroleum.  These  examples  are  only  two  out  of  many  which  might 
be  adduced. 

ORIGIN  OF  PETROLEUM. 

Probably  no  subject  in  geochemistry  has  been  more  discussed  than 
that  of  the  origin  of  petroleum.  Theory  after  theory  has  been  pro- 
posed, and  controversy  is  still  active.  The  evidence  is  abundant,  but 
contradictory,  and  leads  to  different  conclusions  when  studied  from 
different  points  of  view. 

The  theories  so  far  advanced  may  be  divided  into  two  categories — 
the  inorganic  and  the  organic.  Let  us  examine  the  hypotheses  sepa- 
rately. The  earlier  speculations  connecting  the  formation  of  petro- 
leum with  volcanic  phenomena  may  be  passed  over,  for  the  reason  that 
they  were  framed  at  a time  when  essential  evidence  was  not  available. 
They  were  speculations,  nothing  more.  The  modern  era  begins  with  a 
memoir  by  M.  Berthelot,1  published  in  1866. 

Berthelot  started  from  a supposition  of  Daubree  that  the  interior 
of  the  earth  might  contain  free  alkaline  metals.  Upon  these,  as  Ber- 
thelot had  previously  shown,  carbon  dioxide  could  react  at  high  tem- 
peratures, forming  acetylides  from  which,  with  water,  acetylene 
would  be  generated,  with  all  of  its  possibilities  of  condensation  into 
higher  hydrocarbons.  The  weak  point  of  the  hypothesis,  which  Ber- 
thelot only  advances  tentatively,  is  that  no  evidence  exists  to  show 
that  the  alkaline  metals  are  present  in  an  uncombined  state  at  any 
point  below  the  surface  of  the  earth.  The  starting  point  is  a pure 
assumption,  which  is  more  likely  to  be  erroneous  than  true. 

Leaving  out  of  account  the  oft-cited  paper  by  H.  Byasson,2  which 
has  no  present  value,  we  come  next  to  the  famous  carbide  theory  of 
D.  Mendeleef,3  published  in  1877.  This  theory  presupposes  the 
existence  of  iron  carbides  within  the  earth,  to  which  percolating  waters 
gain  access,  generating  hydrocarbons.  If  such  carbides  exist  at  rea- 
sonable depths  below  the  surface  of  the  earth,  the  suggested  reactions 
would  presumably  take  place;  but  the  major  premise  is  as  yet 
unproved.  The  actual  existence  of  the  carbides  in  nature  remains  to 
be  demonstrated. 

Mendeleef’ s hypothesis  naturally  attracted  much  attention  and 
was  rendered  plausible  by  researches  like  those  of  Hahn,  Williams, 
and  Cloez  upon  the  production  of  hydrocarbons  from  cast  iron.  It 
was  still  further  strengthened  by  the  discoveries  of  Moissan  in  his 
development  of  the  electric  furnace,  and  has  had  many  advocates. 

1 Annales  chim.  phys.,  4th  ser.,  vol.  9, 1866,  p.  481. 

8 Compt.  Rend.,  vol.  73, 1871,  p.  611.  A later,  separate  brochure  by  Byasson  I have  not  seen. 

3 Ber.  Deutsch.  chem.  Gesell.,  vol.  10, 1877,  p.  229;  Jour.  Chem  Soc.,  vol.  32,  p.  283.  See  also  Mendel&f’s 
Principles  of  chemistry,  English  translation,  vol.  1, 1891,  pp.  364-366. 


THE  NATURAL  HYDROCARBONS. 


727 


Moissan  1 himself  has  adopted  it,  and  also  suggested  that  volcanic 
explosions  may  perhaps  be  caused  by  the  action  of  water  upon  subter- 
ranean carbides.  He  admits,  however,  that  some  petroleums  are  pos- 
sibly of  organic  origin.  The  presence  of  marsh  gas  in  volcanic  ema- 
nations 2 may  be  cited  in  support  of  Moissan’s  suppositions,  but  this 
well-recognized  fact  can  be  interpreted  otherwise.  Another  favorable 
datum  has  been  furnished  by  O.  Silvestri,3  who  found  in  basaltic  lavas 
from  near  Etna  both  liquid  oils  and  a solid  paraffin  which  melted  at 
56°.  Similar  observations  have  been  made  by  A.  Brun,4  in  his  study 
of  the  Javanese  volcanoes.  He  regards  the  petroleum  of  Java  as  of 
volcanic  origin.  But  these  oils,  as  well  as  the  marsh  gas,  may  con- 
ceivably have  been  formed  either  through  a direct  union  of  carbon 
and  hydrogen  or  from  material  distilled  by  volcanic  heat  out  of 
adjacent  sedimentary  rocks.  The  same  considerations  also  apply 
to  the  petroleum  field  near  Tampico,  Mexico,  as  described  by  E. 
Ordonez,5  which  is  cited  by  E.  Coste  6 in  support  of  his  elaborate 
argument  in  favor  of  the  inorganic  origin  of  petroleum.  In  this  field 
the  oil  rises  close  to  volcanic  cones;  which,  however,  have  been 
forced  up  through  a great  thickness  of  Cretaceous  shales.  The  possi- 
bility of  a distillation  of  oil  from  organic  matter  in  the  sediments 
must  here  be  taken  into  account. 

A different  line  of  investigation  relative  to  the  genesis  of  petroleum 
is  that  proposed  tentatively  by  G.  F.  Becker.7  If  petroleum  is 
derived  from  iron  carbides,  as  the  inorganic  theory  assumes,  there 
should  be  magnetic  irregularities  in  oil-bearing  regions.  This  he 
finds  to  be  the  case  in  the  Appalachian  oil  field,  where  the  lines  of 
magnetic  declination  are  sensibly  deflected.  Similar  irregularities 
appear  in  the  oil  fields  of  California,  and  magnetic  disturbances  are 
also  recorded  in  the  region  of  the  Caucasus.  The  observations  are 
not  absolutely  conclusive,  but  they  are  compatible  with  the  inorganic 
theory. 

Two  other  speculations  upon  the  genesis  of  petroleum  from  inor- 
ganic matter  remain  to  be  mentioned,  if  only  for  the  sake  of  com- 
pleteness. N.  V.  Sokoloff,8  in  1890,  argued  that  the  bitumens  are  of 
cosmic  origin,  formed  initially  during  the  consolidation  of  the  planet, 
inclosed  within  the  primeval  magma,  and  since  emitted  from  the 
earth’s  interior.  In  support  of  this  conception  he  cites  the  occasional. 

1 Compt.  Rend.,  vol.  122,  1896,  p.  1462.  See  also  S.  Meunier,  idem,  vol.  123,  1896,  p.  1327. 

2 See  ante,  Chapter  VIII. 

3 Gazz.  chim.  ital.,  vol.  7, 1877,  p.  1;  vol.  12,  1882,  p.  9. 

* Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  27,  1909,  p.  113. 

5 Min.  and  Sci.  Press,  vol.  95,  1907,  p.  249. 

8 Jour.  Canadian  Min.  Inst.,  vol.  12, 1909,  p.  273.  For  earlier  papers  by  Coste  see  the  same  journal,  vol. 
6, 1903,  p.  73,  and  Trans.  Am.  Inst.  Min.  Eng.,  vol.  35,1905,  p.  288.  F.  Rigaud  (Rev.  univ.  des  mines, 
4th  ser.,  vol.  31, 1910,  p.  145)  has  also  argued  in  favor  of  the  inorganic  origin  of  petroleum. 

t Bull.  U.  S.  Geol.  Survey  No.  401, 1909. 

8 Bull.  Soc.  imp.  nat.  Moscou,  new  ser.,  vol.  3, 1890,  p.  720. 


728 


THE  DATA  OF  GEOCHEMISTRY. 


finding  of  hydrocarbons  in  meteorites,1  cases  in  which  the  possibility 
of  an  organic  origin  seems  to  be  absolutely  excluded. 

The  other  speculation  is  that  of  O.  C.  D.  Ross,2  who  has  tried  to 
show  that  petroleum  may  originate  from  the  action  of  solfataric 
gases  upon  limestones.  Ross  wrote  various  chemical  equations  to 
show  how  the  reactions  might  occur,  but  they  are  improbable  and 
experimentally  unverified. 

It  will  be  seen,  upon  consideration,  that  these  inorganic  theories 
concerning  the  origin  of  petroleum  relate  not  only  to  its  proximate 
genesis,  but  to  fundamental  questions  of  cosmology.  SokolofFs 
hypothesis  is  an  indication  of  this  fact,  and  the  assumption  of  carbides 
within  the  earth  represents  an  effort  in  the  same  direction.  An  illus- 
tration of  this  implication  is  to  be  found  in  Lenicque’s  remarkable 
memoir,3  which  was  cited  in  Chapter  II  of  this  volume.  If  the 
molten  globe  had  at  any  time  a temperature  like  that  of  the  electric 
furnace,  carbides,  silicides,  nitrides,  etc.,  would  be  among  the  earliest 
compounds  to  form,  and  oxidation  could  not  begin  until  later. 
Under  such  conditions  some  carbides  might  remain  unoxidized 
through  many  geologic  ages,  to  be  reached  by  percolating  waters  at 
the  present  day.  The  development  of  hydrocarbons  would  then 
inevitably  follow,  although  to  what  extent  they  might  be  subse- 
quently consumed  no  one  can  say.  The  theory  is  plausible,  but  is  it 
capable  of  proof?  Furthermore,  does  it  account  for  any  accumula- 
tions of  petroleum  such  as  yield  the  commercial  oils  of  to-day? 
These  essential  questions  are  too  often  overlooked,  and  yet  they  are 
the  main  points  at  issue.  We  may  admit  that  hydrocarbons  are 
formed  within  volcanoes,  but  the  quantities  definitely  traceable  to 
such  a source  are  altogether  insignificant.  Bitumens  occur  in  small 
amounts  in  many  igneous  rocks,  but  never  in  large  volume.  They 
are,  moreover,  absent,  at  least  in  significant  proportions,  from  the 
Archean,  and  first  appear  abundantly  in  Paleozoic  time.  From  the 
Silurian  upward  they  are  plentiful,  and  commonly  remote  from  great 
indications  of  volcanic  activity.  Even  such  an  occurrence  as  that  of 
the  Pitch  Lake  in  Trinidad,  where  asphalt  is  associated  with  thermal 
waters,  does  not  necessarily  imply  a community  of  origin.  It-is  at 
least  conceivable  that  the  solfataric  springs  may  have  acted  upon 
sedimentary  accumulations  of  oil,  partly  by  vaporizing  the  latter  and 

1 See  F.  Wohler,  Liebig’s  Annalen,  vol.  109, 1859,  p.  349,  on  carbon  compounds  in  the  meteorite  of  Kaba, 
Hungary.  Also  S.  Meunier,  Compt.  Rend.,  vol.  109, 1889,  p.  976,  on  the  meteorite  of  Mighei,  Russia.  A.  E. 
Nordenskiold  (Poggendorf’s  Annalen,  vol.  141, 1870,  p.  205)  found  carbonaceous  matter  in  the  meteorite  of 
Hessle,  Sweden;  and  G.  Tschermak(Sitzungsb.  K.  Wiss.  Akad.  Wien,  vol.  62,  Abth.  2, 1870,  p.  855) reports 
0.85  per  cent  of  a hydrocarbon  in  the  stone  which  fell  at  Goalpara,  India.  The  well-known  meteors  of 
Orgueil,  France,  and  Cold  Bokkeveld,  South  Africa,  were  largely  carbonaceous.  On  Orgueil,  see  S.  Cloez, 
Compt.  Rend. , vol.  59, 1864,  p.  37.  Graphite  and  amorphous  carbon  are  common  in  meteorites,  and  in  some 
falls  diamonds  have  been  found. 

2 Chem.  News,  vol.  64, 1891,  p.  14.  A criticism  by  Redwood  appears  on  p.  215. 

3M6m.  Soc.  ingen.  civils  France,  October,  1903,  p.  346. 


THE  NATURAL  HYDROCARBONS. 


729 


so  bringing  it  to  the  surface,  and  partly  by  effecting,  with  the  aid  of 
steam  and  sulphur,  the  condensations  or  polymerizations  that  are 
observed.  These  considerations  serve  to  show  the  need  of  great 
caution  in  dealing  with  this  class  of  problems  and  to  warn  us  against 
hasty  generalizations.  Speculations  based  upon  individual  occur- 
rences of  petroleum  are  of  very  little  value.  The  entire  field,  in  all 
of  its  complexity,  must  be  taken  into  account. 

Admitting  that  methane  is  sometimes  formed  as  a volcanic  emana- 
tion, we  must  also  recognize  the  fact  that  it  is  more  commonly  of 
organic  origin.  Its  popular  name,  “ marsh  gas,”  is  verbal  evidence 
of  its  derivation  from  decaying  vegetation.  Ordinarily,  it  is  gener- 
ated in  apparently  small  amounts,  but  gas  in  Iowa  wells  has  been 
described  1 which  occurs  in  the  drift  and  seems  to  be  of  vegetable 
origin.  Buried  vegetation  alone  can  account  for  its  development 
under  the  observed  conditions. 

Apart  from  the  natural  occurrences  of  marsh  gas,  either  in  swamps 
or  as  the  “fire  damp”  of  coal  mines,  its  artificial  production  has  been 
studied  experimentally.  F.  Hoppe-Seyler 2 and  H.  Tappeiner 3 have 
shown  that  it  is  formed  by  the  fermentation  of  cellulose,  together 
with  carbon  dioxide  and  free  hydrogen.  During  the  decay  of  sea- 
weeds, however,  according  to  F.  C.  Phillips,4  a little  methane  is  at  first 
evolved,  the  generated  gases  consisting  largely  of  carbon  dioxide, 
hydrogen,  and  nitrogen.  The  apparatus  in  which  the  experiment  was 
performed  was  allowed  to  stand  in  position  for  two  and  a half  years, 
and  during  that  time,  following  the  first  rapid  evolution  of  gas,  a very 
slow,  continuous  production  was  observed.  At  the  end  of  the  period 
the  gas  consisted  of  methane.  Phillips  concludes,  from  this  evidence, 
that  buried  vegetable  matter,  after  a brief  era  of  rapid  gas  evolution, 
may  pass  into  a condition  of  extremely  slow  decay  when  methane  is 
generated.  It  is  possible,  however,  that  methane  is  not  the  only 
hydrocarbon  thus  produced. 

From  data  of  this  kind,  and  from  the  experiments  cited  in  the  pre- 
ceding section  of  this  chapter,  it  is  evident  that  hydrocarbons  analo- 
gous to  natural  gas,  petroleum,  and  asphalt  may  be  derived  either 
from  animal  or  vegetable  matter,  or  from  both.  This,  I think, 
admits  of  no  dispute,  but  argument  is  possible  relative  to  the  genesis 
of  the  larger  accumulations  of  mineral  oil.  Engler’s  researches 
have  led  to  a widespread  belief  in  the  animal  origin  of  petroleum, 
although  the  details  of  the  transformation  process  are  very  diversely 

1 See  A.  G.  Leonard,  Proc.  Iowa  Acad.  Sci.,  vol.  4,  p.  41.  F.  M.  Witter  (Am.  Geologist,  vol.  9,  1892, 
p.  319)  has  described  a gas  well,  about  100  feet  deep,  near  Letts,  Iowa. 

2 Ber.  Deutsch.  chem.  Gesell.,  vol.  16, 1883,  p.  122. 

3 Idem,  pp.  1734, 1740.  See  also  L.  Popoff,  abstract  in  Jour.  Chem.  Soc.,  vol.  28, 1875,  p.  1209,  on  gas  from 
river  mud  near  sewer  openings. 

4 Am.  Chem.  Jour.,  vol.  16,  1894,  p.  427. 


730 


THE  DATA  OF  GEOCHEMISTRY. 


interpreted.1  Engler  2 himself  ascribes  the  derivation  of  petroleum 
from  animal  remains  to  a putrefactive  process,  which  removes  the 
nitrogen  compounds.  The  fats  remain,  to  be  altered  by  heat  and 
pressure  3 into  hydrocarbons,  whose  boiling  points  lie  below  300°; 
and  these  later  undergo  a partial  autopolymerization  into  denser 
forms.  How  far  such  a polymerization  may  be  possible,  if  indeed 
it  is  possible  at  all,  is  a matter  of  uncertainty.  C.  F.  Mabery  4 holds 
that  the  changes  are  always  in  the  opposite  direction  and  that  the 
more  complex  hydrocarbons  are  formed  first,  partially  breaking 
down  afterward  into  lower  members  of  the  series.  J.  Marcusson  5 
holds  the  same  view.  The  putrefactive  removal  of  the  albuminoid 
substances  is  also  to  be  questioned,  and  it  is  certainly  not  universal. 
The  nitrogen  bases  of  California  petroleum  furnish  perhaps  the 
strongest  evidence  that  the  proteids  contribute  their  share  to  the 
make-up  of  petroleum,  and  show  also  that  these  particular  oils  are 
of  animal  origin. 

Several  other  writers  have  brought  evidence  to  bear  in  favor  of 
the  derivation  of  petroleum  from  fish  remains.  Dieulafait 6 observed 
that  the  copper  shales  of  Mansfeld  are  strongly  impregnated  with 
bitumen,  and  also  rich  in  fossil  fish.  The  petroleum  of  Galicia  is 
always  associated  with  menilitic  schists  in  which  fish  remains  are 
peculiarly  abundant.  C.  Engler 7 cites  some  computations  by  Szaj- 
nocha,  to  the  effect  that  the  annual  catch  of  herring  on  the  north 
coast  of  Germany  would,  if  its  fats  were  half  converted  into  petro- 
leum, yield  in  2,560  years  as  much  oil  as  Galicia  has  produced.  G.  A. 
Bertels,8  on  the  other  hand,  attributes  the  Caucasian  petroleums  to 
the  decomposition  of  mollusks.  In  the  Kuban  district,  the  oil, 

1 For  a very  complete  summary  of  all  the  hypotheses  relative  to  the  formation  of  petroleum,  see  Hofer, 
Das  Erdol,  1906,  pp.  160-229.  See  also  Redwood,  Petroleum  and  its  products,  vol.  1,  1906,  pp.  250-261. 
Other  summaries  are  by  Aisinmann,  Zeitschr.  angew.  Chemie,  1893,  p.  739;  idem,  1894,  p.  122;  C.  Element, 
Bull.  Soc.  beige  geol.,  vol.  11,  proc.  verb.,  1897,  p.  76;  R.  Zuber,  Zeitschr.  prakt.  Geologie,  1898,  p.  84;  and  E. 
Orton,  Bull.  Geol.  Soc.  America,  vol.  9, 1897,  p.  85.  Very  recent  memoirs  on  the  subject  are  by  P.  De  Wilde, 
Arch.  sci.  phys.  nat.,  4th  ser.,  vol.  23,  1907,  p.  559,  and  C.  Neuberg,  Sitzungsb.  K.  Akad.  Wiss.  Berlin, 
May  16,  1907. 

2 Ber.  Deutsch.  chem.  Gesell.,  vol.  30,  1897,  p.  2358.  For  more  recent  articles  by  Engler  see  Zeitschr. 
angew.  Chemie,  vol.  21,  1908,  p.  1585;  Verhandl.  naturwiss.  Vereins,  Karlsruhe,  1908,  vol.  20,  p.  65;  and 
Compt.  rend.  Cong,  internat.  petrole,  Bucarest,  1910,  vol.  2,  p.  1.  The  last-named  volume  contains  many 
papers  on  various  subjects  relating  to  petroleum. 

3 The  importance  of  pressure  in  petroleum  formation  was  also  urged  by  G.  Kramer  and  W.  Bottcher 
(Ber.  Deutsch.  chem.  Gesell.,  vol.  20,  1887,  p.  595),  in  their  comparison  of  the  hydrocarbons  contained  in 
petroleum  and  coal  oil  or  tar.  H.  Monke  and  F.  Beyschlag  (Zeitschr.  prakt.  Geologie,  1905,  pp.  1,  65,  421) 
emphasize  the  putrefactive  process,  which  yields  petroleum,  as  compared  with  the  carbonizing  process, 
which  forms  coal. 

4 Jour.  Am.  Chem.  Soc.,  vol.  28, 1906,  p.  429. 

6  Chem.  Zeitung,  vol.  30, 1906,  p.  788. 

6 Cited  by  A.  Jaccard,  Arch.  sci.  phys.  nat.,  3d  ser.,  vol.  24,  1890,  p.  106. 

7 Ber.  Deutsch.  chem.  Gesell.,  vol.  33, 1900,  p.  16.  See  also  Cong,  internat.  du  p6trole,  1900,  p.  30. 

8 Cited  by  Hofer,  Das  Erdol,  1906,  p.  219.  F.  Hornung  (Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  57,  Mo- 
natsb.,  1905,  p.  534)  argues  in  favor  of  fishes  as  the  raw  material  of  petroleum.  See  also  J.  J.  Jahn,  Jahrb. 
K.-k.  geol.  Reichsanstalt,  vol.  42,  1892,  p.  361.  For  arguments  against  the  theory  of  Engler,  see  D.  Pan- 
tanelli,  Bull.  Soc.  geol.  ital.,  vol.  25,  1906,  p.  795.  Pantanelli  seems  to  favor  the  inorganic  origin  of  petro- 
leum. W.  Ipatief  (Jour,  prakt.  Chem.,  ser.  2,  vol.  84, 1911,  p.  800)  favors  the  organic  origin. 


THE  NATURAL  HYDROCARBONS.  731 

accompanied  by  salt  water,  exudes  directly  from  beds  of  molluscan 
remains,  which  occur  in  enormous  quantities. 

Engler,  of  course,  was  not  the  first  to  advocate  a derivation  of 
petroleum  from  animal  remains.  His  views  have  received  special 
attention  because  of  their  experimental  basis.  C.  Ochsenius,1  for 
instance,  has  sought  to  connect  the  formation  of  petroleum  with  that 
of  the  mother-liquor  salts  which  accumulate  during  the  last  stage 
of  the  evaporation  of  sea  water.  According  to  this  writer,  petroleum 
is  generated  from  marine  organisms,  preferably  the  larger  forms, 
which  are  buried  beneath  air-tight  sediments  and  slowly  acted  upon 
by  the  above-named  saline  residues.  As  an  argument  in  favor  of 
this  hypothesis,  he  calls  attention,  as  many  others  have  done,  to  the 
common  association  of  brine  with  petroleum,  and  cites  analyses  of 
such  waters.  This  association  of  salt  and  oil  is  strongly  emphasized 
by  L.  Mrazec 2 in  his  studies  of  Roumanian  petroleum.  F. 
Heusler 3 also,  while  indorsing  Engler’ s principal  conclusions, 
invoked  the  aid  of  aluminum  chloride  as  an  agent  in  effecting 
a polymerization  of  the  hydrocarbons.  According  to  Ochsenius’s 
theory,  magnesium  chloride  was  the  active  substance.  These  sug- 
gestions are  of  very  little  value,  for  the  reason  that  the  laboratory 
reactions  with  aluminum  chloride  are  effected  with  the  anhydrous 
salt  and  not  with  its  hydrolyzed  aqueous  solutions.  It  is  not  shown 
experimentally  that  the  latter  would  be  effective,  nor  does  aluminum 
chloride  occur  in  any  notable  quantity  in  natural  waters.4  A more 
probable  function  of  the  salts,  according  to  R.  Zaloziecki,5  is  to  retard 
and  modify  the  decay  of  animal  matter  on  or  near  the  seashore,  and 
so  to  give  time  for  its  transformation  into  petroleum.  The  latter 
process  need  not  be  very  slow,  for  E.  Sickenberger 6 has  shown  that  in 
small  bays  of  the  Red  Sea,  where  the  salinity  reaches  7.3  per  cent, 
petroleum  is  actually  forming  as  a scum  upon  the  surface  of  -the  water. 
Living  forms  are  abundant  in  these  bays,  and  their  remains,  after 
death,  furnish  the  hydrocarbons.  The  latter  are  to  some  extent 
absorbed  into  the  pores  of  coral  reefs,  and  so  contribute  to  the  forma- 
tion of  bituminous  limestones.  A still  earlier  publication  by  O.  F. 
Fraas,7  contains  data  of  similar  purport.  Fraas  found  in  Egypt 

1 Chem.  Zeitung,  vol.  15, 1891,  p.  935,  and  Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  48,  1896,  p.  239.  See  also 
his  papers  cited  in  Chapter  VII,  ante. 

2 Compt.  rend.  Cong,  intemat.  petrole,  Bucarest,  1910,  vol.  2,  p.  80.  Also  L’industrie  du  petrole  en 
Roumanie,  Bucarest,  1910.  The  presence  of  methane,  ethane,  etc.,  in  rock  salt  has  been  studied  by  N. 
Cost&chescu,  Annales  sci.  Univ.  Jassy,  vol.  4,  1906,  p.  3.  On  the  animal  origin  of  petroleum  see  also  L. 
Singer,  Inaug.  Diss.,  Zurich,  1893. 

3 Zeitschr.  angew.  Chemie,  1896,  pp.  288, 318. 

* A possible  exception  to  this  statement  is  cited  by  Ochsenius  (Zeitschr.  Deutsch.  geol.  Gesell.,  vol.  48, 

1896,  p.  239),  who  mentions  a water  containing,  in  its  solid  residue,  23.91  per  cent  of  AICI3.  This  water 
accompanied  a petroleum. 

3 Chem.  Zeitung,  vol.  15, 1891,  p.  1203. 

« Idem,  p.  1582. 

1 Bull.  Soc.  sci.  nat.  NeucMtel,  vol.  8,  1868,  p.  58.  See  also  F.  C.  Phillips,  Proc.  Am.  Philos.  Soc.,  vol.  36, 

1897,  p.  121,  on  petroleum  inclosed  in  fossils. 


732 


THE  DATA  OP  GEOCHEMISTRY. 


shells  filled  with  bitumen,  and  noticed  that  the  bituminous  beds  were 
rich  in  fossils,  while  the  nonbituminous  strata  were  poor.  In  the 
region  of  the  Dead  Sea,  also,  Fraas  noticed  that  bitumen  was  abundant 
in  beds  of  baculites,  from  which  it  exudes  to  accumulate  upon  the 
shore.  In  this  connection  it  may  well  be  noted  that  the  brines  which 
are  so  often  associated  with  petroleum  have,  as  a rule,  a composition 
indicative  of  a marine  origin,  and  do  not  resemble  solfataric  or  vol- 
canic waters.1  Furthermore,  Mendel eefs  objection  to  the  possibility 
of  forming  petroleum  at  the  bottom  of  the  sea — namely,  that  being 
lighter  than  water  it  would  float  away  and  be  dissipated — is  not  only 
negatived  by  Sickenberger’s  observations,  but  also  by  the  well-known 
fact  that  mud  and  clay  are  capable  of  retaining  oily  matters  mechan- 
ically. The  littoral  sediments  probably  aid  in  the  process  of  petro- 
leum formation,  if  only  to  the  extent  of  retaining  the  fatty  substances 
from  which  the  oil  is  to  be  produced.  The  beds  of  sulphur  which  occur 
adjacent  to  some  oil  wells,  notably  in  Texas,  were  probably  formed 
by  the  reducing  action  of  organic  matter  upon  sulphates,  such  as 
gypsum,  a mineral  which  is  often  associated  with  marine  deposits  and 
with  petroleum.  The  association  of  gas,  oil,  salt,  sulphur,  and  gyp- 
sum, which  some  writers  have  taken  as  evidence  of  former  volcanism, 
is  much  more  simply  interpreted,  both  chemically  and  geologically, 
as  due  to  the  decomposition  of  organic  matter  in  shallow,  highly  saline 
waters  near  the  margin  of  the  sea. 

The  derivation  of  petroleum  from  vegetable  remains  has  had  many 
advocates,  although  the  hypotheses  have  not  all  been  framed  on  the 
same  lines.  L.  Lesquereux,2  studying  the  Devonian  oils  of  the  eastern 
United  States,  argued  in  favor  of  their  derivation  from  cellular 
marine  plants,  especially  fucoids,  whose  remains  abound  in  the  petro- 
liferous formations.  Ligneous  or  fibrous  plants,  on  the  other  hand, 
yield  coal.*  This  hypothesis  led  Youga  3 to  suggest  that  great  masses 
of  fucus,  like  those  of  the  Sargasso  Sea,  might  sink  to  the  bottom  of 
the  ocean,  and  there,  decomposing  under  pressure,  could  yield  petro- 
leum. Redwood 4 states  that  the  salt  marshes  of  Sardinia  are  some- 
times covered  by  sheets  of  seaweed,  which  are  in  process  of  decompo- 
sition into  an  oily  substance  resembling  petroleum,  and  similar  occur- 
rences have  been  noted  on  the  coast  of  Sweden.  These  phenomena 
are  probably  not  exceptional,  and  deserve  a more  precise  examination 
than  they  have  received  hitherto.  An  observation  by  W.  L.  Watts 5 

1 The  waters  accompanying  the  naphtha  of  the  Grosny  district,  Russia,  as  analyzed  recently  by  K. 
Charitschkoff  (Chem.  Zeitung,  1907,  p.  295),  appear  to  be  exceptional.  In  these  sodium  carbonate  is  more 
abundant  than  the  chloride,  and  salts  of  ammonium  and  the  amines  are  also  present. 

2 Bull.  Soc.  sci.  nat.  Neuchatel,  vol.  7,  1866,  p.  234. 

3 See  discussion  following  Lesquereux’s  communication. 

* Petroleum  and  its  products,  2d  ed.,  vol.  1,  pp.  126,  142. 

6 Bull.  California  State  Min.  Bur.  No.  19,  p.  202.  See  also  Bull.  No.  3 for  more  details.  In  Bull.  No.  16, 
1899,  A.  S.  Cooper  discusses  at  length  the  genesis  of  petroleum  and  asphalt  in  California.  Bulls.  Nos.  31  and 
32  also  relate  to  this  subject. 


THE  NATURAL  HYDROCARBONS. 


733 


• 

that  the  saline  waters  associated  with  petroleum  in  the  central  valley 
of  California  are  unusually  rich  in  iodine  appears  to  have  some  relation 
to  this  class  of  hypotheses.  Watts  connects  this  iodine  with  the 
familiar  content  of  iodine  in  seaweed,  and  regards  the  latter  as  a 
probable  source  of  this  particular  oil. 

Data  of  this  class  might  be  multiplied  almost  indefinitely.  For 
instance,  C.  E.  Bertrand  and  B.  Kenault 1 have  shown  that  Boghead 
mineral,  torbanite,  and  kerosene  shale,  from  which  oils  are  distilled, 
are  derived  from  gelatinous  algae,  whose  remains  are  embedded  in 
what  was  once  a brown  humic  jelly.  This  observation  may  be  cor- 
related with  the  views  advanced  by  J.  S.  Newberry 2 and  S.  F.  Peck- 
ham,3  who  regard  the  liquid  petroleums  as  natural  distillates  from 
carbonaceous  deposits,  which  latter  were  laid  down  at  depths  below 
the  horizons  where  the  oil  is  now  found.  The  heat  generated  during 
metamorphism  is  supposed  to  be  the  dynamic  agent  in  this  process, 
although  many  productive  regions  show  no  evidence  that  any  violent 
metamorphoses  have  ever  occurred.4 

In  1843  E.  W.  Binney  and  J.  H.  Talbot 5 reported  a peculiar  occur- 
rence of  petroleum  permeating  a peat  bog,  Down  Holland  Moss,  not 
far  from  Liverpool,  England.  The  origin  of  this  oil  was  obscure, 
but  was  attributed  by  the  authors  to  an  alteration  of  the  peat  itself, 
a mode  of  genesis  which  later  writers  have  doubted.  J.  S.  New- 
berry,6 however,  states  that  in  the  Bay  of  Marquette,  where  the  shore 
consists  of  peat  overlying  Archean  rocks,  bubbles  of  marsh  gas  arise, 
together  with  drops  which  cover  the  surface  of  the  water,  in  spots, 
with  an  oily  film.  The  following  investigations  seem  to  bear  upon 
the  problems  suggested  by  these  observations : 

In  1899  A.  F.  Stahl 7 and,  independently,  G.  Kramer  and  A.  Spil- 
ker8  called  attention  to  a possible  derivation  of  petroleum  from 
diatoms,  which  abound  in  certain  bogs.  These  organisms,  accord- 
ing to  Kramer  and  Spilker,  contain  drops  of  oily  matter,  and  from 
diatomaceous  peat  a waxy  substance,  resembling  ozokerite,  can  be 
extracted.9  The  theory,  based  upon  these  data,  is  briefly  as  fol- 
lows : A lake  bed  becomes  filled  in  time  with  diatomaceous  accumu- 
lations, over  which  a cover  of  other  growths  or  deposits  is  formed. 

1 Compt.  Rend.,  vol.  117, 1893,  p.  593.  See  also  Bertrand,  Compt.  rend.  VIII  Cong.  geol.  internat.,  1900, 
p.  458.  According  to  E.  C.  Jeffrey  (Proc.Am.  Acad.  Arts  and  Sci.,  vol.  46, 1910,  p.  273),  the  supposed  gelat- 
inous algae  are  the  spores  of  vascular  cryptogams. 

2 Geology  of  Ohio,  vol.  1, 1873,  p.  158.  See  also  an  earlier  paper  by  Newberry,  Rock  oils  of  Ohio,  in  Four- 

teenth Ann.  Rept.  Ohio  State  Board  Agr.,  1859,  p.  605. 

2 Proc.  Am.  Philos.  Soc.,  vol.  10, 1868,  p.  445;  vol.  37, 1898,  p.  108. 

* H.  Stremme  (Centralbl.  Min.,  Geol.  u.  Pal.,  1908,  p.  271)  has  shown  that  the  polymerization  of  petroleum 
may  itself  generate  heat. 

6 Published  in  Trans.  Manchester  Geol.  Soc.,  vol.  8,  1868,  p.  41.  Curiously,  a later  paper  by  Binney 
appears  earlier,  namely,  in  vol.  3,  1860,  p.  9. 

6 Annals  New  York  Acad.  Sci.,  vol.  2,  1882,  p.  277. 

1 Chem.  Zeitung,  vol.  23,  1899,  p.  144.  Also  note  in  vol.  30, 1906,  p.  18. 

8 Ber.  Deutsch.  chem.  Gesell.,  vol.  32,  1899,  p.  2940;  vol.  35,  1902,  p.  1212.  Criticism  by  Engler  in  vol.  33, 
1900,  p.  7. 

9 See  also  C.  E.  Guignet,  Compt.  Rend.,  vol.  91,  1880,  p.  888,  on  wax  from  peat. 


T34 


THE  DATA  OF  GEOCHEMISTRY. 


By  decay  of  the  organic  substances,  ammonium  carbonate  is  pro- 
duced, which  hydrolyzes  the  wax,  and  from  the  resulting  acid  carbon 
dioxide,  carbon  monoxide,  and  water  are  gradually  ehminated. 
Ozokerite  is  thus  formed,  which,  at  moderate  temperatures  and  under 
pressure,  becomes  converted  into  liquid  petroleum.  With  higher 
temperatures  and  pressures,  in  presence  of  sulphur,  heavier  oils  and 
asphalt  may  be  generated.  In  support  of  this  hypothesis  the 
authors  describe  a lake  bed,  near  Stettin,  which  is  about  23  feet 
thick  and  consists  chiefly  of  diatoms.  This  deposit  yields  a wax  con- 
taining over  10  per  cent  of  sulphur,  and  from  it  a hydrocarbon, 
resembling  the  lekene  from  ozokerite,  was  isolated. 

Kramer  and  Spilker’s  views  have  not  met  with  very  general 
acceptance,  but  they  seem  to  contain  elements  of  value.  H.  Potonie’s 
hypotheses,1  for  example,  seem  to  be  a broadening  of  Kramer  and 
Spilker’s.  This  writer  calls  attention  to  the  “faulschlamm”  or 
“sapropel,”  a slime,  rich  in  organic  matter,  which  is  formed  from 
gelatinous  algse,  and  accumulates  at  the  bottom  of  stagnant  waters. 
Such  a slime,  Potonie  believes,  may  be  the  parent  substance  from 
which  bitumen,  by  a process  of  decay,  was  probably  derived.  In  this 
connection,  and  with  reference  to  the  adequacy  of  the  proposed 
source,  it  is  well  to  remember  the  enormous  accumulation  of  “ oozes,” 
namely,  the  radiolarian  and  globigerina  oozes,  on  the  bottom  of  the 
sea.  The  organic  matter  thus  indicated  is  certainly  abundant  enough, 
if  it  can  decay  under  proper  conditions,  to  form  more  hydrocarbons 
than  the  known  deposits  of  petroleum  now  contain.2 

These  remarks  upon  the  oceanic  sediments  at  once  suggest  an  inter- 
mediate group  of  hypotheses,  which  assume  a mixed  origin  for  petro- 
leum. Animal  matter  in  some  cases,  vegetable  matter  in  others,  or 
both  together,  are  supposed  to  be  the  initial  source  of  supply.  A. 
Jaccard,3  for  example,  argues  that  the  liquid  oils  are  derived  from 
marine  plants,  while  the  viscous  or  solid  bitumens  may  originate 
from  mollusks,  radiates,  etc.  Some  oils,  again,  are  supposed  to  be  of 
mixed  origin,  and  it  would  seem  probable  that  the  last  class  is  the 
most  common.  Ideas  of  this  kind  have  repeatedly  been  enunciated 
with  reference  to  American  petroleums — that  of  Pennsylvania  being 
attributed  to  marine  vegetation,  that  of  California  to  animal  remains. 


1 Natur.  Wochenschr.,  vol.  20, 1905,  p.  599. 

2 These  oceanic  sediments  are  especially  noticed  by  Engler  in  a paper  read  before  the  petroleum  congress 
in  1900  (Cong,  intemat.  du  pdtrole,  Paris,  1900,  p.  28).  In  A.  Beeby  Thompson’s  monograph,  The  oil  fields 
of  Russia,  London,  1904,  pp.  85-87,  a theory  is  developed  to  account  for  the  probable  formation  of  bitumens 
on  the  sea  bottom.  Thompson  regards  fish  remains  as  an  important  source  of  supply.  G.  P.  Mikhailovski 
(Bull.  Com.  g6ol.  St.  Petersburg,  vol.  25,  1908,  p.  319)  derives  the  Caucasian  petroleum  from  marine  sedi- 
ments. C.  B.  Morrey  (Bull.  Geol.  Survey  Ohio,  No.  1,  1903,  p.  313)  suggests  that  bacteria  have  been  the 
chief  agents  in  transforming  other  organic  matter  into  hydrocarbons. 

3 Eclog.  Geol.  Helvet.,  vol.  2, 1890,  p.  87.  See  also  Arch.  sci.  phys.  nat.,  3d  ser.,  vol.  23,  1890,  p.  501;  vol. 
24,  1890,  p.  106.  Jaccard  studied  especially  the  bitumens  of  the  Jura. 


THE  NATURAL  HYDROCARBONS.  735 

The  American  literature  of  petroleum  is  rich  in  suggestions  of  this 
order.1 

It  has  long  been  known  that  some  petroleums  are  optically  active; 
that  is,  they  are  able  to  rotate  a ray  of  polarized  light,  sometimes  to 
the  right  and  sometimes  to  the  left.  This,  according  to  P.  Walden,2 
gives  us  an  important  datum  toward  determining  the  origin  of 
petroleum.  Only  the  oils  derived  from  organic  matter,  Walden 
asserts,  can  possess  this  property,  the  hydrocarbons  prepared  from 
inorganic  materials,  such  as  metallic  carbides,  being  optically  inert. 
The  oils  distilled  from  coal,  which  is  evidently  of  vegetable  origin, 
are  active;  and  petroleum,  which  has  the  same  peculiarity,  is  presum- 
ably formed  from  similar  materials.  The  activity  is  attributed  by 
some  writers  to  derivatives  of  cholesterin,  of  animal  origin,  or  else 
to  its  vegetable  equivalent,  phytosterin.3  Apart  from  this  detail  the 
general  conclusions  are  exceedingly  important,  but  need  to  be  more 
thoroughly  tested  before  they  can  demand  universal  acceptance. 
The  presumption,  however,  is  strongly  in  their  favor. 

In  any  attempt  to  discover  the  genesis  of  petroleum  the  quantita- 
tive adequacy  of  the  proposed  sources  must  be  taken  into  account. 
In  such  an  inquiry  superficial  observations  are  deceptive,  for  one  is 
apt  to  overrate  the  visible  and  productive  accumulations  which  fur- 
nish the  oils  of  commerce.  These  seem  large,  but  they  are  relatively 
insignificant.  As  Orton  4 has  said,  disseminated  petroleum  is  well- 
nigh  universal;  the  accumulations  are  rare.  In  certain  districts  the 
shales  and  limestones  are  generally  impregnated  with  traces  of  bitu- 
mens, which  seem  at  first  sight  to  be  insignificant,  but  which  really 
represent  enormous  quantities.  In  the  Mississippian  (“sub-Carbo- 
niferous”)  limestones  of  Kentucky  petroleum  is  generally  present. 
If  it  amounts  to  only  0.10  per  cent,  each  square  mile  of  rock,  with  a 
thickness  of  500  feet,  would  yield  about  2,500,000  barrels  of  oil. 
Even  more  striking  are  the  figures  given  by  T.  Sterry  Hunt,5 6  who 

1 In  addition  to  the  memoirs  already  cited,  see  the  reports  of  the  Second  Geol.  Survey  Pennsylvania. 
Also  J.  A.  Bownocker,  Geol.  Survey  Ohio,  4th  ser.,  Bull.  No.  1,  1903;  S.  S.  Gorby,  Sixteenth  Aim.  Rept. 
Indiana  Dept.  Geol.  and  Nat.  Hist.,  1888;  W.  S.  Blatchley,  idem,  Twenty-eighth  Ann.  Rept.,  1904;  E. 
Haworth,  Kansas  Univ.  Geol.  Survey,  vol.  1,  1896,  p.  232;  H.  P.  H.  Brumell,  Geol.  Survey  Canada,  new 
ser.,  Ann.  Rept.  5,  Q,  1893;  and  W J McGee,  Eleventh  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  1, 1891,  p.  589. 
L.  Harperath  (Bol.  Acad.  nac.  cien.  Cordoba  (Argentina),  vol.  18, 1905,  p.  153)  has  published  a long  memoir 
on  petroleum  and  salt.  L.  V.  Dalton  (Econ.  Geology,  vol.  4,  1909,  p.  603)  advocates  the  organic  origin  of 
petroleum. 

2 Chem.  Zeitung,  vol.  30,  1906,  pp.  391,  1155,  1168.  Walden  cites  many  examples  of  this  optical  activity. 
See  also  Engler,  idem,  p.  711,  and  F.  W.  Bushong,  Science,  vol.  38, 1913,  p.  39. 

3 See  M.  Rakusin,  Chem.  Zeitung,  vol.  30,  1906,  p.  1041;  Ber.  Deutsch.  chem.  Gesell.,  vol.  42,  1908,  pp. 
1211,  1640,  4675;  J.  Marcusson,  Chem.  Zeitung,  vol.  31,  1907,  p.  419;  vol.  32,  1908,  pp.  377,  3917 R.  Albrecht, 
Inaug.  Diss.,  Karlsruhe,  1907;  L.  Ubbelohde,  Ber.  Deutsch.  chem.  Gesell.,  vol.  42,  1909,  p.  3242;  vol.  43, 
1910,  p.  608.  R.  Zaloziecki  and  H.  Klarfeld  (Chem.  Zeitung,  vol.  31,  1907,  pp.  1155,  1170)  question  the 
cholesterin  theory  and  favor  that  of  PotoniA  See  also  Zaloziecki,  Compt.  rend.  Cong,  internat.  pArole, 
Bucarest,  1910,  p.  718. 

4 First  Ann.  Rept.  Geol.  Survey  Ohio,  1890,  chapter  11;  Geol.  Survey  Kentucky,  Report  on  occurrence 

of  petroleum,  etc.,  1888-89. 

6 Chemical  and  geological  essays,  1875,  p.  168. 


736 


THE  DATA  OF  GEOCHEMISTRY. 


estimates  that  in  the  limestone  of  Chicago,  with  a thickness  of  35 
feet,  there  are  7,743,745  barrels  of  oil  to  each  square  mile  of  territory. 
Figures  like  these,  together  with  the  computations,  previously  cited, 
made  by  Szajnocha  relative  to  Galician  petroleum,  lead  to  the  con- 
viction that  the  formation  of  bitumens  is  a general  process  and  by 
no  means  exceptional.  Wherever  sediments  are  laid  down,  inclosing 
either  animal  or  vegetable  matter,  there  bitumens  may  be  produced. 
The  presence  of  water,  preferably  salt,  the  exclusion  of  air,  and  the 
existence  of  an  impervious  protecting  stratum  of  clay  seem  to  be 
essential  conditions  toward  rendering  the  transformation  possible. 
Seaweeds,  mollusks,  crustaceans,  fishes,  and  even  microscopic  organ- 
isms of  many  kinds  may  contribute  material  to  the  change.  In  some 
cases  plants  may  predominate;  in  others  animal  remains;  and  the 
character  of  the  hydrocarbons  produced  is  likely  to  vary  accord- 
ingly, just  as  petroleum  varies  in  different  fields.  In  one  region  we 
find  chiefly  paraffins,  in  another  naphthenes,  and  in  another  nitroge- 
nous or  sulphureted  oils.  Such  differences  can  not  be  ignored,  and 
they  are  most  easily  explained  on  the  supposition  that  different 
materials  have  yielded  the  different  products.  On  this  class  of  prob- 
lems the  chemist,  the  geologist,  and  the  paleontologist  must  work 
together.  Physics  also  is  entitled  to  be  heard;  for,  as  D.  T.  Day1 
has  shown,  petroleum,  by  simple  filtration  through  fuller’s  earth,  can 
be  separated  into  fractions  which  differ  in  density  and  viscosity  and 
are  therefore  of  different  composition.  Such  a filtration,  or,  more 
precisely,  diffusion,  must  take  place  in  nature  wherever  migrating 
hydrocarbons  traverse  permeable  strata. 

By  whatever  class  of  reactions  petroleum  is  generated,  it  doubtless 
appears  first  in  a state  of  dissemination.  How  does  it  become  con- 
centrated ? This  question  does  not  fall  within  the  domain  of  chem- 
istry, and  can  not  be  properly  discussed  here.2  Probably  circulating 
waters  have  much  to  do  with  the  process,  but  whatever  that  may  be 
the  laws  governing  the  motion  of  liquids  must  inevitably  rule.  The 
oils  must  gather  in  proper  channels,  moved  by  gravitation,  or  by 
hydrostatic  pressure  of  waters  behind  or  below  them,  or  by  the  pres- 
sure of  dissolved  and  compressed  gases,  and  they  accumulate  in 
porous  rocks  or  cavities  under  layers  of  impervious  material.  When 
the  latter  are  lacking,  or  when  the  hydrocarbons  enter  large  areas  of 
porous  rocks,  they  may  be  either  evaporated  or  rediffused.  Pressure, 
temperature,  viscosity,  and  the  character  of  the  surrounding  rocks 

1 Cong,  intemat.  p^trole,  Paris,  1900,  p.  53.  See  also  J.  E.  Gilpin  and  O.  E.  Bransky,  Am.  Chem.  Jour., 
vol.  44, 1910,  p.  251;  and  Gilpin  and  P.  Schneeberger,  Am.  Chem.  Jour.,  vol.  50,  1913,  p.  59.  These  authors 
show  that  fuller’s  earth  exerts  a selective  absorption  for  unsaturated  hydrocarbons  and  organic  sulphides. 

2 For  a discussion  of  this  problem,  see  H.  Hofer,  Das  Erdol,  1906,  p.  223.  Also  G.  I.  Adams,  Trans.  Am. 
Inst.  Min.  Eng.,  vol.  33,  1903,  p.  340;  and  D.  T.  Day,  idem,  p.  1053.  Orton’s  reports,  previously  cited, 
contain  important  contributions  on  this  theme. 


THE  NATURAL  HYDROCARBONS.  737 

must  all  be  taken  into  account,  and  each  productive  area  needs  to  be 
studied  independently  with  reference  to  its  local  conditions. 

In  conclusion,  I may  be  allowed  to  suggest  that  nearly  all  of  the 
proposed  theories  to  account  for  the  origin  of  petroleum  embody 
some  elements  of  truth.  Sokoloff’s  cosmic  hypothesis  is  sustained  by 
the  fact  that  hydrocarbons  are  found  in  meteorites.  The  volcanic 
hypothesis  is  sustained  by  the  fact  that  hydrocarbons  occur  among 
volcanic  emanations.  The  organic  origin  of  petroleum,  however, 
seems  to  be  best  supported  by  the  geologic  relations  of  the  hydrocar- 
bons, which  are  found  in  large  quantities  only  in  rocks  of  sedimentary 
character.  Any  organic  substance  which  becomes  inclosed  within 
the  sediments  may  be  a source  of  petroleum,  and  when  the  latter 
happens  to  be  rich  in  nitrogen,  animal  matter  was  probably  the 
initial  material.  There  is  no  evidence  to  show  that  any  important 
oil  field  derived  its  hydrocarbons  from  inorganic  sources.1 

i The  controversies  relative  to  the  genesis  of  petroleum  have  created  a voluminous  literature,  of  which 
only  the  main  points  have  been  considered  here.  For  an  excellent  summary  of  the  subject,  see  Engler 
and  Hofer’s  great  treatise  Das  Erdol,  vol.  2,  Leipzig,  1909,  pp.  59-142.  On  the  genetic  relations  between 
petroleum  and  coal  see  David  White,  Jour.  Washington  Acad.  Sci.,  vol.  5, 1915,  p.  189. 

97270°— Bull.  616—16 47 


CHAPTER  XVII. 

COAL. 

ORIGIN  OF  COAL. 

Although  doubts  may  exist  as  to  the  origin  of  petroleum,  there  are 
none  whatever  as  to  the  essential  origin  of  coal.  It  is  obviously  de- 
rived from  vegetable  matter,  by  a series  of  changes  which  are  plainly 
traceable,  even  though  their  mechanism  is  not  fully  understood. 
Vegetation,  peat,  lignite,  soft  coal,  anthracite,  and  some  graphitic 
minerals  form  a series  of  substances  which  grade  one  into  another  in 
an  unbroken  line,  reaching  from  complex  organic,  oxidized  com- 
pounds at  one  end  to  nearly  but  not  quite  pure  carbon  at  the  other. 
All  these  bodies,  except  perhaps  the  last,  are  indefinite  mixtures 
which  vary  in  composition,  and  it  is  therefore  impracticable  to  write 
chemical  equations  that  shall  properly  represent  their  transforma- 
tions. Such  equations,  to  be  sure,  have  been  suggested  and  written, 
but  they  embody  fallacies  which  are  easily  exposed.  They  start 
from  the  assumption  that  the  principal  initial  compound  contained 
in  vegetation  is  cellulose,  a definite  carbohydrate  of  the  formula 
C6H10O5,  which  gradually  loses  carbon  dioxide,  marsh  gas,  and  water, 
and  so  yields  the  series  of  products  represented  by  the  different  kinds 
of  coal.1  This  assumption,  like  most  other  assumptions  of  its  class,  is 
partly  true  and  partly  false.  Cellulose  is  an  important  constituent 
of  vegetable  matter,  but  it  stands  by  no  means  alone.  When  it 
decays,  it  loses  the  substances  named  above  and  it  also  undergoes 
other  changes  which  are  difficult  to  measure.  In  every  swamp  or 
peat  bog  the  waters  are  charged,  more  or  less  heavily,  with  soluble 
organic  matter  of  which  the  written  reactions  take  no  account.  This 
soluble  matter  is  found  in  the  waters  of  all  bogs  and  streams,  and  it 
is  just  as  much  a factor  in  the  real  reactions  as  are  the  gaseous  prod- 
ucts or  the  solid  carbonaceous  residues. 

If,  instead  of  the  composition  of  cellulose,  we  begin  with  the  com- 
position of  wood,  we  shall  have  a better  starting  point  for  our  series 
of  derivatives.  Wood  or  woody  fiber  is  by  no  means  the  only  sub- 
stance to  be  considered,  but  it  is  the  most  important  one,  and  its 


1 The  formula  C6H10O5  represents  only  the  empirical  composition  of  cellulose,  and  not  its  true  molecular 
weight.  According  to  A.  Nastukofl  (Ber.  Deutsch.  chem.  Gesell.,  vol.  33, 1900,  p.  2237),  the  true  formula 
is  probably  4OC6H10O5,  or  C240H400O200.  This  may  be  an  exaggeration,  but  the  molecular  weight  of  cellulose 
is  certainly  high.  For  an  attempt  to  write  chemical  equations  representing  coal  formation,  see  J.  F.  Hoff- 
mann, Beitr.  Geophys.,  vol.  7,  1905,  p.  327. 

738 


COAL. 


739 


ultimate  composition  has  been  well  determined.  Its  proximate  com- 
position is  not  so  clearly  known,  but  certain  available  facts  are  per- 
tinent to  the  present  discussion.  It  contains  cellulose,  C6H10O5,  and 
a substance  known  as  lignone,  lignin,  or  lignocellulose,  in  about 
equal  proportions,  together  with  other  minor  organic  constituents, 
such  as  gums  and  resins,1  and  some  inorganic  matter  which  forms  its 
ash.  To  lignocellulose,  according  to  Cross  and  Bevan,2  the  formula 
C12H1809  may  be  assigned;  and  it  is  best  represented  by  jute  fiber, 
which  consists  almost  wholly  of  this  substance. 

If,  now,  we  compare  the  percentage  composition  of  cellulose,  ligno- 
cellulose, and  wood,  we  shall  see  how  unsafe  it  is  to  write  equations 
intended  to  show  the  derivation  of  coal  upon  the  basis  of  either  defi- 
nite compound  alone.  The  data  are  as  follows: 

Composition  of  cellulose , lignocellulose , and  wood. 

A.  The  composition  of  cellulose,  calculated  from  its  formula. 

B.  The  composition  of  lignocellulose,  similarly  computed. 

C.  The  average  composition  of  twenty-four  woods,  analyzed  by  Petersen  and  Schodler,  Liebig’s  Anna- 
len,  vol.  17,  1836,  p.  139.  Samples  dried  and  finely  powdered. 

D.  Average  of  thirty-six  analyses  of  five  different  woods,  by  E.  Chevandier,  Annales  chim.  phys.,  3d 
ser.,  vol.  10,  1844,  p.  129.  Samples  dried  in  vacuo  at  140°. 

E.  Average  of  eight  analyses  of  woods  by  W.  Baer,  Jahresb.  Chemie,  1847-48,  p.  1112.  Ash  from  0.53  to 
2.03  per  cent. 

F.  Average  of  seven  Danish  woods,  analyzed  by  E.  Gottlieb,  Jour.  Chem.  Soc.,  vol.  46,  1884,  p.  477 
(abstract).  Dried  at  115°. 

G.  Average  composition  of  five  acrogen  plants,  of  the  genera  Lycopodium,  Equisetum,  Aspidium,  and 
Cyathea,  by  G.  W.  Hawes,  Am.  Jour.  Sci.,  3d  ser.,  vol.  7,  1874,  p.  585.  In  Equisetum  the  ash  ran  as  high 
as  11.82  per  cent. 


A 

B 

C 

D 

E 

F 

G 

c 

44.  43 

47.  06 

49.  31 

51.  21 

49.  16 

49.  76 

48.  83 

H 

6.  22 

5.  89 

6.  29 

6.  24 

6.  10 

6.  14 

6.  37 

O 

49.  35 

47.  05 

44.  40 

42.  55 

44.  74 

44.  10 

44.  80 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

All  of  these  analyses  are  recalculated  to  an  ash-free  basis.  In  the 
table,  for  uniformity,  the  nitrogen  is  added  to  the  oxygen.  Chevan- 
dier found,  in  mean,  1.10  per  cent  of  nitrogen  in  his  woods,  but  Gott- 
lieb obtained  only  0.04  to  0.10.  In  Hawes’s  analyses  the  nitrogen 
ranged  from  1.21  to  2.17  per  cent.  The  differences  between  the  wood 
analyses  are  principally  due  to  differences  in  drying. 

From  these  figures  we  see  that  cellulose  contains  about  5 per  cent 
more  oxygen  than  carbon,  while  in  wood  the  reverse  statement  is  very 
nearly  true.  Even  lignocellulose  contains  less  carbon  than  is  actually 
found  in  wood.  The  figures  for  wood  given  in  column  F approximate 
very  nearly  to  the  formula  C6H904,  and  that  expression  might  be 

1 See  M.  Singer,  Monatsh.  Chemie,  vol.  3,  1882,  p.  395,  on  the  subordinate  constituents  of  wood.  The 
subject  is  one  which  can  not  be  properly  developed  here. 

2 Jour.  Chem.  Soc.,  vol.  55, 1889,  p.  199. 


740 


THE  DATA  OF  GEOCHEMISTRY. 


used  were  wood  a definite  substance.  Its  employment,  however,  is 
more  likely  to  cause  misapprehension  than  to  aid  in  the  elucidation  of 
problems.  At  best  it  can  only  be  taken  as  a convenient  collocation 
of  symbols,  more  easily  borne  in  mind  than  the  actual  percentages. 

It  is  generally  admitted,  I think,  by  all  competent  investigators 
that  coal  originated  from  vegetation  which  grew  in  swampy  or 
marshy  places.  As  the  vegetation  died  it  underwent  a partial  decay 
and  was  buried  under  successive  layers,  either  of  matter  like  itself  or 
else  of  sediments  such  as  clay.  In  that  way  it  was  protected  from 
complete  atmospheric  oxidation  and  at  the  same  time  subjected  to 
a gradually  increasing  pressure  and  doubtless  to  some  heat  gener- 
ated thereby.  The  vegetation  was  of  many  kinds — trees,  ferns, 
grasses,  sedges,  mosses,  etc. — and  these  all  contributed  variously  to 
the  formation  of  the  future  coal.  Trees  standing  erect  within  a bed 
of  coal,  their  roots  still  remaining  embedded  in  an  underlying  stratum 
of  clay,  tell  a part  of  the  story.  Fossil  ferns,  and  even  the  remains 
of  microorganisms,  also  add  their  testimony  to  what  has  occurred. 
In  some  cases  beds  of  lignite  represent  submerged  forests;  and  in 
others,  as  shown  by  many  geologists,  the  coal  was  probably  formed, 
not  from  vegetation  in  place,  but  from  drifted  materials,  a condition, 
however,  which  does  not  affect  the  chemistry  of  the  carbonizing 
process.  The  slow  decay  of  the  buried  substances  is  the  essential 
thing  for  the  chemist  to  consider.  With  the  vegetable  matter  some 
animal  remains  were  undoubtedly  commingled,  helping  to  increase  the 
nitrogen  content  of  the  coal;  and  the  ash  of  the  latter  was  augmented 
by  more  or  less  inorganic  sediment,  derived  from  the  wash  of  the 
land  in  times  of  flood.  Certain  coals  and  carbonaceous  rocks,  such 
as  cannel,  Boghead,  oil  shale,  etc.,  are  attributed  by  H.  Potonie 1 to 
the  decomposition  of  “sapropel,”  a sort  of  slime  made  up  largely  of 
gelatinous  algae,  mixed  with  some  animal  remains.  This  view  has 
received  much  acceptance,  but  E.  C.  Jeffrey2  has  shown  that  in 
some  cases  at  least  the  supposed  fossil  algae  are  really  the  spores  of 
vascular  cryptogams. 

In  their  memoir  on  the  origin  of  coal  D.  White  and  R.  Thiessen 3 
give  an  excellent  summary  of  the  diverse  theories  upon  the  subject. 
Their  conclusions,  based  on  field  studies  and  microscopic  investiga- 
tions, are  that  “ all  coal  was  laid  down  in  beds  analogous  to  the  peat 
beds  of  to-day.”  They  regard  it  as  “ chiefly  composed  of  residues 
consisting  of  the  most  resistant  components  of  plants,  of  which 

1 Die  Entstehung  der  Steinkohle,  Berlin,  1910.  See  also  citation  in  the  preceding  chapter  and  the  refer- 
ences to  the  work  of  Bertrand  and  Renault.  Also  H.  Stremme,  Monatsber.  Deutsch.  geol.  Gesell.,  vol.  59, 
1907,  p.  153. 

* Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  46, 1910,  p.  273.  For  a recent  paper  by  Jeffrey  on  the  origin  of 
coal  see  Jour.  Geology,  vol.  23, 1915,  p.  218. 

8 The  origin  of  coal:  Bull.  U.  S.  Bin* *.  Mines  No.  38,  1913.  Another  important  work  on  the  subject  is 
by  O.  Stutzer,  Kohle  (Allgemeine  Kohlengeologie),  Berlin,  1914. 


COAL. 


741 


resins,  resin  waxes,  waxes,  and  higher  fats,  or  the  derivatives  of  the 
compounds  comprising  them  are  the  most  important.”  The  algal 
and  gelosic  theories  of  the  origin  of  coal  they  dismiss  as  undemon- 
strated. The  views  of  White  and  Thiessen  probably  represent  the 
general  consensus  of  opinion. 

A moment’s  consideration  will  suffice  to  show  that  the  process  of 
vegetable  decay  could  not  have  been  uniform.  The  softer  plant  tissues 
decompose  most  rapidly;  the  more  compact  ligneous  masses  endure 
much  longer.  Even  the  trunks  of  trees  must  exhibit  similar  varia- 
tions, for  woods  differ  in  hardness  and  compactness,  and  the  resinous 
varieties  will  rot  the  slowest  of  all.  The  resins  themselves  show  the 
minimum  of  change,  and  where  they  were  most  abundant  their  fossil 
remnants  are  found.  Amber,  fossil  copal,  the  waxes  found  in  peat 
bogs,  and  a multitude  of  similar  substances  have  been  thus  preserved. 
In  lignite  and  bituminous  coal  aggregations  and  often  large  masses 
of  resinous  bodies  not  infrequently  occur,  and  in  a disseminated 
form,  unrecognizable  by  the  eye,  they  must  be  almost  invariably 
present.  Their  quantity,  of  course,  would  depend  upon  the  exact 
character  of  the  vegetation  from  which  a given  coal  bed  was  formed. 

The  nature  and  distribution  of  the  fossil  resins  deserve  much  more 
careful  study  than  they  have  yet  received.  Much  rarer  than  the 
resins  are  the  salts  of  organic  acids,  which  are  sometimes  found  in 
coal,  especially  in  lignite.  Three  of  these  are  well-defined  species, 
namely,  whewellite,  calcium  oxalate;  humboldtine,  ferrous  oxalate; 
and  mellite,  the  aluminum  salt  of  mellitic  acid,  A1C606.9H20.  Com- 
pounds of  this  class  are  significant  in  showing  the  range  and  variety 
of  the  reactions  which  take  part  in  the  formation  of  coal.  Oxalic 
acid  is  easily  formed  from  cellulose,  and  it  is  therefore  surprising  that 
its  salts  are  not  more  frequently  discovered  in  peat  or  coal.  The 
soluble  oxalates,  of  course,  would  be  leached  away;  but  calcium 
oxalate  is  insoluble  and  ought  to  be  more  common. 

In  addition  to  its  organic  constituents  coal  also  contains  more  or 
less  inorganic  matter  which  on  combustion  remains  as  ash.  This 
was  originally  for  the  most  part  of  sandy  or  clayey  character,  of 
variable  composition;  but  rarer  impurities  are  sometimes  found. 
The  occurrence  of  gold,  silver,  vanadium,  and  uranium  was  already 
noticed  in  Chapter  XV  of  this  work;  and  to  these,  according  to  Stutzer, 
molybdenum  must  be  added.  Stutzer 1 also  mentions,  as  having 
been  found  in  coal,  millerite,  cinnabar,  chalcopyrite,  bornite,  spha- 
lerite, galena,  and  malachite.  Pyrite  or  marcasite  is  commonly  present, 
and  often  in  annoying  quantities.  The  almost  omnipresent  radium 
was  detected  in  certain  Alabama  coals  by  S.  J.  Lloyd  and  J.  Cun- 
ningham.2 


1 Op.  cit.,  pp.  19,  193. 


2 Am.  Chem.  Jour.,  vol.  50,  1913,  p.  47. 


742 


THE  DATA  OF  GEOCHEMISTRY. 


PEAT. 

The  first  stage  in  the  development  of  coal  from  vegetable  matter 
seems  to  be  represented,  at  least  approximately,  by  the  formation  of 
peat.  The  process,  as  observed,  has  already  been  outlined.  Mosses, 
grasses,  and  other  plants — any  plants,  in  fact,  which  can  thrive  in 
marshes — grow,  die,  and  are  buried,  layer  after  layer.  On  the  sur- 
face of  a bog  we  see  the  growing  plants;  a little  below  the  surface, 
their  recognizable  remains;  still  deeper,  we  find  a black,  semigelati- 
nous  substance  from  which  the  vegetable  structure  has  largely  dis- 
appeared.1 This  substance,  saturated  with  moisture,  is  peat;  dried, 
it  becomes  a valuable  fuel. 

Many  analyses  of  peat  have  been  made,  and,  as  might  be  expected, 
they  vary  widely.  The  following  series  by  J.  Websky  2 is  especially 
suggestive.  The  samples  were  dried  at  100°,  and  the  analyses  calcu- 
lated on  an  ash-free  basis. 


Analyses  of  sphagnum  and  peat. 


A.  Sphagnum,  the  chief  plant  of  the  peat  bogs. 

B.  Light  peat,  near  surface. 

C.  Light  peat. 


D.  Moderately  light  peat. 

E,  F.  Black  peat. 

G.  Heavy  brown  peat. 


A 

B 

C 

D 

E 

F 

G 

c 

49.  88 

50.  33 

50.  86 

59.  71 

59.  70 

59.  71 

62.  54 

H 

6.  54 

5.  99 

5.  80 

5.  27 

5.  70 

5.  27 

6.  81 

O 

42.  42 

42.  63 

42.  57 

32.  07 

33.04 

32.  07 

29.24 

N 

1. 16 

1.  05 

.77 

2.  95 

1.  56 

2.  95 

1. 41 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

The  progressive  increase  in  carbon  in  passing  from  sphagnum  to 
heavy  peat  is  clearly  shown. 

A few  other  analyses  of  peat  maybe  profitably  cited,  as  follows:3 


1 On  the  rapidity  of  formation  of  peat,  see  a summary  by  G.  H.  Ashley,  Econ.  Geology,  vol.  2, 1907,  p.  34. 

2 Jour,  prakt.  Chemie,  vol.  92,  1864,  p.  65. 

s For  still  other  analyses,  see  Roth  and  Percy,  as  cited,  and  vol.  1 of  Groves  and  Thorp’s  Chemical  tech- 
nology, pp.  14-20.  In  the  latter  work,  p.  16,  will  be  found  27  analyses  of  peat  ashes,  by  Kane  and  Sullivan. 
Petersen  and  Nessler  (Neues  Jahrb.,  1881,  p.  82)  give  17  ultimate  analyses  of  German  peat,  with  separate 
analyses  of  the  ash.  In  a paper  by  H.  B.  Kiimmel  (Econ.  Geology,  vol.  2,  1907,  p.  24),  there  are  many 
technical  analyses  of  New  Jersey  peat,  with  calorimetric  data.  On  the  mechanism  of  peat  formation,  see 
N.  S.  Shaler,  Sixteenth  Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  4, 1895,  p.  305.  An  important  general  paper  on 
peat,  its  rate  of  growth,  its  resins,  etc.,  by  R.  Angus  Smith,  is  given  in  Mem.  Lit.  Philos . Soc.  Manchester, 
1876,  p.  281.  See  also  T.  R.  Jones,  Proc.  Geologists’  Assoc.,  vol.  6, 1880,  p.  207,  and  C.  A.  Davis,  Rept.  State 
Board  Geol.  Survey  Michigan,  1906,  p.  97,  and  Econ.  Geology,  vol.  5,  1910,  p.  37.  Davis  also  has  a chapter 
on  peat  in  White  and  Thiessen’s  memoir. 


COAL. 


743 


Analyses  of  peat. 

A.  From  Th£sy,  France.  Analysis  by  Marsilly,  Annales  des  mines,  5th  ser.,  vol.  12,  p.406.  Dried  24 
horns  in  vacuo. 

B.  From  Camon,  France.  Also  by  Marsilly,  who  gives  seven  analyses  in  all.  Dried  24  hours  in  vacuo. 

C.  From  ‘‘Horin  Schonen.”  Analysis  by  O.  Jacobsen,  Liebig’s  Annalen,  vol.  157,  1871,  p.  240.  Dried 
at  100°. 

D.  From  a lake  in  Cashmere.  Analysis  by  C.  Tookey.  See  Percy’s  Metallurgy,  vol.  1,  1875,  p.  206. 

E.  Average  of  ten  analyses  cited  by  Roth,  Allgemeine  chemische  Geologie,  vol.  2,  p.  642. 


A 

B 

c 

D 

E 

c 

50.  67 

46. 11 

51.  38 

37. 15 

51.  97 

H 

5.  76 

5.  99 

6.  49 

4.  08 

6.  05 

0 

34.  95 

35.  87 

35.  43 

23.  48 

34.  02 

N 

1.  92 

2.  63 

1.  68 

2.  02 

1.  34 

Ash  

6.  70 

9.  40 

5.  02 

33.  27 

6.  61 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Reduced  to  an  ash-free  basis,  in  order  to  compare  the  organic  mat- 
ter with  that  of  wood,  the  analyses  assume  the  following  form: 

Analyses  of  peat  reduced  to  ash-free  basis. 


A 

B 

c 

D 

E 

C 

54.  31 

50.  89 

54. 10 

55.  67 

55.  65 

H 

6. 18 

6.  61 

6.  83 

6. 11 

6.  48 

O 

37.  46 

39.  58 

37.  30 

35. 19 

36.  43 

N 

2.  05 

2.  92 

1.  77 

3.  03 

1.  44 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

As  compared  with  the  data  already  given  for  wood,  these  figures 
show  an  increase  in  carbon,  a decrease  in  oxygen,  and  a notable  en- 
richment in  nitrogen.  The  last  gain  may  be  partly  from  animal  matter. 

The  nature  of  the  changes  which  have  taken  place  in  the  transfor- 
mation of  vegetable  matter  into  peat  is  imperfectly  understood. 
When  ligneous  fiber  decays  it  yields  an  amorphous  mixture  of  sub- 
stances which  are  known  collectively  as  humus,  and  are  partly  of 
acidic  nature.  These  substances  are  very  ill-defined  bodies,  although 
various  formulae  have  been  assigned  to  them,  but  none  can  be  said 
to  be  established.  The  acid  portions  dissolve  in  alkaline  solu- 
tions, and  so  are  partly  washed  away;  but  the  salts  formed  with  lime 
and  iron,  being  insoluble,  probably  remain  behind.  The  ash  of  peat 
is  commonly  rich  in  lime,  not  as  carbonate,  and  also  in  iron,  the  latter 
appearing  often  in  large  beds  of  bog  ore.  The  formation  of  the  humus 
appears  to  take  place  by  a fermentative  process,  which  eliminates 
some  carbon,  hydrogen,  and  oxygen  in  the  form  of  carbon  dioxide, 
marsh  gas,  and  water;  and  micro-organisms  play  some  part  in  pro- 
ducing the  changes  observed.  On  this  point,  however,  there  is 


744 


THE  DATA  OF  GEOCHEMISTRY. 


some  doubt,  Fruh  and  Schroter,1  for  example,  regarding  the  microbian 
influence  as  very  small. 

Broadly  speaking,  with  temporary  disregard  of  minor  constitu- 
ents, a bed  of  peat  may  be  said  to  consist  of  water,  inorganic  matter, 
vegetable  fiber,  and  humus.  From  this  point  of  view  H.  Borntrager 2 
has  made  analyses  of  peat,  finding  in  the  black  varieties  from  25  to 
60  per  cent  of  humic  substance,  with  30  to  60  of  fiber.  Two  of  his 
analyses  are  as  follows: 

Analysis  of  peat  ( Borntrager ). 


A.  Light-colored  peat,  Hannover.  Mean  of  two  analyses. 

B.  Black  peat,  Oldenburg. 


A 

B 

Water 

29.  50 

20.  0 

Ash 

3.  05 

3.  0 

Fiber 

54.  95 

47.  0 

Humus  acids 

12.  50 

30.0 

100.  00 

100.0 

In  the  light-colored  peat  evidently  the  changes  have  not  gone  so 
far  as  in  the  other. 

In  some  peat  beds  isolated  masses  of  humic  substance  are  found,  to 
which  the  mineralogical  name  dopplerite  has  been  given.3  According 
to  F.  G.  Kaufmann,4  this  substance  is  identical  with  the  part  of  peat 
which  dissolves  in  caustic  alkali  solutions,  and  he  therefore  regards 
peat  as  a mixture  of  dopplerite  with  partly  decomposed  vegetable 
matter.  He  gives  analyses  by  Muhlberg  of  dopplerite  from  the  peat 
of  Obbiirgen,  Canton  Unterwalden,  Switzerland,  which,  in  mean,  are 
as  follows : 

Average  composition  of  dopplerite. 

C 56.  46 

H 5.48 

O+N 38.06 

100.  00 

The  organic  portion  of  dopplerite  from  the  original  locality  at 
Aussee,  Styria,  gave  W.  Demel5 6  nearly  identical  results,  and  he 
assigns  to  the  substance  the  formula  C12H1406.  Its  actual  occur- 
rence in  peat,  however,  is  thought  by  Demel  to  be  as  a lime  salt  and 
not  as  the  free  organic  acid. 


1 Die  Moore  der  Schweiz,  Bern,  1904,  a superb  quarto  monograph  issued  by  the  Swiss  Geological  Com- 
mission. See  especially  chapter  3,  on  peat.  The  volume  contains  a bibliography  of  280  titles.  On  the 
microbian  side  of  the  question,  see  B.  Renault,  Compt.  Rend.,  vol.  127,  1898,  p.  825. 

2 Zeitschr.  anal.  Chemie,  vol.  39,  1900,  p.  694;  vol.  40,  1901,  p.  639. 

3 See  Dana,  System  of  mineralogy,  6th  ed.,  p.  1014.  For  additional  data  on  dopplerite,  see  C.  Claesson, 

Chem.  Zeitung,  vol.  22, 1898,  p.  523,  and  W.  Alexejeff,  Zeitschr.  Kryst.  Min.,  vol.  20, 1902,  p.  187. 

* Jahrb.  K.-k.  geol.  Reichsanstalt,  vol.  15, 1865,  p.  283. 

6Ber.  Deutsch.  chem.  Gesell.,  vol.  15, 1882,  p.  2961. 


COAL. 


745 


Peat  also  contains  some  ill-defined  resinous  substances,  which  are 
extractable  by  solution  in  hot  ether  or  alcohol.  In  O.  Jacobsen’s 
experiments  1 their  quantity  ran  from  2.5  to  3.26  per  cent.  A crystal- 
line hydrocarbon,  fichtelite,  is  sometimes  found  in  the  buried  conifer- 
ous woods  of  peat  beds.  It  appears  to  have  been  derived  from  the 
terpenes  of  the  wood,  but  its  exact  nature  is  uncertain.2  C.  Hell 
assigned  it  the  formula3  C30H54,  and  L.  Spiegel  has  argued  in  favor 
of  C18H30.  The  possible  derivation  of  petroleum-like  hydrocarbons 
from  peat  was  discussed  in  the  preceding  chapter. 

In  its  youngest  forms  peat  is  loosely  compacted,  but  as  it  accumu- 
lates the  under  portions  become  compressed,  and  what  was  once  a 
foot  thick  may  shrink  to  3 inches.4  In  various  localities  peat  beds 
have  been  found  buried  beneath  sediments  or  drift.  Dawson  5 men- 
tions peat  underlying  bowlder  clay  in  Cape  Breton  Island,  and  beds 
covered  by  drift  have  been  reported  in  Iowa.6  In  all  probability 
these  occurrences  are  not  exceptional,  and  the  pressure  developed  by 
the  covering  material  doubtless  aids  in  the  transformation  of  peat 
into  coal.7 

LIGNITE. 

Under  the  names  lignite  and  brown  coal  a number  of  substances 
are  comprised  which  lie  between  peat  on  one  side  and  bituminous 
coal  on  the  other.  The  names  are  conventional  and  not  always 
appropriate,  for  some  lignites  are  not  ligniform,  and  others  are  not 
brown,  but  black.  Geologically,  they  are  modern  coals,  Tertiary  and 
Mesozoic,  and  their  composition  bears  some  relation  to  their  age. 
The  most  recent  approach  peat;  the  oldest  are  nearer  the  true 
coals.  This  is  a general,  not  an  absolute  relation,  for  in  some  cases 
lignites  have  been  transformed  into  apparently  bituminous  coals,  or 
even,  by  metamorphic  action,  into  anthracitic  varieties.8  In  many 
instances  fossil  charcoals  have  been  observed,  resembling  ordinary 
charcoal;  and  these  owe  their  peculiarities,  perhaps,  to  forest  fires, 
produced  either  by  lightning  or  by  eruptions  of  igneous  rocks.8 


1 Liebig’s  Annalen,  vol.  157,  1871,  p.  240.  See  also  Mulder,  idem,  vol.  32,  1839,  p.  305. 

2 On  fichtelite,  see  T.  E.  Clark,  Liebig’s  Annalen,  vol.  103,  1857,  p.  236;  C.  Hell,  Ber.  Deutsch.  chem. 
Gesell.,  vol.  22, 1889,  p.  498;  E.  Bamberger,  idem,  p.  635,  and  L.  Spiegel,  idem,  p.  3369.  Also  M.  Schuster, 
Min.  pet.  Mitt.,  vol  7,  1885,  p.  88. 

3 Reduced  to  simpler,  comparable  terms,  these  formulae  become  respectively,  C15H27  and  C15H25.  The 
difference  is  slight. 

4 See  G.  H.  Ashley,  Econ.  Geology,  vol.  2,  1907,  p.  34. 

8 Acadian  geology,  2d  ed.,  p.  68. 

6 See  T.  H.  MacBride,  Proc.  Iowa  Acad.,  vol.  4,  1897,  p.  63;  and  T.  E.  Savage,  idem,  vol.  11,  1903,  p.  103. 

7 On  American  peats,  see  H.  Ries,  Fifty-fifth  Ann.  Rept.  New  York  State  Mus.,  1903,  p.  r55;  A.  L. 
Parsons,  idem,  Fifty-seventh  Ann.  Rept.,  vol.  1,  1905,  p.  16.  Parsons  cites  many  analyses.  In  Ann. 
Rept.  State  Geologist  New  Jersey,  1905,  p.  223,  W.  E.  McCourt  and  C.  W.  Parmelee  describe  peat  deposits 
and  give  a bibliography  of  the  subject.  See  also  R.  Chalmers,  Min.  Res.  Canada,  1904,  Bull,  on  Peat,  for 
Canadian  data.  A partial  bibliography  of  peat  is  given  by  J.  A.  Holmes  in  Bull.  U.  S.  Geol.  Survey  No. 
290, 1906,  pp.  11-15. 

3 These  transformations  have  been  doubted  by  Donath,  whose  work  is  cited  later. 

8 See,  for  example,  A.  Daubrde,  Compt.  Rend.,  vol.  19,  1844,  p.  126,  on  “mineral  charcoal”  from  the 
Saarbriicken  coal  field. 


746 


THE  DATA  OP  GEOCHEMISTRY. 


Among  the  lignites  several  distinct  varieties  exist,  which  have 
received  characteristic  names,  as  follows : 

1.  True  or  xyloid  lignite.  This  is  essentially  fossil  wood  in  which 
the  ligneous  structure  is  more  or  less  perfectly  preserved. 

2.  Earthy  brown  coal.  This  variety  is  earthy  in  structure,  as  its 
name  indicates,  and  it  is  often  accompanied  by  mineral  resins  or 
fossil  hydrocarbons. 

3.  Common  brown  coal.  The  common,  compact  form  of  lignite, 
and  the  one  best  known  as  a fuel. 

4.  Pitch  coal,  a compact  variety,  so  named  for  its  peculiar  luster. 

5.  Glance  coal.  A hard  and  very  compact  form  of  lignite,  most 
nearly  resembling  the  Carboniferous  coals. 

6.  Jet.  A very  hard  variety,  probably  derived  from  the  fossilization 
of  coniferous  wood.1  Used  for  j ewelry  and  other  ornamental  purposes. 

As  might  be  supposed,  the  lignites  exhibit  a wide  range  of  variation 
in  their  composition.  The  following  analyses,  selected  from  a table 
in  Percy’s  Metallurgy,2  show  this  fact  clearly.  They  have  been  recal- 
culated upon  an  ash-free,  water-free  basis. 

Analyses  of  foreign  lignites. 

A.  From  Teuditz,  Germany.  Analysis  by  Wagner. 

B.  From  Sardinia.  Analyst  not  named. 

C.  From  Schonfeld,  Bohemia.  Analysis  by  Nendtwich. 

D.  From  European  Turkey.  Analyzed  by  W.  J.  Ward  in  Percy’s  laboratory. 

E.  From  Sardinia.  Analyzed  by  C.  Tookey,  in  Percy’s  laboratory. 


A 

B 

c 

D 

E 

c 

57.  02 

63.  71 

69.  82 

75.  08 

82.  26 

H 

5.  94 

5.  05 

5.  90 

5.44 

6.  52 

O+N 

37.04 

31.  24 

24.  28 

19.  48 

11.22 

100.00 

100.  00 

100.  00 

100.  00 

100.  00 

For  technical  purposes  coal  analyses  are  commonly  reported  in  a 
different  form.  Moisture  and  ash  are  important  factors  to  consider, 
and  so,  too,  is  the  distinction  between  the  “volatile  matter”  and  the 
“fixed  carbon.”  In  lignites  the  moisture  is  usually  very  high,  for 
these  coals  are  peculiarly  hygroscopic.  Like  other  coals,  they  also 
contain  sulphur,  which  is  partly  organic,  partly  present  as  inclosures 
of  pyrite  or  marcasite,  and  partly  in  the  form  of  sulphates,  such  as 
gypsum.3  The  following  analyses  from  the  reports  of  the  fuel-test- 
ing  plant  of  the  United  States  Geological  Survey 4 are  fair  examples 
of  the  technical  mode  of  statement.  All  samples  were  air  dried. 

1 See  P.  E.  Spielmann,  Chem.  News,  vol.  94, 1906,  p.  281;  vol.  97, 1908,  p.  181.  For  an  analysis  of  Spanish 
jet  see  J.  B.  Boussingaulf,  Annales  chim.  phys.,  5th  ser.,  vol.  29, 1883,  p.  382.  The  latter  memoir  contains 
many  other  analyses  of  fossil  combustibles. 

2 1875  edition,  Vol.  1,  pp.  312-313.  From  a table  of  41  analyses. 

8 The  resinoid  substances  which  have  been  named  quisqueite,  tasmanite,  and  trinkerite  are  rich  in 
organic  sulphur  compounds  of  undetermined  character.  See  Dana,  System  of  mineralogy,  6th  ecL,  p.  1010. 

4 Prof.  Paper  No.  48,  pt.  1,  and  Bull.  No.  290, 1906.  Analyses  made  under  the  direction  of  E.  E.  Sommer- 
meier. 


COAL. 


747 


Analyses  of  American  lignites. 

A.  Brown  lignite,  Williston,  North  Dakota. 

B.  Lignite  from  Texas. 

C.  Lignite  from  Tesla  mine,  Alameda  County,  California. 

D.  Lignite  from  Wyoming. 

E.  Black  lignite  from  Red  Lodge,  Montana.  A coal  of  doubtful  character.  Not  certainly  lignite. 


A 

B 

C 

D 

E 

Moisture 

16.  70 

22. 48 

18.  51 

17.  69 

9.  05 

Volatile  matter 

37. 10 

31.  36 

35.  33 

37.  96 

36.  70 

Fixed  carbon 

39.49 

26.  73 

30.  67 

39.  56 

43.  03 

Ash 

6.  71 

19.43 

15.  49 

4.  79 

11.22 

Sulphur 

100.  00 
.63 

100.  00 
.56 

100.  00 
3.  05 

100.  00 
.63 

100.  00 
1.  76 

The  elementary  analyses  of  these  coals,  when  ash,  moisture,  and 
sulphur  are  thrown  out,  show  less  variation. 


Elementary  analyses  of  American  lignites. 


A 

B 

C 

D 

E 

C 

72.  62 

73.  63 

75. 19 

75.  97 

77. 47 

H 

4.  93 

5. 07 

6. 18 

5. 36 

5.  44 

N 

1.  20 

1.35 

1.04 

1.41 

1.  75 

O... 

21.  25 

19.  95 

17.  59 

17.  26 

15.  34 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

For  further  comparison  of  the  lignites  with  other  fossil  fuels,  the 
subjoined  averages  will  be  useful.  The  data  are  reduced  to  an  ash- 
free and  water-free  standard. 


Average  analyses  of  lignites. 


A.  Average  of  22  Texas  lignites,  analyzed  by  Magnenat  and  Wooten.  Dried  at  105°.  From  E.  T. 
Dumble’s  Report  on  the  brown  coal  and  lignite  of  Texas:  Geol.  Survey  Texas,  1892,  p.  213.  This  volume 
contains  many  technical  analyses  of  lignites,  and  also  tables  of  analyses  of  German,  Austrian,  and  Italian 
brown  coals. 

B.  Average  of  10  analyses  from  the  report  of  the  fuel-testing  plant  of  the  United  States  Geol.  Survey, 
already  cited. 

C.  Average  of  29  lignites  from  various  parts  of  the  world.  Analyses  by  C.  Tookey  and  W.  J.  Ward  in 
Percy’s  laboratory.  Percy’s  Metallurgy,  vol.  1,  pp.  312-321. 


A 

B 

C 

69.  82 

74.  86 

74. 17 

4.  72 

5.  32 

5.  67 

| 25.  46 

18.  51 
1.31 

} 20.16 

100.  00 

100.  00 

100.  00 

748 


THE  DATA  OF  GEOCHEMISTRY. 


Data  of  this  kind  might  he  almost  indefinitely  multiplied.1 

The  resinoids  and  fossil  hydrocarbons  are  especially  abundant  in 
brown  coals,  both  as  visible  masses  and  in  a disseminated  condition. 
Organic  solvents,  such  as  benzene,  will  extract  matter  of  this  kind 
from  lignite,  but  the  substances  thus  obtained  are  not  of  definite  com- 
position. In  some  cases  oily  fluids  exude  from  brown  coal,2  although 
instances  of  this  kind  are  probably  rare.  Solid  bodies  are  the  rule. 
An  extreme  example  of  extractive  matter  in  coal  is  that  reported  by 
Watson  Smith,3  who,  in  a Japanese  lignite,  found  9.5  per  cent  of  sub- 
stance soluble  in  benzene. 

In  their  behavior  toward  reagents  the  lignites  are  more  akin  to 
peat  than  to  the  Carboniferous  coals.  Like  peat,  they  contain  humic 
compounds  which  are  soluble  in  solutions  of  caustic  alkalies.  Accord- 
ing to  E.  Fremy,4  peat  yields  abundant  “ulmic  acid”  to  alkaline 
solvents,  xyloid  lignite  yields  less,  and  compact  lignite  little  or  none 
at  all.  The  bituminous  coals  and  anthracite  are  insoluble  in  alkaline 
solutions.  Occasionally  these  humic  bodies  are  found  in  remarkable 
concentrations.  The  “ paper  coals”  of  Russia,  for  example,  con- 
tain layers  of  humic  matter,  which  is  soluble  in  ammonia.5  In  the 
brown  coal  of  Falkenau,  Bohemia,  C.  von  John6  found  a native 
humus,  soluble  in  ammonia  or  sodium  carbonate  solution,  which 
had  approximately  the  composition  C46H46025.  Von  John  cites 
other  examples  reported  by  other  observers.  Furthermore,  the 
pigment  known  as  Cassel  brown  is  a fossil  humus  from  the  Tertiary 
near  Cassel,  Germany.7 

Fremy  found  that  lignite  was  also  soluble  in  alkaline 'hypochlorites, 
while  the  true  coals  were  not.  It  was  also  strongly  attacked  by  nitric 
acid,  with  conversion  into  a yellow  resinous  body,  soluble  in  an 
excess  of  the  reagent  or  in  solutions  of  the  alkalies.  Bituminous  coal 
and  anthracite,  on  the  other  hand,  were  feebly  attacked,  anthracite 
in  particular  with  extreme  slowness.  These  coals,  however,  dis- 
solved in  mixtures  of  nitric  and  sulphuric  acids,  yielding  solutions 
from  which  water  precipitated  a humus  compound.  Woody  tissue, 
heated  during  several  days  to  200°,  became  comparable  with  lignite 
in  its  behavior  toward  reagents. 

1 See  the  great  monograph  by  C.  Zincken,  Die  Physiographic  der  Braunkohle,  Hannover,  1867;  and  its 
Erganzung,  published  at  Halle  in  1871.  In  Grove  and  Thorpe’s  Chemical  technology,  vol.  1,  many  analyses 
are  given;  and  others  are  cited  in  F.  Fischer’s  Chemische  Technologie  der  Brennstoffe,  Braunschweig, 
1897,  vol.  1.  E.  F.  Burchard,  in  Proc.  Sioux  City  (Iowa)  Acad.,  vol.  1,  1904,  p.  174,  has  reported  data  for 
some  Nebraska  lignites. 

2 See  A.  A.  Hall,  Jour.  Soc.  Chem.  Ind.,  vol.  26,  1907,  p.  1223;  J.  B.  Cohen  and  C.  P.  Finn,  idem,  vol.  31, 

1915,  p.  12;  P.  P.  Bedson,  idem,  vol.  26,  1907,  p.  1224.  White  and  Thiessen  (The  origin  of  coal,  p.  274) 
regard  the  oils  in  coal  as  derived  from  spore  exines  and  pollen  grains. 

8 Jour.  Soc.  Chem.  Ind.,  vol.  10,  p.  975,  1891. 

* Compt.  Rend.,  vol.  52,  1861,  p.  114. 

6 See  R.  Zeiller,  Bull.  Soc.  g6ol.  France,  3d  ser.,  vol.  12,  1884,  p.  680. 

8 Verhandl.  K.-k.  geol.  Reichsanstalt,  p.  64,  1891. 

7 See  a recent  des9ription  by  P.  Malkomesius  and  R.  Albert,  Jour,  prakt.  Chemie,  2d  ser.,  vol.  70,  1904, 
p.  509. 


COAL. 


749 


Since  Fremy’s  time  the  action  of  nitric  acid  and  other  oxidizing 
agents  upon  coal  has  been  studied  by  various  investigators.  E.  Gui- 
gnet,1  for  example,  found  that  nitric  acid  acted  upon  coal  with  the 
formation  of  products  more  or  less  analogous  to  the  nitrocelluloses, 
and  similar  observations  were  recorded  by  R.  J.  Friswell.2  A com- 
mittee of  the  British  Association 3 also  conducted  some  experiments 
upon  the  proximate  constitution  of  coals.  They  not  only  studied  the 
action  of  solvents  to  some  extent  but  also  examined  the  action  of 
hydrochloric  acid  and  potassium  chlorate  upon  coal.  That  powerful 
oxidizing  mixture  produced  compounds  which  resembled  the  chlo- 
rinated derivatives  of  jute  fiber.  The  work  of  the  committee  seems 
never  to  have  been  pushed  to  completion. 

The  researches  thus  briefly  summarized,  it  will  be  observed,  relate 
partly  to  lignite  and  partly  to  other  coals.  They  suggest  relations 
between  the  coals  and  vegetable  fiber,  but  for  several  reasons  they 
are  inconclusive.  The  records  are  often  inexplicit,  and  the  experi- 
ments are  not  all  strictly  comparable.  When  nitric  acid,  for  example, 
is  employed  as  a test  reagent,  it  should  be  under  commensurable  con- 
ditions, such  as  uniform  fineness  of  subdivision  on  the  part  of  the 
coal  and  equality  of  concentration  on  the  side  of  the  acid.  Time  and 
temperature  also  must  be  taken  into  account.  A hot,  strong  acid, 
applied  to  a finely  powdered  coal,  would  act  differently  from  a cold, 
weak  acid  on  coarser  material.  To  neglect  of  details  like  these  some 
of  the  discordances  in  the  records  are  probably  due. 

In  recent  years  E.  Donath  and  his  associates  4 have  studied  one 
phase  of  the  nitric  acid  reaction  with  much  care.  Dilute  nitric  acid, 
one  part  to  nine  of  water,  at  a temperature  of  70°,  will  attack  lignite 
vigorously,  but  is  without  action  upon  bituminous  coal.  Even  a 
brown-coal  “anthracite,”  a product  of  contact  metamorphism  by  an 
intrusion  of  phonolite,  behaved  like  ordinary  lignite  toward  nitric 
acid.  From  evidence  of  this  kind  Donath  concludes  that  lignite  and 
true  coal  are  chemically  unlike  and  of  dissimilar  origin.  They 
behave  differently  toward  reagents,  and  yield  different  products  upon 
destructive  distillation.  Neither  by  time,  according  to  Donath,  nor 
by  heat,  can  lignite  be  transformed  into  coal.  Lignite,  he  thinks,  is 
derived  from  materials  rich  in  lignocellulose,  as  shown  by  the  pres- 
ence of  humic  compounds  in  it.  The  true  coals,  on  the  other  hand, 
were  formed  from  substances  which  were  either  free  from  woody 

1 Compt.  Rend.,  vol.  88,  1879,  p.  590. 

2 Proc.  Chem.  Soc.,  vol.  8,  1892,  p.  9.  W.  C.  Anderson  and  J.  Roberts  (Jour.  Soc.  Chem.  Ind.,  vol.  17, 
1898,  p.  1013)  have  aiso  studied  the  action  of  nitric  acid  on  coal  and  made  several  analyses  of  the  “coai 
acids”  so  obtained. 

» Ann.  Rept.  Brit.  Assoc.,  1894,  p.  246;  idem,  1896,  p.  340. 

* Donath,  Chem.  Zeitung,  1905,  p.  1027,  and  Zeitschr.  anorg.  Chemie,  1906,  p.  657.  Donath  and  H.  Ditz, 
Oesterr.  Zeitschr.  Berg-  u.  Hiittenw.,  vol.  51, 1903,  p.  310.  Donath  and  F.  Braunlich,  Chem.  Zeitung,  1904, 
pp.  180, 953. 


750 


THE  DATA  OF  GEOCHEMISTRY. 


fiber,  or  nearly  so.  In  the  formation  of  bituminous  coal,  which  is  often 
rich  in  nitrogen,  the  proteids  of  animal  matter  probably  took  part. 

It  would  be  premature,  I think,  to  accept  Donath’s  conclusions 
throughout,  but  his  evidence,  taken  together  with  that  of  earlier 
investigators,  shows  distinct  chemical  differences  between  the  lignites 
and  the  coals.  In  lignites  the  humic  compounds  are  readily  detected, 
but  in  coal  they  are  less  apparent.  Nitric  acid  acts  easily  on  lignite, 
but  with  much  less  vigor  upon  bituminous  coal  or  anthracite.  How 
far  the  latter  substances  are  derivable  from  the  former,  however,  is  a 
separate  question. 

BITUMINOUS  COAL. 


In  composition,  at  least  empirically,  the  bituminous  coals  lie 
between  the  lignites  and  anthracite.  To  some  extent  they  overlap 
the  lignites,  so  that  it  is  not  always  easy  to  say  where  one  group 
ends  and  the  other  begins.  The  following  analyses  of  bituminous 
coals,  all  of  Carboniferous  age,  are  taken  from  the  reports  of  the  fuel- 
testing plant  of  the  United  States  Geological  Survey.  They  are 
selected  in  order  to  show  something  of  the  recognized  variations.1 

First,  there  are  the  conventional  proximate  analyses: 


Proximate  analyses  of  bituminous  coals. 


A.  Ehrenfeld,  Pennsylvania.  Bull.  No.  290,  p.  179. 

B.  Bruce,  Pennsylvania.  Idem,  p.  184. 

C.  Vigo  County,  Indiana.  Idem,  p.  109. 


D.  Altoona,  Iowa.  Prof.  Paper  No.  48,  p.  223. 

E.  Shawnee,  Ohio.  Bull.  No.  290,  p.  145. 

F.  Staunton,  Illinois.  Idem,  p.  63. 


A 

B 

C 

D 

E 

F 

Moisture 

3.  51 

2.  61 

9.  55 

4.  52 

9.  90 

13.  72 

Volatile  matter 

16.  82 

34.  92 

36. 19 

40.  96 

33.  66 

36.  24 

Fixed  carbon 

73.  04 

56.  30 

43.  65 

38.  99 

44.  86 

39.  72 

Ash 

6.  63 

6. 17 

10.  61 

15.  53 

11.  58 

10.  32 

Sulphur 

100.  00 
.94 

100.  00 
1.  26 

100.  00 
3.  72 

100.  00 
6.  83 

100.  00 
1. 81 

100.00 
3.  96 

With  one  exception  the  volatilizable  part  of  these  coals  is  less  in 
amount  than  the  fixed  carbon.  With  the  lignites  the  reverse  state- 
ment is  generally  true.  The  ultimate  analyses  of  the  same  coals, 
recalculated  to  a water,  ash,  and  sulphur  free  basis,  are  as  follows: 

Ultimate  analyses  of  bituminous  coals. 


A 

B 

c 

D 

E 

F 

C 

90.  78 

85.  73 

84. 19 

82.  92 

82.  20 

81.  87 

H 

4.  69 

5.  49 

5.  82 

6.  06 

5.  45 

5.  85 

N 

1.  40 

1.  75 

1.  42 

1.  27 

1.  60 

1.  36 

O 

3. 13 

7.  03 

8.  57 

9.  75 

10.  75 

10.  92 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

i The  high  moisture  of  these  coals  is  due  to  the  fact  that  the  samples  were  sealed  up  immediately  after 
collection  in  the  mines  and  were  not  dried.  Many  analyses  of  American  coals  are  given  in  Bull.  U.  S.  Bur. 
Mines  No.  22, 1913,  by  N.  W.  Lord.  See  also  Bull.  85, 1914,  for  many  other  analyses. 


COAL.  751 

The  reciprocal  variation  of  carbon  and  oxygen,  the  latter  rising  as 
the  former  falls,  is  here  very  well  shown. 

Even  in  a single  mine  the  composition  of  the  coal  may  vary  within 
fairly  wide  limits.  For  example,  F.  Fischer  1 gives  24  comparable 
analyses  of  coal  from  the  Unser  Fritz  mine,  district  of  Arnsberg, 
Westphalia.  From  the  table,  in  which  the  analyses  are  reduced  to 
an  ash  and  sulphur  free  standard,  I select  the  following  examples, 
which  show  the  maximum  and  minimum  proportion  of  each  con- 
stituent. In  the  last  column  I give  the  average  of  the  entire  series: 


Analyses  of  coal  from  Unser  Fritz  mine. 


c 

85.  33 

85.  06 

84.  28 

82.  34 

80.  69 

83.  81 

H 

5.  20 

4.  66 

4.  85 

4.  94 

4.  94 

4.  98 

N 

1.  49 

1.  35 

1.  87 

1. 18 

1.  29 

1.  47 

O 

7.  98 

8.  93 

9.  00 

11.  54 

13.  08 

9.  74 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Other  variations,  due  to  the  peculiar  character  of  certain  coaly 
material,  are  illustrated  by  the  following  analyses : 


Analyses  of  fossil  plants  and  cannel  coal. 

A.  Average  of  six  analyses  of  fossil  plants,  from  the  coal  beds  of  Commentry,  France,  by  S.  Meunier,  in 
Fremy’s  Encyclopedic  chimique,  vol.  2 (Complement,  pt.  1),  p.  152.  The  plants  were  perfectly  preserved 
as  to  structure,  but  entirely  transformed  into  coal.  The  genera  Calamodendron,  Cordaites,  Lepidodendron, 
Psaronius,  Ptychopteris,  and  Megaphyton  are  represented  in  this  average.  The  variations  between  themare 
small. 

B.  Analysis  of  Wigan  cannel,  by  F.  Vaux,  Jour.  Chem.  Soc.,  vol.  1, 1840,  p.  320. 

C.  Analysis  of  Tyneside  cannel,  by  H.  Taylor,  Edinburgh  New  Philos.  Jour.,  vol.  50, 1851,  p.  145.  All 
three  analyses  are  here  recalculated  to  the  ash-free  basis. 


A 

B 

c 

C 

82.  45 

83.  58 

87.  89 

H 

4.  75 

5.  77 

6.  53 

N 

.43 

2.  21 

2.  08 

0 

12.  37 

8.  44 

3.  50 

100.  00 

100.  00 

100.  00 

The  suggestive  feature  of  the  foregoing  trio  is  in  the  proportion  of 
nitrogen.  The  fossil  plants  contain  very  little  nitrogen;  the  cannels 
are  abnormally  high.  The  inference  is  that  plant  remains  have  con- 
tributed but  a small  part  of  the  nitrogen  contained  in  coal,  and  that 
the  main  supply  has  come  from  other  sources.  The  most  obvious 
source  is  animal  matter,  and  this  was  probably  the  source  of  the  nitro- 
gen in  cannel.  Newberry  2 long  ago  pointed  out  that  fish  remains 

1 Zeitschr.  angew.  Chemie,  1894,  p.  605.  See  also  his  Chemische  Technologie  der  Brennstoffe,  vol.  1,  pp. 
518-520. 

2 Am.  Jour.  Sci.,  2d  ser.,  vol.  23,  1854,  p.  212.  J.  Rofe  (Geol.  Mag.,  1866,  p.  208)  has  also  called  attention 
to  the  fish  remains  in  Lancashire  cannel.  B.  Renault  (Bull.  Soc.  ind.  min.,  3d  ser.,  vol.  14,  p.  138)  regards 
cannel  as  formed  from  the  spores  of  cryptogams.  No  algae  are  found  in  it,  or  very  few.  See  also  E.  C. 
Jeffrey,  Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  46, 1910,  p.  273. 


752 


THE  DATA  OF  GEOCHEMISTRY. 


are  abundant  in  cannel  coal,  and  he  argues  that  the  beds  were  laid 
down  under  water.  Vegetable  matter  formed  a carbonaceous  paste, 
in  which  the  fish  remains  became  embedded  and  which  consolidated 
to  produce  cannel  coal. 

For  comparison  with  other  varieties  of  coal,  the  subjoined  averages 
will  be  useful.  Moisture,  sulphur,  and  ash  are  excluded  from  the 
table,  except  when  otherwise  specified. 

Average  analyses  of  bituminous  coal. 

A.  Average  of  20  analyses  of  bituminous  coals  from  Pennsylvania,  Maryland,  Virginia,  and  West  Vir- 
ginia. Combined  from  data  given  in  the  reports  of  the  fuel-testing  plant  of  the  United  States  Geological 
Survey. 

B.  Average  of  40  analyses  of  bituminous  coals  from  Ohio,  Indiana,  Illinois,  Iowa,  and  Missouri.  Also 
from  the  above-named  reports. 

C.  Average  of  15  analyses  of  Scotch  coals,  by  W.  D.  Anderson  and  J.  Roberts,  Jour.  Soc.  Chem.  Ind., 
vol.  17,  1898,  p.  1013.  Sulphur  is  included  in  the  figure  for  oxygen. 

D.  Average  of  18  coals  from  Newcastle,  28  from  Lancashire,  and  7 from  Derbyshire,  England.  Recalcu- 
ated  from  averages  cited  by  Fischer,  in  Chemische  Technologie  der  Brennstoffe,  vol.  1,  p.  512. 


A 

B 

c 

D 

c 

87.  52 

82.  91 

83.  65 

84. 19 

H 

5.  20 

5.  70 

5. 48 

5.  58 

N 

1.  61 

1. 49 

1.  86 

1.  41 

0 

5.  67 

9.  90 

9.  01 

8. 82 

100.  00 

100.  00 

100. 00 

100. 00 

The  peculiar  chemical  differences  between  the  bituminous  coals 
and  lignite  were  described  in  the  preceding  section  of  this  chapter. 
Many  coals,  which  are  apparently  bituminous,  and  in  fact  are  bitu- 
minous so  far  as  technical  uses  are  concerned,  are  really  lignitic;  at 
least  so  far  as  can  be  judged  from  their  origin.  Their  true  character 
must  be  determined  by  researches  like  those  of  Fremy  and  Donath, 
but  refined  methods  of  investigation  are  yet  to  be  devised. 

ANTHRACITE. 

In  anthracite  the  transformation  of  vegetable  matter  into  carbon 
approaches  its  limit.  On  one  side  of  this  class  of  coals  we  find  the 
variety  known  as  semianthracite;  on  the  other  they  approximate  to 
graphite.  The  technical  analyses  of  anthracite  show  a large  pro- 
portion of  fixed  carbon,  with  relatively  little  volatilizable  matter — a 
relation  which  appears  in  the  following  table. 


COAL. 


753 


Proximate  analyses  of  anthracite. 

A.  Semianthracite,  Coal  Hill,  Arkansas.  From  report  of  the  coal-testing  plant,  Prof.  Paper  U.  S.  Geol. 
Survey  No.  48,  1906,  p.  202. 

B.  Anthracite  culm,  Scranton,  Pennsylvania.  Idemrp.  245. 

C.  Lykens  Valley,  Pennsylvania. 

D.  Schuylkill  coal,  Pennsylvania. 

E.  Cameron  coal,  Pennsylvania.  Analyses  C,  D,  and  E by  A.  S.  McCreath,  Rept.  Second  Geol.  Survey, 
Pennsylvania,  vol.  MM.  This  volume  contains  many  other  proximate  analyses  of  coals.  See  also  C.  A. 
Ashburner,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  14,  1875-76,  p.  706,  for  a tabulated  classification  of  Pennsyl- 
vania anthracites.  A large  number  of  proximate  analyses  are  there  cited.  For  analyses  of  Colorado 
anthracites,  see  W.  P.  Headden,  Proc.  Colorado  Sci.  Soc.,  vol.  8,  1907,  p.  257. 


A 

B 

C 

D 

E 

Moisture 

1.  28 

2.  08 

2.  27 

2.  98 

1.  82 

Volatile 

12.  82 

7.27 

8.  83 

3.  38 

6. 18 

Fixed  carbon 

73.  69 

74.  32 

78.  83 

87. 13 

86.  75 

Sulphur  

.68 

.66 

.75 

Ash 

12.  21 

16.33 

9.  39 

5.  85 

4.  50 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Ultimate  analyses  of  anthracites  are  much  less  numerous  than  for 
the  other  varieties  of  coal.  The  subjoined  table,  however,  is  enough 
for  present  purposes.  Ash,  sulphur,  and  moisture  are  excluded. 

Ultimate  analyses  of  anthracite. 

A.  Semianthracite,  Arkansas;  the  same  as  A in  the  preceding  table. 

B.  Welsh  anthracite,  analysis  by  F.  Vaux,  Join-  Chem.  Soc.,  vol.  1,  1848,  p.  324. 

C.  From  Scranton,  Pennsylvania.  Coal  B of  the  preceding  table. 

D.  From  Mauch  Chunk,  Pennsylvania.  Analysis  by  J.  Percy,  Quart.  Jour.  Geol.  Soc.,  vol.  1,  1845, 
p.  204. 

E.  From  Province  of  Hunan,  China.  Analysis  by  F.  Haeussermann  and  W.  Naschold,  Zeitschr.  angew. 
Chemie,  1894,  p.  263.  This  paper  contains  twenty-eight  analyses  of  Chinese  coals,  most  of  them  anthracitic. 

F.  From  the  Bajewka,  Ural.  Analysis  by  Alexejeff,  cited  by  Bertelsmann  in  an  important  memoir 
upon  the  nitrogen  of  coal,  in  Ahren’s  Sammlung  chemischer  und  chemisch-technischer  Vortrage,  vol.  9, 
p.  339.  A valuable  table  of  coal  analyses  is  there  given. 

G.  Average  of  sixteen  analyses  of  anthracite,  compiled  from  various  sources. 


A 

B 

C 

D 

E 

F 

G 

c 

91.47 

92.  73 

93.  90 

94.  63 

94.  68 

97.  46 

93.  50 

H 

4.  25 

3.37 

3.22 

2.  73 

2.  29 

.61 

2.  81 

N 

1.  64 

.85 

1.  00 

1.  36 

.76 

.35 

.97 

O 

2.  64 

3.  05 

1.  88 

1.  28 

2.  27 

1.  58 

2.  72 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

Anthracite,  however,  is  not  the  extreme  end  of  the  coal  series. 
There  are  pre-Carboniferous  coals,  which  are  found  only  in  small 
quantities,  and  which  approach  still  more  closely  to  pure  carbon. 
The  following  substances  belong  in  this  class,  with  the  possible  excep- 
tion of  the  first  example.  The  crude  analyses  are  given  first. 

97270°— Bull.  616—16 48 


754 


THE  DATA  OF  GEOCHEMISTRY. 


Analyses  of  anthraxolite,  schungite , and  graphitoid. 

A.  Anthraxolite,  near  Kingston,  Canada.  Analysis  by  W.  H.  Ellis,  Chem.  News,  vol.  76,  1897,  p.  186. 
Found  in  Lower  Silurian  limestone. 

B.  Anthraxolite,  near  Sudbury,  Canada.  Analysis  by  Ellis,  loc.  cit.  Found  in  the  Cambrian.  Ellis 
gives  partial  analyses  of  anthraxolites  from  three  other  localities.  See  also  A.  P.  Coleman,  Sixth  Ann. 
Rept.  Ontario  Bur.  Mines,  1897. 

C.  Schungite,  from  Schunga,  near  Lake  Onega,  Russia.  Mean  of  six  analyses,  reduced  to  anhydrous 
form,  by  A.  Inostranzeff,  Neues  Jahrb.,  1880,  Band  1,  p.  97;  see  also  the  same  journal  for  1886,  Band  1, 
p.  92.  Found  in  the  Huronian. 

D.  Graphitoid,  from  the  mica  schist  and  phyllite  of  the  Erzgebirge.  Analysis  by  A . Sauer,  Zeitschr. 
Deutsch.  geol.  Gesell.,  vol.  37,  1885,  p.  441. 


A 

B 

c 

D 

c 

90.  25 

94.  92 

98. 11 

24.  855 

H 

4. 16 

.52 

.43 

.06 

N 

.52 

1.  04 

.43 

S 

. 66 

. 31 

0 

3.  69 

1.  69 

h2o 

1.  01 

Ash 

.72 

1.  52 

1.  09 

73.  854 

100.  00 

100.  00 

100.  06 

99.  779 

Rejecting  ash,  water,  and  sulphur,  these  analyses  assume  the  fol- 
lowing form,  comparable  with  the  analyses  of  other  coaly  substances: 


Recalculated  analyses  of  anthraxolite,  schungite,  and  graphitoid. 


‘ 

A 

B 

c 

D 

C 

91.  53 
4.  22 
.53 
3.  72 

96.  69 
.53 
1.  05 
1.  73 

99. 12 
.44 
.44 

99.  76 
.24 

H 

N 

0 

100.  00 

100.  00 

100.  00 

100.  00 

These  minerals,  and  many  anthracites  also,  might  be  properly 
described  as  metamorphic  coals.  They  cannot,  however,  even  in  the 
extreme  cases,  be  termed  graphitic,  for  they  consist  mainly  of  amor- 
phous carbon.  Graphite  is  a crystalline  mineral,  and  upon  treat- 
ment with  powerful  oxidizing  agents  it  can  be  transformed  into  a 
substance  known  as  graphitic  acid,1  CnH405.  The  amorphous  car- 
bons do  not  yield  this  derivative,  and  Inostranzeff  failed  to  obtain  it 
from  schungite.  The  approach  to  graphite,  therefore,  is  empirical 
only,  and  not  constitutional — a conclusion  which  needs  to  be  checked 
by  a study  of  many  other  so-called  ‘‘graphitic  coals.’ ’ That  term 
may  be  applicable  in  some  cases,  but  they  are  yet  to  be  established. 


i See  B.  C.  Brodie,  Liebig’s  Annalen,  vol.  114, 1860,  p.  6. 


COAL. 


755 


THE  VARIATIONS  OF  COAL. 

For  comparison  of  all  the  fuels,  starting  with  wood  and  ending 
with  anthracite,  the  subjoined  table  has  been  compiled  from  the 
data  given  in  the  preceding  pages.  In  the  case  of  wood  the  figure 
for  nitrogen  is  the  mean  of  the  determinations  by  Chevandier,  Gott- 
lieb, and  Hawes. 

Average  composition  of  fuels. 


C 

H 

N 

0 

Wood 

49.  65 

6.  23 

0.  92 

43.  20 

Peat 

55.  44 

6.  28 

1.  72 

35. 56 

Lignite 

72.  95 

5.  24 

1. 31 

20.  50 

Bituminous  coal 

84.  24 

5. 55 

1.  52 

8.  69 

Anthracite 

93.  50 

2. 81 

.97 

2. 72 

This  table  may  be  restated  in  a different  form,  so  as  to  show  the 
proportion  of  the  other  elements  to  100  parts  of  carbon.  It  then 
appears  as  follows: 


Comparative  proportions  of  constituents  of  fuels. 


C 

H 

N 

0 

Wood 

100 

12.5 

1.  8 

87.  0 

Peat 

100 

11.  3 

3. 1 

64. 1 

Lignite 

100 

7.  2 

1.8 

28. 1 

Bituminous  coal 

100 

6.  6 

1.8 

10.  3 

Anthracite 

100 

3.0 

1.3 

2.9 

A steady  decrease  in  hydrogen  and  oxygen  thus  becomes  apparent. 
The  data  for  nitrogen,  however,  are  less  conclusive,  because  of  the 
uncertainty  in  the  analyses  of  wood.  If  Hawes’s  average  for  the 
acrogen  plants,  1.59  per  cent  of  nitrogen,  be  taken,  then  its  ratio 
becomes  3.1,  identical  with  the  figure  for  peat,  and  a definite  decrease 
follows.  New  analyses  of  wood,  with  reference  especially  to  its 
nitrogen  content,  are  much  to  be  desired. 

A closer  scrutiny  of  the  foregoing  table  reveals  still  another  fact, 
namely,  that  the  proportional  decrease  in  oxygen  is  greater  than  in 
the  case  of  hydrogen.  In  cellulose,  C6H10O5,  these  two  elements  exist 
in  exactly  the  proportions  required  to  form  water.  In  wood  the 
hydrogen  is  slightly  in  excess  of  that  ratio  (1:8),  and  the  excess 
steadily  increases  until,  in  anthracite,  it  is  proportionally  very  large. 
In  wood  the  ratio  is  nearly  1:7;  in  anthracite,  roughly,  1:1. 

This  progressive  variation  in  the  ultimate  composition  of  the 
coals  implies  a corresponding  variation  in  their  proximate  character, 
a class  of  changes  to  which  attention  has  already  been  called.  Even 


756 


THE  DATA  OF  GEOCHEMISTRY. 


the  crudest  analyses  are  conclusive  in  regard  to  one  form  of  varia- 
tion. Peat,  ignited  in  a covered  crucible,  yields  much  volatile  matter 
and  relatively  little  fixed  carbon.  In  lignite  the  fixed  carbon  is 
higher,  but  commonly  less  than  the  volatile  products.  Bituminous 
coal  is  progressively  richer  in  fixed  carbon,  while  in  anthracite  the 
volatile  portion  has  become  exceedingly  small.  This  particular 
variability  is  so  characteristic  that  the  ratio  between  fixed  carbon 
and  volatile  matter  has  been  adopted  by  some  authorities  as  a basis 
for  the  classification  of  coals.1  Such  a method  of  classification  has 
the  merit  of  convenience,  for  it  requires  only  proximate  analyses, 
which  are  numerous  and  easily  made,  although  it  must  be  admitted 
that  their  accuracy  is  often  questionable.  Moreover,  the  nature  of 
the  volatile  matter  varies  in  different  kinds  of  coal,  a part  of  it  being 
combustible,  and  a part  consisting  of  water  and  other  noncom- 
bustible products  formed  during  the  process  of  burning.  In  fact, 
the  volatile  matter  is  exceedingly  complex,  as  is  shown  by  a study  of 
the  substances  formed  when  coal  is  distilled  for  the  production  of 
illuminating  gas.  The  gas  itself  may  contain  hydrocarbons,  free 
hydrogen,  both  oxides  of  carbon,  nitrogen,  and  compounds  of  sul- 
phur. Ammoniacal  water  solutions  are  also  produced,  together  with 
coal  tar;  and  in  the  latter  a number  of  complex  hydrocarbons  are 
found,  and  also  oxidized  bodies  such  as  phenol.  In  20  analyses  of 
coal  gas,  P.  F.  Frankland  2 found  the  following  range  of  variations 
in  the  percentages  of  the  principal  constituents: 

Variations  in  composition  of  coal  gas. 


C02 0 to  2.73 

02 0 to  1.00 

N2 - 2.07  to  10.84 

H2 33.24  to  53.79 

CO 2.46  to  7.14 

CH4 36.55  to  42.93 


The  other  products  of  distillation,  obviously,  must  have  been 
equally  variable.  The  destructive  distillation  of  wood  yields  sub- 
stances quite  unlike  those  derived  from  coal;  methyl  alcohol,  acetone, 
and  acetic  acid  being  conspicuous  among  them.3 

On  account  of  this  distinction  between  the  combustible  and  non- 
combustible portions  of  the  distillates  from  coal,  S.  W.  Parr 4 has 
proposed  a technical  classification  of  these  fuels  which  differs  essen- 
tially from  the  system  above  mentioned.  His  scheme  is  based  upon 
the  ratio  between  the  total  carbon  and  the  carbon  of  the  volatile 
matter,  which  latter  is  largely  but  not  wholly  combustible.  He  also 

1 See,  for  example,  P.  Frazer,  Trans.  Am.  Inst.  Min.  Eng.,  vol.  6,  1877-78,  p.  430,  and  C.  A.  Ashbumer, 
idem,  vol.  14,  1885-86,  p.  706. 

2 Jour.  Soc.  Chem.  Ind.,  vol.  3,  1884,  p.  273. 

3 A good  article  on  the  distillation  of  wood  is  in  Watts’s  Dictionary  of  applied  chemistry,  vol.  3, 1893,  p. 
1026.  The  subject  can  not  be  discussed  at  length  here. 

* Bull.  No.  3,  Illinois  Geol.  Survey,  1906.  Also  Jour,  Am.  Chem.  Soc.,  vol.  28,  1906,  p.  1425. 


COAL. 


757 


takes  into  account  the  percentage  of  “ inert  volatile”  matter,  which 
seems  to  vary  in  a manner  characteristic  of  the  different  groups  of 
coals.  M.  R.  Campbell/  on  the  other  hand,  has  argued  in  favor  of 
the  ratio  C : H,  with  which  he  has  classified  the  analyses  made  at  the 
fuel-testing  plant.  These  classifications  are  chiefly  of  technological 
significance,  and  their  discussion  falls  outside  the  range  of  this  work. 

The  most  important  variations  in  coal,  however,  are  those  which 
were  outlined  under  lignite.  Passing  from  peat  to  anthracite  there* 
is  a progressive  diminution  in  the  proportion  of  humus  substances 
and  also  in  the  solubility  of  the  coals  in  various  reagents.  The 
necessary  details  to  illustrate  these  variations  have  already  been 
given  and  need  no  further  repetition  here. 

THE  GASES  IN  COAL. 

Both  peat  and  coal,  the  latter  in  all  its  varieties,  contain  occluded 
or  enclosed  gases,  often  in  large  amount.  In  coal  mines  they  some- 
times escape  in  formidable  volume,  forming  the  so-called  choke  damp 
and  fire  damp  of  mining  parlance.  The  choke  damp  consists  of 
carbon  dioxide  or  nitrogen  or  both  together;  the  fire  damp  is  prin- 
cipally methane. 

The  development  of  these  gases  can  be  traced  back  to  the  earliest 
stages  of  coal  formation,  when  marsh  gas  was  produced,  along  with 
carbon  dioxide,  in  the  process  of  vegetable  decay.  The  evolution  of 
methane  from  swamps  was  mentioned  in  the  preceding  chapter,  with 
reference  to  its  existence  in  petroleum  and  as  natural  gas.  Its  ema- 
nation from  peat  is  another  example  of  the  same  phenomenon,  and 
is  mentioned  now  for  the  reason  that  it  was  quantitatively  studied 
by  Websky.1 2  In  a single  analysis  of  gas*  extracted  from  peat  he 
obtained  the  following  percentages: 

C02 2.  97 

CH4 43.36 

N2 53.67 

100.  00 

The  nitrogen  from  this  gas  is  presumably  a residue  from  the  ground 
air,  the  oxygen  of  the  latter  having  been  consumed,  partly  to  form 
carbon  dioxide  and  partly  water. 

The  gases  occluded  by  lignite,  so  far  as  our  information  now  goes, 
are  of  quite  a different  character.  As  analyzed  by  J.  W.  Thomas,3 
who  obtained  his  material  by  heating  lignite  in  vacuo  to  50°,  100°, 
and  200°,  successively,  they  consist  principally  of  carbon  dioxide,  with 

1 Prof.  Paper  U.  S.  Geol.  Survey  No.  48,  1906,  pp.  156-173.  See  also  P.  Frazer,  Bull.  Am.  Inst.  Min.  Eng., 
March,  1906;  L.  P.  Breckenridge,  Bull.  U.  S.  Geol.  Survey  No.  325, 1907,  p.  68. 

2 Jour,  prakt.  Chemie,  vol.  92, 1864,  p.  76. 

3 Jour.  Chem.  Soc.,  vol.  32,  1877,  p.  146.  See  also  Zitowitsch,  Jour,  prakt.  Chemie,  2d  ser.,  vol.  6, 1873,  p.  79, 
on  gases  from  Bohemian  lignites. 


758 


THE  DATA  OF  GEOCHEMISTRY. 


subordinate  carbon  monoxide  and  nitrogen,  and  insignificant  propor- 
tions of  oxygen  and  hydrocarbons.  The  following  examples  are  suffi- 
cient to  show  the  general  nature  of  his  analyses: 

Analyses  of  gases  from  lignite. 

A.  Gas  from  Bohemian  lignite,  extracted  at  100°. 

B.  Gas  from  Bovey  Heathfield  lignite  at  50°;  100  grams  of  coal  gave  56.1  cubic  centimeters  of  gas. 

C.  Gas  from  the  same  coal  at  100°,  59.9  cubic  centimeters. 

D.  Steam  coal.  147.4  cubic  centimeters  gas. 

E.  Gas  evolved  from  sample  D on  heating  to  200°. 


A 

B 

C 

D 

E 

COo 

96.  41 
1.  20 

87.  25 
3.  59 

89. 53 
5. 11 

96.05 
3.  20 

86.  30 
7.41 
3.  34 
2.  08 
.53 

CO 

ch4 

Olefines 

Traces. 

.33 

C,HS 

o 

02 

.32 
2. 17 

.24 
8.  92 

.33 
5.  03 

No 

.42 

.34 

al00. 10 

100.  00 

100.  00 

100.  00 

100.  00 

a The  error  in  summation  is  probably  due  to  an  unidentifiable  misprint  in  the  original. 


Marsh  gas,  it  will  be  seen,  only  appears  in  the  product  of  heating 
lignite  to  200°  after  decomposition  had  begun.  In  these  lignites,  at 
least,  marsh  gas  is  not  normally  occluded,  but  it  would  be  rash  to  say 
that  all  other  lignites  follow  the  same  rule.  It  is  desirable  that  many 
more  lignites  should  be  examined  in  order  to  see  whether  or  not  they 
exhibit  the  same  peculiarity.  The  samples  studied  by  Thomas  may 
possibly  be  exceptional. 

In  another  investigation  Thomas 1 examined  the  gases  extracted  in 
vacuo  at  100°  from  camrel  coal  and  jet.  The  analyses  are  subjoined, 
with  a statement  of  the  volume  of  gas  yielded  by  100  grams  of  each 
sample. 

Analyses  of  gases  from  cannel  coal  and  jet. 

A.  Wigan  cannel.  421.3  cubic  centimeters  gas. 

B.  Wigan  cannel.  350.6  cubic  centimeters  gas. 

C.  Scotch  cannel,  Wilson  town.  16.8  cubic  centimeters  gas. 

T>.  Scotch  cannel,  Lesmahago.  55.7  cubic  centimeters  gas. 

E.  Cannel  shale,  Lasswade,  near  Edinburgh.  55.7  cubic  centimeters  gas. 

F.  Whitby  jet.  30.2  cubic  centimeters  gas. 


A 

B 

c 

D 

E 

F 

co2 

6.  44 

9.  05 

53.  94 

84. 55 

68.  75 

10.  93 

CEL.. 

80.  69 

77. 19 

VAA4##  

4.  75 

7.  80 

2.  67 

v2AJ-6*  

CoHa.  . 

.91 

V3XA8* * 

86.  90 

No 

8. 12 

5.  96 

46.  06 

14.  54 

28.  58 

2. 17 

100.  00 

100.  00 

100.00 

100.  00 

100.00 

100.00 

i Jour.  Chem.  Soc.,  vol.  30, 1876,  p.  144. 


COAL. 


759 


The  variations  here  are  most  remarkable.  Methane  predominates 
in  the  gases  from  two  cannels,  carbon  dioxide  and  nitrogen  in  the 
other  three.  In  jet  the  proportion  of  butane  is  extraordinary,  espe- 
cially for  the  reason  that  jet  is  essentially  a fossil  wood,  or,  in  other 
words,  a lignite. 

The  gases  occluded  by  bituminous  coal  have  been  studied  by  several 
chemists.  E.  von  Meyer  1 investigated  a number  of  German  coals, 
and  also  a series  from  the  north  of  England.  Several  coals  from  the 
Newcastle  region  were  studied  by  P.  P.  Bedson  2 and  W.  McConnell.3 
For  Welsh  coals  there  are  data  by  J.  W.  Thomas.4  In  Thomas’s 
memoir  both  bituminous  coals  and  anthracite  are  included,  and  from 
it  I select  the  following  analyses.  The  gases  were  extracted  at  100° 
in  vacuo,  and  in  volumes  which  are  referred  to  the  uniform  standard 
of  100  grams  of  coal. 

Analyses  of  gases  from  bituminous  and  anthracite  coal. 

A.  Bituminous  coal.  55.9  cubic  centimeters  gas. 

B.  Bituminous  coal.  39.7  cubic  centimeters  gas. 

C.  Bituminous  coal.  55.1  cubic  centimeters  gas. 

D.  Steam  coal.  147.4  cubic  centimeters  gas. 

E.  Steam  coal.  194.8  cubic  centimeters  gas. 

F.  Anthracite.  600.6  cubic  centimeters  gas. 

G.  Anthracite.  555.5  cubic  centimeters  gas. 


A 

B 

C 

D 

E 

F 

G 

co2 

36.  42 

9.  43 

5.  44 

18.  90 

5.  04 

14.  72 

2.  62 

ch4 

31.  98 

63.  76 

67.  47 

87.  30 

84. 18 

93. 13 

Oo 

.80 

2.25 

1.05 

1.02 

.33 

N2 

62.  78 

56.  34 

29.  75 

12.  61 

7.  33 

1. 10 

4.  25 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.  00 

100.00 

The  gases  obtained  by  Yon  Meyer  from  Saxon  and  Westphalian 
coals  were  similarly  variable  in  composition.  In  some  of  them  ethane 
was  reported  up  to  23  per  cent;  and  also  hydrocarbons,  in  small 
amount,  of  undetermined  character.  By  weight  the  gases  form  only 
a fraction,  usually  a small  fraction  of  1 per  cent  of  any  coal. 

The  variability  thus  shown  may  easily  be  misinterpreted.  The 
coals  emit  gases  even  in  the  mines,  and  the  laboratory  samples,  there- 
fore, do  not  represent  the  true  character  of  the  material  under  ground. 
Something  is  lost  in  transit  from  the  mine  to  the  laboratory,  and  its 
amount  is  conditional  upon  the  texture  of  the  coal.  A hard,  compact 
anthracite  retains  much  of  its  gaseous  charge;  a porous  coal,  on  the 
other  hand,  will  lose  much.  So  we  see  that  the  bituminous  coals  con- 
tain, as  a rule,  less  gas  in  the  laboratory  than  the  anthracites,  although 

1 Jour,  prakt.  Chemie,  2d  ser.,  vol.  5, 1872,  pp.  144, 407;  vol.  6, 1873,  p.  389.  Data  reproduced  in  Percy’s 
Metallurgy,  vol.  1, 1875,  p.  283. 

2 Trans.  North  of  England  Inst.  Min.  Mech.  Eng.,  vol.  37,  p.  245. 

3 Jour.  Soc.  Chem.  Ind.,  vol.  13, 1894,  p.  25. 

* Jour.  Chem.  Soc.,  vol.  28, 1876,  p.  793. 


760 


THE  DATA  OF  GEOCHEMISTEY. 


the  bituminous  mines  are  the  most  seriously  affected  by  fire  damp. 
In  the  coal  beds  themselves  the  bituminous  coals  are  richest  in 
gaseous  occlusions.  McConnell,  in  the  memoir  previously  cited, 
also  points  out  that  in  the  Newcastle  region  the  older  and  deeper  coals 
contain  the  most  methane,  while  in  the  younger  seams  carbon  dioxide 
may  predominate  even  to  the  exclusion  of  combustible  gases.  In  his 
investigation  of  the  Welsh  coals,  Thomas  analyzed  14  samples  of  gases 
emitted  from  crevices  or  “blowers”  in  the  mines,  and  found  that  they 
contained  from  47.37  to  97.65  per  cent  of  methane,  with  over  94 
per  cent  in  all  but  two  of  them.  Other  earlier  analyses  of  colliery 
gases  have  told  essentially  the  same  story.1  Methane  is  the  principal 
gas  of  coal  beds. 

ARTIFICIAL,  COALS. 

Various  attempts  have  been  made  to  prepare  artificial  coals  in  the 
hope  of  gaining  some  information  upon  the  genesis  of  the  natural 
products.  Two  lines  of  research  are  represented  in  these  efforts,  but 
neither  has  yet  led  to  any  final  conclusions. 

In  the  first  class  of  experiments  it  was  sought  to  produce  coals  by 
pressure.  W.  Spring  2 subjected  peat  to  a pressure  of  6,000*  atmos- 
pheres, and  transformed  it  into  a hard,  black,  brilliant  solid  which 
was  outwardly  undistinguishable  from  coal.  On  the  other  hand,  R. 
Zeiller,3  working  with  pressures  of  2,000  to  6,000  kilograms  to  the 
square  centimeter,  found  that  peat  and  also  the  “ulmic  acid”  from 
the  paper  coals  of  Russia  were  merely  compacted  without  change 
of  chemical  character.  They  retained  their  solubility  in  ammonia 
and  showed  no  evidence  of  a true  transformation  into  coal.  Some 
experiments  by  Giimbel,4  who  subjected  lignite  to  pressure  as  high 
as  20,000  atmospheres,  showed  that  even  under  such  conditions  no 
serious  changes  were  produced  and  that  the  vegetable  structure  was 
in  great  measure  preserved. 

In  the  second  class  of  experiments  heat  is  used  as  the  transforming 
agent.  In  the  ordinary  process  of  charcoal  burning  wood  is  heated 
out  of  free  access  of  air,  decomposition  ensues,  volatile  matter  is 
expelled,  and  a form  of  amorphous  carbon  finally  remains  in  the 
kiln.  Violette,5  who  has  studied  this  process  with  great  care,  found 

1 See  G.  Bischof,  Edinburgh  New  Philos.  Jour.,vol. 29, 1840, p.  309;  vol.  30, 1840,  p.  127;  T.  Graham,  Mem. 
Chem.  Soc.,  vol.  3,  1845,  p.  7;  Lyon  Playfair,  Mem.  Geol.  Survey  Great  Britain,  vol.  1, 1846,  p.  460.  A 
recent  paper  on  the  gases  in  coal  is  by  F.  G.  Trobridge,  Jour.  Soc.  Chem.  Ind.,  vol.  25, 1906,  p.  1129.  See 
also  the  analyses  of  explosive  gases  from  American  coals  by  R.  T.  Chamberlin,  in  Bull.  U.  S.  Geol. 
Survey  No.  383,  1909.  In  them  methane  is  the  important  constituent.  On  the  other  hand,  gases  from 
Silesian  coal  analyzed  by  J.  Meyer  (Jour,  prakt.  chem.,  2d  ser.,  vol.  90, 1914,  p.  141)  contained  principally 
carbon  dioxide  (choke  damp),  with  some  oxygen  and  nitrogen,  and  methane  occasionally.  Recent  work 
on  gases  in  coal  by  C.  H.  Porter  and  F.  K.  Ovitz  is  published  in  Tech.  Paper  U.  S.  Bur.  Mines  No.  2, 1911. 

2 Bull.  Acad.  roy.  sci.  Belgique,  vol.  49, 1880,  p.  367. 

* Buil.  Soc.  g6ol.  Frahce,  3d  ser.,  vol.  12, 1884,  p.  680. 

4 Sitzungsb.  Math.-phys.  Classe,  K.  bayer.  Akad.  Wiss.  Miinchen,  vol.  13, 1883,  p.  141. 

6 Annales  chim.  phys.,  3d  ser.,  vol.  32, 1851,  p.  304. 


COAL. 


761 


that  when  wood  was  heated  nearly  to  400°  in  a sealed  tube,  78.5  per 
cent  of  it  remained  as  a solid  residue  which  had  all  the  appearance 
of  a fatty  coal.  In  this  case  the  volatile  substances  exerted  a great 
pressure  upon  the  contents  of  the  tube,  and  a product  very  different 
from  ordinary  charcoal  was  formed.  By  heating  wood  under  con- 
ditions which  permitted  the  volatile  matter  to  escape,  he  obtained 
a series  of  charcoals  which  varied  in  composition  according  to  the 
temperature  at  which  they  were  prepared.  The  experiments  were 
conducted  at  temperatures  ranging  from  150°  to  the  melting  point 
of  platinum;  and  his  analyses  of  the  products  thus  formed,  28  in 
all,  show  progressive  changes,  analogous  to  the  changes  observed  in 
the  passage  from  wood  to  anthracite.  The  charcoals,  however,  are 
not  identical  with  coal,  but  differ  from  it  both  texturally  and 
chemically.  A finished  charcoal  is  really  the  analogue  of  coke,  being 
in  fact  the  coke  of  wood;  but  in  its  preparation  it  is  possible  to  trace, 
step  by  step,  the  breaking  down  of  the  original  ligneous  fiber.  For 
that  reason  it  is  most  desirable  that  the  chemistry  of  charcoal  burning 
should  be  studied  much  more  in  detail  than  it  has  been  hitherto. 

Violette’s  experiments  with  wood  in  sealed  tubes  were  not  the  first 
of  their  kind.  Early  in  the  nineteenth  century  Sir  James  Hall 
obtained  an  artificial  coal  by  heating  wood  in  a closed  cylinder  of 
iron,  and  in  1850  or  1851  C.  Cagniard-Latour  1 performed  essentially 
the  same  experiment  in  tubes  of  glass.  These  earlier  experiments, 
however,  were  merely  qualitative,  for  the  products  obtained  were  not 
analyzed. 

In  1879  Fremy  2 published  an  interesting  series  of  observations, 
based  upon  experiments  with  carbohydrates  other  than  cellulose,  and 
upon  the  so-called  “ulmic  acid”  from  two  sources.  One  example  of 
ulmic  acid  was  extracted  from  peat;  the  other  was  prepared  from  a 
constituent  of  woody  tissue  to  which  Fremy  gave  the  name  vasculose. 
The  substances  were  all  heated  in  sealed  glass  tubes  to  temperatures 
which  seem  to  have  been  near  300°  and  yielded  residues  which 
behaved  in  all  respects  like  coal.  When  heated  to  redness,  they 
gave  off  water,  gas,  and  tar  and  left  behind  a remainder  of  coke. 
These  artificial  coals  had  the  following  composition : 


Composition  of  artificial  coals. 


c 

H 

0 

Coal  from  sugar 

66.  84 

4.  78 

28.  43 

Coal  from  starch 

68.  48 

4.  68 

26.  84 

Coal  from  gum  arabic 

78.  78 

5.  00 

16.  22 

Coal  from  ulmic  acid,  peat 

76.  06 

4.  99 

18.  95 

Coal  from  ulmic  acid,  vasculose 

78.  78 

5.31 

18.  26 

i Compt.  Rend.,  vol.  32, 1851,  p.  295.  2 idem,  vol.  88,  1879,  p.  1048. 


762 


THE  DATA  OF  GEOCHEMISTRY. 


The  similarity  of  these  products  to  natural  coals,  especially  in  the 
last  three  examples,  is  evident. 

Still  more  recent  experiments  of  this  order  are  those  of  S.  Stein.1 
He  heated  wood  with  water  in  sealed  tubes,  but  at  different  tempera- 
tures, and  partially  analyzed  the  coaly  substances  thus  obtained. 
His  results  are  briefly  as  follows: 


Experiments  to  obtain  coaly  products  from  wood. 


Temperature. 

Time  of 
heating. 

c 

H 

Hours. 

Per  cent. 

Per  cent. 

245 

9 

64.3 

5.4 

250 

6 

69.2 

5.1 

255 

6 

70.3 

5.2 

265 

5 

72.8 

4.7 

275 

6 

74.0 

4.5 

280 

5 

77.6 

4.1 

290 

5 

81.3 

3.8 

Here  we  have  a series  of  products  ranging  in  composition  from  a 
substance  near  peat  to  one  more  closely  resembling  coal.  Only,  it 
must  be  observed,  the  hydrogen  toward  the  end  of  the  series  is  lower 
than  in  coals  showing  the  same  percentage  of  carbon.  The  parallel- 
ism between  the  artificial  and  the  natural  substances  is  therefore  not 
quite  complete.  The  natural  inference  from  this  conclusion  is  that 
agencies  other  than  heat  and  pressure  have  taken  part  in  the  car- 
bonization of  vegetable  matter,  and  these  may  have  been  microbian 
in  character.  The  function  of  heat  is  to  decompose  the  organic  com- 
plexes; that  of  pressure  is  to  retard  the  change  and  to  prevent  the 
escape  of  the  volatile  products;  the  combined  effect  must  vary  with 
variations  in  the  intensity  of  the  two  agencies.  If  an  exact  adjust- 
ment of  heat  and  pressure  could  be  arranged,  it  is  possible  that  a 
true  artificial  coal  might  be  prepared,  but  this  is  a mere  supposition. 

From  one  point  of  view  the  experiments  with  sealed  tubes  appear 
to  be  irrelevant.  The  change  of  woody  fiber  to  peat  or  lignite  is 
initiated  at  low  temperatures  and  under  nearly  atmospheric  pressure, 
conditions  quite  unlike  those  which  either  Yiolette  or  Stein  adopted. 
As  the  rotted  material  becomes  buried  the  pressure  upon  it  increases; 
but,  except  where  igneous  intrusions  have  operated,  there  is  nothing 
to  show  that  especially  high  temperatures  have  been  at  work.  The 
element  of  time,  however,  must  be  considered.  The  natural  processes 
are  carried  on  slowly;  and  it  may  be  that  the  laboratory  methods 
merely  accelerate  them.  So  far,  then,  the  experiments  are  pertinent 
but  inconclusive.  They  certainly  do  not  cover  all  the  ground.  All 


1 Chem.  Centralbl.,  1901,  pt.  2,  p.  950.  From  a Hungarian  original  which  I have  not  seen.  F.  Bergius 
(Jour.  Soc.  Chem.  Ind.,  vol.  32, 1913,  p.  462)  heated  cellulose  with  water  under  pressure  of  340°,  and  ob- 
tained a product  undistinguishable  from  coal. 


COAL. 


763 


that  can  be  said  is  that  moderate  temperatures  and  pressures,  oper- 
ating for  a long  time,  may  produce  results  resembling  those  which 
are  brought  about  rapidly  in  the  laboratory. 

In  order  to  account  for  what  we  might  call  the  anthragenetic 
process,  various  hypotheses  have  been  framed.  J.  F.  Hofmann,1  for 
example,  has  used  the  analogy  offered  by  the  spontaneous  combus- 
tion of  grain,  flax,  and  hay,  and  suggested  that  something  of  the 
same  sort  may  happen  in  the  buried  materials  from  which  coal  is 
formed.  In  that  phenomenon  heat  is  generated  by  fermentation, 
and  when  actual  inflammation  is  prevented  for  lack  of  air  a partial 
carbonization  may  occur.  In  cases  of  this  kind  heat  is  generated 
locally  and  an  imperfect  combustion  occurs.  Hofmann’s  suggestions 
are  interesting,  but,  so  far  as  the  formation  of  coal  is  concerned,  the 
evidence  in  their  favor  is  very  incomplete. 

How  far  micro-organisms  are  active  in  the  formation  of  coal  is 
doubtful.  They  abound  in  the  stagnant  waters  of  swamps,  and 
certainly  have  much  to  do  with  the  earlier  stages  of  vegetable  decay. 
They  start  the  process,  but  at  the  same  time  they  generate  antiseptic 
compounds  which  limit  their  activity.  Peat,  not  far  below  the  sur- 
face, is  distinctly  antiseptic  and  inimical  to  microbian  life.  Never- 
theless, a number  of  authorities  have  argued  strongly  in  favor  of 
these  organisms  as  principal  agents  in  an thr agenesis.  B.  Renault 2 
has  found  their  remains  in  lignite  and  coal  in  significant  abundance 
and  variety. 

THE  CONSTITUTION  OF  COAL. 

In  the  preceding  pages,  under  other  captions,  I have  cited  a good 
deal  of  evidence  relative  to  the  substances  found  in  coal  or  from 
which  coal  has  been  derived.  Its  vegetable  orgin  is  clear  and  needs 
no  further  discussion  now;  its  present  constitution  is  more  difficult 
to  determine. 

The  question  of  constitution  presents  itself  under  two  aspects,  the 
one  structural  the  other  chemical.  On  the  one  side  microscopic  evi- 
dence is  available,  and  it  is  seen  that  coal  contains  vegetable  remains, 
micro-organisms,  resinoid  bodies,  and  so  on.  In  some  coals  spores  or 
spore  cells  are  abundant;3  in  others,  as  shown  by  Renault,  remains  of 


1 Zeitschr.  angew.  Chemie,  1902,  p.  821. 

2 Bull.  Soc.  ind.  min.,  3d  ser.,  vol.  13,  1899,  p.  865;  vol.  14, 1900,  p.  1.  See  also  L.  Lemiere,  idem,  4th  ser., 
vol.  4,  1905,  pp.  851,  1248,  and  vol.  6,  1906,  p.  273.  Also  in  Compt.  rend.  VIII  Cong.  g6ol.  intemat.,  1900, 
p.  502.  Lemi&re  regards  the  soluble  or  diastatic  ferments,  derived  from  living  vegetation,  as  also  operative 
in  the  process  of  vegetable  decay. 

8 See  J.  W.  Dawson,  Am.  Jour.  Sci.,  3d  ser.,  vol.  1,  1871,  p.  256.  *E.  Orton  (idem,  vol.  24,  1882,  p.  171) 
states  that  spore  cases  are  abundant  in  the  “ sub-Car boniferous”  rocks  of  Ohio,  and  are  also  found  in  the 
Devonian.  On  the  microscopic  structure  of  the  natural  hydrocarbons,  resins,  and  coals,  see  Fischer  and 
Rust,  Zeitschr.  Kryst.  Min.,  vol.  7,  1882,  p.  209.  The  important  memoirs  by  Bertrand  and  Renault  and 
by  Jeffrey  have  already  been  referred  to.  See  also  White  and  Thiessen’s  bulletin  on  the  origin  of  coal, 
already  cited,  for  a full  summary  of  this  subject,  with  many  additional  details. 


764 


THE  DATA  OF  GEOCHEMISTRY. 


algae  are  found.  The  lignites  are  obviously  derived  from  woody  fiber, 
and,  in  short,  in  many  cases  the  proximate  origin  of  the  coals  is  not 
difficult  to  determine.  Their  structure,  microscopic  or  macroscopic, 
tells  a pretty  clear  story. 

On  the  chemical  side  the  problems  are  much  less  simple.  The 
proximate  constituents  of  coal  are  most  imperfectly  known  and  the 
little  knowledge  we  have  is  mainly  qualitative.  The  necessary 
investigations  are  difficult,  the  methods  are  not  well  formulated,  and 
the  available  data  are  scattered  and  fragmentary.  ’To  what  extent 
free  carbon  exists  in  coals  is  still  an  open  question.  It  is  probably 
absent  from  lignite  and  abundant  in  the  extreme  anthracites;  but 
its  quantitative  determination  can  not  be  effected  by  any  known 
analytical  process. 

There  are  two  distinct  lines  of  attack  upon  the  problem  in  ques- 
tion. First,  by  means  of  solvents,  to  extract  certain  constituents  of 
coal  and  to  identify  them.  Some  of  these  constituents,  which  are 
commonly  small  in  amount,  can  be  dissolved  by  gasoline,  ether,  ben- 
zene, chloroform,  alcohol,  and  other  organic  solvents.  The  extrac- 
tive matter  thus  obtained  is,  unfortunately,  not  simple,  but  seems 
to  contain  a mixture  of  substances  whose  nature  is  yet  to  be  determ- 
ined. By  handling  large  quantities  of  material  these  bodies  may  be 
obtained  in  sufficient  abundance  for  more  complete  investigation, 
and  their  separation  into  definite  fractions  is  by  no  means  hopeless.1 
The  remarkable  solvent  action  of  pyridine  upon  some  of  the  con- 
stituents of  coal,  as  studied  in  recent  years  by  several  investigators,2 
also  offers  a promising  line  of  attack  upon  the  problems. 

Alkaline  solvents,  such  as  caustic  soda,  caustic  potash,  and  ammo- 
nia, dissolve,  as  we  have  already  seen,  humic  substances  from  peat 
and  brown  coal,  but  not  from  the  older  carbons.  These  substances 
are  indefinite,  but  in  time  their  nature  may  be  determined,  and  their 
correlation  with  the  ligneous  carbohydrates  ought  then  to  become 
possible.  If,  however,  as  is  supposed,  some  coals  are  derived  from 
gelatinous  algae,  the  problem  becomes  more  complex.  The  chemical 
constitution  of  those  forms  of  vegetation  is  still  very  obscure.  Up 
to  the  present  time  the  mistake  has  been  made,  by  chemists  engaged 
in  the  study  of  coal,  of  assuming  that  the  celluloses  are  the  chief 
starting  points — an  assumption  which  is  not  unqualifiedly  true.  Car- 

1 On  this  subject  see  the  authorities  already  cited.  Also  P.  Siepmann,  Preuss.  Zeitschr.  Berg-,  Hiitten- 
u.  Salinenwesen,  vol.  39,  1891,  p.  27.  F.  Muck  (Die  Chemie  der  Steinkohle,  Leipzig,  1891)  gives  a good 
summary  of  earlier  investigations  by  Dondorff,  Reinsch,  etc.  An  interesting  memoir  by  W.  C.  Anderson 
(Proc.  Philos.  Soc.  Glasgow,  vol.  29,  1897,  p.  72)  also  describes  a number  of  important  experiments. 

2 T.  Baker,  Trans.  Inst.  Min.  Eng.,  vol.  20, 1900,  p.  159;  and  P.  P.  Bedson,  Join-.  Soc.  Chem.  Ind.,  vol.  27, 
1908,  p.  147.  See  also  E.  Donath,  Chem.  Zeitung,  vol.  32, 1908,  p.  1271;  L.  Vignon,  Compt.  Rend.,  vol.  158, 
1914,  p.  1421;  A.  Wahl,  idem,  vol.  154,  p.  1095.  J.  C.  W . Frazer  and  E.  G.  Hoffman  (Tech.  Paper  U.  S.Bur. 
Mines  No.  5, 1912)  have  studied  the  extracts  obtained  from  coal  with  phenol.  A . Pictet  and  L.  Ramseyer 
(Ber.  Deutsch.  chem.  Gesell,vol.  44,  1911,  p.  2486),  by  extraction  with  hot  benzene  obtained  hexhydro- 
fluorene,  C13  H16.  By  solution  with  carbon  disulphide  E.  Donath  and  O.  Manouschek  (Chem.  Zeitung, 
1908,  p.  1271)  extracted  anthracene  and  chrysene  from  a German  coking  coal. 


coal.  765 

bons  of  animal  origin  also  require  attention.  Much  preliminary  work 
of  this  kind  remains  to  be  done. 

The  direct  separation  of  its  constituents  from  coal  is,  however, 
possible  only  to  a very  limited  extent.  Hence  the  second  line  of 
attack,  the  conversion  of  these  bodies  into  recognizable  derivatives, 
is  also  essential.  Not  only  do  we  need  more  experiments  along  the 
line  developed  by  Donath,  whose  distinction  between  the  lignites  and 
the  true  coals  has  already  been  discussed,  but  much  more  needs  to  be 
done  in  the  study  of  oxidation  products,  chlorine  derivatives,  etc. 
For  example,  in  addition  to  the  researches  upon  the  nitrocompounds 
derivable  from  coal  and  the  chlorination  experiments  reported  to  the 
British  Association,  there  are  investigations  like  that  conducted  by 
L.  Schinnerer  and  T.  Morawsky.1  These  chemists  fused  lignite  with 
caustic  soda,  and  by  distillation  of  the  melt  obtained  pyrocatechin, 
which  is  a benzene  derivative.  The  true  coals,  so  far  as  examined, 
did  not  yield  this  compound,  which  seems  to  have  been  produced 
from  the  resinoid  constituents  of  the  lignite.  By  experiments  of  this 
order  the  compounds  existing  in  coal  can  be  correlated  with  other 
substances  of  known  constitution,  and  some  at  least  of  the  problems 
which  confront  us  may  be  solved.  The  future  chemistry  of  coal  will 
be  shaped  by  a study  of  its  immediate  constitution  and  not  by  the 
multiplication  of  empirical  analyses. 


1 Ber.  Deutsch.  chem.  Gesell.,  vol.  5, 1872,  p.  185. 


INDEX. 


A.  Page. 

Aar,  River,  analysis  of  water 97 

Abbot,  C.  G.,  and  Fowle,  F.  E.,  carbon  diox- 
ide and  climate. 48, 146 

Abbot,  H.  L.  See  Humphreys  and  Abbott. 

Abert  Lake,  analysis  of  water 161, 176 

Abich,  H.,  analyses  of  spinel 342 

Abilena  well,  analysis 187 

Abilene  artesian  well,  analysis 182 

Absorption,  of  substances  by  soils 211, 501, 502 

Acanthite 650 

Acetylene 716,723,724 

Acetylene  series 717 

Acheson,  E.  G.,  artificial  graphite 326 

d’ Achiardi,  A . , origin  of  borates 245 

d’Achiardi,  G.,  minerals  in  marble 622,623 

origin  of  borates 245 

Ackroyd,  W.,  atmospheric  transport  of  salt. . 52, 

149,168 

relative  abundance  of  elements 28 

Acmite 379-381 

Actinium 12,314 

Actinolite 384 

Actinolite-magnetite  schist 384,610 

Adamellose 453 

Adamite 672 

Adams,  B.  F.,  cited 45 

Adams,  F.  D.,  allanite  and  epidote 408 

alteration  of  pyroxene 383 

amphibolite 623 

analyses  by 87,185 

compression  of  granite 33 

melilite  rocks 400 

monmouthite 446 

primary  calcite 418 

Adams,  F.  D.,  and  Harrington,  B.  J.,  has- 

tingsite 387 

Adams,  F.  D.,  and  Lawson,  A.  C.,  scapolite 

diorite 405,597 

Adams,  G.  L,  concentration  of  petroleum 736 

gypsum 232,576 

native  sulphur 577 

salt  deposits 229 

zinc  deposits 675 

Adams,  L.  H.  See  Johnston  and  Adams. 

Adirondackiase 467 

Adler,  River,  analysis  of  water 98 

Adobe  soil 509-511 

Adriatic  Sea 122 

Adschi-Darja.  See  Karaboghaz. 

Aegirite 378-381 

Aenigmatite 388,389 

Agate 357 

Aguilarite 652 

Aguilera,  J.  G.,stibnite 689 

Aichino,  G.,  bauxite 497 


Page. 

Aigner,  A.,  polyhalite 227 

Aikinite 661,662 

Air,  dissolved,  composition  of 477 

See  also  Atmosphere. 

Aisinmann, , origin  of  petroleum 730 

Aitken,  J.,  atmospheric  dust 53 

Akermanite 398 

Akerose 440, 442, 445, 455, 456 

Alabama  River,  analysis  of  water 74 

Alaskite 434 

Alaskose 435,437 

Albanose 447 

Albert,  R.  See  Malkomesius  and  Albert. 

Albertite 719,720 

Albite 363-368,600 

Albite  mosaic 594 

Albrecht,  R.,  optical  activity  of  petroleum. . 735 

Aldebaranium 21 

Alexandrolite 696 

Alexejeff,  W.,  dopplerite 744 

Alferric  minerals 425 

Algae,  as  limestone  makers 555,565,568 

as  source  of  bitumens 733 

in  relation  to  coal 740 

magnesium  carbonate  in 565 

siliceous...  i 515 

Algodonite 658 

Aiipite 695 

Alkali,  in  soils 237-242 

Allanite 406-408,712 

Allegheny  River,  analysis  of  water 78 

Allemontite 688 

Allen,  E.  T.,  aluminum  hydroxide 498 

analyses  by 232,332 

native  iron 331 

synthesis  of  quartz 358 

See  also  Day  and  Allen. 

Allen,  E.  T.,  and  Clement,  J.  K.,  water  in 

amphiboles 387 

Allen,  E.  T.,  and  Crenshaw,  J.  L.,  greenockite.  670 

pyrite  and  marcasite 334 

sulphides  of  mercury 666 

sulphides  of  zinc 670,671 

Allen,  E.  T.,  Johnston,  J.,  and  Crenshaw,  J. 

L.,  sulphides  of  iron 334 

Allen,  E.  T.,  and  White,  W.  P.,  fusion  of  lime 

silicate 292,300 

synthesis  of  diopside 379 

wollastonite 378,621 

Allen,  E.  T.,  Wright,  F.  E.,  and  Clement, 

J.  K.,  magnesium  silicate 292, 

377,385,390 

Allen,  I.  C.,  and  Burrell,  G.  A.,  natural  gas  . . 714 

Allen,  O.  D.,  analyses  by 155, 

159,203,235,236,237,238 
Alloclasite 692 


767 


768 


INDEX. 


Page. 

Allopalladium 700 

Allophane 415,500,611 

Alma  well,  analysis  cited 185 

Almandite 400 

Aloisi,  P.,  spinel  rocks 343 

Altai,  Lake,  analysis  of  water 170, 174 

saline  deposit 234 

Altaite 676 

Altmuhl,  River,  analysis  of  water 101 

Aluminum,  distribution 13 

in  sea  water 121 

Alum  shale 545 

Alums 249,259,270 

Alunite — 259,497 

Alunogen 259 

Alway,  F.  J.,  and  Gortner,  R.  A.,  water  anal- 
ysis   163 

Amalgam 644 

Amazon  River,  analyses  of  water 91, 107 

Amber 741 

Amblygonite 686 

Amesite 397-398 

Ammiolite 664 

Ammonia,  in  rainfall 50 

in  sea  water 120 

Ammonium  fluoride,  in  volcanic  gases 261 

Amphiboles 383-389 

Amphibolite 592,623 

Amsoldingen,  Lac 95 

Ana  River,  analysis  of  water 161 

Analcite 368-371 

Analcite  rocks , 449-451 

Anamorphism,  zone  of 584 

Anatase 350-352 

Andalusite 409, 410, 601, 612 

Andalusite  rocks 614 

Anderlini,  F.  See  Nasini,  R. 

Andersen,  O.  See  Bowen  and  Andersen. 

Anderson, , cited 168 

Anderson,  W.,  cited 160 

Anderson,  W.  C.,  experiments  on  coal 764 

Anderson,  W.  C.,  and  Roberts,  J.,  coal 749, 752 

Anderson,  W.  S.,  solubility  of  calcium  car- 
bonate  128 

See  also  Irvine  and  Anderson. 

Andesine 364 

Andesite 453-455,487 

Andesner,  H.,  fusion  of  gabbroid  magma. . 306, 422 

Andorite 653,678 

Andose 452,455,456,458,461,462 

Andouard,  A.,  phosphate  rock 521 

Andradite 401 

Andr6,  G.,  cited 480 

Andr6e,  K.,  bibliography  of  oceanic  sedimen- 
tation  515 

fluorite  in  sediments 582 

Andrew,  A . R . , gold  in  country  rock 642 

phosphate  rock 528 

Andrews,  E.  C.,  magmatic  assimilation 310 

Andrews , T . , native  iron 328 

Androscoggin  River,  analysis  of  water 71 

Androussof,  N.,  reduction  of  sulphates  by 

bacteria 148,515 

Anemousite 364 

Anger,  F.  A.,  shale 547 

Angemsee , analysis  of  water 104 


Page. 

Anglesite 680 

Angstrom,  K . J . , carbon  dioxide  and  climate . 48 

Anhydrite 223, 229, 232, 247, 249, 251, 255 

Animikite 650 

Ankerite 563,571 

Annabergite 694 

Annecy,  Lake  of,  analysis  of  water 94 

Anorthite 363-368 

Anorthoclase 363 

Anorthosite 462 

Ansdell,  G.  See  Dewar  and  Ansdell. 

Ansel,  H.,  iron  ores 575 

Anthon,  E . F . , precipitation  of  sulphides 639 

Anthophyllite 383 

Anthracite 752-754 

Anthraxolite 754 

Antimony,  distribution 14 

ores  of 687-691 

Ants,  geological  work  of 485 

d’Aoust,  V.,  oolite 550 

Apatite 354-355,519 

Aphrosiderite 397 

Aphthitalite 223 

Apjohn,  J.,  water  of  the  Dead  Sea 169 

Aplite 434,437 

Apophyllite 416,417 

Aragonite 251, 417, 551, 552 

Aral,  Sea  of,  analysis  of  water 166, 175 

Arapahite 468 

Arapahose 468 

Arctic  Ocean,  analyses  of  water 124 

Arctowski,  H.,  synthesis  of  hematite 347 

Ardennite 707 

Arfvedsonite 388,389 

Argali,  P.,  distribution  of  nickel 691 

Argentite 650 

Argon,  distribution 14, 41 

infumaroles 268 

in  spring  waters 180 

Argyrodite 653 

Arias,  Rio  de,  analysis  of  water 92 

Arkansas  Hot  Springs,  analysis  of  water 195 

Arkansas  River,  analysis  of  water 66, 81 

Arkansose 447 

Arkite 447 

Arnold,  R.,  and  Anderson,  R., .alteration  of 

shale 609 

Aromatic  hydrocarbons 717 

Arrhenius,  S.  A. , carbon  dioxide  and  climate.  47, 145 

nature  of  earth’s  interior 57 

volcanic  explosions 285, 286 

Arsandaux,  H. , analysis  by 522 

bauxite 496 

laterite 494 

Arsem,  C.  W.,  graphite 328 

Arsenic,  distribution 14 

in  sea  water 120 

ores  of 687-691 

Arsenolite 690 

Arsenomiargyrite 654 

Arsenopyrite 652,688 

Arva-Polhora,  analysis  of  water 184 

Arve  River,  analysis  of  water 94 

Arzruni,  A.,  cassiterite  as  a furnace  product.353, 684 

cuprite 662 

hematite 347 


INDEX, 


769 

Page. 


Page. 

Asbestos 384 

Asbolite 534,694,695 

Aschan,  O.,  humus  in  natural  waters 108 

iron  ores 531 

waters  of  Finland 104 

Ascharite 225,250 

Ashburner,  C.  A.,  anthracite 753 

classification  of  coals 756 

Ashley,  G.  H.,  antimony  deposits 690 

formation  of  peat 742, 745 

See  also  Blatchley  and  Ashley. 

Ashley,  J.  M.,  cited... 93 

Askwith,  W.  R. , antimony  mines 690 

Aspasiolite 406 

Asphalt 719,720-721 

Assiniboine  River,  analysis  of  water 87 

Aston , E . , analysis  by 606 

Astrakanite 223 

Atacamite 265,662 

Atherton,  T.  W.  T.,  gold  sulphide 643 

Atlantic  Ocean,  analyses  of  water 123, 124 

Atlin,  spring  near,  analysis 191 

Atmosphere,  composition  of 41-47 

mass  of 22 

the  primitive 53-57 

Atomic  weights 13 

Atopite 691 

Atrek  River,  analysis  of  water 166 

Atterberg , A . , alteration  of  topaz 409 

laterite 494 

Attwood , G. , decomposition  of  diabase 288 

Audoynaud , A . , ammonia  in  sea  water 120 

Auerbach  F. , cited 202 

Auerbach,  H.  S.,  tungsten  deposits 700 

Aug6, , bauxite 496 

Augite 381-383 

Austin,  W.  L.,  nickel  ores 695 

Autunite 707 

Auvergnose 456, 458, 461, 462 

Avalite 696 

Awaruite 330,331,691 

Awerkiew , N . , solubility  of  gold 647 

Azurite 663 

B. 

Babingtonite 382 

Babitsee,  analysis  of  water 104 

Bacon,  R.  F.,  analyses  cited 200 

Bacteria  as  agents  in  rock  decomposition 485 

Bacterial  precipitation  of  calcium  carbonate . . 549 

Bad  Elster,  analysis  of  water  from 193 

Baddeckite 391 

Baddeleyite 711 

Backstrom,  H.,  fusion  of  micas 396,448 

on  Soret’s  principle 309 

synthesis  of  acmite 380 

Baer,  W.,  analyses  of  wood 739 

Baerwald,C.,  pseud  omorphs  of  chrysocolla.. . 662 

Baeumler, , nickel  in  shale 691 

Baeumlerite 225 

Baikal,  Lake , analysis  of  water 104 

Bailey,  E.  H.  S.,  analyses  by 80, 187, 188, 715 

zinc  in  mine  waters 632 

Bailey,  E.  H.  S.,  and  Case,E.  C.,  analyses  by . 182, 231 

97270°— Bull.  616—16 49 


Bailey,  E.  H.  S.,  and  Franklin,  E.  C.,  water 

analyses 80 

Bailey,  E.  H.  S.,  and  Porter,  F.  B.,  analysis 

by 182 

Bailey,  G.  E.,  California  borates 246 

soda  niter 254 

Bailey,  R.  K.,  analyses  by 155 

Bain,  H.  F.,  fluorite 582 

lead  and  zinc  deposits 675 

Baker,  A.  L.,  bromine  in  bittern 233 

synthesis  of  livingstonite 667 

Baker,  H.  B.,  cited 49 

Baker,  T. , extracts  from  coal 764 

Bakerite 248 

Balatonsee,  analysis  of  water 102 

Balch,  D.  M.,  potassium  chloride  in  algae 139 

Baldacci,  L.,  sulphur  deposits 578 

Baldauf,  R.,  cryolite 336 

Balland, , cited 66 

Ballo,  M. , water  analysis 101 

Balld,R.,and  Dittler,E., mineral  syntheses.  380 

B allston  waters , analyses 186 

Baltic  sea,  analysis  of  water 123 

Baltimoriase 464 

Baltimorose 464 

Bamberger,  E . , fichtelite 745 

Bancroft,  G.  J.,  origin  of  ore  bodies 639 

Bancroft,  H. , platinum  in  dikes 702 

Bandose 453,461 

Bandrowsky,  F.  X.,  nitrogen  in  petroleum. . 718 

Baragwanath,  W. , platinum 704 

Barber,  W.  B.  See  Nutter  and  Barber. 

Barbier,  P.,  and  Prost,  A.,  composition  of 

feldspars 364 

Barbierite 364 

Barbour,  E.  EL,  and  Torrey,  J.,  siliceous 

oolite 544 

Barcenite 664 

Barchatow  bitter  lake,  analysis  of  water. . . 171, 175 
Baret,  C.  See  Lacroix  and  Baret. 

Barima  River,  analysis  of  water 90 

Barite 136, 537-539, 579-581 

Barium,  distribution 14 

in  sea  water 121 

Barkevikite 388,389 

Barlow,  A.  E.,  nickel  deposits 693,695 

Barnard,  H.  E.,  analysis  of  water 71 

Barnes,  H.  T.  See  Rutherford  and  Barnes. 

Barnitzke,  J.  E.,  kaolinization 492 

Barr,  W.  M.,  analyses  by.  75, 76, 77, 78, 79, 81, 82, 199 

Cove  Creek  ac  id  water 199 

Barrandite 520,522 

Barrell,  J.,  magmatic  assimilation 310 

Barrois,C.,chloritoid  rocks 613 

Barschall,  H.  See  Van’t  Hoff  and  Barschall. 

Bartow,  E.,  waters  of  Illinois 63 

Baras,  C. , electricity  in  ore  bodies 640 

sedimentation 506 

thermo-couple 291 

water  glass 297,298,585,637 

Baras,  C.,  and  Iddings,  J.  P.,  electric  con- 
ductivity of  molten  rocks 299 

Barysilite 683 


770 


INDEX, 


Page. 

Basalt 450,456,460,468 

fusibility 296,299 

Basanite 441 

Basch,  E.  E.,  syngenite  and  polyhalites 227 

Basic  rocks 466-469 

Baskerville,  C.,  analyses  by 344, 696 

vanadium  in  peat 705 

See  also  Corse  and  Baskerville. 

Bassett,  H.,  cited 154 

Bassler,  R.  S.,silicification  of  fossils 558 

Bastin,  E . S . , colloidal  gold 648 

diagnostic  criteria  of  metamorphic  rocks . 624 

origin  of  graphite 327 

pegmatite 303,434 

pyrrhotiticperidotite 335,466 

secondary  enrichment 639 

Bastin,  E.  S.,  and  Hill,  J.  M.,  magmatic  sul- 
phides  335 

See  also  Palmer  and  Bastin. 

Bastite 377 

Baubigny , H. , synthesis  of  sphalerite 670 

Bauer,  H.,  and  Vogel,  H.,  cited 97 

Bauer,  K. , fusion  of  mineral  mixtures 306 

Bauer,  M. , laterite 493, 494 

nephelite  in  schists 373 

Bauerman,  H.,  and  Foster,  C.  Le  Neve, 

celestite 579 

Baumann,  A.,  and  Gully,  E.,  humus  acids. . 484 

Baumert,  M.,  composition  of  dissolved  air. . . 477 

Baur,  E . , hydrothermal  syntheses 586 

synthesis  of  quartz  and  tridymite 358 

synthesis  of  quartz  and  feldspars 367 

Bauxite ..  493-501 

Bayldonite 682 

Bayley,  W.  S., actinolite-magnetite schist 384 

graywacke 540 

iron  ores 346,572 

talcose  schist 622 

B earn,  W . , water  analyses 106 

Bear  River,  analysis  of  water 156 

Beaumont,  E.  de,  distribution  of  the  elements  13 

volcanic  emanations ^ 261 

Beauvallet,  P.,  vanadium  in  clay 705 

Beaverite 681 

B echamp,  A . , equilibrium  in  mineral  waters . 202 

hydrogen  sulphide  and  calcium  carbon- 
ate   577 

B echi,  E . , origin  of  borates 245 

distribution  of  vanadium 705 

Bechilite 243,249 

Beck,  R.,  cassiterite  in  granite 353 

diamond 325 

gases  from  obsidian 283 

magnetite 346 

native  copper 657 

native  silver 649 

nickel  deposits 693 

ore  deposits 626 

primary  gold 332 

tin  ores 685 

Beck,  R.,  and  Fircks,  W.  von,  copper  ores 659 

stibnite 690 

Becke,  F.,  amphibolite 592 

changes  of  volume  in  metamorphism . . 588, 589 

eclogite 599 

graphic  symbols 475 


Page. 

Becke,  F.,  hornblende  pseudomorphs 386 

saussurite  gabbro 595 

scapolite  rock 597 

specific  gravity  of  igneous  rocks 420 

See  also  Stgp  and  Becke. 

Becker,  A.,  fusion  of  hornblende 386 

fusion  of  limestone 556 

Becker,  G.  F.,  age  of  minerals 318,320 

age  of  ocean 149,152 

arsenic  and  antimony  in  sinter 689 

borates 243 

Borax  Lake 160,243 

constitution  of  amphiboles  and  pyroxenes  386 

epidote  from  chlorite 597 

eutectic  classification  of  rocks 299, 423 

formation  of  native  sulphur 576 

fractional  crystallization  in  magmas 311 

geological  significance  of  wollastonite. . 378, 621 

glaucophane  rocks 388, 591 

gold  in  sinter 645 

heavy  metals  in  granite 628 

magma  tic  differentiation 309 

mercury  ores 664, 666, 668 

minerals  in  sandstone 540 

nature  of  magmatic  solutions 299 

oceanic  chlorine 141 

origin  of  petroleum 727 

pore  space  in  sandstone 538 

radioactivity 317,318,320 

serpentine 414,415,603 

solvents  of  gold 646 

Steamboat  Springs 186, 206 

viscosity  of  lava 309 

waters  of  Sulphur  B ank 197 

Becker,  G.  F.,  and  Melville,  W.  H.,  mercury 

in  sinter 669 

B ecquerel,  A . C . , synthesis  of  dioptase 663 

synthesis  of  lead  ores 677, 679, 680, 681 

Becquerel,  H.,  and  Moissan,  H.,  free  fluorine 

in  fluorite 335 

Bedson,  P.  P.,  barium  in  water 579 

constitution  of  coal 764 

gases  in  coal 759 

paraffin  in  coal 748 

Beegerite 678 

Beemerose 445 

Beerbachose 456,461 

Beilstein,  F.,  and  Wiegand,  E.,  ozokerite 719 

Beisk,  Lake,  analyses  of  water 170, 174 

saline  deposits 234 

Beistle,  C.  P.  See  Frear  and  Beistle. 

Belcherose 464 

Beldongrite 534 

Bell,  J.  B.,  platiniferous  quartz 703 

Bell,  J.  M.  See  Cameron  and  Bell. 

Bell,  J.  M.,  and  Clarke,  E.  de  C.,  mercury  in 

sinter 668 

Bell,  R.,  corrosion  of  limestone 558 

nickel  deposits 693 

Bellucci,  G.,  chlorides  in  rain 52 

B glohoubek,  A . , water  analysis 98 

Bemmelen,  J.  M.  van,  absorbent  power  of 

hydrogels 501 

absorption  of  potassium  by  clays 138,211 

aluminum  hydroxides 499 

decomposition  of  rocks 492 


INDEX, 


771 

Page. 


Page. 

Bemmelen,  J.  M.  van,  hydroxides  of  iron. . 529-531 


laterite 494 

tropical  soils 499 

zeolitic  silicates  in  soil 211 

Bemmelen,  J.  M.  van,  Hoitsema,  C.,  and 

Ivlobbie,  E.  A.,  bog  iron  ore. . . 529,532 
Bemmelen,  J.  M.  van,  and  Klobbie,  E.  A., 

iron  hydroxides 531 

B enedicks , C . , sericitic  rocks 593 

Benedict,  F.  G.,  atmospheric  oxygen 42 

Bennett,  J.  See  Haworth  and  Bennett. 

Benzene  series 717 

Beraunite 520 

Beresovite 681 

Berg,  L.,  Sea  of  Aral 166 

B ergeat , A . , boric  acid  from  V ulcano 243 

nontronite 491 

occurrence  of  titanium  minerals 352 

ore  deposits 626 

volcanic  sublimates 270 

Bergenose 467 

B ergius,  F . , artificial  coal 762 

Berglund,  E .,  bromine  in  sea  water 122 

Bergstrasser, , cited 166 

Bergt, , analysis  by 544 

Bertels,  G.  A.,  origin  of  petroleum 730 

Berthelot,  M.,  gases  in  native  iron 288 

origin  of  petroleum 726 

synthetic  hydrocarbons 723,724 

Berthier, , synthesis  of  olivine 390 

Berthierine 575 

Berthierite 688 

Bertrand,  C.  E.,  and  Renault,  B.,  origin  of 

bitumen 733 

Bertrandite 414 

Berwerth,  F.,  constitution  of  hornblende 387 

Beryl 413,414 

Beryl,  gases  from 275 

Beryllium.  See  Glucinum. 

Beryllonite 414 

Berzelianite 658 

Best,  A.  See  Coates  and  Best. 

Beudantite 682 

B eyer , S . W . , clays 508 

Beyerinck,  M.W.,  cited Ill 

Beyrichite 692 

Beyschlag,  F.,  cobalt  ores 691 

See  also  Monke  and  Beyschlag. 

Beyschlag,  Krusch,  and  Vogt,  ore  deposits. ..  626 

Bickell,  C.,  analysis  by 207 

Biddle,  H.  C.,  precipitation  of  copper 657 

Biddle,  H.  J.,  nickel  ores 695 

Bieberite 694 

Big  Blue  River,  analysis  of  water 80 

Big  Lake,  analysis  of  water 163 

Biggs,  J.  W.  H.  See  Clowes,  F. 

Bigstone  Lake,  analysis  of  water 76 

Biljo  Lake,  analysis  of  water 170, 177 

Biltz,  W.,  and  Marcus,  E.,  borates  at  Stass- 

furt 250 

copper  in  Stassfurt  salts 222 

nitrates  and  ammonia  in  Stassfurt  salts. . 223 

See  also  Marcus  and  Biltz. 

Binder,  G.  A.,  solubility  of  cinnabar 667 

solubility  of  sulphides 630 

Bindheimite 683 


Bingham,  H.  See  Jamieson  and  Bingham. 
Binney,  E.  W.,  and  Talbot,  J.  H.,  petroleum 


in  peat 733 

Biotite 392-396,601 

Biquard,  R.  See  Moureu,  C. 

Bird,  M.,  analysis  by 182 

Bisbeeite 663 

Bischof,  G.,  analyses  by 101, 102, 172,505 

cements  in  sandstone 538 

dolomitization 567 

gases  in  coal 760 

origin  of  salt  beds 220 

reduction  of  silver  sulphide 649 

solvents  of  gold 646 

sphalerite  in  sinter 671 

zinc  carbonate 673 

Bischofite 224 

Bismite 690 

Bismuth,  distribution 14 

ores  of 687-691 

Bismuthinite 688 

Bismutite 690 

B ismutosmaltite 692 

Bismutosphserite 690 

Bistineau;  brine,  analysis  of 182 

Bitter  Lake,  analysis  of  water 170, 174 

Bitterns 218,232,233 

Bitumen 719,721 

Bituminous  coal 750-752 

Bizio,  G.,  lithium  in  sea  water 120 

Black  Lake  (California),  analysis  of  water. . . 160 

Black  Lake  (Roumania) 172 

Black  Sea,  analysis  of  water 125 

Blackwelder,  phosphate  rock 527 

Blackwell,  G.  G.,  bauxite 497 

Blairmorite 449 

Blake,  J.  F.,  glaucophane  schist 591 

Blake,  R.  F.,  cited 45 

Blake,  W.  P.,  bauxite 497 

gilsonite  and  wurtzilite 720 

primary  gold 642 

Terlingua  mines 665 

tin  deposits 684,697 

tungsten  ores 699 

zinc  deposits 675,676 

Blanc,  G.  A.,  radiothorium 315 

Blanckenhorn,  M.  See  Semper  and  Blanck- 
enhorn. 

Blatchley,  W.  S.,  clays 508 

petroleum 735 

Blatchley,  W.  S.,  and  Ashley,  G.  H.,  marl.  550,551 

Bleeck,  A.  W.  G.,  jadeite 381 

Bleicher, , iron  ores 575 

Blende 335,669 

Bloedite 223,255 

Blount,  B.  See  Chadwick  and  Blount. 

Bluejoint  Lake,  analyses  of  water 161, 176 

Blue  Lick  Springs,  analysis  of  water 183 

Blum,  W.,  Great  Salt  Lake 155 

Blum  and  Leddin,  Carlsbad  spriidelstein 204 

Bobierre,  composition  of  rainfall 52 

Bobierrite . 521 

Bode,  G.,  cited 69 

Bodenbender,  G.,  wolframite 700 

Bodlander,  G.,  analysis  by 573 

melilite  in  Portland  cement 399 


7 72 


INDEX, 


Page. 

Bodlander,  G.,  sedimentation 506 

Bodtker,  clay 515 

Boggild,  O.,  cryolite 336 

Boeke,  H.  E.,  borates  in  potash  salts 250 

bromine  in  potash  salts 222 

camallite  and  tachhydrite 224 

fusion  of  carbonates 557 

garnet 401 

graphic  representation  of  Stassfurt  salts. . 224 

iron  in  potash  salts 225 

rinneite 225 

Bottcher,  W.  See  Kramer  and  Bottcher. 

Boettker,  E.,  Norwegian  pyrite 335 

Boghead  mineral 733,740 

Bog  iron  ore 530,571 

Boleite 680 

Bolley,  P.,  origin  of  borates 245 

Bolton,  H.  C.,  solubility  of  minerals  in  or- 
ganic acids 484 

Bolton,  W.  von,  recrystallization  of  diamond  324 

tantalum 711 

Boltonite 391 

Boltwood,  B.  B.,  age  of  minerals 318 

radioactivity  of  hot  springs 215 

Bone,  W.  A.,  and  Coward,  H.  F.,  union  of 

carbon  and  hydrogen 724 

Bone,  W.  A.,  and  Jerdan,  D.  S.,  synthetic 

hydrocarbons 724 

Bonneville,  Lake 154-157 

Bonney,  G.  T.,  glaucophane  eclogite 591 

matrix  of  diamond 325 

serpentine 602 

Bonyssy.  See  Henriet  and  Bonyssy. 

Booth.  J.  C.,  and  Muckle,  A.,  Dead  Sea 169 

Boracite 225,250 

Borates 225-253 

Borax 243,247,250,256 

Borax  Lake,  analysis  of  water 160, 176 

borax  from 243 

Bordas,  F.  See  Girard,  C. 

Borgstrom,  L.  H.,  hackmannite 373 

scapolite 404 

Boric  acid 243,244,270 

Boriekite 520 

Borne,  G.  von  dem,  radioactivity  of  granite. . 316 

Bomite 335,658,659,660,741 

Bomtrager,  EL,  analyses  of  peat 744 

Borocalcite 243 

Borodowsky,  W.,  orpiment  and  realgar 689 

Boron,  distribution 14 

in  sea  water 120 

nitride 245 

sulphide 245 

Boronatrocalcite 248 

Bosworth,  T.  O.,  Scottish  sands 504 

Bothamley,  C.  EL,  analysis  by 184 

Boudouard,  O.,  melting  point  of  silica 293 

Boulangerite 678 

Bouquet,  J.,  analyses  by 191,205 

spring  deposits 204,205 

Bouquet  de  la  Grye,  A.,  cited 126 

Bourcart,  E.,  Swiss  lakes 95 

Bourgeois,  L.,  cassiterite  in  scoria 684 

formation  of  perofskite 349 

fusion  of  garnet 401 


Page. 

B ourgeois,  L. , synthesis  of  crocoite 681 

of  hydrocerusite 679 

of  iolite c 405 

ofmeionite 404 

of  melilite  and  gehlenite 399, 400 

of  opal 357 

of  smithsonite 673 

of  spessartite 402 

oftitanite 350 

of  wollastonite 377 

Bourgeois,  L.,  and  TFaube,  H.,  synthesis  of 

dolomite 562 

Bourgoin  and  Chastaing,  analysis  by 197 

Boumonite 661 

Boussingault,  J.  B.,  analyses  by 199,233 

carbon  dioxide  from  volcanoes 46 

Dead  Sea 168 

jet 746 

manganese  nodules 133 

nitrate  earth 253 

origin  of  acid  in  volcanic  waters 200 

Boussingaultite 244 

Boutan,  E.,  diamond 326 

Boutron-Charlard,  A.  F.,  and  Henry,  O., 

Dead  Sea 169 

Boutwell,  J.  M.,  camotite 709,710 

Bowen,  N.  L.,  carnegieite 364 

differentiation  in  silicate  melts 312 

fusion  of  enstatite 306 

melting  points  of  silicates 292, 357 

nephelite 372 

Bowen,  N.  L.,  and  Andersen,  O.,  forsterite. . . 390 

magnesium  metasilicate 312,377 

melting  points  of  minerals 292 

Bownocker,  J.  A.,  petroleum 735 

Bow  River,  analysis  of  water 88 

Brackebuschite 682 

Brackett,  R.  N.,  analyses  by 81, 544 

Brackett,  R.  N,,  and  Williams,  J.  F.,  rec- 

torite 611 

Braconnier, •,  analysis  by 187 

Bradley,  F.  H.,  unakite 598 

Bradley,  W.  M.  See  Foote  and  Bradley. 
Braunlich,  F.  See  Donath  and  Briiunlich. 
Bragard.  See  Fernandez  and  Bragard. 

Brand,  A.,  artificial  breithauptite 692 

Brandenbourg,  R . , water  analysis 94 

Branner,  J.  C.,  antimony  deposits 690 

bacterial  decomposition  of  rocks 485 

bauxite 498 

clays 508 

diamond 326 

geological  work  of  ants 485 

magnesia  in  coral  reef 567 

novaculite 542 

phosphorite 526 

sandstone  reefs 538 

tallow  clays 675 

thermal  disintegration  of  rocks 476 

zinc  deposits 675 

Branner,  J.  C.,  and  Newsom,  J.  F.,  phosphor- 
ite  526 

Bransky,  O.  E.  See  Gilpin  and  Bransky. 

Branson,  O . E. , origin  of  salt  beds 220 

Brauner,  B.,  gold  telluride 645 

synthesis  of  hessite 652 


INDEX. 


773 


Page. 

Braunite 533 

Brauns,  R.,  alteration  of  olivine 391 

conchite 552 

gold  in  a cement 646 

graphite  and  molybdenite  in  basalt 328, 335 

origin  of  salite 379 

silvialite 404 

theory  of  micas 397 

webskyite 414 

Bravo,  J.  J.,  vanadium  ores 706 

Brazier,  J.  S. , analyses  by 5.13 

Brazos  River,  analyses  of  water 82 

Breckenridge,  L.  P., classification  of  ooals 759 

Breese,  C.  M.  See  Failyer  and  Breese. 

Breitenlohner,  J.  J.,  on  the  Elbe 98 

Breithauptite 692 

Breunnerite 417,571 

Brewer,  W.  H.,  sedimentation 506 

Brewsterite 416 

Briegleb,  EL,  synthesis  of  apatite 354 

Briner,  E.,  and Wroczynski,  A.,  polymeriza- 
tion of  acetylene 724 

Brinsmade,  R.  B.,  cerusite  deposit 679 

Brochantite 662,663 

Brock,  R.  W.,  gold  in  igneous  rocks 642 

platinum 704 

Brodie,  B.  C.,  graphitic  acid 754 

synthesis  of  methane 279 

Brogger,  W.  C.,  alteration  of  acmite  to  anal- 

cite 370,381 

alteration  of  analcite 371 

of  arfvedsonite  and  barkevikite 389 

of  elseolite 373 

classification  of  igneous  rocks 425 

composition  of  barkevikite 388 

formula  of  asnigmatite 388 

gibbsite  and  diaspore 498 

magmatic  differentiation 298, 308 

nepheline  syenites 446 

nordenskioldine 684 

occurrences  of  fluorite 335 

of  zircon 354 

spreustein 375 

sulphides  in  pegmatite 335 

Brogger,  W.  C.,  and  Backstrom,  H.,  the  gar- 
net group 374,401 

Broggerite 707,708 

Brokaw,  A.  D.,  solubility  of  gold 647 

Bromine,  distribution 14 

in  bittern 233 

Bromly,  A.  H.,  tin  deposits 685 

Bromyrite 655 

Brongniardite 653,678 

Bronze,  minerals  formed  on 657, 659, 662 

Bronzite 376 

Brookite 350-352 

Brooks,  A.  H.,  tin  deposits 686 

Brooks,  W.  K.,  abundance  of  life  in  ocean 147 

Brown,  A.  P.,  pyrite  and  marcasite 334 

Brown,  B.  E.,  water  analyses 83, 156 

Brown,  C.  R.  See  Judd  and  Brown. 

Brown,  F.C.,  geologic  time 320 

Brown,  L.  See  Meadows  and  Brown. 

Brown,  L.  P.,  phosphorite 526 

Browne,  D.  H.,  nickel  deposits 693 


Page. 

Brucite 414,564 

Brugnatelli,  L.,  titanolivine 389 

Bruhns,  W.,  synthesis  of  corundum 337 

synthesis  of  hematite 347 

of  ilmenite 348 

of  quartz  and  tridymite 358 

Brumell,  H.  P.  H.,  petroleum 735 

Brun,  A.,  deposition  of  sulphur 270 

fusibility  of  basalt 296 

granite 434 

melting  points  of  minerals 292-294 

origin  of  petroleum 727 

synthesis  of  corundum 337 

of  hydrocarbons 723 

of  quartz  and  tridymite 359 

of  zoisite 406 

volcanic  gases 282-284 

volcanic  hydrocarbons 727 

volcanism 282-284 

water  in  muscovite 284 

Brun,  A.,  and  Collet,  L.  W.,  volcanism ,,  282 

Brunlechner,  A.,  formation  of  iron  ores 573 

Brunswick  well,  analysis 183 

Brush,  G.  J.,  pyroxene  in  slag 379 

Brush,  G.  J.,  and  Dana,  E.  S.,  alteration  of 

spodumene 380 

eucryptite 373 

Brushite , 520 

Buchanan,  D.  G.,  analysis  by 255 

Buchanan,  J.,  section  of  nitrate  deposit 254 

Buchanan,  J.  Y.,  density  of  sea  water 126 

manganese  nodules 132 

marine  mud 515 

oceanic  carbonic  acid 144 

Buchner,  E.  H.,  radioactivity  of  rocks 315 

Buchrucker,  L.,  babingtonite  in  slags 383 

Buckley,  E.  R.,  clays 508 

Bucking,  H.,  occurrence  of  iolite 406 

Buckley,  E.  R.,  and  Buehler,  H.  A.,  zinc  de- 
posits  675 

Buckman,  H.  O.,  clays  and  kaolin 492 

Buehler,  H.  A.,  and  Gottschalk,  V.,  analyses 

of  mine  waters 632 

Buehler,  H.  A.  See  also  Buckley  and 
Buehler. 

Bujor,  P.,  cited 172 

Buluktii-Kul,  analysis  of  water 171-175 

Bunsen,  R.  W.,  composition  of  dissolved 

air 49,477 

fundamental  magmas 308 

gases  in  rock  salt 274 

magmatic  solutions 308 

oxygen  of  the  atmosphere 42 

volcanic  gases 261,262 

Bunsenite 694 

Burada,  A.,  the  Black  Sea 122 

Burchard,  E.  F.,  lignite 748 

Burgess,  G.  K.  See  Waidner  and  Burgess. 

Burgess,  J.  A.,  halide  ores  of  silver 655 

Burrell,  G.  A.,  natural  gas 714 

See  also  Allen  and  Burrell. 

Burton,  C.  V.,  artificial  diamond 324 

Buseb,  E.  R.,  nickel  deposits 693 

Buschmann,  J.  O.,  von,  Das  Salz 230 

Bushong,  F.  W.,  petroleum 717,735 


774 


INDEX. 


Page. 

Bushong,  F.  W.,  and  Weith,  A.  J.,  analyses 


by 80,81 

Busz,  K.,  analysis  by 495 

corundum 338 

Butler,  B.  S.,  epidote 407 

plumbojarosite 681 

Butler,  B.  S.,  and  Gale,  H.  S.,  alunite 259 

Butler,  F.  H.,  kaolinization 492 

Biitsehli,  O.,  calcareous  organisms 553 

Butte,  Montana,  mine  water 189 

Buttgenbach,  G.,  Argentine  borates 249,250 

Byasson,  H.,  origin  of  petroleum 726 

Byerlite 721 

Byerly,  J.  H.  See  Mabery  and  Byerly. 

Bygden,  A.,  eutectics 302,423 

Byske-elf,  analysis  of  water 103 

Bytownite 364 

C. 

Caballero,  G.  de  J.,  cobalt  in  Mexico 691 

ramirite 706 

Cabrerite 694 

Cache  la  Poudre  River,  analyses  of  water 65 

Cacoxenite 520 

Cadell,  H.  M.,  cited  on  Stassfurt  salts 221 

Cadmium,  distribution 15 

ores  of 669 

Cady,  H.  P.,  and  McFarland,  D.  F.,  compo- 
sition of  natural  gas 714 

Caesium,  distribution 15,28 

in  sea  water 121 

Cagniard-Latour,  artificial  coal 761 

Cahaba  River,  analysis  of  water 74 

Cailletet,  L.,  hydrogen  in  iron 287 

Calamine 672 

Calaverite 645 

Calb,  G.  See  Jannasch  and  Calb. 

Calcareous  algae 555,565 

Calcareous  sinter 203, 549, 550 

Calcioferrite 520 

Calciovolborthite 706 

Calcite 247, 251, 417, 418, 537, 549, 551, 552 

inclosing  sand 537 

Calcium,  distribution 15 

Calcium  carbonate,  circulation  of 130 

proportions  on  ocean  floor 128-130 

solubility  of 128,129 

Calculation  of  rock  analyses 473 

Calderon,  C.  S.,  Chaves,  D.  F.,  and  Pulgar, 

P.  del,  glauconite 516 

Caledonite 680 

Caliche 254,255 

California  geysers 199 

Californite 403 

Calker,  F.  J.  P.  van,  pseudogaylussite 158 

Callainite 520 

Calomel 664 

Cameron,  F.  K.,  alkali  in  soils 242 

water  analyses 156 

Cameron,  F.  K.,  and  Bell,  J.  M.,  solubili- 
ties  229,478 

Cameron,  F.  K.,  and  Hurst,  L.  F.,  solubility 

of  calcium  phosphate 519 

Cameron,  F.  K.,  and  McCaughey,  W.  J.,  syn- 
thesis of  apatite 355 


Page. 

Cameron,  F.  K.,  and  Seidell,  A.,  solubility  of 


calcium  phosphate 519, 520 

Campbell,  H.  D.  See  Howe,  J.  L. 

Campbell,  J.  M.,  laterite. 494 

Campbell,  M.  R.,  borate  deposits 246,248 

classification  of  coals 757 

Campbell,  N.  R.,  radioactivity 314,317 

Campbell,  N.  R.,  and  Wood,  A.,  radioac- 
tivity  317 

Campbell,  W.,  and  Knight,  G.  W.,  cobalt  ores.  694 

nickel  deposits 693 

Campbell,  W.  D.,  pseudomorph  of  gold 647 

Campo,  A del,  ammonium  fluoride  in  volcanic 

gases 261 

rare  metals  in  ores 669 

Camptonite 456 

Camptonose 456, 458, 461, 462 

Canadase 462 

Cancrinite 373-375 

Cancrinite  syenite 375 

Canfieldite 653 

Cannel  coal 740, 751, 758 

Cape  Fear  River,  analysis  of  water 73 

Caracolite 680 

Carbides,  metallic 723, 726, 727 

Carbon,  distribution 15 

Carbon  dioxide  in  the  atmosphere 45-48 

Carbonates  in  sea  water 128-130 

Carbonates,  alkaline 237-242 

origin  of 210 

Carbonic  acid,  oceanic 143-146 

Carbonyls,  metallic 330 

Carborundum 326 

Carles,  P.,  barium  and  sulphates  in  natural 

water 204 

fluorine  in  shells  of  mollusks 120 

in  spring  water 192 

Carlsbad  Sprudel  water,  analysis 193 

Carminite 682 

Carnallite 224 

Carnegieite 364 

Carnelley,  T.,  on  periodic  law 37 

solubility  of  copper 656 

Carnot,  A.,  fluorine  in  phosphates 524 

fluorine  in  sea  water 119, 524 

galena 676 

minervite 522 

phosphate  rock 522-524 

syntheses  o f stibnite  and  bismuthin  ite . . . 688 

water  analysis 172,197 

Camotite 707,709 

Caron,  H.  See  Deville  and  Caron. 

Carpenter,  W.  L.,  oceanic  carbonic  acid..  147,554 

Carrollite 658,692 

Carstone 541 

Caryinite 682 

Casares,  J.,  fluorine  in  spring  water 192 

Case,  E.  C.  See  Bailey  and  Case. 

Case,  W.  H.,  zinc  deposits 675 

Casoria,  E.,  palmerite 522 

volcanic  sublimates 271 

Caspari,  W.  A.,  glauconite 517 

red  clay 513 

Caspian  Sea 165, 166, 175, 221 

Cassel  brown 748 

Casseliase 465 


INDEX, 


775 


Page. 

Casselose 459 

Cassiopeium 21 

Cassiterite 352-353, 683-687 

Castorina,  G.  T.,  radioactivity  of  lava 315 

Catapleiite 711 

Catharinet,  J.,  copper  ores 660 

gold  in  pegmatite 642 

sperrylite  in  pegmatite 704 

Cathrein,  A. . alterations  of  garnet 402 

chloritoid  rock 613 

epidotization 597 

leucoxene 349 

occurrence  of  chloritoid 395 

pseudomorphs  after  gehlenite 400, 403 

after  scapolite 405 

saussurite 595 

titaniferous  magnetite 348 

Catlett,  C.,  analyses  by 558, 644 

See  also  Clarke  and  Catlett. 

Cayeux,  L.,  chalk 553 

gaize 542 

glauconite 516,518 

glauconitic  iron  ore 531 

oolitic  iron  ores 530, 575 

phosphatic  nodules 134 

soils 508 

Cecilose 464 

Cedar  River,  Iowa,  analysis  of  water 77 

Cedarstrom,  A . , cited 349 

Celadonite. . . 1 517, 518 

Celestite 247,578,579 

Cellulose 738,739 

Celsian 364 

Celtium 13 

Cementation,  belt  of 584 

Cements  in  sandstone 537, 538 

Centeno,  J.,  analyses  by 200 

Cerargyrite 655 

Cerite 711 

Cerium,  distribution 15 

sources  of 711-712 

Cerusite 679 

Cervantite 690 

Cesaro,  G.,  synthesis  of  crocoite  and  wulfen- 

ite 682 

Cevollite 400 

Chabazite 416,417 

Chabrid, , Algerian  saltpeter 253 

Chadwick,  O.,  and  Blount,  B.,  analysis  by . . 106 

Chalcanthite 662,663 

Chalcedony 357 

Chalcocite 658,659,660 

Chalcophanite 672 

Chalcophyllite 662 

Chalcopyrite 335, 658, 659, 660, 741 

Chalcostibite 661 

Chalk 553 

Chalmers,  R.,  peat 745 

Chalmersite 658 

Chamberlin,  R.  T.,  borax  lake  of  Ascotan. . . 249 

gases  from  coal 760 

gases  from  rocks 281, 286, 287 

Chamberlin,  T.  C.,  carbon  dioxide  in  atmos- 
phere  46,47 

influence  of  oceanic  carbonates  on  cli- 
mate  146,147 


Page. 

Chamberlin,  T.  C.,  loess 510 

planetesimal  hypothesis 56, 140, 286 

zinc  ores 675 

Chamberlin,  T.  C.,  and  Salisbury,  R.  D., 

clays 507 

volcanism 286 

volume  of  ground  water 33 

Chamosite 397,574 

Champex,  Lac 95 

Champlain,  Lake,  analysis  of  water 70 

Ch  amplainiase 467 

Chance,  H.  M.,  origin  of  iron  ores 529 

Chancourtois,  E.  de,  metals  in  earth’s  interior  330 

water  analysis 169 

Chandelon,  J.  T.  P.,  cited 94 

Chandler,  C.  F.,  analyses  by 70,71,185,186 

Chaper,  M.,  diamonds  in  pegmatite 326 

Chaplin  Lake 163 

Charante,  G.  M.  van,  analysis  of  water 529 

Charcoal 760 

Charcoal,  fossil 745 

Charitschkoff,  K.,  synthetic  hydrocarbons...  724 

waters  accompanying  naphtha 732 

Charlton,  A.  G.,  nickel  ores 691 

Charlton,  H.  W.,  analysis  by 450 

Chastaing, . See  Bourgoin  and  Chastaing. 

Chatard,  T.  M.,  analyses  by 64,156, 

157, 159, 160, 161 , 237, 238, 239, 240, 382, 
464, 465, 527, 541, 546, 558, 573, 615, 697 

natural  soda 239 

origin  of  corundum 339 

tallow  clay 675 

Chateau, , Algerian  phosphates 524 

Chattahoochee  River,  analysis  of  water 74 

Chautard,  J.,  lateritization 494 

Chautard,  J.,  and  Lemoine,  P.,  lateritization.  494 
Chaves,  D.  F.  See  Calderon,  C.  S.,  etc. 

Chazal,  P.  E.,  phosphate  rock 526 

Chehalis  River,  analysis  of  water 86 

Chdlif,  River,  analyses  of  water 67 

Cheltenham  waters,  analysis 186,187 

,Ch£lu,  A.,  sediment  of  the  Nile 115,506 

water  of  the  Nile 106 

Chemical  denudation 111-118 

Chenevixite 662 

Cherrydale  mineral  water 197 

Chert 542-545 

Chester,  A.  H.,  on  waters  of  New  Jersey 71 

Chester,  F.  D.,  epidotization : 598 

Chevallier,  A.,  cited 126 

Chevandier,  E.,  analyses  of  wood 739, 755 

Chewaucan  River,  analysis  of  water 161 

Chiastolite  schist 614 

Chicago  drainage  canal 109 

Chichen-Kanab,  Lake,  analysis  of  water 164 

Chiemsee,  analysis  of  water 96 

Chilenite 650 

China  Sea,  analysis  of  water 125 

Chippewa  River,  analysis  of  water 76 

Chiviatite 678 

Chloanthite 692,694 

Chlorides  in  rainfall 52 

Chlorine,  distribution 15 

in  atmosphere 51-53 

in  potable  waters 51,109,110 

in  sea  water,  origin  of 139, 141 


776 


INDEX, 


Page. 

Chlorine,  in  volcanic  gases 283 

Chlorites 396-398 

Chloritization 600 

Chloritoid 393,395,612 

Chloritoid-phyllite 614 

Chlormanganokalite 271 

Chlorophyllite 406 

Chloropal 493 

Chloropite 600 

Chlorothionite 271 

Chlorspodiosite 355 

Cholesterin 735 

Chondrodite 603 

Chotose 447 

Christie,  W.  A.  K.,  Cis-Indus  salt  beds 228 

See  also  Holland  and  Christie. 

Christy,  S.  B.,  synthesis  of  cinnabar 666 

Chromic  iron  ore.  See  Chromite. 

Chromite 344,696,697 

Chromitite 344 

Chromium,  distribution 15 

ores  of 696,697 

Chrompicotite 344 

Chrustschoff,  K.,  artificial  diamond 323 

synthesis  of  hornblende 385 

of  mica 394 

of  quartz  and  feldspar 366 

of  quartz  and  tridymite 358,359 

of  zircon 354 

Chrysocolla 663 

Chrysolite 389 

Chuard,  E.,  alteration  of  bronze 659 

Church,  A.  H.,  silicification  of  coral 515,543 

Cimarron  River,  analysis  of  water 81 

Cimolite 415,493,611 

Cincinnati  artesian  well,  analysis 182 

Cinnabar 664-669,741 

Ciplyte 523 

City  Creek,  analysis  of  water 156 

Claesson,  C.,  dopplerite 744 

Clapp,  F.  G.,  limestones 557 

Claraz,  G.  See  Heusser  and  Claraz. 

Clark,  A.  H.,  crinoids 565 

Clark,  G.  F.,  cited 93 

Clark,  J.  D.  See  Tolman  and  Clark. 

Clark,  T.  E.,  fichtelite 745 

Clark,  W.  B.,  greensand 517 

Clarke,  F.  W.,  age  of  ocean 149 

alteration  of  iolite 406 

analyses  by 64, 156, 158, 183, 

193,465,558,645,696 

average  abundance  of  minerals 419 

average  composition  of  igneous  rocks 24-27 

brucite-serpentine 415-606 

chemical  denudation 58, 115 

clays 493 

constitutional  formula? 600 

constitution  of  amphiboles 386, 388 

of  pyroxenes 383 

cookeite 392 

cryptomorphite' 251 

evolution  of  the  elements 12 

formula  of  canerinite 374 

glauconite  and  greenalite 517, 574 

molecular  weight  of  silica 361 

roscoelite 392 


Page. 

Clarke,  F.  W.,  solubility  of  minerals 480 

specific  gravity  of  igneous  rocks 420 

theory  of  chlorites 397 

total  run-off  of  rivers 58 

zeolites 417 

Clarke,  F.  W.,  and  Catlett,  C.,  nickel  ore. . . 693, 704 
Clarke,  F.  W.,  and  Darton,  N.  H.,  iron  mica.  391 
Clarke,  F.  W.,  and  Diller,  J.  S.,  alteration  of 

topaz 408,409 

nickel  silicate 695 

Clarke,  F.  W.,  and  Schneider,  E.  A.,  calcina- 
tion of  talc 415 

formation  of  spinel 343 

micas  and  vermiculites 396,398 

Clarke,  F.  W.,  and  Steiger,  G.,  abundance  of 

heavy  metals 28,629 

ammonium  analcite  and  leucite 368 

cadmium 669 

vesuvianite... 403 

Clarke,  F.  W.,  and  Wheeler,  W.  C.,  echino- 

derms 565,566 

Claude,  G.,  composition  of  air 41,44 

Claudetite 690 

- Claus,  C.,  phosphatic  sandstone 539 

Clausmann,  P.  See  Gautier  and  Clausmann. 

Clausthalite 676,677 

Claypole,  E.  W.,  tin  deposits 687 

Clays 507,508 

dehydration  of 610-614 

plasticity  of ". 502 

Clays,  oceanic 130-132, 512-515 

Clear  Lake,  analysis  of  hot  spring  near 197 

Clement,  J.  K.  See  Allen,  E.  T. 

Clements,  J.  M.,  iron  ores 346,572 

Clemm,  W.,  silication  of  limestones 558 

Clermont,  P.  de,  and  Frommel,  J.  solubility 

of  sulphides 630,636 

Cleveite 707,708 

Climate,  influence  of  carbon  dioxide  on 47,48, 

146,147 

Clinochlore 397,398 

Clinoclasite 662 

Clinohedrite 672 

Clinozoisite 406 

Clintonite 393 

Cloez,  S.,  hydrocarbons  in  iron 722,723,728 

Clouet,  J.,  synthesis  of  chromite 697 

Clough,  C.  T.,  and  Pollard,  W.,  occurrence 

of  olivine 391 

Clowes,  F.,  barytic  deposits 579 

barytic  sandstones 539 

Cowes,  F.,  and  Biggs,  J.  W.  H.,  solubility  of 

oxygen  in  sea  water 141 

Coal 738-765 

Coates,  C.  E.,  and  Best,  A.,  petroleum 717 

Cobalt,  distribution 15 

i n ashes  of  sea  weeds 121 

ores  of 691-696 

Cobaltite 652,692 

Cochenhausen,  E.  von,  water  analysis 155 

Codington,  E.  W.,  phosphate  rock 527 

Cohen,  E.,  matrix  of  diamond 324 

salt  lake  in  Transvaal 173 

Cohen,  E.,  and  Raken,  M.,  solubility  of  cal- 
cium carbonate. 129 


Cohen,  J.  B.,  and  Finn,  C.  P.,  oils  from  coal. . 748 


INDEX, 


777 


Page. 

Cohn,  F.,  travertine 550 

Cole,  G.  A.  J.,  bauxite 496 

Cole,  G.  A.  J.,  and  Little,  O.  H.,  calcite  and 

aragonite  i n fossils 552 

Coleman,  A.  P.,  anthraxolite 754 

corundum-nepheline  syenite 339 

heronite 371 

magnetic  assimilation 310 

nickel  deposits 693 

Colemanite 247,248 

Collet,  L.  W. , oceanic  deposits 130 

phosphatic  nodules 134 

See  also  Brun  and  Collet. 

Collet,  L.  W.,  and  Lee,  G.  W.,  glauconite 517 

Collier,  A.  J.,  tin  deposits 686 

Collier,  P . , native  platinum 701 

Collins,  H.  F.,  mercury  ores 664 

Collins,  J.  H.,  nickel  deposits 693 

tin  ores 684,685 

Collins,  W.  D.,  analyses  of  water 70, 

71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 82 

Collophanite 521,523 

Collot,  L.,  distribution  of  barium  and  stron- 
tium  579 

Collyrite 611 

Colomba,  L.,  alteration  of  glaucophane 388 

Colorado  River  (Argentina) , analysis  of  water.  91 
Colorado  River  (Arizona),  analysis  of  water. . . 82 

flow  of 82 

Colorado  River  (Texas),  analysis  oi  water 82 

Coloradoite 644,664 

Columbia  River,  analysis  of  water 84 

Columbite 687,710 

Columbium,  distribution 15 

sources 710 

Colvocoresses,  G.  M.,  cobalt  ores 695 

Comanducci,  E.,  copper  and  cobalt  in  volcanic 

ash 628 

Conchite 552 

Condit,  D.  D.,  minerals  in  sand 504 

Conichalcite 662 

Connarite 695 

Connate  waters 213 

Conneautsville  well,  analysis 185 

Consanguinity  of  rocks 308 

Contamination  of  river  waters 109 

Convection  in  magmas 311 

Cook,  E.  H.,  cited 46 

Cook,  G.  H.,  clays 508 

greensand  marl 517 

marl 550 

native  iron 328 

Cooke,  H . C . , secondary  enrichment 649 

Cooke,  J.  P.,  vermiculites 396 

Cooke,  W.  T.  See  Mawson  and  Cooke. 

Cookeite 392 

Cookose 462 

Coolgardite 644 

CoomarA-Swdmy , A.  K. , Ceylonese  graphite. . 327 

corundum 338 

minerals  in  limestone 623 

Cooper,  A.  S.,  origin  of  petroleum 732 

Copal. 741 

Copiapo,  Rio,  analysis  of  water 92 

Copper,  distribution 16 

in  sea  water 121 

ores  of 655-664 


Page. 

Coppock,  J.  B.,  cited 125 

Coquand,  H.,  antimony  ores 689, 690 

bauxite 496 

borates 245 

itabirite 609 

Coquina 555,558 

Coral 525,555,558 

silicification  of 515, 543 

Coral  rock 551, 555, 567 

Cordierite 338,405 

Cornet,  F.  L.,  phosphatic  chalk 525 

Comet,  J.  See  Renard  and  Comet. 

Cornish,  V.,  and  Kendall,  P.  F.,  calcite  and 

aragonite  in  shells 552 

Comu,  F.,  acid  reactions  of  minerals 478 

color  of  salt 231 

hibscnite 412 

rock-forming  apophyllite 416 

tests  for  calcite  and  dolomite 564 

See  also  Redlich  and  Cornu. 

Comu,  F.,  and  Vetter,  F.,  aragonite  sinter. . . 204 

Coronadite / 534 

Corongamite,  Lake,  analysis  of  water 173 

Corse,  M.  B.,  and  Baskerville,  C.,  analysis  by.  518 

Corstorphine,  G.  S.,  matrix  of  diamond 325 

Cortese,  E . , hot  springs  of  V enezuela 243 

Cortlandtite 463, 464, 465 

Cortlandtose 465 

Corundophilite 397 

Corundum 336-341 

Corundum  rocks 467 

Corynite 692 

Cosalite 653,678 

Cossa,  A.,  synthesis  of  scheelite 699 

tellurium  in  sulphur 270 

volcanic  sublimates 270 

Cossyrite 388 

Costachescu,  N.,  gases  in  salt 231, 731 

Coste,  E . , origin  of  petroleum 727 

salt  and  oil 229 

Cotunnite 679 

Courantyne  River,  analysis  of  water 90 

Cove  Creek,  U tah,  sulphur  bed 199 

Covellite 658-660 

Coward,  H.  F.  See  Bone  and  Coward. 

Cowen,  J.  L.,  arsenic  mine 690 

Cox,  E.  T.,  antimony  ores 690 

phosphate  rock 527 

Cox,  G.  H.,  zinc  deposits 675 

Craig,  A.  W.,  and  Wilsmore,  N.  T.  M.,  water 

analysis 173 

Cramer,  E.,  volatility  of  silica 273 

Cransac,  analysis  of  water  from 197 

Crater  Lake,  analysis  of  water 86 

Craw,  J.  W.,  analysis  by 198 

Crawley,  J.  T.,  and  Duncan,  R.  A.,  absorp- 
tion of  potassium  by  soils. 211 

Credner,  H.,  native  copper 656 

Crednerite 662 

Crenothrix 205 

Crenshaw,  J.  L.  See  Allen,  Johnston,  and 
Crenshaw. 

Cresson,  C.  M.,  cited 71 

Crinoids,  composition  of 565 

Cristobalite 356-363 

Crocidolite 388 

Crocoite 681 


778 


INDEX. 


Page. 

Cronstedtite 397,575 

Crook,  A.  R.,  molybdenite 698 

Crook,  T.,  dedolomitization 623 

Crook,  T.,  and  Davis,  G.  M.,  fluorite  in  sand.  504 

Crook,  T.,  and  Jones,  B.  M.,  geikielite 349 

Crookes,  Sir  W.,  artificial  diamond 324,325 

Crookesite 658 

Crosby,  W.  O.,  coloration  of  clay 508 

sandstone  dikes 541 

Crosnier,  L.,  crystallized  sands 538 

Cross,  C.  F.,  and  Bevan,  E.  J.,  lignocellulose. . 739 

Cross,  W.,  analcite  basalt 370 

analcite  in  phonolite 449 

classification  of  rocks 423, 425 

epidote 598 

garnet  in  rhyolite 402 

phlogopite  in  wyomingite 395 

quartz  - alunite  and  quartz  - diaspore 

rocks 259,497 

sandstone  dikes 541 

topaz  in  rhyolite 409 

See  also  Iddings  and  Cross. 

Cross,  W.,  and  Hillebrand,  W.  F.,  cryolite. . 336 

Cross,  Iddings,  Pirsson,  and  Washington, 

quantitative  classification 425-433 

Crossite 388 

Cruzy  well,  analyses 187 

Cryohydrates 301 

Cryolite 336 

Cryophyllite 392,395 

Cryptomorphite 251 

Crystallization,  fractional,  in  magmas 311 

Cubanite ' 658 

Cumberland  River,  analysis  of  water 78, 107 

Cumberlandite 468 

Cumenge,  E.  See  Friedel  and  Cumenge. 

Cumengeite 680 

Cummingtonite 384 

Cundell,  J.  T.,  and  Hutchinson,  A.,  zincite. . 672 

Cunningham,  J.  See  Lloyd  and  Cunning- 
ham. 

Cunningham,  J.  A.,  order  of  deposition  of 

minerals 307 

Cuprite 662 

Cuprobismutite 661 

Cuprodescloizite 682 

Cuproiodargyrite 655 

Cuprotungstite 699 

Curie,  M.  S.,  radioactivity 320 

Curie,  P.,  and  Laborde,  A.,  heat  from  radium.  314 

Currie,  J.,  cited,  on  Stassfurt  salts 221 

Curtis,  J.  S.,  gold  and  silver  in  quartz  por- 
phyry   628 

origin  of  lead  ores 683 

Cusack,  R.,  melting  points  of  minerals 292,293 

Cushman,  A.  S.,  plasticity  of  clays 502 

solubility  of  minerals ,. 480 

Cushman,  A.  S.,  and  Hubbard,  P.,  extrac- 
tion of  potash  from  feldspar 480 

Custerose 465 

Cyanite.  See  Kyanite. 

Cyanchroite 271 

Cylindrite 678,684 

Cymatolite 380 

Cyrtolite 712 

Czakd,  E.,  helium  in  natural  gas 714 


D.  Page. 

Dacite 453 

Dafert,  F.  W.,  caliche 255 

Dahllite 355,523 

Dahms,  P„  analysis  by 590 

Dale,  T.  N.,  slate 547 

Dali,  W.  H.,  coquina 555 

Dali,  W.  H.,  and  Harris,  G.  D.,  Florida 

phosphates 521 

Dallas,  mineral  spring  near,  analysis 189 

Dalmer,  K.,  metamorphosis  of  phyllite.  398, 410, 611 

Dalton,  L.  V.,  origin  of  petroleum 735 

Daly,  R.  A.,  average  composition  of  rock 

types 420 

evolution  of  limestones 557 

magmatic  differentiation  in  Hawaii 298 

magmatic  stoping * 310 

origin  of  alkaline  rocks 446 

pre-Cambrian  ocean 140 

the  fundamental  magma 26 

Damour,  A.  A.,  analysis  by 207 

Icelandic  geysers 196 

native  platinum 701 

predazzite 570 

titanolivine 389 

Damourite 391 

Dan  River,  analysis  of  water 72 

Dana,  J . D . , dolomitization 567 

gypsum  and  salt 228, 229 

serpentine 603 

volume  of  ground  water 33 

Dana,  E.  S.,  thinolite 158 

See  also  Brush  and  Dana. 

Dana,  E.  S.,  and  Penfield,  S.  L.,  lead  silicate.  683 

Danalite 214,672 

Dannemorite 384 

Danube  River,  analysis  of  silt 505 

analyses  of  water 101, 107 

Daphnite 397 

Darapskite 249,254,255 

Darapsky,  L.,  Chilean  borates 249 

Chilean  nitrates 254, 255 

Darton,  N.  H. , Florida  phosphates 521 

See  also  Clarke  and  Darton. 

Darwin,  C. , volcanic  islands 312 

Dathe,  E .,  scapolite  rocks 597 

Datolite 416 

Daubr6e,  A. , alteration  of  bronze 659 

arsenic  in  sea  water 120 

arsenic  and  antimony  in  basalt 628 

associations  of  platinum 703 

calcination  of  serpentine 376 

ferrous  chloride  in  native  iron 141 

formation  o f galena 677 

ofhyaliteand  zeolites  at  Plombieres..  210 

of  olivine 390 

fossil  charcoal 745 

origin  of  cassiterite 686 

of  native  iron 329,330 

sea  water  and  volcanism 141, 286 

solubility  of  orthoclase 367,478 

synthesis  of  apatite 354 

ofbrookite 351 

of  cassiterite 353,684 

ofdiopside 379 

ofenstatite 376 


IttDEX, 


779 


Page. 

Daubr6e,  A.,  synthesis  of  gahnite 673 

of  hematite 346,347 

of  quartz 357,358 

of  topaz 408 

of  willemite 673 

of  zinc  ores 673 

zeolites  at  Plombieres 210, 417 

Daubr^e,  A.,  and  Meunier,  S.,  native  iron. . . 328 

Daubr6eite 6.90 

Daubr^elite 696 

Daudt,  H.  W. , analysis  by 163 

David,  T.  W.  E.,  glendonite 158 

matrix  of  diamond 326 

Davidson,  W.  B . M. , phosphate  rocks 521, 527 

Davies , D . C . , W elsh  phosphates 525 

Davies,  G.  M.  See  Crook  and  Davies. 

Daviesite 680 

Davis,  C.  A.,  diatoms  in  peat 211 

marl 550 

peat 742 

Davison,  C. , loess 509 

Davison,  J.  M. , platinum,  etc.,  in  meteorites . 703 

Dawson,  H.  M.  See  Van’t  Hoff,  Kenrick, 
and  Dawson. 

Dawson,  J.  W.,  origin  of  gypsum 251,576 

peat 745 

spore  cases  in  coal 763 

Dawsonite 499 

Day,  A.  L.,  melting  points  of  minerals 292, 296 

Day,  A.  L.,  and  Allen,  E.  T.,  fusion  of  feld- 
spars   292 

sublimation  of  feldspars 273 

syntheses  of  feldspars 304, 366 

Day,  A.  L.,  and  Shepherd,  E.  S.,  &kerman- 

ite  silicate 398 

formation  of  quartz  and  tridymite 360 

lime  silicates 292,302 

phase  rule 304 

quartz  glass 357 

temperature  of  lava 282, 296 

volatility  of  quartz 273 

volcanic  gases 269 

Day,  A.  L.,  and  Sosman,  R.  B.,  feldspars — 364 

graphite 326 

melting  points  of  minerals 292,294 

Day,  D.  T.,  filtration  of  petroleum 736 

phosphate  rock 528 

platinum 702 

Day,  D.  T.,  and  Richards,  R.  H.,  platinifer- 

ous  sands 702 

Day,  W.  C.,  artificial  asphalt 725 

gilsonite 720 

pitch  coal 720 

Dead  Sea 167,168,174 

Death  Gulch,  water  from 205 

De  Benneville,  J.  S.,  potash  in  beryl 414 

Debray,  H. , synthesis  of  apatite 355 

synthesis  of  pyromorphite 682 

ofscheelite 699 

of  silver  halides 655 

See  also  Deville  and  Debray. 

Dechen,  H.  von,  cerusite  sinter 679 

Decomposition  of  rocks 476-536 

Dedolomitization 623 

Dee,  River,  analysis  of  water 93 

De  Groot,  H. , California  borates 246, 247 


De  Gouvenain, , fluorine  in  V ichy  water.  192 


Page. 

De  Launay,  L.  See  Launay,  L.  De. 

Delaware  River  (Kansas),  analysis  of  water. . 80 

Delaware  River  (N.  J.),  analysis  of  water. . . 71, 107 

Delebecque,  A.,  Lac  L6man 94 

Delebecque,  A. , and  Duparc,  L. , French  lakes  94 

Delesse,  A.,  volume  of  ground  water 33 

Delessite 397 

Delkeskamp,  R.,  barium  in  natural  waters. . 204, 

539, 579 

bauxite 496 

vadose  and  juvenile  carbonic  acid 213, 215 

Delvauxite 705 

Demaret,  L. , zinc  deposits 668 

Demargay,  E . , vanadium 705 

Demel,  W.,dopplerite 744 

Demerara  River,  analysis  of  water 90 

Dermis,  W.  D., cited 248 

Denudation,  aerial 138 

Denudation,  chemical 111-118 

Denver,  spring  near,  analysis 187 

Derby,  O.  A.,  Brazilian  diamonds 326 

Brazilian  topaz 409 

disintegration  of  rocks 482 

gold  on  1 imonite 645 

manganese  ore 535 

novaculite^ 542 

occurrence  of  monazite  and  xenotime 356 

Derbylite 691 

Desaulesite 695 

Deschutes  River,  analysis  of  water 85 

Des  Cloizeaux,  A.,  formation  of  anorthite 365 

nickel  ores 693 

Descloizite 672,682 

De  Smet,  Lake,  analysis  of  water 163 

Des  Moines  River,  analysis  of  water 77 

Deville,  C.  Sainte-Claire,  dolomitization 560 

fumar  oles  of  V esuvius 264 

Deville,  C.  Sainte-Claire,  and  Leblanc,  F., 

boric  fumaroles 245 

volcanic  gases 262,263 

volcanic  sublimates 270 

Deville,  H.  Sainte-Claire,  synthesis  of  cassit- 

erite 353,684 

synthesis  of  hematite 347 

of  magnetite 345 

of  willemite 673 

of  zeolites 416 

of  zircon 353 

titanium  and  vanadium  in  bauxite 500, 705 

topaz 408 

water  analyses 94,97 

Deville,  H.  Sainte-Claire,  and  Caron,  H., 

synthesis  of  apatite 354 

synthesis  of  cassiterite 353, 684 

of  gahnite 673 

of  pyromorphite 682 

of  rutile 351 

of  staurolite  (? ) 410 

of  zircon 353 

Deville,  H.  Sainte-Claire,  and  Debray,  H., 

native  platinum 701, 702 

synthesis  of  cinnabar 665 

Deville,  H.  Sainte-Claire,  and  Troost,  L., 

occlusion  of  gases  by  glass 276 

synthesis  of  greenockite  and  wur tzite 670 

Deville,  H.  Sainte-Claire,  and  Wohler  F., 

boron  nitride 245 


780 


INDEX. 


Page. 

Devils  Inkpoi,  analysis  of  water 199 

Devils  Lake,  analysis  of  water 163,177 

Dewar,  J.,  cited 44 

Dewar,  J.,  and  Ansdell,  G.,  gases  in  meteorites  287 

Dewey,  F.  P.,  solubility  of  gold 647 

Deweylite 415 

De  Wilde,  P.,  gold  in  sea  water 122 

origin  of  petroleum 730 

Diabantite 397,600 

Diabase 460,461,488 

Diallage 379 

Diamond 322-326 

Diapborite 653,678 

Diaspore 495,498 

Diatom  ooze 131,512 

Diatoms,  as  sources  of  petroleum 733 

in  peat 211 

Dick,  A.  B.,  minerals  in  sand 503 

Dickson,  C.,  formation  of  barite 581 

Dickson,  C.  W.,  nickel  deposits 693 

platinum  ores 704 

Dickson,  E.  See  Holland  and  Dickson. 

Dieffenbach,  O .,  gold  on  siderite 645 

Diersche,  M. , origin  of  graphite 327 

Diesel,  W.,  tests  for  calcite  and  aragonite 552 

Dietze,  A.,  water  analysis 92 

Dietzeite 255,696 

Dieulafait,  L.,  ammonia  in  sea  water 120 

barite 579 

bitumen  in  shale 730 

boric  acid  in  natural  waters 196 

Chilean  nitrates 256 

copper  in  sea  water 121 

lithium  in  sea  water 120 

manganese  in  sea  water 121 

manganese  nodules 133 

origin  of  borates 251,252 

precipitation  of  iron  ores 571 

serpentine 604 

strontium  in  sea  water 121 

sulphur  deposits 578 

thermochemistry  of  iron  and  manga- 
nese  §35,536 

vanadium 705 

zinc  and  copper  in  rocks 628 

zinc  in  limestone 674 

in  sea  water  1 121 

Diller,  J.  S.,  alteration  of  pyrope. 403 

loess 510 

melilite  and  gehlenite  in  slags 399 

occurrence  of  perofskite 349 

priceite 248 

quartz  basalt 362 

sandstones 540,541 

See  also  Clarke  and  Diller. 

Diopside 378,379 

Dioptase 663 

Diorite 456,488 

Dipyre 404 

Dissociation  in  magmas 299,303 

Ditte,  A.,  metals  in  the  atmosphere 53 

origin  of  vanadates 706 

synthesis  of  apatite 354 

of  cassiterite 353,684 

of  cinnabar 666 

of  greenockite 670 


Page. 

Dittler,  E.,  melting  points  of  silicates 294 

synthesis  of  plagioclase 365 

of  wulfenite 682 

See  also  Ballo  and  Dittler,  Doelter  and 
Dittler. 

Dittler,  E.,  and  Doelter,  C.,  bauxite 499 

Dittmar,  W.,  analyses  of  dissolved  air . . 142, 143, 144 

analyses  of  ocean  water 23,123 

oceanic  salts 23,119 

water  of  Hayes  River 87 

Dittmarite 520 

Ditroite 446 

Dittrich,  M.,  decomposition  of  rocks 487 

relations  between  spring  waters  and 

rocks 212,501 

Ditz,  H.  See  Donath  and  Ditz. 

Divers,  E.,  and  Shimidzu,  T.,  tellurium  in 

sulphur 270 

Dniester,  River,  analysis  of  water 104 

Dodge,  J.  A.,  analysis  of  water 75, 76, 83 

Doelter,  C.,  alteration  of  andalusite 410 

constitution  of  pyroxene 383 

formation  of  augite 382 

of  anorthite 365 

of  magnetite 345 

of  melilite 400 

of  spinel 343,398 

fusibility  of  rocks 296 

fusion  of  clinochlore 398 

ofepidote 406 

of  garnet 401 

of  glaucophane 388 

of  micas 343,396 

of  tourmaline 413 

gehlenite  in  limestone 622 

magmatic  dissociation 299,303 

melting  points  of  minerals 292, 293, 295 

solubility  of  minerals 352, 

480,630,631,636,684,689 

solvent  of  gold 646 

stability  fields  of  minerals 304, 307 

synthesis  o f acmite 380 

ofboumonite 661 

of  cinnabar 665 

of  covellite  and  chalcopyrite 659 

of  feldspar 365,366 

of  galena 677 

o f hornblende 385 

ofjamesonite 678 

ofleucite 369 

ofmeionite 404 

of  mica : 394 

of  nephelite  and  kaliophilite 372 

of  olivine 390 

o f pyrite  and  pyrrhotite 333 

ofsulphosalts 654 

of  wollastonite 377,378 

of  zeolites 416 

volcanic  chlorine 141 

volcanic  explosions 285 

Doelter,  C.,  and  Dittler,  E.,  the  silicate 

MgAhSiOs 387 

Doelter,  C. , and  Hoemes,  R. , dolomitization . . 567 

Doelter,  C.,  and  Hussak,  E.,  formation  of 

anorthite 365 

formation  of  melilite 400 

of  spinel 343 


INDEX. 


781 


Page. 


Doelter,  C.,  and  Hussak,  E.,  fusion  of  garnet.  401 

of  mineral  mixtures 310 

of  vesuvianite 403 

Doering,  A.,  analyses  by 92, 236 

cited 164 

Doherty,  W . M. , manganese  nodules 533 

Dole,  R.  B.,  analyses  of  water 69, 

70, 71, 72, 73, 74, 75, 76, 78, 79, 81, 82 

brines  of  Silver  Peak  marsh 181 

rejoinder  to  Shelton 153 

statement  of  water  analyses 59 

Dole,  R.  B.,  and  Stabler,  H.,  chemical  denu- 
dation   113 

silt  carried  by  rivers 506 

Dolerophanite 271 

Dolomite 247,417,559-571 

Domeykite 658 

Domingite 678 

Domoshakovo,  Lake,  analysis  of  water — 170, 174 

saline  deposits 234 

Don,  River,  analysis  of  water 93 

Don,  J.  R.,  distribution  of  gold 642, 643 

gold  in  sea  water 121 

solvent  of  gold 647 

Donath,  E.,  action  of  nitric  acid  on  coal 749 

extracts  from  coal 764 

humus  substances 750 

Donath,  E.,  and  Braunlich,  F.,  reactions  of 

lignite 749 

Donath,  E.,  and  Ditz,  H.,  reactions  of  lig- 
nite  749 

Donath,  E.,  and  Manouschek,  O.,  hydro- 
carbons from  coal 764 

Dopplerite 744 

Doss,  B . , anatase  pseudomorphs 350 

artificial  hematite 347 

grahamite 720 

melnikovite 334 

pseudobrookite 349 

sand  in  gypsum 537 

synthesis  of  rutile  and  anatase 351 

Doubs,  River,  analysis  of  water 94 

Doughty  Springs 204 

Douglas,  J.  A.,  volume  of  molten  minerals. . 296 

Douglasite 224 

Douro,  River,  analysis  of  water 94 

Drabble,  G.  C.,  see  Wedd  and  Drabble. 

Dragendorff,  J.  G.  W.,  analysis  of  water 104 

Drasche,  R.  von,  eclogite 598 

Drevermann,  A.,  syntheses  of  lead  ores 681 

Drew,  G.  H.,  bacterial  precipitation  of  cal- 
cium carbonate 549 

Drown,  T.  M.,  chlorine  maps 51 

Duane,  W.,  heat  from  radium 314 

Duboin,  A.,  synthesis  of  kaliophilite 372 

synthesis  of  leucite 369 

Dubois,  E.,  atmospheric  transport  of  salt 52 

chemical  denudation 149 

circulation  o f calcium  carbonate 130 

ratio  of  sodium  to  chlorine  in  rivers 139 

Du  Bois,  G.  C.,  laterite 493, 494 

Ducatte,  F . , sulphosalts  of  copper 662 

sulphosalts  o f lead 678 

Ducloux,  E.  H.,  analysis  of  sea  water 123 

loess 509 

mineral  springs  of  Argentina 216 


Page. 

Dudley,  W.  L.,  vivianite 520 

Duffield,  S.  P.,  analysis  cited 181 

Dufrenite 520 

Dufrenoysite 678 

Dumas,  J.  B.,  origin  of  boric  acid 245 

synthesis  of  argentite 650 

Dumble,  E.  T.,  grahamite 720 

iron  ores 575 

Dumont,  J.,  decomposition  of  potassium 

carbonate  by  clay 501 

solubility  of  rocks 480 

Dumortierite 412,616 

Duncan,  R.  A.  See  Crawley,  J.  T. 

Dundasite 499,679 

Dunin-Wasowicz  and  Horowitz,  J.,  analysis 

by 186 

Dunite 463,465 

Dunn,  E.  J.,  diamond 325 

Dunn,  J.  T.,  barium  and  strontium  in  mine 

waters 580 

Dunn,  W.  H.,  analysis  of  salt 231 

Dunnington,  F.  P.,  deposition  of  manganese.  536 

titanium  in  clays 500 

Dunose 465 

Dunstan,  W.  R.,  laterite 494 

Duparc,  L.,  analysis  of  water 94 

hot  springs 552 

transformation  of  pyroxene 384 

Uralian  platinum 702 

See  also  Delebecque. 

Duparc,  L.,  and  Holtz,  H.  C.,  Uralian  plati- 
num  700 

Duparc,  L.,  and  Hornung,  T., uralitization.  384, 589 

' Durand-Claye,  L.,  cited 125 

Durocher , J. , copper  sulphide 659 

liquation  in  magmas 312 

synthesis  of  argentite 650 

of  cinnabar 665 

of  dolomite 559 

of  galena— 676 

of  greenockite  and  sphalerite 670 

of  pyrite 333 

of  stibnite  and  bismuthinite 688 

of  sulphosalts 653 

the  fundamental  magmas 308 

Durun  Lake 165 

Dust,  atmospheric 53 

Dutoit,  A.  L.,  matrix  of  diamond 325 

Dutton,  C.  E.,  radioactivity  and  volcanism. . 316 

Dwina,  River,  analysis  of  water 104 

Dyscrasite 650 

Dyson,  F.  W.,  radium  in  the  sun 319 

Dysprosium 16,711 

E. 

Eakins,  L.  G.,  analyses  by 187, 

342, 382, 436, 445,  455, 456,458, 464, 
465, 510, 511, 546, 558,  570, 614, 628 

fluorine  in  fossil  bone 524 

xanthitane 350 

Eakle,  A.  S.,  lawsonite 411 

East  Saginaw,  brine,  analysis  of 182 

Eaton,  F.  M.  See  Van  Winkle  and  Eaton. 
Ebaugh,  W.  C.,  and  Macfarlane,  W.,  Great 

Salt  Lake 155 

Ebaugh,  W.  C.,  and  Williams,  K.,  Great  Salt 

Lake 155 


782 


INDEX, 


Page. 

Ebelmen,  J.  J.,  synthesis  of  beryl 414 

synthesis  of  bunsenite 694 

of  chromite 697 

ofenstatite 376 

offorsterite 390 

of  gahnite 672 

of  magnetite 345 

ofperofskite 349 

of  rutile 351 

Eberhard,  G.,  scandium 19 

Ecdemite 682 

Echinoderms,  comdosition  of 566 

Eckel,  E.  C.,  gypsum 232 

limestone  and  cement 557 

phosphorite 526 

slate . 547 

See  also  Hayes  and  Eckel. 

Eclogite 388, 402, 598, 599 

Eddingfield,  F.  T.,  deposition  of  gold 648 

Edenite 384 

Edingtonite 416 

E d wards,  M . G . , aluminum  hydrates  in  c lay . 499 

Eger  River,  analyses  of  water 98 

E gger , E . , analyses  of  water 97 

Egglestone,  W.  M.,  fluorspar 582 

Egleston,  T.,  solvents  of  gold 646,647 

Eglestonite 664 

Ehrlich,  F.  See  Kolkwitz,  R. 

Eichleiter,  C.  F.,  arsenical  spring 188 

Eilers,  A.,  platinum  and  palladium  in  copper.  704 

Eisenhulh,  K.,  analysis  by 573 

Eitel,  W.,  sillimanite, 410 

Elseolite 371 

Elseolite  syenite 445,487 

Elaterite 719 

Elbe  River,  analyses  of  water 98,99 

Elbow  River,  analysis  of  water 88 

Eldridge,  G.  H.,  asphalt 720,721 

Florida  phosphates 527 

Electrical  activity  in  ore  bodies 640 

Electrum 644 

Elements,  distribution 13-22, 39 

nature 12 

periodic  classification 35-39 

relative  abundance 22-35 

table  of. 13 

Ellis,  E.  E.,  zinc  deposits 675 

Ellis,  W.  H.,  anthraxolite 754 

Ells,  R.  W.,  manjak 721 

Elschner,  C.,  phosphate  rock 528 

Elsden,  J.  V.,  chemical  geology. . .s. 11 

Elton  Lake,  analysis  of  water 169, 174 

Embolite 655 

Emerson,  B.  K.,  amphibolite 593 

andalusite  and  sillimanite 612 

emery 340 

serpentine 602 

Emery 336,501 

Emmons,  S.  F.,  fluorite 582 

loess 509 

ores  of  Leadville 683 

platinum 704 

secondary  enrichmen  t 639 

serpentine 603 

silver  in  eruptive  rocks 628 

zinc  ores 675 


Page. 

Emmons,  W.  H.,  manganese  and  gold 647 

molybdenite 335 

secondary  enrichment 639 

Emmons,  W.  H.,  and  Harrington,  G.  L., 

mine  waters 631 

Emplectite 661,662 

Enargite 661,662 

Endell,  K.,  acids  of  moor  waters 484 

origin  of  kaolin 492 

See  also  Smits  and  Endell. 

Endell,  K.,  and  Rieke,  R.,  cristobalite 357,360 

spodumene 381 

Endemann,  H.,  asphalt 721 

Endlichite 682 

Engelhardt,  A.,  phosphate  rock 524 

Engelhardt,  F.  E.,  analysis  by 182 

Engler,  C.,  artificial  petroleum 725 

origin  of  petroleum 730,733 

Engler,  C.,  and  Lehmann,  T.,  artificial  pe- 
troleum  725 

Engler,  C.,  and  Severin,  E.,  artificial  pe- 
troleum  725 

Enstatite 376,377 

Epecu6n,  Lagoon,  analysis  of  water 164, 174 

Epiboulangerite 678 

Epichlorite 397 

Epidosyte 407,599 

Epidote 406-408,597,598 

Epidote  rocks 597,598 

Epidotization 597,598 

Epigenite 661 

Epistilbite 416 

Epsomite 223,249,255 

Erbium 16,711 

Erdmann,  — — , water  analysis 169 

Erdmann,  E.,  blue  rock  salt 231 

Stassfurt  salts 221 , 222, 223, 226, 231 

Erdmann,  H.,  abundance  of  nitrogen 34 

nitrogen  in  minerals 274 

Erie,  Lake,  analysis  of  water 69 

Erinite 662 

Erionite 416 

Erlau,  River,  analysis  of  water 101 

Erof6ef,  M.,  and  Latschinoff,  P.,  diamonds  in 

meteorite 324 

Erwin,  R.  W.,  cited 50 

Erythrite 694 

Erythrosiderite 271 

Escher,  B.  G.,  igneous  rocks 475 

Essen,  J.  von,  solubility  of  carbonates 549 

Essequibo  River,  analysis  of  water 90 

Essexose 444,459 

Etard,  A.,  and  Olivier,  L.,  reduction  of  sul- 
phates by  microbes 577 

Ettinger, . See  Franck  and  Ettinger. 

Eucairite 653 

Eucryptite 371,380 

Euctolite 459 

Eudialyte 711 

Europium 16,711 

Eutectics 301-304,423-424 

Euxenite 707,710 

Evansite 520 

Evans,  J.  R.,  analyses  of  water 73, 74, 75, 78 

Evans,  J.  W.,  analcite  in  monchiquite 370 

quantitative  classification 433 


INDEX. 


783 


Page. 


Evans,  N.  N.,  analysis  by 619 

Eve,  A.  S.,  radioactivity 315 

Eve,  A.  S.,  and  McIntosh,  D.,  radioactivity.  315 

Everding,  H.,  Stassfurt  salts 221 

Ewald, , analysis  by 205 

Ewing,  A.  L.,  limestone  erosion 559 

Excelsior  Spring,  analysis 191 


Eydmann,  E.  See  Kohlschiitter  and  Eyd- 
mann. 


F. 


Fahlunito 406 

Failyer,  G.  H.,  barium  in  soils 14 

See  also  Schreiner  and  Failyer. 

Failyer,  G.  H.,  and  Breese,  C.  M.,  nitrogen 

compounds  in  rain 50 

Failyer,  G.  EL,  Smith,  J.  G.,  and  Wade,  H.  R., 

composition  of  soil  particles 504 

Fairbanks,  H.  W.,  analcite-diabase 371 

tin  deposits 687 

Fairchild,  H.  L.,planetesimal  hypothesis...  56,140 

Fairhaven  Springs,  analysis 193 

Famatinite 661 

Farr,  C.  C.,  and  Florance,  D.  C.  H.,  radium  in 

rocks 315 

Farrington,  O.  C.,  formula  ofiolite 405 

meteorites 40 

Farup,  P.  See  Van’t  Hoff  and  Farup. 

Faujasite 416 

Fayalite 389-391 

Feld,  W.,  synthesis  of  pyrite 334 

Feldspars 363-368 

alterations  of 368 

melting  points 364 

sublimation  of 273 

Femic  minerals 426,427 

rocks 463-466 

Fennel,  A.  C.  See  Judge,  J.  F. 

Fenneman,  N.  M.,  petroleum 717 

Fennor,  C.  N.,  resorption  of  olivine 298 

silica 357,360 

Ferberite 699 

Fergusonite 712 

Fermor,  L.  L.,  garnet 402 

laterite 494,495 

manganese  ores 534 

Fernandez  and  Bragard,  analyses  by 580 

Fernandinite 707 

Femekes,  G.,  precipitation  of  copper 657 

Ferrier,  W.  F.  See  Weeks  and  Ferrier. 
Ferrieresand  Dupont,  synthesis  of  bunsenite.  695 

synthesis  of  zincite 672 

Ferrodolomite 573 

Fersmann,  A.  E.,  relative  abundance  of 


elements 26 

Fibrolite 409 

Fichtelite 719,745 

Fiedlerite 680 

Field,  F.,  analysis  by 574 

silver  in  sea  water 121 

synthesis  of  copper  minerals 662, 663 

Finckh,  L.,  igneous  rocks 475 

serpentine  from  gabbro 414 

Finkbiner,  N.  M.,  analysis  by 86 

Finlay,  G.  I.,  calculation  of  norms 432 

dumortierite 412 


Page. 

Finlayson,  A.  M. , genesis  of  lead  and  zinc  ores.  674 


Firm,  C.  P.  See  Cohen  and  Finn. 

Fircks,  W.  von,  tin  deposits 685 

See  Beck  and  Fircks. 

Fischer,  F.,  coal  analyses 751 

Fischer,  H.,  formation  of  oolite 553 

mercury  deposits 668 

Fischer  and  Rust,  microscopic  structure  of 

coal 763 

Fischer,  T.  See  Wedding  and  Fischer. 

Fischerite 520 

Fish  Creek,  analysis  of  water 88 

Fisher,  O.,  criticism  of  Joly 149 

internal  temperature  of  the  earth 291 

Fisher,  W.  W.,  water  of  Thames 93 

Flagg,  J.  W.,  Chilean  nitrates 254 

Flechsig,  R.,  analysis  by 193 

Fleck,  H.,  water  analysis 168 

Fleck,  El.,  and  Haldane,  W.  G.,  carnotite 709 

Fleischer,  A.,  volume  of  molten  basalt 296 

Fleissner,  H.,  Diamonds  in  slag 324 

Fletcher,  A.  L.,  melting  points  of  minerals...  292 

radioactivity  of  rocks 315 

See  also  Joly  and  Fletcher. 

Flint 542-545 

Flint  River,  analysis  of  water 74 

Florance,  D.  C.  H.  See  Farr  and  Florance. 

Fliickiger,  F.  A.,  analysis  by 199 

Fluocerite 336 

Fluorine,  distribution 16 

free,  in  fluorite 335 

in  mineral  waters 68,192 

in  sea  water 119 

in  volcanic  gases 261 

Fluorite 271,335,336,504,582 

Fluorspar.  See  Fluorite. 

Foerste,  A.  F.,  Clinton  iron  ores 531 

Forstner,  H.,  wurtzite  as  furnace  product 668 

Fohs,  F.  J.,  fluorspar 582 

Foote,  E.  A.  See  Koenig  and  Foote. 

Foote,  H.  W.,  analyses  by 344,450,697 

calcite  and  aragonite 551 

See  also  Penfleld  and  Foote. 

Foote,  H.  W.,  and  Bradley,  W.  M.,  analcite. . 368 

nephelite 372 

Foote,  W.  M.,  leadhillite 681 

Forbes,  D.,  borate  from  hot  springs 252 

Chilean  nitrates 254 

South  American  borates 249 

Forbes,  E.  H.  See  Penfleld  and  Forbes. 

Forbes,  R.  H.,  and  Skinner,  W.  W.,  water 

analyses 82 

Forbesite 694 

Forchhammer,  G.,  chemistry  of  the  ocean. . 119, 121 

heavy  metals  in  rocks 627 

magnesia  in  shells  and  corals 555, 565 

synthesis  of  apatite 354 

Ford,  W.  E.,  formula  of  dumortierite 412 

See  also  Penfleld  and  Ford. 

Forel,  F.  A.,  on  Lac  L6man 94 

Formaldehyde  in  atmosphere 45 

Formenti,  C.,  bauxite 497 

Formulae,  constitutional 600-602 

Forsberg, , cited 124, 126 

Forsberg,  E.  See  Geuther  and  Forsberg. 

Forsterite 389-391 


784 


INDEX. 


Page. 

Forstner,  W.,  mercury  ores 669 

Foster,  C.  Le  Neve,  Owens  Lake 239 

See  also  Bauerman  and  Foster. 

Foulk,  C.  W.,  analysis  by 182 

Foullon,  H.  B.  von,  gummite 708 

nickel  deposits 693,695 

rhodusite 388 

Fouque,  F.,  formation  of  melilite 399 

magmatic  differentiation 298 

steam  from  Etna 260 

volcanic  gases 264, 266, 267, 268 

Fouque,  F.,  and  Gorceix,  H.,  boric  fumaroles.  245 
Fouque,  F.,  and  Michel-Levy,  A.,  crystalliza- 
tion of  silica 361 

formation  of  hematite 347 

of  magnetite 344 

ofmelanite 399,402 

of  nephelite 372 

of  spinel 343 

fusion  of  biotite  and  microcline 369, 448 

of  scapolite  rock 405, 596 

scapolite  gabbro 596 

synthesis  of  augite 382 

ofenstatite 376 

of  feldspars 365,366 

of  leucite 369 

of  melilite 399 

of  mica  trachyte 394 

of  olivine 390 

Fournet,  J.,  synthesis  of  chalcopyrite 658 

synthesis  of  zinkenite 678 

Fox,  C.  J.  J.,  carbon  dioxide  in  sea  water. . . 145 

Fox,  R.  W.,  electrical  activity  in  ore  bodies. . 640 

Foyaite 446 

Fraas,  O.  F.,  formation  of  bitumen 731 

Fraatz,  T.  See  Werner  and  Fraatz. 

France,  lakes  of 94 

Franchi,  S.,  glaucophane  rocks 591 

jadeite  rocks 381 

Franchi,  S.,  and  Stella,  A.,  lawsonitein schist.  411 
Franck,  L.,  and  Ettinger,  diamonds  in  steel. . 323 

Franckeite 678,684 

Francolite 523 

Frank,  A.,  iodine  in  potash  salts 222 

Frankforter,  G.  B.,  water  from  Death  Gulch. . 205 

Frankland,  P.  F.,  coal  gas 756 

water  analysis 91 

Franklin,  E.  C.  See  Bailey,  E.  H.  S. 

Franklinite 672,676 

Fraps,  G.  S.,  and  Tilson,  P.  S.,  water  of  Rio 

Grande 82 

Frazer,  J.  C.  W.,  and  Hoffman,  E.  J.,  experi- 
ments on  coal 764 

See  also  Kastle,  J.  H.,  etc. 

Frazer,  P.,  classification  of  coals 756, 757 

Frear,  W.,  and  Beistle,  C.  P.,  soils 508 

Freeh,  F . , carbon  dioxide  and  climate 48 

Freda  well,  analysis  cited 185 

Freda,  G.,  volcanic  sublimates 271 

Free,  E . E .,  aerial  denudation 138 

Freis,  R.,  fusion  of  mineral  mixtures 306 

Freieslebenite 653,678 

Fremy , E .,  artificial  coal 761 

humic  substances  in  coal 748 

synthesis  of  anglesite 680 

ofeerusite 679 


Page. 

Frenzel,  A . , B olivian  tin  ores 684 

formula  of  pseudobrookite 349 

mine  water 632 

Fresenius,  O.  R.,  analysis  by 184 

manganese  and  iron  in  spring  waters 535 

Fresenius,  H.,  analysis  by 168 

Friedel,  C.,  diamond 323 

lead  oxychlorides 680 

nesquehonite 563 

synthesis  of  atacamite 662 

Friedel,  C.,  and  Cumenge,  E.,  carnotite 709 

Friedel,  C.  and  G.,  alteration  of  muscovite.  396 

artificial  cancrinite 374 

conversion  of  muscovite  into  nephelite..  372 

formation  of  leucite 369 

syntheses  of  feldspars 365, 366 

Friedel,  C.,  and  Guerin,  J.,  synthesis  of  ilmen- 

ite 348 

Friedel,  C.,  and  Sarasin,  E.,  formation  of 

quartz  and  feldspar 366 

synthesis  of  analcite 369 

ofhopeite 672 

ofphosgenite 679 

of  quartz  and  tridymite 358 

of  topaz 408 

Friedel,  G.,  hydration  of  analcite 368 

lead  oxychlorides 680 

synthesis  of  corundum 337 

of  kaliophilite 372 

Friedel,  G.,  and  Grandjean,  F.,  synthesis  of 

chlorite 398 

Friedlander,  J.,  artificial  diamond 323 

Friedmann,  A.,  analysis  by 168 

Frieseite 653 

Frio,  Rio,  analysis  of  water 92 

Friswell,  R.  J.,  action  of  nitric  acid  on  coal. . . 749 

Frochot,  M.,  tin  deposits 687 

Frommel,  J.  See  Clermont  and  Frommel. 

Frtih  and  Schroter,  peat 744 

Fuchsite 391 

Fuller,  M.  L.,  corrosion  of  quartz 363,481 

volume  of  ground  water 33 

Fuller’s  earth 508,736 

Fumaroles 262-269 

Fumaroles,  boric 243 

Funafuti,  atoll  of 568 

Funk,  W.,  decomposition  of  feldspars 480 

Fyris,  River,  analysis  of  water 103 

G. 

Gabbro 462,463 

Gabbro-nelsonite 468 

Gadolinite 712 

Gadolinium 16,711 

Gaertner,  A.,  bog  iron  ore 530 

Gagel,  C.,  and  Stremme,  H.,  origin  of  kaolin..  492 

Gages,  A.,  synthesis  of  serpentine 414 

Gahnite 341,672 

Gaize 541,542 

Gale,  H.  S.,  carnotite 709,710 

colemanite 248 

salines  of  Great  Basin 236 

Gale,  H.  S.,  and  Richards,  R.  W.,  phosphate 

rock 527 

Gale,  H.  S.,  and  Schaller,  W.  T.,  minerals  of 

Searles  Marsh. . v 247 


INDEX. 


785 


Page. 

Gale,  L.  D.,  cited 154 

Galena 335,676,677,741 

Galenobismutite 678 

Gallium,  distribution 16,28,669 

Ganomalite 683 

Gans,  R.,  clay  silicates 500 

Garda,  Lago  di,  analysis  of  water 96 

Gardner,  R.  F.,  analysis  by 233 

Garnet 400-403,598,601 

Garnet  rocks 598, 599, 624 

Gamier,  J.,  nickel  deposits 693 

Gamierite 695 

Garonne,  River,  analysis  of  water 94 

Garwood,  E.  J.,  calcareous  algse 555 

Gas,  natural 714,715 

Gases  in  coal 756,757-760 

Gassner,  L.,  phosphatization 558 

precipitation  of  metals 641 

Gaubert,  P.,  cristobalite 357 

Gaukhane  Lake,  analysis  of  water 169, 173 

Gautier,  A.,  arsenic  in  sea  water 120 

chemistry  of  volcanism 280-285 

decomposition  of  galena 677 

fluorine  in  volcanic  gases 261 

fumarole  gases 261, 283, 284 

galena 677 

hydrogen  in  atmosphere 44 

iodine  in  sea  water 119 

juvenile  and  vadose  waters 213 

minervite 521-523 

nitrogen,  argon,  arsenic,  iodine  in  granite.  437 

occluded  and  volcanic  gases 276-279 

origin  of  nitrates 257 

reduction  of  copper  sulphide 657 

thermal  springs  and  volcanism 214 

Gautier,  A.,  and  Clausmann,  P.,  fluorine  in 

natural  waters 68, 120, 192 

Gautier,  F.,  tin  deposits 686 

Gay  Lussac,  cited 49 

formation  of  hematite 346 

Gaylussite 159,238,247 

Gebbing,  J.,  cited 95 

Gebbart,  H.,  synthesis  of  barite 581 

Gedrite 383,384 

Gedroiz,  EL,  humus  in  soils 484 

Gegenbaur,  V.,  water  of  the  Adriatic 122 

Gehlenite 398-400,601 

Geijer,  P.,  magnetite  syenite 469 

Geikie,  Sir  A.,  bog  iron  ore 530 

elevation  of  continents 31 

order  of  magmatic  eruptions 310 

saline  matter  in  rivers 113, 114 

temperature  of  molten  lava 296 

Geikielite 349 

Geitner,  C.,  synthesis  of  argentite 650 

synthesis  of  beyrichite 692 

of  greenockite 670 

of  pyrite 333 

Genesee  River,  analysis  of  water 70, 107 

Genth,  F.  A.,  alteration  of  corundum 341 

alteration  of  orthoclase  to  albite 368 

of  talc 384,415 

analyses  by 608 

gummite 708 

lansfordite 563 

97270°— Bull.  616—16 50 


Page. 

Genth,  F.  A.,  pseudomorphous  cassiterite. . . 685 


vermiculites 396 

water  of  Dead  Sea 168 

Genth,  F.  A.,  and  Penfield,  S.  L.,  nesque- 

honite 563 

Genthite 695 

Geocronite 678 

Geological  thermometer 228, 621 

George,  R.  D.,  tungsten  deposits 700 

Georgiadesite 680 

Gerhardtite 663 

Germanium 16 

Gersdorflite 692 

Geuther,  A.,  formula  of  gypsum 223 

Geuther,  A.,  and  Forsberg,  E.,  synthesis  of 

wolframite 699 

Geyserite 207 

Gibb,  A.,  and  Philip,  R.  C.,  precipitation  of 

silver  sulphide 651 

Gibbsite 495, 496, 498, 499 

Gibson,  J.,  analysis  of  manganese  nodule. . 133, 134 
See  also  Irvine,  R. 

Giebeler,  H.,  radium  in  Nova  Geminorum. . . 319 

Gigantolite 406 

Gil,  J.  C.,  fluorine  in  spring  waters 192 

barium,  etc.,  in  spring  waters 184 

Gila  River,  analysis  of  water 82 

Gilbert,  G.  K.,  Lake  Bonneville 154 

mirabilite  at  Great  Salt  Lake 234 

salts  of  Sevier  Lake 235 

tufa 550 

Gilbertite 391 

Giles,  W.  B.,  bakerite.*. 248 

Gilman,  F.,  nickel  deposits 694 

Gilpin,  J.  E.,  and  Bransky,  O.  E.,  fuller’s 

earth 736 

Gilpin,  J.  E.,  and  Schneeberger,  P.,  fuller’s 

earth 736 

Gilsonite 720 

Ginsburg,  A.  S.,  synthesis  of  nephelite 372 

Ginsburg,  I.,  kaolin 492 

Girard,  C.,  and  Bordas,  F.,  spring  deposits. . 204 

Girardin,  J. , magnesian  travertine 561 

Gismondite , 416 

Glance  coal 746 

Glasenapp,  M.,  niter  in  sandstone 253 

Glaser,  M.  See  Kalmann,  W. 

Glaserite 223,228 

Glass,  occlusion  of  gases  by 276 

Glasser,  B.,  nepouite 695 

Glauberite 223, 228, 247, 249, 255, 270 

Glaucochroite 389 

Giaucodot 692 

Glauconite 135,516-518,573 

Glaucophane 387,388 

G laucophane  schists 591, 592 

Gleditsch,  E.,  uranium  and  radium 319 

Glendonite 158 

Glenn,  W.,  chromite  deposits 697 

Glinka,  K.,  glauconite 517,518 

kaolin 499 

weathering  o f minerals 483 

Globigerina  ooze 131, 512 

Glucinum,  distribution 16 

Gmelinite 416 


786 


INDEX. 


Page. 

Gmundenersee,  analysis  of  water 96 

Gneiss 487,618-620 

Goebel,  A. , cited 169 

Gockel,  A.,  radioactivity  of  rocks 315 

Godeffroy,  R . , analysis  o f water 96 

Gorgey , R.,  salts  of  Hall,  Tyrol 227 

Goessmann,  C.  A.,  analyses  by 182, 233 

Goethite.i 529 

Gotz,  J . , ottrelite  rocks 613 

Gold , distribution 16 

in  coal 646 

in  igneous  rocks 332 

in  sea  water 121,122 

ores  of 641-648 

solvents  of 646,647 

Goldberg,  A . , cited 193 

Goldsberry,  P.  See  Kraus  and  Goldsberry. 
Goldschmidt,  V.,  composition  of  tourmaline.  413 

Goldschmidtite 644 

Gooch,  F . A . , analyses  by 203 

Gooch,  F.  A.,  and  Whitfield,  J.  E.,  analyses 


Goodenough  Lake,  analysis  of  water 162, 176 

Goose  Lake,  analy  sis  of  water 86 

Gorby,  &.  S.,  petroleum 735 

Gorceix,  H . , volcanic  gases 268 

See  Fouqud  and  Gorceix. 

Gordon,  C.  H.,  change  of  augite  to  horn- 
blende  590 

nomenclature  o f gneiss 618 

Gorgeu , A . , analyses  by 534 

synthesis  o f fay  alite 390 

ofnephelite 373 

of  pseudo- wollastonite 377 

of  pyroxene 379 

ofspessartite 402 

ofwillemite 673 

of  zincite 672 

wad 533 

Gortner,  R.  A.  See  Alway,  F.  J. 

Gorup-Besanez,  E.  von,  formation  of  mag- 
nesian carbonates 561 

Goslarite 672 

Gosling,  E.  B.,  ozokerite 719 

Goss,  A . , water  analysis 82 

Gosselet,  J.,  phy  llites 613 

Gossner,  B.,  on  glaserite 223 

Gottlieb,  E.,  analyses  of  wood 739, 755 

Gottschalk,  V.  H.,  and  Buehler,  H.  A., 

electrical  activity  in  ore  bodies . . 640 

See  also  Buehler  and  Gottschalk. 

Gouvenain,  C.  A.  de,  alteration  of  bronze. . . 659 

Goyder,  G.  A.,  sulvanite 706 

Grabau,  A.  W.,  classification  of  sedimentary 

rocks 537 

Graftiau,  J.,  cited 45, 50 

Graham,  T.,  coUiery  gases 760 

gases  from  meteorites 287 

Graham,  T.,  Miller,  W.  A.,  and  Hofmann, 

A.  W.,  water  of  the  Thames 93 

Grahamite 706,719,720 

Gramann,  A.,  alteration  of  andalusite 410 

Grand  River,  analysis  of  water 70 

Grand  Ronde  River,  analysis  of  water 85 

Grandjean, , formation  of  dolomite 566 


Page. 

Grange,  J. , analyses  of  water 94 

Granite 433-438,473,487 

radioactivity  of 316 

sulphur  waters  from 203 

Granitite 437 

Grant,  U.  S.,  zinc  deposits 675 

Graphite 326-328,754 

Graphitic  acid 754 

Graphitoid 754 

Graton,  L.  C.,  tin  deposits 353,686,687 

See  also  Hess  and  Graton. 

Graton,  L.  C.,  and  Murdoch,  J.,  copper-iron 

sulphides 658 

Gray,  G.,  impurities  in  air 50,52 

Graywacke 540,541 

Great  Salt  Lake,  analyses  of  water 155, 173 

Greenalite 346,517,574 

Greenlee,  W.  B.,  volume  of  ground  water.. . 33 

Greenockite 669,670 

Greensand.  See  Glauconite. 

Greinacher,  H.,  radioactivity 314 

Greiner,  E . , silicate  fusions 307 

Greisen 686 

Greshoff,  M.,  analysis  by,  cited 197 

Griffiths,  A.  P.,  mercury  ores 668 

Grimsley,  G.  P.,  clays 508 

gypsum 232,576 

Griswold,  L.  S.,  novaculite 542 

Groddeck,  A.  von,  sericitic  rocks 593 

topazfels 408 

Grossmann,  M.,  gases  from  lava . 281 

Grossularite 400 

Groth,  P. , constitution  of  kyanite 409 

Ground  water,  volume  of 33 

Grout,  F.  F.,  average  composition  of  Minne- 
sota rocks 25 

copper  in  country  rock 657 

plasticity  of  clays 502 

precipitation  of  gold 648 

of  silver 651 

Grubenmann,  U.,  crystalline  schists 588 

glaucophane  rocks 588, 589, 591 

Griinsberg,  K. , carbonates  of  alkaline  earths  . 569 

Grunerite 384 

Griinerite-magnetite  schist 610 

Grinding,  F.,  maucherite 692 

Griinlingite 688 

Guano 253,257,258,520,521,523 

Guadalcazarite 664 

Guanajuatite 688 

Gurnbel,  C.  W.  von,  chloropite 600 

compression  of  lignite 760 

dolomite 565 

glauconite 516,517 

itabirite 609 

origin  of  manganese  nodules 132 

Gunther,  R.  T.,  and  Manley,  J.  J.,  water 

analysis 169 

Gunther,  S.,  interior  of  earth 57 

Gurich,  G.,  ore  deposits 626 

Gu4rin,  J.  See  Friedel  and  Guerin. 

Gueymard,  E.,  platinum  in  tetrahedrite 704 

Guignet,  E.,  action  of  nitric  acid  on  coal 749 

Guignet,  C.  E.,  wax  from  peat 733 

Guitermanite 678 


INDEX, 


787 


Page. 

Gulf  of  Mexico,  analysis  of  water 123 

Gully,  E.  See  Baumann  and  Gully. 

Gummite 708 

Gunnarite 692 

Gunning,  J.  W.,  analyses  of  water 94,97 

Gurlt,  A.,  talc 605 

tungsten  deposit 699 

Gustavsen,  C.  N.,  analysis  of  water 81 

Guthrie,  F.,  change  of  obsidian  to  pumice. . . 298 

cryohydrates 301 

eutectics 301-302,423 

Gypsum ...  223, 226, 229, 232, 247, 250, 251, 255, 537, 576 
Gyrolite 416 

H. 

Habermann,  J.,  formation  of  gypsum 576 

Hackmannite 373 

Haefcke,  H.,  constitution  of  hornblende 387 

Haefele,  P.  E.,  alteration  of  andalusite 410 

Hagele,  C.  See  Hell  and  Hagele. 

Haehnel,  O.,  kaolinization 492 

Haeussormann,  F.,  and  Naschold,  W.,  coal 

analyses 753 

Hager,  L.,  salt  deposits 229 

Hague,  A.,  origin  of  Yellowstone  hot  springs.  213 

scorodite  in  spring  deposit 208, 689 

Hahn,  H.,  hydrocarbons  in  iron 722 

Haldane,  W.  G.  See  Fleck  and  Haldane. 

Hale,  r».  J.,  marl 551 

Halite 224,247 

See  also  Salt. 

Hall,  A.  A.,  oils  from  coal 748 

Hall,  A.  D.,  and  Miller,  N.  J.  H.,  nitrogen  in 

rocks 34 

Hall,  C.  W.,  and  Sardeson,  F.  W.,  dolomite. . 567 

Hall,  Sir  J.,  artificial  coal 761 

fusion  of  limestone 556 

Hall,  R.  D.,  and  Lenher,  V.,  tellurides.  645, 648, 652 

Halley,  E.,  age  of  ocean 148 

Hallock,  W.,  effects  of  pressure 651 

Hall  oy  site 415, 493, 500, 611 

Hallstatt,  Lake  of,  analysis  of  water 96 

Halotrichite 259 

Halse,  E.,  mercury  ores 664 

tin  deposits 685 

Hamberg,  A.,  cited 142, 144 

native  lead 676 

Hamilton,  N.  D.  See  Parr  and  Hamilton. 

Hammerle,  V.,  silicate  fusions 306 

Hammerschmidt,  F.,  cited 227 

Hanamann,  J.,  waters  of  Bohemia 98,99, 100 

Hancock,  D.  See  Phillips  and  Hancock. 

Hanks,  H.  G.,  California  borates 243,246 

Hanksite 247 

Hannay,  J.  B.,  artificial  diamond 323 

occlusion  of  gases  by  glass 276 

Hannayite 521 

Harder,  E.  C.,  manganese  ores 535 

Hardin,  M.  B.,  analysis  by 198 

Hardman,  E.  T.,  analysis  by 544 

See  also  Hull  and  Hardman. 

Hardpan 484,530 

Hardystonite 672 

Harger,  H.  S.,  diamonds 325 


Page. 


Harker,  A.,  average  composition  of  igneous 

rocks 25 

crystallization  of  magmas 311 

hybridism 308 

origin  of  pegmatite 434 

primary  polite 406 

quantitative  classification  of  rocks 433 

Harkness,  R.,  dolomite 567 

Harmotone 416 

Harney  Lake,  analysis  of  water 161, 176 

Harper,  H.  W.,  asphalt 721 

Harperath,  L.,  Argentine  salt 231 

petroleum  and  salt 735 

Harrington,  B.  J.,  analysis  by 590 

bornite 658 

hydrogen  sulphide  in  calcite 274, 549 

See  also  Adams  and  Harrington. 

Harrington,  G.  L.  See  Emmons  and  Har- 
rington. 

Harris,  G.  D.,  salt  deposits 230 

See  also  Dali  and  Harris. 

Harris,  J.  E.,  absorption  in  soils 501 

Harrison,  J.  B.,  heavy  metals  in  rocks 629 

laterite 494 

rain  water 52 

Harrison,  J.  B.,  and  Jukes-Brown,  A.  J.,  coral 

rock .............................  555 

red  clay 513 

Harrison,  J.  B.,  and  Reid,  R.  D.,  waters  of 

British  Guiana 90 

Harrison,  J.  B.,  and  Williams,  J.,  chlorides  in 

rain 52 

nitrogen  compounds  in  rain 50 

Harrogate,  analyses  of  waters 184 

Hartite 719 

Hartleb,  R.  See  Stutzer  and  Hartleb. 

Hartley,  W.  N.,  gases  in  rocks 274 

reduction  of  sulphates 148 

Hartley, W.  N.,  and  Ramage,  H.,  distribution 

of  rare  elements 28, 529, 648 

Hartsalz 225 

Harzose 452,453 

Hasselberg,  B.,  absence  of  uranium  from  sun.  319 

Hasshagen, , water  analysis 169 

Hasslinger,  R.  von,  artificial  diamond 323 

Hasslinger,  R.  von,  and  Wolff,  J.,  diamond. . 323 

Hastings,  J.  B.,  gold  ores 642,643 

origin  of  pegmatite 434 

Hastingsite 387 

Hatch,  F.  H.,  classification  of  igneous  rocks. . 425 

diamonds 325 

Hatch,  F.  H.,  and  Rastall,  R.  H.,dedolomiti- 

zation 623 

Hatchettite 719 

Hauenschild,  G.,  predazzite 570 

Hauer,  K.  von,  analysis  of  water 172 

Hauke,  M.,eutecties 306 

Hatty nite 214,373-375 

Hatiynophyre 148 

Haushofer,  dolomite  and  magnesite 564 

solubility  of  minerals 478 

Hausmann,  J.  See  Zaloziecki  and  Hausmann. 

Hausmann,  J.  F.  L.,  wulfenite 681 

Hausmannite 533 


788 


INDEX. 


Page. 

Hautefeuille,  P.,  synthesis  of  enstatite 376 

syntheses  of  feldspars 366 

of  greenockite  and  wurtzite 670 

ofleucite 369 

oflithium-aluminumsilicates 381 

ofnephelite 372 

of  olivine 390 

of  perofskite 349 

of  quartz  and  tridymite 359 

of  rutile,  brookite,  and  anatase 351 

titanite 350 

vanadinite 682 

See  also  Troost  and  Hautefeuille. 

Hautefeuille,  P.,  and  Margottet,  J., synthesis 

of  quartz  and  tridymite 359 

synthesis  of  staurolite  (?) 411 

Hautefeuille,  P.,  and  Perrey,  A.,  crystalliza- 
tion of  titanic  oxide 351 

synthesis  of  beryl 414 

of  corundum 337 

of  zircon 353 

Hautefeuille,  P.,  and  Saint-Gilles,  L.  P.  de, 

synthesis  of  mica 394 

Hawes,  G.  W.,  alteration  of  granite 616, 617 

analyses  by 739,755 

chloritization 600 

native  iron 328 

Hawes,  G.  W.,  and  Wright,  A.  W.,  gases  in 

quartz 274 

Hawkins,  J.  D.  See  lies  and  Hawkins. 

Haworth,  E . , petroleum 717, 735 

zinc  deposits . 675 

Haworth,  E.,  and  Bennett,  J.,  native  copper.  657 

Hayes,  A.  A.,  distribution  of  vanadium 705 

sodium  iodate  in  Chilean  niter 249, 255 

South  American  borates 249 

Hayes,  C . W : , alunogen  deposits 259 

bauxite 497,498 

corrosion  of  quartz 363, 481 

iron  ores 530 

phosphatic  sandstones 539 

phosphorite 526 

Hayes,  C.  W.,and  Eckel,  E.  C.,  iron  ores. . 530 

Hayes,  C . W . , and  Kennedy,  W . , salt  deposits  229 

Texas  petroleum 717 

Hayes,  C.  W.,  and  Ulrich,  E.  O.,  phos- 
phorite  526 

Hayes  River,  analysis  of  water 87 

Hayhurst,  W.,  and  Pring,  J.  W.,  ozone  in 

atmosphere 43 

Haywood,  J.  K. , analysis  by 195 

Haywood,  J.  K.,  and  Smith,  B.  H.,  analyses 

cited 186,197 

Headden,  W.  P.,  action  of  water  on  orthoclase  481 

alunogen 259 

analyses  of  river  waters 61, 65, 66 

anthracite 753 

bary  tic  sinter 204,580 

carbonate  waters 190 

cubanite 658 

natron 242 

nitrates  in  soil .253 

stannite 684 

Heath,  G.  L., cited 69 

Heazlewoodite 692 


Page. 

Heberdey,  P . , melilite  and  gehlenite  in  slags . . 399 

wollastonite  in  slags 377 

Hedburg,  E . , zinc  deposits 675 

Heddle,  M.  F.,  analysis  by 518 

Hedenbergite 378-379 

Hedrumite 446 

Heider,  A.,  analysis  by 169 

Heileman,  W.  H.,  water  analyses 82 

Hein,  H.,  fibrous  silica 357 

Heinisch,  W.,  graphite  in  soils 327 

Heintzite 225,250 

Helium,  distribution 16, 41 

generation  from  radium 317, 318, 319 

in  fumarole  gases 268 

in  natural  gas 714 

in  spring  waters 180 

Hell,  C.,  fichtelite 745 

Hell,  C.,  and  Hagele,  C.,  artificial  paraffin-  - - 714 

Helmhacker,  R . , chromite  deposits 697 

Helvite 214 

Hematite 271,346-348 

Hempel,  W. , melting  points  of  minerals 292, 293 

oxygen  of  the  atmosphere . 42 

volcanic  gases 268 

Henrich,  F.,  cited 213,480 

volcanic  sublimates 271 

Henriet,  H.,  formaldehyde  in  atmosphere  ...  45 

Henriet  and  Bonyssy,  ozone 43 

Henriot,  E .,  redioactivity 317 

Henriot,  E.,  and  Varon,  G.,  radioactivity 317 

Henwood,  W.  J.,  electrical  activity  in  ore 

bodies 640 

Heraeus,  W.  C.,  melting  points  of  shales  and 

clays 292 

Herapath,  T.  J.,  and  W.,  the  Dead  Sea 169 

Herbst,  C. , ocean  water 123 

Hercynite 341 

Herderite 414 

Heron  Lake,  analysis  of  water 76 

Heronite 371,450 

Hess,  F.  L.,  origin  of  camotite 710 

Hess,  F.  L.,  and  Graton,  L.  C.,  distribution  of 

tin 684 

Hess,  F.  L .,  and  Schaller,  W.  T.,  vanadium 

minerals 710 

See  also  Watson  and  Hess. 

Hess,  V.  F.  See  Schweidler  and  Hess. 

Hess,  W.  H.,  cave  nitrates 253 

Hessite 652 

Hessose 455,458 

Heterogenite 694 

Heubachite 694 

Heulandite 416 

Heumite 446 

Heusler , F. , formation  of  hydrocarbons 731 

Heusser,C.,  and  Claraz,  G.,  Brazilian  dia- 
monds  326 

Hewett,  D.  F.,  sulphur  in  Wyoming 577 

vanadium  ores 706 

Hewettite 707 

Heycock,  C.  T.,  and  Neville,  F.  H.,  silver 

antimonide 650 

Heyward , B . H. , tallow  clays 675 

Hezner , L. , amphibolite 592 

eclogite 599 


INDEX, 


789 


Page. 

Hibschite 412 

Hicks , H. , phosphatic  fossils 525 

Hicks,  W.  B.,  analyses  by 160 

Hidden,  W.  E . , Llano  County  minerals 712 

sperrylite 704 

xenotime  in  granite 356 

See  also  Judd  and  Hidden. 

Hidden,  W.  E.,  and  Mackintosh,  J.  B., 

gadolinite,  etc 712 

Hidden,  W.  E.,  and  Pratt,  J.  H.,  sperrylite..  704 

Hidden,  W.  E.,  and  Warren,  C.  H.,  yttro- 

crasite 712 

Hiddenite 379 

Hieratite 270-271 

Highwood  River , analysis  of  water 88 

Highwoodose 440 

Hikutaia  Spring,  analysis 191 

Hilgard,  E.  W.,  analyses  by 83, 160,238 

arid  and  humid  soils  compared 491 

carbonates  as  solvents  of  silica 483 

d isintegration  of  rocks 490 

origin  of  alkaline  carbonates  in  soil.  210, 241, 242 

soils 508 

Hilger , A . , analy s is  of  holothur ian 566 

Hill,  B.  F.,  Terlingua  mines 665 

Hill,  J.  B.,and  MacAlister,D.  A.,  Cornish  tin 

ores 684 

Hill,  J.  M.  See  Bastin  and  Hill. 

Hill,  R.  T.,  salt  deposits 229 

Terlingua  mines 665 

Texas  petroleum 717 

Hillebrand , Sylvia,  nephelite 372 

Hillebrand,  W.  F.,  analyses  by 188, 189, 191, 


382, 435, 436, 437, 439, 440, 442, 444, 445, 
447, 450, 453, 455, 456, 458, 461, 462, 464 , 
465, 467, 508, 514, 534, 546, 548, 570, 573, 
592,614,615, 619, 624, 632, 645, 708, 709 


copper  arsenates 662 

distribution  of  vanadium 705 

heavy  metals  in  rocks 628 

kleinite 665 

patronite 707 

quisqueite 707 

rare-earth  minerals 712 

roscoelite 707 

slate 547 

zinc-bearing  clay 675 

See  also  Cross  and  Hillebrand. 

Hillebrand,  W.  F.,  Merwin,  H.  #E.,  and 
Wright,  F.  E.,  vanadium  min- 
erals  707,710 

Hillebrand,  W.  F.,  and  Ransome,  F.  L., 

carnotite 709 

Hillebrand,  W.  F.,  and  Schaller,  W.  T., 

Terlingua  minerals 665 

See  also  Schaller  and  Hillebrand. 

Himmelbauer , A . , scapolite 404 

Himstedt,  F.,  radioactivity 315 

Hinde,  G.  J.,  flint  and  chert 543 

Hinden , F . , dolomite  and  limestone 564 

Hinsdalite 682 

Hiortdahl , T. , synthesis  of  jaipurite 692 

Hiortdahlite 383 

Hirschwald,  J.,  nitrogen  compounds  in 

rain 51 


Pago. 

Hitchcock,  C.  H. , albertite 720 

phosphate  rock 521 

steatite 605 

Hobbs,  W.  H. , allanite  and  epidote 408 

secondary  galena 677 

tungsten  deposit 699 

Hodges,  J.  F.,  water  analysis 93 

Hodges,  R.  S.,  cited 74 

Hodgkinsonite 672 

Hogbom,  A.  G.,  cited  by  Arrhenius 48 

dolomitization 565,566 

Hoernes,  R.  See  Doelter  and  Hoemes. 

Hoff.  See  Van’t  Hoff. 

Hoffman,  E.  J.  See  Frazer  and  Hoffman. 

Hoffmann,  E.  W.,  solubility  of  minerals 479 

Hoffmann,  G.  C.,  allanite  in  granite 408 

analysis  by,  cited 181 

baddeckite 391 

native  iron 332 

native  platinum 701 

souesite 330,331 

Hoffman,  L.,  iron  ores 575 

Hoffmann,  R.,  synthesis  of  nephelite 373 

Hofman,  H.  O.,  eutectics  in  slags 302 

Hofmann,  J.  F.,  formation  of  coal 738, 763 

Hofmann-Bang,  O.,  rivers  of  Sweden 103 

Hoitsema,  S.  See  Bemmelen,  J.  M.,  van,  etc. 
Holland,  P.,  and  Dickson,  E.,  decomposition 

of  diabase 488 

Holland,  T.  H.,  barite 581 

bauxite 498 

corundum  rock 339 

desert  salts 235 

disintegration  of  rocks 482 

graphite  in  syenite 328 

laterite 493 

primary  calcite 418 

Holland,  T.  H.,  and  Christie,  W.  A.  K.,  the 

Sambhar  salt  lake 150 

Hollandite 534 

Hollick,  A.  See  Kemp  and  Hollick. 

Holmes,  A.,  age  of  earth 318 

distribution  of  radium 316 

laterite 494 

radioactivity 318 

Holmes,  H.  N.,  ozone  in  atmosphere 43 

Holmes,  J.  A.,  peat 745 

Holmium 17,711 

Holmquist,  P.  J.,  cristobalite  and  tridymite.  359 

synthesis  of  perofskite 349 

Holmquistite 388 

Holothurian,  analysis  of 566 

Holtz,  H.  C.  See  Duparc  and  Holtz. 

Holway,  R.  S.,  eclogite 599 

Hood, , analysis  by 696 

Hopeite 672 

Hopkins,  A.  T.,  chlorine  maps 51 

Hopkins,  T.  C.,  limestones 557 

Hopmann,  H.,  water  analysis 173 

Hoppe-Seyler,  F.,  formation  of  marsh  gas 729 

synthesis  of  dolomite 561 

Hornblende 384 

Homblendite 463 

Horner,  L.,  silt 505 

Hornstein,  F.  F.,  native  iron 328 


790 


INDEX, 


Page. 

Homung,  F.,  origin  of  petroleum 730 

Homung,  M.,  analysis  of  red  mud 513 

Homung,  T.  See  Duparc  and  Homung. 

Horowitz,  J.  See  Dunin-Wasowiez. 

Horsford,  E.  W.,  cited 71 

Horsfordite 658 

Hortonolite 389 

Horwood,  A.  R.,  calcite  and  aragonite  in 

fossils 552 

Hoskins,  A.  P.,  glauconite 517,518 

Hovey,  E.  O.,  artesian  well  at  Key  West 569 

cordierite  gneiss 406 

siliceous  oolite 544 

How,  H.,  borates  of  Nova  Scotia 251 

Howard,  C.  C.,  natural  gas 715 

Howard,  C.  D.,  analyses  by 78,714 

Howe,  E.,  magnetic  sulphides 335 

Howe,  J.  L.,  and  Campbell,  H.  D.,  on  Chi- 

chen-Kanab 164 

Howlite 251 

Huacachima,  Lake,  analysis  of  water 164, 177 

Huantajayite 655 

Hubbard,  P.  See  Cushman  and  Hubbard. 

Hiibnerite 699 

Hudleston,  W.  H.,  phosphatic  fossils 525 

Hudson,  E.  J.  See  Mabery  and  Hudson. 

Hiittner,  K.,  gases  in  rocks 278 

Hudson  River,  analyses  of  water 71, 107 

Hughes,  G.,  phosphate  rock 521 

Hull,  E.,  cited 93 

Hull,  E.,  and  Hardman,  E.  T.,  chert 542,543 

Hulsite 684 

Humboldt  and  Gay  Lussac,  cited 49 

Humboldt  Lake,  analysis  of  water 159, 176 

Humboldt  River,  analysis  of  water 159 

Humboldt  salt  well,  analysis 182 

Humboldtine 741 

Hume,  W.  F.,  loess 509 

Humphreys,  A.  A.,  and  Abbot,  H.  L.,  sedi- 
ment of  Mississippi  River 506 

Humphreys,  W.  J.,  gases  in  atmosphere 42,43 

rare  earths  in  fluorite 335 

volcanic  dust  and  climate 48 

Humus  acids 107, 108, 484, 743, 748, 750, 761 

Hundeshagen,  L.,  platinum  in  wollastonite- . 703 

Hungary,  salt  and  warm  lakes  of 172 

Hunt,  A.  E.,  bauxite 497 

Hunt,  T.  S.,  abundance  of  petroleum 735 

alteration  of  siderite 572 

analyses  by 69,185,198 

cosmical  atmosphere 54 

formation  of  dolomite 560 

on  atmospheric  carbon  dioxide 47 

origin  of  alkaline  carbonates 241 

primeval  ocean 140 

salt  and  gypsum 229 

sedimentation 506 

serpentine 604 

See  also  Logan  and  Hunt. 

Hunt,  W.  F.  See  Kraus  and  Hunt. 

Hunter,  J.  F.  See  Larsen  and  Hunter. 

Hunter,  M.,  analysis  by 450 

Hunter,  M.,  and  Rosenbusch,  H.,  monchi- 

quite 449 

Huntilite 650 

Hunyadi  Janos,  origin  of  water 212 


Page. 

Hurlbut,  E.  B.,  analysis  by 442 

Huron,  Lake,  analysis  of  water 69 

Hurst,  L.  F.  See  Cameron  and  Hurst. 

Hussak,  E.,  associates  of  diamond 326 

chalmersite 658 

leucite  pseudomorphs 371 

native  iron 328 

palladium  gold 644, 703 

perofskite-magnetite  rock 349, 350 

platinum  and  palladium 701 

primary  iolite 406 

synthesis  of  wollastonite 377 

See  also  Doelter  and  Hussak. 

Hussak,  E.,  and  Prior,  G.  T.,  derbylite,  etc..  691 

Hussak,  E.,  and  Reitinger,  J.,  monazite  sand.  356 

Hutchings,  W.  M.,  minerals  in  sand 503 

ottrelite 613 

willemite  in  slag 673 

Hutchins,  W.  M.,  apatite  in  slag 355 

clays  and  shales 547 

Hutchinson, , cited 50 

Hutchinson,  A.,  Meigen’s  reaction 552 

See  also  Cundell  and  Hutchinson. 

Hutchinson,  brine,  analysis  of 182 

Hutton,  R.  S.  See  Pring  and  Hutton. 

Hyalite 357 

Hyalophane 364 

Hyalosiderite 389 

Hyalotekite 683 

Hydrargillite.  See  Gibbsite. 

Hydroboracite 225,250 

Hydrocarbons 713-737 

in  lava 281 

Hydrocerusite 679,682 

Hydrogen,  distribution 17 

in  atmosphere 44 

Hydrogen  dioxide  in  atmosphere 43 

Hydrogoethite 529 

Hydromagnesite 414 

Hydronephelite 416 

Hydrozincite 672 

Hypersthene 376,377 

I. 

Iceland,  analysis  of  geyser  water  from 1% 

sinter  from 196,207 

volcan  ic  gases  from 261 

Iddings,  J.  P.,  consanguinity  of  rocks 308 

fay  alite-i  n rhyolite 391 

magmatic  differentiation 298, 308 

order  of  igneous  eruptions 311 

quartz  basalt 362 

rock  diagrams 475 

See  also  Barns  and  Iddings. 

Iddings,  J.  P.,  and  Cross,  W.,  primary  allan- 

ite 407 

Iddings,  J.  P.,  and  Penfield,  S.  L.,  fayalitein 

rhyolite 391 

Idocrase.  See  Vesuvianite. 

Idrialite 719 

Igelstrom,  L.  J.,  molybdenum  in  hematite. . . 348 

Igneous  rocks 419-475 

average  composition 27 

classification  of 420-433 

Ihlseng,  M.  C.,  phosphate  rock 528 

Ijolite 445 


INDEX, 


791 


Page. 

lies,  M.  W.,  and  Hawkins,  J.  D.,  precipitated 


zinc  sulphide 671 

Iletsk  salt  lake,  analysis  of  water 171, 173 

Illiacus,  A.  See  Ramsay  and  Illiacus. 

Illinois  River,  analysis  of  water 77, 109 

chlorine  in 109 

Illy4s  Lake,  analysis  of  water 172, 173 

Ilmenite 348,349 

Ilmenite-nelsonite 468 

Ilmenite  norite 467 

Ilosvay,  L.  von,  water  analysis 102 

Ilz,  River,  analysis  of  water 101 

Imperial,  Pennsylvania,  analysis  of  brine 185 

Indalself,  analysis  of  water 103 

Indian  Ocean 125 

Indium,  distribution 17, 28, 669 

Infusorial  earth 542, 544 

Ingalls,  W.  R.,  tin  deposits 685 

Ingol,  Lake 104 

Inn,  River,  analysis  of  water 101 

Inostranzeff,  A.,  native  iron 331 

native  platinum 702 

schungite 754 

d’Invilliers,  E.  V.,  phosphate  rock 521 

Iodine,  distribution 17 

in  sea  water 119 

in  spring  water 183 

Iodobromite 655 

Iodyrite 655 

Iolite 338,405 

Ionian  Sea 122 

Ionium 12,314 

Iowa  River,  analysis  of  water 77 

Ipatief,  W.,  origin  of  petroleum 731 

Ippen,  J.  A.,  amphibolite 592 

eclogite 598 

synthesis  of  cinnabar 666 

Iridium . 17,700-704 

Iridosmine 700,702 

Irish  Sea,  analysis  of  water 123 

Iron,  distribution 17 

hydroxides  of 528-533 

in  sea  water 121 

meteoric,  chlorides  in 140 

native 328-332 

nitride 272 

occlusion  of  gases  by 287 

Iron  bacteria 530 

Iron  ore 528-533,571-575 

titaniferous 467 

Irvine,  R.  See  Murray,  Sir  J. 

Irvine,  R.,  and  Anderson,  W.  S.,  phosphati- 

zation 558,641 

Irvine,  R.,  and  Gibson,  J.,  manganese  nod- 
ules   133 

Irvine,  R.,  and  Young,  G.,  solubility  of  cal- 
cium carbonate 128 

Trving,  J.  D.,  tin  deposits 687 

Irving,  J.  D.,  and  Emmons,  S.  F.,  tungsten 

ores 699 

Irving,  R.  D.,  native  copper 656 

quartzite 607 

Irving,  R.  D.,  and  Van  Hise,  C.  R.,  chert 544 

enlargement  of  quartz  grains 538 

Isar  River,  analysis  of  water 101 

Iser  River,  analyses  of  water 98 


Page. 

Is§re,  River,  analysis  of  water 94 

Isochlors 51,149 

Issyk-Kul,  analysis  of  water 171, 175 

Istrati,  C.  I.,  Roumanian  salt 230 

Itabirite 609 

Itacolumite 326 

J. 

Jaccard,  A.,  origin  of  petroleum 730,734 

Jackman,  W;  F.,  cited 69 

Jackson,  D.  D.,  cited 51 

Jacobsen,  O.,  analyses  of  dissolved  air 142,144 

analysis  of  peat 743 

resins  in  peat 745 

Jacquot,  E.,and  Willm,  E.,  mineral  springs...  210 

Jaczewski,  L.,  origin  of  graphite 327 

Jadeite 379,381 

Jaeger,  F.  M.,  analysis  by 532 

Jaeger,  F.  M.,  and  §imek,  A.,  synthesis  of 

spodumene 381 

Jaeger,  F.  M.,  and  Van  Klooster,  H.  S.,  syn- 
theses of  sulphides 654, 678 

Jaffa,  M.  E.,  alkaline  carbonates 241 

Jaffe,  R.,  pitchblende 707 

Jaggar,  T.  A.,  and  Palache,  C.,  zoisite  rock. . 595 

Jahn,  J.  J.,  origin  of  petroleum 730 

Jaipurite 692,693 

James  River,  analyses  of  water 72, 107 

Jamesonite 678 

Jamieson,  G.  S.,  nickel-irons 330 

See  also  Penfield  and  Jamieson. 

Jamieson, G.  S.,  and  Bingham,  H.,  analysis  of 

water 164 

Janda, , uranium  ores 707 

Janeirose 447 

Jannasch,  P.,  and  Calb,  G.,  composition  of 

tourmaline 413 

Jannasch,  P.,  and  Weingarten,  P.,  vesuvi- 

anite 403 

Jannetaz,  E.,  formation  of  anglesite 680 

Janssen,  J.,  volcanic  gases 269 

Jaqerod,  A.,  and  Perrot,  F.  L.,  helium 319 

Jaquet,  J.  B.,  platinum  in  ironstone 703 

serpentine 414,602 

Jarman,  J.  L.,  analysis  by 534 

Jasper 357 

Jaspilite 609 

Java,  rivers  of 105 

Jeffersonite 379,672 

Jeffrey,  E.  C.,  origin  of  petroleum  and  coal . . 733, 

740, 751 

Jenkins, , analysis  by 534 

J enney , W . P . , artificial  grahamite 720 

recent  blende 671 

zinc  deposits 675 

Jennings,  E.  P.,  magmatic  iron  ores 346 

Jensch,  E.,  cadmium 669 

Jensen,  H.  I.,  copper  in  andesite 629 

origin  of  alkaline  rocks 446 

Jentzsch,  A.,  German  lakes 102 

Jerden,  D.  S.  See  Bone  and  Jordan. 

J erem^ef , P . , chalcopyrite  and  chalcocite 660 

pseudomorphous  garnet 403 

pseudomorphs  after  olivine 391 

Jervis,  W.  P.,  Tuscan  fumaroles 251 


792 


INDEX, 


Page. 

Jet 746,758 

Joannis,  A.,  fusion  of  limestone 557 

J ockamowitz,  A borax 250 

Jodidi,  S.  L.,  organic  matter  of  soils 108 

Johansson,  H.  E.,  eutectics 302,423 

John,  C.  von,  humus  acid  in  coal 748 

kainite  and  camalite 227 

Nile  mud 505 

John,  W.  von,  native  tantalum 711 

John  Day  River,  analysis  of  water 85 

Johns,  C.,  transition  point  of  quartz 359 

Johnson,  B.  H.,  and  Warren,  C.  H.,  cumber- 

landite 468 

Johnson,  H.  S.,  cited 101 

Johnson,  J.  P.,  diamond 325 

Johnson,  L.  C.,  Florida  phosphates 521 

Johnston,  J.,  and  Adams,  L.  H.,  effects  of 

pressure 585,651 

Johnston,  J.,  and  Niggli,  P.,  metamorphism..  583 
Johnston,  J.  See  also  Allen,  E.  T. 

Johnston,  R.  A.  A.,  analyses  by 332,344 

awaruite 330 

Johnston-Lavis,  H.  J.,  absorption  of  rocks  by 

magmas 310 

quartz  in  basalt 299 

V asuvian  sublimates 271 

Johnstone,  A.,  action  of  water  on  micas 396 

solubility  of  minerals 132, 479 

Johnstrup,  F.,  cryolite 336 

Joly,  J.,  age  of  the  earth 140, 149, 150, 151 

age  of  minerals 320 

meldometer , 292 

melting  point  of  minerals 292,293 

order  of  deposition  of  minerals 307,316 

radium  and  geology 315 

radium  in  rocks 317 

radium  in  sea  water 122 

radioactivity  and  volcanism 317 

sedimentation 506 

sublimation  of  enstatite 273 

volume  of  oceanic  salts 24 

volume  of  oceanic  sediments 138 

Joly,  J.,  and  Fletcher,  A.  L.,  pleochroic 

halos 320 

Joly,  J.,  and  Rutherford,  E.,  pleochroic  halos.  320 

Jones,  E.  J.,  barite  modules 136 

Jones,  L.  J.  W.,  mine  water 632 

Jones,  T.  R.,  chert 542 

peat 742 

Jones,  W.  R.,  cited 206 

Jones ville  acid  water,  analysis 198 

Jordan  River,  analysis  of  water 168 

Jordan  River  (Utah),  analysis  of  water 156 

Jordanite 678 

Jorissen,  A.,  vanadium  in  delvauxite 705 

Joseite 688 

Josephinite 330,331,691 

Joukowsky,  E.,  eclogite 599 

Jovitschitsch,  M.  Z.,  chromitite 343 

Jowa,  L.,  synthesis  of  selenite 229,576 

Judd,  J.  W.,  alteration  of  plagioclase  to  scapo- 

lite 368 

atoll  of  Funafuti 568 

corundum  rock 339 

origin  of  scapolite 404, 596 

pressure  and  chemical  change 291 

scapolite  rock 596 


Page. 


Judd,  J.  W.,  and  Brown,  C.  R.,  Burmese  co- 
rundum  339 

Judd,  J.  W.,  and  Hidden,  W.  E.,  ruby 339 

Judge,  J.  F.,  and  Fennel,  A.  C.,  analysis  by. . 183 

Judithose 444 

Jukes  Browne,  A.  J.  See  Harrison  and  Jukes 
Brown. 

Julien,  A.  A.,  alteration  of  spodumene 380 

decomposition  of  pyrite 334 

geological  effects  of  humus  acids . . . 108, 210, 484 

phosphate  rock 521 

J uvenile  waters 213 

K. 

Kaersutite 389 

Kahlenberg,  L.,  and  Lincoln,  A.  T.,  hydroly- 
sis of  silicates 195 

Kahlenberg,  L.,  and  Schreiner,  O.,  borate 

ions 196 

Kainite 223 

Kaiser,  E.,  African  diamonds 325 

alteration  of  basalt 500 

decomposition  of  rocks 487 

Kalamazoo  River,  analysis  of  water 70 

Kaleczinzky,  A.,  water  analysis 172 

Kalgoorlite 644 

Kaliophilite 371 

Kalkowsky,  E.,  corundum  granulite 339 

Kallerudose 437 

Kallilite 692 

Kalmann,  W.,  and  Glaser,  M.,  analysis  by.  184, 188 

Kanab  Creek,  analysis  of  water  from  near 185 

Kanolt,  C.  W.,  melting  points  of  oxides 292, 336 

Kansas  River,  analysis  of  water 80 

Kaolin 491-493,499 

Kaolinite 415,491,500,611 

Kapouran,  analysis  of  water 185 

Karaboghaz,  Gulf 165,166,175,221 

Karlsbrunn,  analysis  of  water  from 191 

Karlsdorf  waters,  analysis 186 

Karstens,  K.,  volume  of  the  ocean 22 

Kasarnowski,  H.  See  Wohler  and  Kasar- 
nowski. 

Kaskaskia  River,  analysis  of  water 77 

Kastle,  J.  H.,  Frazer,  J.  C.  W.,  and  Sullivan, 

G.,  phosphatic  chert 544 

Katamorphism,  zone  of 584 

Katwee  salt  lake,  analysis  of  water 173 

Katzer,  F.,  analyses  of  Amazon  water 91 

analyses  ox  sea  water  cited 122 

mercury  deposits 668 

Kauer,  A.,  analysis  by 187 

Kauimann,  F.  G.,  dopplerite 744 

Kay,  G.  F.,  nickel  ores .-...  695 

Kayser,  E.,  carbon  dioxide  and  climate 48 

Kayser,  R.,  sulphur  in  petroleum 718 

Kedabekase 462 

Kehoeite 672 

Keith,  A.,  zinc  deposits 675 

Keller,  G.,  formation  of  limonite 571 

Keller,  H.  F.,  and  Lane,  A.  C.,  chloritoid — 393 

Keller,  O.,  volume  of  ground  water 33 

Kellermann,  K.  F.,  and  Smith,  W.  R.,  bacte- 
rial precipitation  of  calcium  car- 
bonate  549 

Kelly,  A.,  conchite 552 

Kelsey,  H.  G.,  cited 183 


INDEX, 


793 


Page. 

Kelvin,  Lord,  effect  of  pressure  on  fusibility.  291 


primitive  atmosphere 55 

Kelyphite 403 

Kemp,  J.  F.,  bornite  in  pegmatite 660 

Franklin  zinc  ores . . . 676 

gneiss  defined 618 

gravitative  differentiation  in  magmas. . 311, 312 

ground  water 33 

iron  ores 469 

magmatic  magnetite 346 

metamorphosed  dolomite 623 

molybdenite  in  pegmatite 335 

nickel  ores 694 

ore  deposits 626,634 

platinum  ores 332, 700, 702, 703, 704 

relative  abundance  of  elements 28 

secondary  enrichment 639 

tellurides 644 

Kemp,  J.  F.,  and  Hollick,  A.,  limestone 623 

Kemp  ton,  C.  W.,  tin  deposits 685 

Kendall,  J.,  solubility  of  calcium  carbonate..  129 


Kendall,  P.  F.,  calcite  and  aragonite  in  shells.  553 
Kennedy,  "W.  See  Hayes  and  Kennedy. 

Kennedy,  W.  T.  See  McLennan  and  Ken- 
nedy. 

Kenngott,  A.,  alkaline  reaction  of  minerals..  478 


composition  of  tourmaline 413 

vesuvianite 403 

Kendrick,  F.  B.  See  Van’t  Hoff, Kendrick, 
and  Dawson. 

Kentallenose 455,456 

Kentrolite 683 

Kentucky  River,  analysis  of  water 78 

Kermesite 688 

Kern-theorie 425 

Kerner,  G.,  water  analysis 97 

Kerosene  shale 733 

Kerr,  W.  C.,  marl 551 

Kersantite 456 

Kettner,  C.  H.,  analysis  by 532 

Keyes,  C.  R.,  borax  deposits 246 

genesis  lead  and  zinc  ores 675 

gypsum 576 

linnseite 694 

loess 509 

ore  deposits 626 

origin  of  cerargyrite 655 

primary  epidote 407 

recent  blende 671 

ultimate  source  of  ores 627 

Kieserite 223,228 

Kikuchi, , occurrence  of  iolite 406 

Kilauea,  gases  from 269 

Kilbrickenite 678 

Kilroe,  J.  R.,  laterite  and  bauxite 494 

Kimball,  J.  P.,  grahamite 720 

iron  ores 530,571 

Kimberlite 325 

Kinahan,  G.  H.,  bauxite 497 

Kinch,  E.,  sodium  chloride  in  rain 52 

King,  C.,  internal  temperature  of  the  earth. . 291 

King,  F.  P.,  Georgia  corundum 339 

Kingsbury , J.  T . , waters  of  U tah 155 

Kirk,  M.  P.,  and  Malcolmson,  J.  W.,  Ter- 

lingua  minerals 665 

Kirunose 469 


Page. 

Kisil-Kul,  analysis  of  water 170, 174 

saline  deposits 234 

Ki§pati6,  M.,  bauxite 499 

Kitchell,  W.,  marl 550 

Kitchin,  E.  S.,  and  Winterson,  W.  G.,  argon 

and  helium  in  minerals 274 

Klaprotholite 661 

Klarelf,  analysis  of  w ater 103 

Klarfeld,  H.  See  Zaloziecki  and  Klarfeld. 

Kleinite 664,665 

Element,  C.,  analyses  by 134,614 

formation  of  dolomite 562 

laterite 494 

origin  of  petroleum 730 

Klementite 397 

Klemm,  G.,  minerals  in  sandstone 540 

Klobbie,  E.  A.,  analysis  by 532 

See  also  Bemmelen,  J.  M.  van,  etc. 

Knebelite 389 

Knight,  C.  W.,  analcite  trachyte 371 

See  also  Campbell  and  Knight. 

Knight,  H.  G.,  water  analyses 86,162 

Knight,  W.  C.,  platinum  in  covellite. 704 

Knisely,  A.  L.,  water  analyses 86 

Knop,  A.,  enlargement  of  quartz  grains 538 

Knopf,  A.,  Alaska  tin  deposits 686 

platinum  and  palladium 704 

Knopf,  A.,  and  Schaller,  W.  T.,  hulsite  and 

paigeite 684 

Knox,  J.,  mercury  sodium  sulphide 666 

Knox,  W.  J.,  impurities  in  rain 50 

Knoxvillite 696 

Kobellite 678 

Koch,  A.,  celestite  and  barite 579 

. cited 349 

Kochelsee,  analysis  of  water 96 

Kobrich , bauxite 496 

Koehlichen,  K.,  cited 222 

Koehn,  E.,  cited 101 

Koene,  C.  J.,  primitive  atmosphere 55 

Koenenite 225 

Koenig,  A.,  genesis  of  diamond 326 

Koenig,  G.  A.,  analysis  cited 185 

synthesis  of  domeykite 658 

Koenig,  G.  A.,  and  Foote,  A.  E.,  diamonds 

in  meteorite 324 

Konig,  T.,  and  Pfordten,  O . von  der,  ilmenite.  348 

Koenigsberger,  J.,  radioactivity 317 

temperature  relations 295 

Konigsberger,  J.,  and  Muller,  W.  J.,  syn- 
thesis of  quartz  and  tr idymite ...  358 

Konigsee,  analysis  of  water 96 

Konlite 719 

Kottigite 672 

Koettstorfer,  J.,  iodine  in  sea  water 119 

Kohlmann,  W.,  associates  of  cassiterite 353 

Kohlrausch,  F.,  hydrolysis  of  silicates 195 

Kohlschiitter,  V,  and  Eydmann,  E.,  hair  sil- 
ver  649 

Koken,  E .,  carbon  dioxide  and  climate 48 

Koko-Nor,  analysis  of  water 169, 177 

Kolenko,  B.,  hornblende  pseudomorphs 386 

Kolderup,  C.  F.,  analysis  by 467 

Kolkwitz,  R.,  and  Ehrlich,  F.,  on  the  Elbe. . 98 

Kolotoff,  S.,  analysis  of  sea  water 125 

Koninck,  L.  L.  de,  synthesis  of  cinnabar ....  666 


794 


INDEX. 


Page. 

Koninckite 520 

Kornerupine 381,613 

Kosmann,  H.  B.,  silver  halides 655 

Koto,  B.,  chloritoid  rock 613 

glaucophane  rocks 591 

piedmontite . 407 

Kovaf,  J.,  kyanite  in  limestone 410 

Kramer,  G.,  and  Bottcher,  W.,  origin  of  pe- 
troleum  730 

Kramer,  G.,  and  Spilker,  A.,  origin  of  petro- 
leum  730,733,734 

Kragerite 469 

Kraus,  E.  H.,  celestite 579 

Kraus,  E.  H.,  and  Goldsberry,  P.,  copper-iron 

sulphides 658 

Kraus,  E.  H.,  and  Hunt,  W.  F.,  celestite — 538 

Kraut,  K.,  diffusion  of  cobalt  and  nickel 691 

Kraze,  K.,  Stassfurt  salts 222 

Kremersite 271 

Krennerite 645 

Kretschmer,  A.,  composition  of  fahlerz 661 

Kreusler,  U.,  oxygen  of  the  atmosphere 42 

Kreutz,  S.,  amphibole 387 

the  Meigen  reaction 552 

Krogh,  A.,  annual  consumption  of  coal 46 

oceanic  carbonic  acid 143, 146 

air  from  Greenland 46 

Kriimmel,  O.,  volume  of  the  ocean 22 

Kruft,  L.,  phosphorite 524 

Krugite 223 

Krusch,  P.,  platinum  in  graywacke 704 

Krypton * 17,41,180 

Kryptotile 393,611 

Ktypeite 552 

Kiimmel,  H.  B.,  clays ^ 508 

peat * 742 

Kuhlmann,  F.,  phosphate  rock 524 

silication  of  limestone 558 

synthesis  of  cerargyrite 655 

Kulaite 459 

Kultascheff,  N.  V.,  fusion  of  mixed  silicates.  300, 302 

Kunz,  G.  F.,  Montana  corundum 340 

Kunz,  G.  F.,  and  Washington,  H.  S.,  Arkan- 
sas diamonds 325 

Kunzite 379 

Kupfier , A . E . , native  iron 331 

Kurnakoff,  N.  S.,  on  Karaboghaz 165 

Kurtz,  C.  M.,  analyses  by 244 

Kusnetsoff,  S.,  on  Karaboghaz 165 

Kuss,  H.,  mercury  deposits 668 

Kvassay,  E . von,  origin  of  alkaline  carbonates  241 

Kyanite 409,410,612 

Kyanite  schist 614 

Kyle,  J.  J.,  Argentine  borates 249 

vanadium  in  lignite 706 

water  analyses 91 

Kyschtymase 467 

Kyschtymite 339,467 

L. 

Laa  bitter  spring,  analysis 187 

Laach,  Lake,  analysis  of  water 172, 176 

Laborde,  A.  See  Curie  and  Laborde. 

Labradorite 364 

Laby,  T.  H.  See  Mawson  and  Laby. 

Lachat, , celestite 579 


Page. 

Lachaud  and  Lepierre,  lead  chromates 681 

Lachmann,  R.,  later ite 496 

Lacroix,  A.,  absorption  of  limestone  by  gran- 
ite  310 

allanite  and  epidote 408 

alteration  of  bronze 659 

alteration  of  hornblende  to  auglte 386 

alteration  of  serpentine 415 

berthierine 575 

boric  acid  in  fumaroles 245 

chalcocite  on  old  coins 657 

constitution  of  phosphorite 523 

dumortierite  in  gneiss 412 

eclogite  rocks 599 

formation,  of  zeolites 417 

glauconite 517 

ktypeite 552 

later  ite 494 

miner  vite 522 

Mont  Pelee 268,362 

occurrence  of  lawsonite 411 

phosphates  of  lime 523 

phosphatized  andesite 521 

plancheite 663 

recent  cerusite 679 

scapolite  rocks 404, 597 

spinel  in  troctolite 343 

tridymite 362 

villiaumite 373 

volcanic  sublimates 271 

wollaston ite  in  aplite 378 

See  also  Michel-Levy  and  Lacroix. 

Lacroix,  A.,  and  Baret,  C.,  wemerite rock. . . 597 

Lacroix,  A.,  and  de  Schulten,  A.,  Laurium 

slag  minerals 680 

Lacu  Sarat,  analysis  of  water 172, 174 

saline  deposits 234 

Laczczynski, , analysis  of  chromite 344, 697 

Ladd,  G.  E.,  clays 508 

Ladureau,  A.,  sulphur  in  atmosphere 45 

Lagonite 243 

Lagorio,  A.,  eutectics 423 

formation  of  leucite 370 

fusibility  and  solubility  distinguished. . . 307 

glass-base 309 

pyrogenic  corundum 338,339 

solubility  of  minerals  in  magmas 310 

Lagoriolite 401 

Lahontan,  Lake 157-160 

Laine,  E.  See  Muntz  and  Laine. 

La  Junta  artesian  well,  analysis 191 

Lake,  P.,laterite 493,494 

Lampadite 533,662 

Lamprophyre 442 

Lanarkite 680 

Lane,  A.  C. , criticism  of  Brun 283 

eutectics 302,423 

magmatic  gases 283 

mine  waters 631 

native  copper 656 

the  ocean 127 

volcanism 283,285,286 

waters  of  Michigan 70, 185, 212 

See  also  Keller  and  Lane. 

Lane,  A.  C.,  and  Sharpless,  F.  F.,  griinerite.  384 

Lang,  J.,  bauxite 496 


INDEX. 


795 


Page. 

Lang,  R.,  lublinite 551 

Langbeinite 223,228 

Lansfordite 563 

Lanthanite 17 

Lanthanum 17,711 

Lapis  lazuli 374 

Lapparent,  A.  de,  distribution  of  solfataras. . 212 

Laramie  lakes,  analyses  of  water 163, 174 

Laramie  River,  analyses  of  water 79 

Larderellite 243 

Larsen,  E.  S.,  perofskite  rock 350,468 


See  also  Washington  and  Larsen;  Wright 
and  Larsen. 

Larsen,  E.  S.,  and  Hicks,  W.  B.,  scarlesite. . 247 

Larsen,  E.  S.,  and  Hunter,  J.  F.,  melilite 


rock 400 

Larsen,  E.  S.,  and  Schaller,  W.  T.,  cevollite.  400 

Lartet,  L.,  on  Dead  Sea 168,561 

Lasaulx,  A.  von,  alteration  of  rutile 348 

kelyphite 403 

sulphur  deposits 577 

See  also  Sartorius  and  Lasaulx. 

Laschenko,  P.  V.,  aragonite 551 

Lasne,  H.,  phosphorite 528 

Laspeyres,  H.,  olivine  as  a furnace  product. . 390 

sericite 593 

Lassenose . 435,453 

Lateral  secretion 627 

Laterite 493-501 

Latite 451,452 

Latouche,  T.  H.  D.,  and  Christie,  W.  A.  K., 

analysis  by 173 

Latschinoff,  P.  See  Erofeel  and  Latschinofl. 

Lattermann,  G. , bary tic  sinter 580 

Lattimore,  S.  A.,  analysis  by 235 

Laubanite 416 

Laumontite 416 

Launay,  L.  De,  average  composition  of 

igneous  rock 26 

cited 213 

diamond 325 

magmatic  w aters 634 

mean  atomic  weight  of  lithosphere 26 

ore  deposits 626,638 

Laur,  F.,  bauxite 496 

gold  and  silver  in  Triassic  rocks 641, 642 

Laurdalite 446 

Laurdalose 442,444 

Laurionite 680 

Laurite 19,700 

Laurvikose 440 

Lautarite 17,255 

L&venite 383 

Lawrenceite 140 

Lawson,  A.  C.,  chert 543 

corundum  rock 339 

mine  water 631 

See  also  Adams  and  Lawson. 

Lawson,  A.  C.,  and  Palache,  C.,  chert 543 

Lawson,  R.W.,  age  of  earth 318 

Lawsonite 411 

Lazurite 214 

Lead,  distribution 17 

from  uranium 317 

occurrence  in  a coral 

ores  of 676,683 


Page. 

Leadhillite 681 

Lebedintzeff,  A.,  water  analyses 166 

Leblanc,  F.  See  Deville  and  Leblanc. 

Lechartier,  G.,  synthesis  of  mimetite 682 

syntheses  of  olivine 390 

synthesis  of  pyroxene 379 

Le  Chatelier,  H.,  Algerian  alkaline  deposits..  241 

clay  substances  in  marl 559 

constitution  of  clay  silicates 493 

formation  of  granite 434 

fusion  of  limestone 557 

modifications  of  quartz 360 

thermocouple 291 

Le  Chatelier,  H.,  and  Wologdine,  S.,  graphite  326 

Lechler,  M.,  Bavarian  waters 101 

Leckie,  J.  S.,  nickel  ores 695 

Le  Conte,  J. , N evada  borates 246 

Le  Conte,  J.,  and  Rising,  W.  B.,  mercury 

deposits 668 

Leddin, . See  Blum. 

Ledoux,  A.  R.,  nickel  ores 695 

Leduc,  A.,  hydrogen  in  atmosphere 44 

Lee,  G.  W.  See  Collet  and  Lee. 

Lee,  W.  T.,  Cove  Creek  sulphur 199, 578 

Leffman,  H.,  waters  of  Yellowstone  Park 196 

Lefort,  J.,  analysis  by 200 

Legendre,  R.,  carbon  dioxide  in  air 46 

Leguizamon,  M.  M.,  water  analysis 164 

Lehder,  J. , phosphatic  nodules 528 

Lehrbachite 664,676 

Lehmann,  B.,  sericitic  rocks 593 

Lehmann,  T.  See  Engler  and  Lehmann. 

Leibius,  A. , gold 643 

Leighton,  H.  See  Newland  and  Leighton. 

Leighton,  M.  O.,  analyses  of  water 70 

normal  and  polluted  waters no 

Leith,  C.  K.,  actinclite-magnetite  schist 384 

glauconite  and  greenalite 517, 573, 574 

origin  of  magnetite 346 

See  also  Van  Hise  and  Leith. 

Leith,  C.  K.,  and  Mead,  W.  J.,  iron  ores 531 

Leitmeier,  H.,  dimorphism  of  calcium  car- 
bonate  551,563 

spring  deposits 204 

Lekene 719 

Leman,  Lac,  analysis  of  water 94 

Lemberg,  J.,  alterations  of  feldspar 368 

alteration  of  spodumene  and  jadeite 381 

of  topaz 409 

artificial  cancrinite 374 

chlorite  pseudomorphs 398,402 

composition  of  sodalite 374 

decomposition  of  rocks 487 

double  decompositions  in  silicates 501 

epidotization 598 

fusion  of  limestone 556 

kaliophilite  and  nephelite 372 

leucite  and  analcite 368,369 

predazzite 570 

primitive  atmosphere 55 

reactions  with  andalusite  and  kyanite ...  410 

with  gehlenite 400 

serpentine 602,603 

silication  of  limestones 558 

syntheses  of  zeolites • 417 

tests  for  calcite  and  dolomite 558, 564 


796 


INDEX, 


Page. 

Lem6tayer,  P.,  water  analysis 92 

Lemi^re,  L.,  formation  of  coal 763 

Lemoine,  P.  See  Chautard  and  Lemoine. 

Lenarcic,  J.,  formation  of  augite 382 

formation  of  magnetite 345 

ofnephelite 373 

fusion  of  mineral  mixtures 306 

recrystallization  of  albite 366 

Lenecek,  O . , predazzite 570 

Lengenbachite 678 

Lengyel,  B.  von,  analysis  of  water 172 

Lenher,  V.,  gold  telluride 645 

solution  of  gold 647,648 

See  also  Hall  and  Lenher. 

Lenicque,  H.,  carbide  theory  of  volcanism. . . 281 

origin  of  petroleum 728 

primitive  atmosphere 56 

Lenk,  H.,  augite-scapolite  rock 405 

Lenox,  L.  R.,  corals 555, 567 

Lenz,  O.,  itabirite 609 

Lenz,  R . , laterite 494 

Leonard,  A.  G.,  gas  well 729 

zinc  deposits 675 

Leonite 223 

Lepape,  A.  See  Moureu  and  Lepape. 

Lepidolite 392-396,686 

Lepidomelane 393 

Lepidophseite 534 

Lepierre,  C.,  fluorine  in  spring  waters 192 

Lepsius,  B.,  composition  of  dissolved  air 477 

Lepsius,  It.,  glaucophane  schists 591 

Lermondose .' 466 

Lesley,  J.  P.,  grahamite 720 

Lesquereux,  L.,  origin  of  petroleum 732 

Letheby,  H.,  water  analyses 106 

Letts,  E.  A.,  and  Blake,  R.  F.,  carbon  dioxide 

in  air 45 

Leube,  G. , dolomite 564, 565 

Leucite 368-371 

melting  point 292 

Leucite  basalt 459 

Leucite  rocks 447,459 

Leucite  syenite 447 

Leucitite 447 

Leucopyrite 688 

Leucoxene 349 

Leuk,  analysis  of  water 187 

Levat,  E.  D.,  gold  and  silver  in  diabase 629 

nickel  ores 695 

phosphate  rock 526 

Leverett,F.,  loess 509 

Leverrierite 393,611 

Levi,  M.  G.,  radioactivity  of  lava 315 

Levin,  M. , decay  of  uranium 317 

Levin,  M. , and  Ruer,  R. , radioactivity 314, 317 

Levings,  J.  H.,  gelatinous  silica  in  ore  bodies.  357 

Levison,  W.  G.,  decomposition  of  rocks 477, 481 

L6vy.  See  Miehel-L£vy;  Fouqud  and  Michel- 
L4vy. 

Levy,  A. , nitrogen  compounds  in  rain 50 

Levynite 416 

Lewin,  L.  See  Schweinfurth  and  Lewin. 

Lewis,  H.  C.,  origin  of  diamond 325 

Lewis,  J.  V.,  North  Carolina  corundum 339 

See  also  Pratt  and  Lewis. 

Lewisite 691 


Lewy,  H.,  analysis  by 199 

Lherzolite 463,464 

Libbey,  W. , volcanic  gases 269 

Liebenow,  C. , radioactivity 316 

Lieber , O . M. , itabirite 609 

Liebert,  H. , uranium  in  coal 710 

Liebisch,  T. , silver  antimonides 650 

Liebrich,  A. , bauxite 496, 497 

Lienau,H.,  bauxite 498 

Lignin 739 

Lignite 706,745-750 

Lignocellulose 739 

Lignone 739 

Lillianite 678 

Limburgite , fusibility 296 

Limburgose 459 

Limestone 548-559, 620-624 

average  composition 28 

formation  of 129-130 

Limnite 529 

Limonite 529-530,571-573 

Linarite 680 

Linek,  G. , associates  of  spinel 342 

oolite 553 

origin  of  clay 492 

origin  of  dolomite 560 

orthoclase  in  dolomite 622 

solubility  of  calcium  carbonate 129 

troilite 332 

Lincoln,  A.  T.  See  Kahlenberg,  L. 

Lincoln,  F.C.,  gold 646 

magmatic  gases 290 

Lindemann,  B.,  minerals  in  limestone 623 

Lindgren,  W.,  analcite  in  rocks 370, 449 

brochantite 663 

chalcocite 660 

fluorite  in  sinter 204 

magmatic  magnetite 346 

magmatic  waters  as  vein  fillers 213 

monazitesand 356 

native  copper 656 

Ojo  caliente 191 

ore  deposits 634,635 

orthoclase  as  a gangue  mineral 368 

pseudomorphous  galena 677 

sericite  and  calcite 594 

sodalite  syenite 375 

stibnite  in  sinter 689 

tin  deposits 686 

tungsten  ores 700 

Lindgren,  W.,  and  Hillebrand,  W.  F.,  corona- 

dite 534 

Lindgren,  W.,  and  Whitehead,  W.  L.,  jame- 

sonite 678 

Linnaeite 692,694 

Linosite 389 

Liparite 434 

Liparose 435,437,473 

Lipp,  A.,  analysis  by 184 

Lisboa,  A. , monazite  sand 356 

Litchfieldite 446 

Lithiophilite 687 

Lithium,  distribution 17 

in  sea  water 120 

Lithosphere,  average  composition 24-35 

volume  of 22 


INDEX. 


797 


Page. 

Little,  G.,  lead  selenide 677 

Little,  O . H.  See  Cole  and  Little. 

Liveing,  G.  D.,  cited 44 

Liversidge,  A., analyses  by 185, 696 

bog  iron  ore 532 

cobalt  ores 695 

coral 555 

distribution  of  silver 648 

gold  in  recent  pyrite 645 

in  sea  water 121 

in  rock  salt 641 

mercury  in  sinter 668 

precipitation  of  gold 648 

silver  in  sea  water 121 

solvents  of  gold 646 

Livingstonite 664,667 

Ljubavin,  N.,  cave  earth 253 

Ljusnan,  River,  analysis  of  water 103 

Lloyd,  S.  J.,  radium  in  sea  water 122 

Lloyd,  S.  J.,  and  Cunningham,  J.,  radium  in 

coal 741 

Loch  Baile  a Ghobhainn,  analysis  of  water...  93 

Locke,  J.  M. , uintaite 720 

Lockyer,J.N.,  cited 12 

Loebisch,  W.,  and  Sipocz,  L.,  water  analysis.  125 

Lollingite 335,688 

Loess. 509-511 

Loew,  O., analyses  by 82, 156, 160, 236 

Loewe,  L. , cited,  on  Stassfurt  salts 221 

Lowenstein,  H. , clays 500 

Loewinson-Lessing  F.,  average  composition 

of  igneous  rocks 26 

classification  of  igneous  rocks 425 

eutectics 423 

fractional  crystallization 312' 

magmatic  differentiation 298, 305, 308 

origin  of  volcanic  gases 280 

solubility  of  minerals  in  magmas 310 

Loewite 223,228 

Logan,  W.  E.,  and  Hunt,  T.  S.,  phosphatic 

shell 525 

Lohmann,  P . , eclogite 599 

Loire,  River,  analysis  of  water 94 

Lonar  Lake,  analysis  of  water 173, 176 

Long,  J.  H.,  cited 69 

Longbanite 691 

Lorandite 688 

Lord,  E.  C.  E.,  analysis  by 462 

Lord,  N.  W. , coal 750 

Lorenz,  N.  von,  water  analysis 96 

Lorenz,  R.,  synthesis  of  greenockite  and 

wurtzite 670 

synthesis  of  troilite 333 

Lorenzen,  J.,  graphite  in  basalt 328 

Loretz,  H . , iron  ores 575 

Losanitsch,  S.  M.,  chromiferous  clays 696 

Lossen,  C.,  itabirite 609 

quartzite 607 

Lossen,  K.  A.,  albite  alterations 594 

Lossenite 682 

Lossier,  L.,  water  analyses 94 

Lost  River,  analysis  of  water 86 

Lotti,  B . , copper  ores 659 

stibnite  and  cinnabar 689 

Louderback,  G.  D.,  radioactivity  and  vol- 

canism 317 


Page. 


Loughlin,  G.  F.,  clays 508 

Louisville  artesian  well,  analysis 186 

Lotz,  H.,  cited 483 

Lozinski,  V.  von,  chemical  denudation 149 

Lublinite 551 

Luca,  S.  de,  analysis  by 199 

Lucas,  A.,  chemistry  of  the  Nile 106 

natural  soda 239 

Lucas,  R . , physical  properties  of  clays 502 

Ludlamite 520 

Ludwig,  A.,  artificial  diamond 323 

Ludwig,  E.,  analyses  by 188, 191 

Ludwig,  F.,  analyses  by 104, 170,234 

Ludwig,  F.  J.  H.,  analysis  by 205 

Luedecke,  O.,  water  of  the  Oder 102 

Luedeking,  C.,  lead  chromates 681 

Luedeking,  C.,  and  Wheeler,  H.  A.,  barite.  580,581 

Luneburgite 250 

Lujavrose 444 

Lukens,  H.  S.,  scandium  in  wolfram 19 

Lunge,  G.,  cited,  on  Stassfurt  salts 226 

natural  soda 239 

Lunge,  G.,  and  Millberg,  C.,  solubility  of 

quartz 363 

Lunge,  G.,  and  Schmidt,  R.  E.,  analysis  by. . 187 

.Lunn,  A.  C.,  internal  temperature  of  the 

earth 291 

Lunquitz,  E.  E.,  gold  sands 648 

Lupton,  N.  T.,  analysis  of  water,  cited 78 

Lutecite 357 

Lutecium 17,21,711 

Luz,  A.,  bauxite 499 

Luzi,  W.,  corrosion  of  diamond 325 

formation  of  graphite 327 

Lyell,  C.,  precipitated  calcium  carbonate 549 

Lyons,  A.  B.,  copper  in  lava 629 

soils 508 

M. 

Mabery,  C.  F.,  natural  gas 714 

petroleum 716, 717, 718, 719, 730 

See  also  Robinson,  A.  E. 

Mabery,  C.  F.,  and  Byerly,  J.  H.,  byerlite. . . 721 

Mabery,  C.  F.,  and  Hudson,  E.  J.,  petro- 
leum  716,717,718 

Mabery,  C.  F.,  and  Palm,  O.  H.,  Ohio  petro- 
leum  717 

Mabery,  C.  F.,  and  Quayle,  W.  O.,  petro- 
leum  716,718 

Mabery,  C.  F.,  and  Smith,  A.  W.,  Lima  oil. . 718 

Mabery,  C.  F.,  and  Takano,  S.,  Japanese  pe- 
troleum   716 

MacAlister,  D.  A.  See  Hill  and  MacAlister. 

Macallum,  A . B . , cited 127 

MacBride,  T.  H.,  peat 745 

McCaleb,  J.  F.,  cited 227 

McCalley , H . , bauxite 497 

McCallie,  S.  W.,iron  ores 530,575 

limestones 557 

phosphate  rock 528 

waters  of  Georgia 63 

McCaughey,  W.  J.,  solubility  of  gold 647 

McClelland  well,  analysis 191 

McConnell,  W. , gases  in  coal 759 

McCourt,  W.  E.,  and  Parmelee,  C.  W.,  peat.  745 

McCreath,  A . S . , coal  analyses 753 


798 


INDEX. 


Page. 

Mac6, , synthesis  of  anglesite 680 

Macfarlane,  W.  See  Ebaugh  and  Macfarlane. 

McGee,  W J,  bitumens 735 

laterite 493 

loess 509 

Mcllheney,  P.  C.,  solvent  of  gold 646 

McIntosh,  D . See  Eve,  A.  S. 

Mclvor,  R.  W.  E.,  guano  phosphates 520 

maldonite 644 

McKee,  R.  EL,  mass  of  atmosphere 54 

McKenzie,  J.  D.,  blairmorite 449 

primary  analcite 371 

Mackie,  W.,  allanite  in  granite 408 

analyses  of  clays 507 

analyses  of  sand 504 

calcium  fluoride  as  cement 539 

on  age  of  the  earth 149 

sandstones 541 

Mackintosh,  J.  B.  See  Hidden  and  Mackin- 
tosh. 

Mackintoshite 712 

Maclaren,  J.  N.,  gold  and  silver  in  sinter 207, 646 

hot  springs  of  New  Zealand 213 

Maclaren,  M.,  laterite 494 

Maclaurin,  J.  S.,  cited,  on  New  Zealand 

spring  waters 196, 200 

mine  waters 631 

McLennan,  J.  C.,  and  Kennedy,  W.  T.,  radio- 
activity   317 

McNaim,  W.  H.,  apatite 523 

Macomb  deep  well,  analysis  of  water 193 

Mactear,  J.,  mercury  ores 664 

Madupite 447 

Madupose 447 

Maey , E . , silv  er  antimonide 650 

Magdeburgose 435,436,437 

Magma,  temperature  of 291-296 

Magmatic  assimilation 309, 310 

Magmatic  differentiation 307-313 

Magmatic  dissociation 299 

Magmatic  solutions 298-300 

Magmatic  stoping 310 

Magmatic  waters 634 

Magnenat  and  Wooten,  analyses  by 747 

Magnesioferrite 341 

Magnesite 414,417,564 

Magnesium,  distribution 17 

Magnetite 344-346 

Magnetite  basalt 346, 468 

Magnetite  spinellite 467 

Magnetite  syenite 469 

Magnochromite 697 

Hahanuddy  River 105 

Mahler,  O.,  cal  cite  and  dolomite 562, 564 

Main,  River,  analysis  of  water 97 

Majima,  M.  See  Yamashita  and  Majima. 

MajoraDa,  Q.,  diamond 323 

Makin,  C.  J.  S.,  analysis  of  sea  water 123 

Malacca,  Straits  of 125 

Malachite 663,741 

Malaguti,  Durocher  and  Sarzeaud,  silver  in 

sea  water 121 

Malbot,  H.,  and  A.  phosphorite 525 

Malcolmson,  J.  W.  See  Kirk  and  Malcolm- 
son. 

Maldonite... 644 


Page. 

Malheur  Lake,  analysis  of  water 161, 176 

Malignose 445 

Malkomesius,  P.,  and  Albert,  R.,  Cassel 

brown 748 

Mallard,  E .,  cristobalite 357 

lead  oxychlorides 680 

Mallet,  F.  R.,  Indian  corundum 339 

laterite 493 

lateritic  manganese 534, 535 

on  langbeinite 224 

Mallet,  J.  W.,  allanite 712 

analysis  by 207 

gases  from  meteorites 287 

silver  in  volcanic  ash 271, 628 

Maltha 720 

Manchot,  W.,  ilmenite 349 

Mangandolomite 573 

Manganese,  distribution 18 

in  sea  water 121 

ores  of 533-536 

Manganese  nodules 132, 133 

Manganite 533 

Manganosite 533 

Manitoulin  Island,  analysis  of  water  from 185 

Manjak 721 

Manley,  J.  J.  See  Gunther,  R.  T. 

Mann,  P.,  alteration  of  titanite 350 

constitution  of  pyroxenes 383 

Manouschek,  O.  See  Donath  and  Manou- 
schek. 

Manross,  N.  S.,  asphalt 721 

synthesis  of  apatite 354 

of  lead  ores 680,681,682 

of  scheelite 699 

Marcano,  V.  See  Muntz,  A. 

Marcasite 334 

Marck,  W.  von  der,  analysis  of  sandstone. . 538, 539 

Marckwald,  W.,  radioactivity 320 

uranium  ores 707 

Marcus,  E .,  salt  clay 222 

Marcus,  E .,  and  Biltz,  W.,  Stassfurtsalt  clay  222, 705 
See  also  Biltz  and  Marcus. 

Marcusson,  J.,  artificial  petroleum 725 

origin  of  petroleum 730 

optical  activity  of  petroleum 735 

Mare  Morto,  analysis  of  water 125 

Margarite 393 

Margarodite 391 

Margottet,  J.,  reduction  of  silver  sulphide — 649 

synthesis  of  argentite 650 

See  also  Hautefeuille  and  Margottet. 

Marialite 403-405,600 

Maricose 464 

Marienquelle,  analysis  of  water 184 

Marignac,  C.  de,  synthesis  of  dolomite 559 

Marigny,  F.  D.,  Algerian  waters 66 

synthesis  of  bomite 658 

synthesis  of  galena 676 

Marl 550 

Marmora,  Sea  of,  analysis  of  water 124 

Marsden,  R.  S.,  artificial  diamond 323 

formation  of  crystalline  silica 358 

Marsh  gas 729, 757, 758 

Marshite 662 

Marsilly, , analysis  of  peat 743 

Martens,  P. , Chilean  thermal  waters. ........  252 


INDEX, 


799 


Page. 

Martin,  K. , phosphate  rock 521 

Martin,  W.  J. , platinum  ores 700 

Martinite 520 

Masing,  E.,  synthesis  of  anglesite 680 

Mason,  W.  P.,  analysis  by 191 

Massicot 679 

Massol,  G. , helium  in  spring  water 180 

Matthews,  E.  B.,  classification  of  rocks 433 

Matildite 653,654 

Matlockite 680 

Matson,  G.  C.,  phosphorite 527 

Matteucci,  R.  V.,  volcanic  ammonium  chlo- 
ride  272 

Matthews , W . D . , phosphatic  nodules 525 

Maucherite 692 

Maumee  River,  analysis  of  water 70, 107 

Maumen6,  E . , manganese  in  sea  weeds 121 

Mauritz,  B . , synthetic  wollastonite 378 

Mauzeliitel 691 

Mawson,  D.,  carnotite 710 

Mawson,  D.,  and  Cooke,  W.  T.,  phosphates 

from  guano 522 

Mawson,  D.,  and  Laby,  T.  H.,  radioactivity 

of  minerals 315 

Maxwell,  W.,  Hawaiian  lavas  and  soils.  493, 494, 499 

Mayengon , , artificial  galena 677 

sulphides  formed  in  burning  coal  mine. . 689 

Mayr,  F.  See  Simmersbach  and  Mayr. 

Mayrhofer,  J.,  cited 101 

Mead,  W.  J.,  average  composition  of  igneous 

rocks 24 

bauxite 498 

relative  proportions  of  sedimentary  rocks . 32 

Meadows, T.  C.,  and  Brown,  L.,  phosphorite . 526 

Mecca,  holy  well  at,  analysis  of  water 197 

Mediterranean  Sea,  analysis  of  water 124, 218 

Medve  Lake 172 

Mehu,  M.  C.,  synthesis  of  cinnabar 665 

Meigen,  W.,  calcite  and  aragonite 551, 552 

calcium  carbonate  as  precipitant  of  metals  64 1 

dolomite 560 

laterite 494 

Meionite 403-405, 601 

Melanite 401 

Melanochroite 681 

Melanotekite 683 

Meldrum,  R.,  solubility  of  copper 656 

Melilite 398-400 

Mellite 741 

Mellor,  J.  W.,  clay  silicates 493,611 

Melnikorite 334 

Meionite 692 

Melting  points  of  minerals 292-296 

Melvill,  E.  H.  V.,  diamonds 325 

Melville,  W.  H.,  analyses  by 160, 186, 

197, 450, 541, 546, 592, 606, 610, 668, 689 

glaucophane  rock 591 

josephinite 330 

Menaccanite 348 

Mendel4ef,  D.,  origin  of  petroleum 726 

periodic  classification 37 

Mendipite 680 

Meneghinite 678 

Mennell,  F.  P.,  average  composition  of  igne- 
ous rock 26 

laterite. 494 


Page. 

Merawoe  River,  analysis  of  water 105 

Mercury,  distribution 18 

ores  of 664-669 

Merensky , H . , diamonds 325 

Merian,  A.,  constitution  of  pyroxenes 383 

Merivale,  W. , manjak 721 

Merrill,  F.  J.  H.,  gypsum 576 

Merrill,  G.  P.,  analyses  by 487 

asbestos 384 

cave  gypsum 229 

disintegration  of  rocks 481, 484, 487, 488, 489 

gold  in  granite 332,642 

meteorites 37,700 

onyx  marble 549 

serpentine 384,602,603 

Merrill,  J.  A.,  flint 543 

Merrimac  River,  analysis  of  water 71 

Merwin,  H.  E.  See  Hillebrand,  Merwin,  and 
Wright. 

Merz , A . R . , and  Gardner,  R . F . , analyses  by . 233 

Merz,  C.,  water  analysis 97 

Mesitite 417,571 

Mesolite 416 

Metabrushite 520 

Metachlorite 397 

Metacinnabarite 664-669 

Metahewettite 710 

Metallic  ores 626-712 

Metamorphic  rocks 583-625 

Metastibnite 688,689 

Meteorites,  average  composition 39-40 

diamonds  in 324 

gases  from 237 

hydrocarbons  in 728 

Metzer,  C.,  water  analysis 101 

Meunier,  S.,  analysis  by 185 

bauxite 496 

carbon  in  meteorite 728 

composition  of  fossil  plants 751 

origin  of  petroleum 727 

of  platinum 703 

planetary  atmospheres 54 

synthesis  of  anorthite 365 

synthesis  of  brochantite 663 

of  chromite 344,697 

ofenstatite 376 

ofleucite 369 

of  nephelite 372 

of  olivine 390 

of  phcenicochroite 681 

of  spinel 342 

of  tridymite 359 

tin  in  sinter 206,684 

troilite 332 

volcanic  explosions 297 

See  also  Daubr6e  and  Meunier. 

Meuse,  River,  analysis  of  water 94 

Mexico,  Gulf  of 123 

Meyer,  E .,  von,  gases  in  coal 759 

Meyer,  J. , gases  in  coal 760 

Meyer,  O . , calcite  and  dolomite 564 

Meyerhoffer,  W. , phase  rule 304 

See  also  Van’t  Hoff  and  Meyerhoffer. 

Miami  River,  analysis  of  water 78 

Miagyrite 653,654 

Miaskose 444, 450 


800 


INDEX. 


Page. 

Micas 391-396 

Mica  schist 614-617 

Michael , P . , saussur  ite  gabbro 595 

Michel,  L.,  bismuth  in  molybdenite 698 

synthesis  of  azurite 663 

of  lead  ores 682 

ofmelanite 402 

of  minium  and  plattnerite 679 

of  powellite 698 

of  rutile 351 

oftitanite 350 

of  tungsten  minerals 699 

Michel-L6vv,  A.,  magmatic  differentiation.  310,311 

minerals  in  sand 503 

primary  epidote 407 

quantitative  classification 433 

scapol  ite  gabbro 596 

Michel-L^vy,  A.,  and  Lacroix,  A.,  envelop- 
ment of  allanite 408 

Michel-Ldvy,  A.,  and  Munier-Chalmas,  E., 

chalcedony 357 

Michigan,  waters  of 70 

Michigan,  Lake,  analysis  of  water 69 

Microcline 363-368 

Micrometric  analysis  o f rocks 475 

Micro-organisms  in  coal  formation 763 

Micropegmatite,  as  an  eutectic 302 

Microsommite 374 

Middlemiss,  C.  S.,  Indian  corundum 339 

Miersite 655 

Mikhailovsky,  G.  P.,  origin  of  naphtha 734 

Miklucho-Maclay,  M.  von,  occurrence  of  cas- 

siterite 353 

Milch,  L.,  glaucophaue  rocks 591 

quantitative  classification 433 

Milford,  L.  R.,  cited 186 

Millar,  C.  C.  H.,  phosphates 526 

Millberg,  C.  See  Lunge  and  Millberg. 

Mille  Lacs  Lake,  analysis  of  water 76 

Miller,  A.  M.,  phosphatic  fossils 525 

Miller,  B.  L.,  graphite 328 

Miller,  N.  H.  J.,  composition  of  rain  water.  45, 50, 52 

Miller,  W.  G.,  cobalt  ores 694 

corundum  anorthosite 339 

limestone 557 

nickel  in  magnetite 345 

Miller,  W.  G.,  magmatic  assimilation 310 

Millerite 692, 693, 694, 741 

Mills,  J . E . , geological  work  o f ants 485 

Milosin 696 

Mimetite 682 

Minasragrite 707 

Minervite 521,522 

Minette 442 

Minette  (iron  ore) 575 

Mine  waters 631-633 

Mineral  waters,  classification 174-177, 180-181 

Mingaye,  J.  C.  H.,  analysis  by 193 

cave  phosphates 522 

mine  water 631 

platinum 703,704 

vanadium  in  clay 705 

Minium 679 

Minnesota  River,  analysis  of  water 76 

Minnetonka,  Lake,  analysis  of  water 76 

Minor,  J.  C.  See  Penfield  and  Minor. 


Page. 

Minssen,  H.,  and  Tacke,  B.,  solubility  of 


calcium  phosphate 519 

Mirabilite 172, 227, 234, 247, 249, 251, 255 

Miser,  H.  D.,  Arkansas  diamonds 325 

Mispickel 688 

Missouri  River,  analyses  of  water 79 

Missourite 447 

Mississippi  River,  analyses  of  water 75 

chlorine  in 109 

sedimentation  in , , . . 505 

silt 505 

Mittagong  chalybeate  spring,  analysis 193 

Mitchell, , water  analysis  cited 169 

Mitchellite 697 

Mixite 662 

Mizzonite 404 

Moricke,  W.,  gold  in  pitchstone 332, 642 

Mofettes 262 

Mohawkite 658 

Mohawk  River,  organic  matter  in 107 

Mohr,  E.  C.  J.,  laterite 494 

rivers  of  Java 105 

Moissan,  H.,  analyses  of  volcanic  gases 268 

carborundum  in  meteorite 326 

graphite  in  native  iron 328 

melting  point  of  corundum 336 

metallic  carbides 723 

on  diamond 323,324 

origin  o f petroleu  m 727 

origin  of  volcanic  activity 281 

volatility  of  metallic  oxides 272, 273 

See  also  Becquerel  and  Moissan. 

Moitessier,  A . , artificial  dolomite 561 

Moldau  River,  analysis  of  water 98 

Moldenhauer,  F.,  analysis  by 97 

the  Dead  Sea 169 

Molengraaf,  G-  A.  F.,  cordierite  vitrophyrite.  405 

Molengraaf , P . F .,  cassiterite 687 

Molybdenite 335,698,741 

Molybdenum,  distribution 18 

in  mine  water 631 

ores  of. . . 698 

Molybdic  ocher 698 

Molybdophyllite 683 

Molybdosodalite 373 

Monazite 355,356,712 

Monchiquite 450 

Monchiquose 450 

Monckton,  G.  F.,  mercury  deposits 668 

Monetite 520 

Monke,  H.,  and  Beyschlag,  F.,  origin  of 

petroleum 730 

Monmouthite 446 

Mono  Lake,  analysis  of  water 160, 177 

Monongahela  River,  analysis  of  water 78 

Montesano  Springs,  analysis 183 

Monticellite 389 

Montmorillonite 415,500,611 

Montroy  dite 664 

Monzonite 451,452 

Monzonose 440,452,456 

Moore,  C.  C.,  barytic  sandstones 539 

sandstones 541 

Moore,  E.  J.,  bog  iron  ore - 530 

Moore,  E.  S.,  siliceous  oolites 544 

Moore,  G.  E.,  analysis  by 197 


INDEX. 


801 


Page. 

Moore,  R.  B.,  and  Kithil,  K.  L.,  uranium- 


vanadium  ores 709 

Moosehead  Lake,  analysis  of  water 71 

Morawsky,  T.  See  Schinnerer  and  Morawsky. 

Mordenite 416 

Moreing,  C.  A.,  manganese  ores 535 

Morenosite 694 

Morey,  G.  W.,  and  Niggli,  P.,  hydrothermal 

syntheses 586 

Morley,  E.  W.,  variations  in  atmospheric 

oxygen 42,43 

Morlot,  A.,  von,  sand  calcites 537 

synthesis  of  dolomite 560 

Morozewicz,  J.,  alteration  of  diorite 488 

analysis  by 467 

artificial  feldspars 365 

composition  of  nephelite 372 

formation  of  acmite 380 

of  augite 382 

of  corundum 337-339 

of  enstatite 377 

of  hematite 347 

ofiolite 338,405 

of  magnetite 345 

ofmelilite 399 

of  mica 394 

of  nephelite 373 

of  quartz  and  tridymite 361 

of  sillimanite 410 

of  spinel 338 

lagoriolite 401 

gravitative  adjustment  in  magmas 312 

syntheses  of  noselite,  haiiynite,  and  soda- 

lite 375 

of  pyroxenes 377,379 

solubility  of  alumina  in  magmas 305 

Morrey,  C.  B.,  origin  of  petroleum 734 

Morse,  H.  W.,  gases  in  fluorite 335 

Morton,  E.  H.  See  Thorpe,  T.  E. 

Moses,  A.  J.,  mercury  minerals 665 

Moses,  O.  A.,  phosphate  rock 526 

Moses  Lake,  analysis  of  water 162, 176 

Mosesite .?i.- - 664, 665 

Moss,  E . L . , on  Arctic  air 46 

Mottramite 706 

Moulton,  F.  R.,  internal  temperature  of  the 

earth 291 

Moureu,  C.,  and  Biquard,  R.,  argon  and 

helium  in  waters 180 

radioactivity  of  waters 180 

Moureu,  C.,  and  Lepape,  A.,  helium  in  spring 

waters 319 

Mourlot,  A.,  vanadium  in  coal 706 

Mrazec,  L.,  petroleum 731 

Mrazec,  L.,  and  Teisseyre,  W.,  Roumanian 

salts 172 

salt  lakes  of  Roumania 234 

Mrha,  J . , kelyphite 403 

Muchin,  J.,  von,  analyses  by 701 

Muck,  F.,  constitution  of  coal 764 

Muck,  J.,  ozokerite 719 

Muds,  oceanic 512-514 

Miigge,  O.,  calcite  and  aragouite 551 


Page. 


Miigge,  O.,  fluorite  as  cement 539 

forms  of  silica 360 

lublinite 551 

occurrence  of  perofskite 350 

scapolite  amphibolite 597 

transition  of  quartz 360 

Miilhauser,  O.,  artificial  graphite 326 

Muller,  E.,  water  analysis 101 

Muller,  H.,  mine  water 632 

Muller,  R.,  solubility  of  minerals 355, 478, 519 

Muller , W . , artific  ial  magnetite 345 

Muller,  W.  J.  See  Konigsberger  and  Muller. 
Muller,  W.  T.,  and  Konigsberger,  J.,  hydro- 

thermal  syntheses 586 

Muellerite 520 

Munster,  C.  A.,  gold  in  sea  water 121 

Munster,  bauxite. 496 

Mumford,  E.  M.,  iron  bacteria 530 

Munroe,  C.  E.,  artificial  hematite 347 

Muntz,  A.,  atmospheric  transport  of  salt 52 

bacterial  decomposition  of  rocks 485 

bromine  in  Chilean  niter 256 

nitrates  in  the  Nile 106 

origin  of  nitrates 257 

Muntz,  A.,  and  Aubin,  E.,  oxygen  of  the 

atmosphere 42 

Muntz,  A.,  and  Lain6,  E.,  nitrates  in  the  at- 
mosphere  51 

Muntz,  A.,  and  Marcano,  V.,  black  waters  of 

South  America 90 

cave  nitrates 253 

nitric  acid  in  rainfall 50 

Murdoch,  J.  See  Graton  and  Murdoch. 

Murdoch,  J.  A.  W.,  atacamite ...  662 

Murgoci,  G.  M.,  amphiboles 387 

glaucophane  schists 591 

riebeckite  rocks 389 

Murray,  Sir  J.,  chemical  reactions  on  ocean 

floor 131 

oceanic  carbonic  acid 144 

origin  of  manganese  nodules 132 

saline  matter  in  rivers 112 

total  annual  rainfall  and  run-off 58 

volume  of  the  ocean 22 

Murray,  J.,  and  Irvine,  R.,  ammonia  in  sea 

water 120 

calcium  carbonate  in  sea  water 128 

discharge  of  rivers 127 

formation  of  siliceous  ooze 515 

maintenance  of  marine  life 147 

manganese  nodules 132 

re-solution  of  c oral  rock 128 

secretion  of  lithe  salts  by  marine  animals.  130 

sediment  in  sea  water 506 

silica  in  sea  water 120 

Murray,  J.,  and  Renard,  A.  F.,  deep-sea  de- 
posits  130, 131, 132, 134, 511 

glauconite 135,516 

oceanic  sediments 511,512 

phosphatie  nodules 134, 524 

solubility  of  silica 130 

Murray,  R.  M.,  the  Dead  Sea 169 

Muscovite 391-396,600 


97270°— Bull.  616—16 51 


802 


INDEX. 


Page. 

Muskingum  River,  analysis  of  water 78 

Muthmannite 644 

N. 

Naab  River,  analysis  of  water 101 

N acken , R . , synthesis  of  apatite 355 

Nadorite 683 

Nagyagite 676 

Nahe,  River,  analysis  of  water 97 

N ahnsen , M . , dolomite 569 

N ant  ier , A . , phosphorite 528 

Nantokite 662 

Napalite 719 

Naphtenes 716 

Naphthalene 717,718 

Naschold,  W.  See  Hauessermann  and 
Naschold. 

Nasini,  R.,  origin  of  boric  acid 245 

See  also  Perrone  and  Nasini. 

Nasini,  R.,  and  Anderlini,  F.,  analysis  by. . 184 

Nasini,  R.,  Anderlini,  F.,  and  Salvadori,  R., 

fumarole  gases 180, 245, 264 

Nasini,  R.,  and  Levi,  M.  G.,  radioactivity  of 

lava 315 

Nasini,  R.,  Levi,  M.  G.,  and  Ageno,  F.,  water 

analysis 188 

Nason,  F.  L.,  Franklin  zinc  ores 676 

iron  ores 575 

scapolite  rocks 597 

Nasonite 676,683 

Nastukofl,  A.,  cellulose 738 

Natrolite . 416 

Natron 162,239,247 

Natron  Lake,  analysis  of  water 173 

Natterer,  K.,  ammonia  in  sea  water 120 

analyses  of  water 124, 169 

carbonates  in  sea  water 144 

diffusion  of  salts 174 

marine  muds 515 

potash  in  marine  sediments 139 

Natural  gas 714,715 

Naumannite 652,676 

Navarro,  F.,  native  iron 328 

Neagh,  Lough,  analysis  of  water 93, 107 

Nebular  hypothesis 139-140 

Negro,  Rio,  analysis  of  water 91,107 

Nelson,  J.  L.,  analysis  by 385 

Nelson  River,  analysis  of  water 87 

Nelsonite 468 

Nelsonose 468 

N endtwich, , analysis  by 746 

Nentien, , antimony  ores 689 

Neodymium 18,711 

Neon 18,41 

N eosho  River , analysis  of  water 81 

Nephelite 371-373,600 

Nephelite  basalt 459 

Nephelite  rocks 443,446 

Nephelite  syenite 445 

Nepouite 695 

Nesquehonite 563 

Nessler.  See  Petersen  and  Nessler. 

Neuberg,  C.,  origin  of  petroleum 730 

Neumann,  P.,  diamonds  in  iron 324 

Neuse  River,  analysis  of  water 72 

Nevadite 434 


Page. 

N evius , J.  N . , tin  deposits 685 

Nevyanskite 700 

Newberry,  J.  S.,  bog  iron  ore 530 

cannel  coal 751 

origin  of  petroleum 733 

ozokerite 719 

Newbery,  J.  C.,  gold  in  iron  ore 645 

Newberyite 521 

N ew land , D . H . , iron  ores 469 

N ewland , D . H. , and  Leighton,  H. , gypsum. . 232 

Newsom,  J.  F.  See  Branner  and  Newsom. 

N ewton,  W . , origin  of  nitrates 257 

Newtonite 415,611 

New  Zealand  geysers,  analyses  of  waters. . . 196, 200 

sinter  from 207 

Niccolite 652,692,694 

Nichols,  H.  W.,  cave  nitrates 253 

corals  and  crinoids 555, 565 

sand  barites 538 

N icholson , E . , analysis  of  water 105 

Nickel,  distribution 18 

in  ashes  of  sea  weed 121 

ores  of 691-696 

Nickel-iron,  native 330,331 

N icolardot , P . , hydroxides  of  iron 531 

Niederstadt,  K.,  Meigen’s  reaction 552 

Niggli,  P. , gas  mineralizers 290 

hydrothermal  syntheses 586 

metamorphic  rock  series 588 

See  also  Johnston  and  Niggli;  Morey  and 
Niggli;  Schlaeppfer  and  Niggli. 

Nile  River,  analysis  of  mud 505 

analyses  of  water 106, 107 

sedimentation  in 115, 505, 506 

Niobium.  See  Columbium. 

Nishihara,  G.  S.,  secondary  enrichment 662 

Niton 18,315 

Nitrate  deposits 253-259 

Nitric  acid  in  rainfall 50 

N itrogen , distribution 18 

in  sea  water 120 

proportions  in  the  atmosphere 41 

volcanic 272 

Nitrogen  bases  in  petroleum 718 

Nitroglauberite 254,255 

Nitze,  H.  B.  C.,  iron  ores 575 

monazite 356,712 

Nivenite 707,708,712 

Nivoit,  E .,  phosphate  rock 519 

Nocerite 271 

Noeggerath,  J.  J.,  pyromorphite  in  slag 682 

Noellner,  C.,  origin  of  nitrates 257 

Noelting,  J.,  zinc  blende 669 

Noir,  Lac 95 

Noll,  J.C.,  cited 97 

Nontronite 491 

Nordenskiold,  A . E . , carbon  in  meteorite ....  728 

native  iron  in  Greenland 328 

uranium  in  coal 710 

Nordenskioldine 684,686 

N ordmarkite 439 

Nordmarkose 439,445 

Norite 462 

North  Platte  River,  analysis  of  water 79 

Northupite 247 

Norton,  J.  H.,  cited 80 


INDEX. 


803 


Page. 

Norzi,  G.,  see  Porlezza  and  Worzi. 

Nosean.  See  Noselite. 

Nosean  sanidinite 448 

Noselite 374-375 

Noumeite 695 

Novaculite 542,544 

Noyes,  W.  A.,  analyses  by . . . . 69, 70, 76, 87, 189, 487 
Nutter,  E.  H.,  and  Barber,  W.  B.,  glauco- 

phane  rocks 591 

Nutting,  P.  G.,  uranium  and  solar  spectrum.  319 
N yholm , E . T . See  Ramsay  and  N yholm . 


O. 

Oak  Orchard  acid  spring,  analysis 198 

Obalski,  J.,  uranium  in  pegmatite 710 

Obsidian 435 

Occlusion  of  gases  in  rocks 274-285 

Ocean,  age  of 148-150 

composition  of 23 

elements  in 119-122 

gases  in 141-147 

influence  of  living  organisms  on 147 

the  primeval 140 

volume  of 22 

Ocean  water,  carbonates  in 128-130 

changes  in  composition  due  to  freezing. . . 126 

concentration  of 122-126 

density  and  salinity  of 122-126 

Oceanic  salts,  composition  of 23,122-128 

volume  of 24 

Oceanic  sediments 130-138,511-515 

Ochers  as  spring  deposits 204, 205 

Ochrolite 683 

Ochsenius,  C.,  average  composition  of  igneous 

rock 26 

cited,  on  Stassfurt  salts 220, 221 

on  Great  Salt  Lake 155 

origin  of  alkaline  carbonates 242 

of  borates 252 

of  petroleum 731 

of  salt  beds 220-221 

saltpeter  deposits 254, 258 

Ocmulgee  River,  analysis  of  water 73 

Oconee  River,  analysis  of  water 73 

Octahedrite 350-352 

Oden,  S.,  organic  matter  of  soils : 108 

Oder,  River,  analysis  of  water 102 

Oebbeke,  K.,  glaucophane  rocks 388,591 

Oehmichen,  H.,  chalcanthite 663 

Ogden  River,  analyses  of  water 156 

Oil  shale 740 

Ojo  Caliente,  analysis  of  water 191 

Okechobee,  Lake,  analysis  of  water 73 

Okenite 416 

Oklahoma,  river  waters 80 

Oldham,  R.  D.,  laterite 493 

Old  Wives  Lake,  analysis  of  water 163,174 

Olefines 716 

Olette  Springs,  analysis 195 

Oligoclase 364 

Olivenite 662 

P Olivier,  V.,  Chilian  nitrates 254 

Olivine 389-391 

Om,  River,  analysis  of  water 104 

Omak  Lake,  analysis  of  water 162, 176 

Omeose 437 


Page. 

Omphacite 598,599 

Onega,  Lake,  analysis  of  water 104 

Onofrite 664 

Onyx  marble 549 

Oolite,  calcareous 550, 553 

Oolite,  siliceous 544 

Oolitic  sand 550,558 

Oostanaula  River,  analysis  of  water 74 

Opal 357-363 

Ophicalcite 622 

Ophiolite 603 

Ordonez,  E . , petroleum 727 

Organic  matter  in  rock  decomposition 483-484 

Organic  matter  in  waters 107, 210 

Orpiment 688,689 

Orthite 406 

Orthoclase 363-368,600 

Orthogneiss 618 

Ortlieb,  J.,  ciplyte 523 

Orton,  E.,  dissemination  of  petroleum 735 

origin  of  petroleum 730 

spore  cases  in  coal 763 

Osage  River,  analysis  of  water 81 

Osann , A. , classification  of  igneous  rocks 425 

holmquistite 388 

rock  diagrams 475 

Osmium 18,700-704 

Osteolite 520 

Oswegatchie  River , analysis  of  water 70 

Ottawa  River,  analysis  of  water 70 

Otten,  F.  K.,  river  waters 166 

Ottrelite 393,395,612 

Ottrelite  schist 613,614 

Outwater,  R. , analysis  of  water 72 

Ovenstone 606 

Ovitz,F.  K.  See  Porter  and  Ovitz. 

Owens  Lake,  analysis  of  water 160, 177 

soda  from 239 

Owens  River,  analysis  of  water 160 

Owyhee  River,  analysis  of  water 85 

Oxygen,  concentrated  by  solution 49 

distribution 18 

proportions  in  the  atmosphere 42 

solubility  in  salt  water 143 

Ozokerite ' 719,734 

Ozone  in  atmosphere 43 

P. 

Pack,  J.  W.,  gold  in  sea  water 122 

Packard , R . L. , analysis  by 487 

Pagenstecher,  J.  S.  F.,  water  analyses 97 

Pahua  Spring,  analysis 183 

Paigeite 684 

Palache,  C. , crossite 388 

See  also  Jaggar  and  Palache;  Lawson  and 
Palache;  Ransome  and  Palache. 

Palic  Lake,  analysis  of  water 176 

Palladium 18,700-704 

Palladium  gold 644, 700, 703 

Palm,  O.  H.  See  Mabery  and  Palm. 

Palmer,  A.  W.,  chlorine  in  river  waters 109 

Palmer,  C.,  alkali  determinations 68 

analyses  by 70, 71, 72, 73, 74, 75, 76, 78, 79, 82 

composition  of  crinoids 565 

diatoms  in  peat 211 


804 


INDEX. 


Page. 

Palmer,  C.,  interpretation  of  water  analyses. . 63 

sulphides  of  nickel 692 

Palmer,  C.,  and  Bastin,  E.  S.,  precipitation 

of  silver  and  gold  by  ores . . 648, 651, 652 

Palmerite 522 

Palmier ite 271,681 

Panebianco,  G.,  Meigen’s  reaction 552 

Pandermite 248 

Pantanelli,  D . , origin  of  petroleum 730 

Papagayos , Rio  de  los,  analysis  of  water 92 

Papa vasiliu,  S.  A.,  emery 340 

Pappe,  A.,  and  Richmond,  H.  D.,  water 

analysis 173 

salt 231 

Paraffin  series 714 

Paragonite 392,395,600 

Paragneiss 618 

Paralaurionite 680 

Paramo  de  Ruiz,  hot  spring,  analysis 199 

Parana,  River,  analysis  of  water 91 

Pargasite 384 

Parinacochas,  Lake,  analysis  of  water 164, 174 

Park,  J.,  mercury  ores 668 

Parker,  E . G. , absorption  by  soils 501 

Parker,  H.  N.,  and  Bailey,  E.  H.  S.,  waters 

of  Kansas 68 

Parmelee,  C.  W.  See  McCourt  and  Parmelee. 
Parmentier,  F.,  alumina  in  mineral  waters. . 496 

synthesis  of  quartz  and  tridymite 359 

Parr , S . W . , classification  of  coals 756 

Parry , J . , gases  in  iron 287 

Par  sons , A . L . , gypsum 232 

peat 745 

Paschen,  F.,  heat  of  radium 314 

Pascoite 707 

Passarge,  S.,  laterite 493 

Patronite 706 

Patten,  H.  E.,  and  Waggaman,  W.  H.,  ab- 
sorption in  soils 501 

Patton,  H.  B.,  formation  of  tourmaline 413 

Pay en , A . , Tuscan  f umaroles 245 

Pearce,  R. , solvent  of  gold 647 

uraninite 707 

Pearceite 653 

Pearl  River,  analysis  of  water 74 

Peat 742-745 

cupriferous 657 

diatoms  in 211 

Pecher,  F.,  cited 101 

Peckham,  S.  F.,  albertite 720 

origin  of  petroleum 733 

petroleum 718 

Peckham,  S.  F.  and  H.  E.,  sulphur  in  petro- 
leum  Ti 718 

Pecos  River,  analysis  of  water 82 

Pectolite 378,416 

Peedee  River,  analysis  of  water 73 

Peganite 520 

Pegmatite 434 

Peile , W . , bauxite 497 

Peipus,  Lake,  analysis  of  water 104 

Pekatjangan,  River,  analysis  of  water 105 

Pelabon,  G. , jamesonite  and  zinkenite 678 

Pelican  Lake,  analysis  of  water 162, 176 

Pelikan,  A.,  analcite  phonolite 371 


Page. 

Pellini,  G.,  and  Quercigh,  E.,  tellurides  of 


gold 645 

tellurides  of  silver 653 

Pemberton,  H.,  and  Tucker,  G.  P.,  water 

analyses 163 

Pencatite 570 

Penfield,  S.  L.,  analyses  by 712 

caesium  beryl 413 

sulphohalite 247 

See  also  Dana  and  Penfield;  Genth  and 
Penfield;  Iddings  and  Penfield; 

Wells  and  Penfield. 


Penfield,  S.  L.,  and  Foote,  H.  W.,  composi- 
tion of  tourmaline. 413 

magnesia  in  ilmenite 348 

Penfield,  S.  L.,  and  Forbes,  E.  H.,  fayalite 

in  granite 391 

Penfield,  S.  L.,and  Ford,  W.  E.,  sand  calcite..  537 

Penfield,  S.  L.,  and  Jamieson,  G.  S.,  tychite.  247 

Penfield,  S.  L.,  and  Minor,  J.  C.,  formula  of 

topaz 408 

Penfield,  S.  L.,  and  Pratt,  J.  EL,  formula  of 

staurolite 411 


Penfield,  S.  L.,  and  Sperry,  F.  L.,  chlorite 


pseudomorphs 402 

Penfield,  S.  L.,  and  Stanley,  F.  C.,  composi- 
tion of  hornblende 384,385,387 

Penfieldite 680 

Penhale,  M. , chromite  deposits 697 

Penninite 397 

Penrose,  R.  A.  F.,  alterations  of  oredeposits.  638 

causes  of  ore  shoots 638 

Chilean  nitrates 225, 258 

iron  ore  from  glauconite 530, 573 

manganese  ores 535 

phosphate  rock 519, 526, 528 

tin  deposits 685 

Pentlandite 692,693 

Perchlorates  in  Chilean  niter 256 

Percy,  J.,  coal  analysis 753 

copper  in  peat 657 

Percylite 680 

Periclase 570,623 

Peridot 380 

Peridotite 465,466 

Periodic  classification  of  theelements 35-30 

Perofskite 340 

Perofskite-apatite-magnetite 468 

Perrey,  A.  See  Hautefeuille  and  Perrey. 

Perrone,  E . , origin  of  borates 245 

Perrot,  F.  L.  See  Jaquerod  and  Perrot. 

Peter,  R.,  matter  extracted  from  soil  by 

plants 484 

cited 183 

Petermann,  A.,  and  Graftiau,  J., cited 45 

Petersen,  T . , bauxite 496 

nickel  in  magnetite 345 

Petersen  and  N essler , analyses  of  peat 742 

Petersen  and  Schodler,  analyses  of  wood 730 

Petersson,  W. , analysis  by 467 

Petrasch  K. , f usion  of  mineral  mixtures 306 

Petrenko,  G.  I.,  silver  antimonide 650 

Petroleum 713-737 

Petterson,  A . , heat  of  radium, 314 

Pettersson,  O . , on  brine  from  melting  ice 126 


INDEX. 


805 


Page. 

Pettersson,  O.,  and  Sond<§n,  K.,  on  air  from 


sea  water 49, 142 

Petzite 644,645 

Pfaff , F.  W. , dolomitization 562, 563 

Pfeiffer,  E . , cited  on  Stassfurt  salts 221, 222 

Pfordten,  O.  von  der.  See  Konig,  T. 

Phacelite 371 

Phalen,  W.  C. , celestite 579 

unakite 598, 599 

Pharmacolite 691 

Pharmacosiderite 691 

Phenol,  in  petroleum 718 

Philip,  R.  S.  See  Gibb  and  Philip. 

Philippi,  E . , carbon  dioxide  and  climate 48 

dolomite 563 

Phillips,  F.  C. , formation  of  marsh  gas 729 

natural  gas 715 

petroleum  in  fossils 731 

Phillips,  J.  A.,  action  of  sea  water  on  rocks 569 

desert  sand 503 

gold  on  cinnabar 646 

mercury  deposits 668 

mine  waters 631 

sandstone 541 

Phillips,  W.  B.,  iron  ores 575 

petroleum 717 

phosphorite 526 

T erlingua  mines 665 

Phillips,  W.  B . , and  Hancock,  D . , bauxite — 497 

Phillipsite 416,417 

Phipson,  T . L. , primitive  atmosphere 55 

Phlegrosse 439 

Phlogopite 392-396 

Phoenicochroite 681 

Phonolite 444 

Phosgenite 679 

Phosphate  rock 519-528 

Phosphatic  nodules 134-135 

Phosphorite 523-528 

Phosphorus , distribution 19 

in  sea  water 120 

Phosphosiderite 520 

Pbyllite 611,613 

Phytostearin 735 

Pichard,  P.,  solubility  of  minerals 478 

Pickeringite 249 

Picotite 343 

Picrite 463,464 

Picromerite 223 

Pictet,  A.,  and  Ramseyer,  L.,  experiments 

on  coal 764 

Piedmontite 406-408 

Pierre,  I.,  salts  in  rainfall 52 

Pigeon  River,  analysis  of  water 70 

Pilotti,C.,  phosphates 525 

Pimelite 695 

Pinite 406 

Pinnoite 225,250 

Pinnow,  J.  See  Will  and  P innow. 

Pintadoite 710 

Piolti,  G.,  precipitation  of  zinc  by  calcite 673 

synthesis  of  anglesite 680 

Pirovaroff,  J.,  chlorine  in  rain 52 

Pirsson,  L.  V.,  cassiterite  in  hematite 685 

crystallization  of  magmas 311 


Page. 

Pirsson,  L.  W.,  primary  analcite 370, 449 

See  also  Weed  and  Pirsson. 

Pirssonite 247 

Pisani,  F.,  analysis  of  spinel 342 

See  also  Saemann  and  Pisani. 

Pisolite 552 

Pissis,  A.,  nitrates 254 

Pistomesite 571 

Pitchblende 707 

Pitch  coal 719,720,746 

Piutti,  A.,  helium  in  minerals 319 

Plagionite 678 

Planch^ite 663 

Planetesimal  hypothesis 56, 140, 286 

Plata,  River,  analysis  of  water 91, 107 

Platania,  G.,  temperatures  at  Etna 296 

Platiniridium 702 

Platinum,  distribution 19 

in  igneous  rocks 332 

ores  of 700-704 

Platte  River,  analyses  of  water 61, 79 

Plattensee,  analysis  of  water 102 

Plattnerite 679 

Plauchud,  E.,  reduction  of  sulphates  by  mi- 
crobes   577 

Playa  Lakes 237,509 

Playfair,  L.,  colliery  gases 760 

Pleochroic  halos 320 

Pleonaste 343 

Plombieres,  action  of  hot  waters  at,  on  brick.  210 

analyses  of  waters  cited 210 

Plumbogummite 681 

Plumbojarosite 680,681,704 

Plummer,  G.  W.,  pyrite  and  marcasite 334 

Podolite 355 

Poeschl,  V.,  silicate  fusions 306 

Pogue,  J.  E.,  sand  barites 537,538 

Pollard,  W.,  uranium  and  vanaaiumin  rocks.  705 
See  also  Clough  and  Pollard. 

Polianite 533 

Polonium 12,314 

Polyargyrite 653,654 

Polybasite 653 

Polydymite 692,704 

Polyhalite 223 

Polylithionite 392 

Polymethylenes 716 

Pomeroy,  Ohio,  brine 182 

Ponte,  G.  G.,  Etna 265 

Ponteil,  O.  du,  water  analysis 200 

Poole,  H.  H.,  radioactivity 315 

Popocatepetl,  water  from 200 

Popoff,  L.,  gas  from  river  mud 729 

Popoff,  S.  P.  See  Vernadsky  and  Popoff. 
Popovici,  Saligny  and  Georgesco,  water 

analysis 172 

Popp,  O.,  boron  nitride 245 

urao 238 

water  analysis 106 

Porcher,  S.,  electrum 644 

Porlezza,  C.,  and  Norzi,  G.,  argon  and  helium 

infumaroles 268 

Porter,  F.  B.  See  Bailey,  E.  H.  S. 

Porter,  H.  C.,  and  Ovitz,  F.  K.,  gases  in  coal.  760 
Porter,  J.  L.,  analysis  of  water 75 


806 


INDEX. 


Page. 

Porter,  J.  T.,  fuller’s  earth 508 

Posepny,  F.,  atmospheric  transport  of  salt...  52 

lateral  secretion 627 

heavy  metals  in  waters 631, 634 

ore  deposits 626 

Posewitz,  T.,  asphalt  and  petroleum 721 

Posnjak,  E.,  experiments  on  copper  ores 651 

Potaro  River,  analysis  of  water 90 

Potassium,  distribution 19 

in  seaweed 139 

proportion  of,  in  ocean 138, 139 

Potassium  nitrate.  See  Saltpeter. 

Potassium  salts,  absorption  by  clays 211 

Potomac  River,  analysis  of  water 72 

Potonie,  H. , origin  of  coal 740 

origin  of  petroleum 734 

Pouget,  I.,  artificial  pyrargyrite 654 

Powder  River,  analysis  of  water  cited 85 

Powellite 698 

Power,  F.  D.,  nickel  ores 695 

Pozzi-Escot,  E.,  analysis  by 164 

Pozzuoli,  analysis  of  solfatara  water 199 

Praseodymium 19,711 

Praseolite 406 

Pratt,  J.  H.,  chromite  deposits 344,697 

corundum 339-340 

gaylussite,  northupite,  pirssonite 247 

occurrence  of  spinel 343 

origin  of  talc 415 

talc 605 

See  also  Hidden  and  Pratt;  Penfield  and 
Pratt. 

Pratt,  J.  H.,  and  Lewis,  J.  V.,  chromite  de- 
posits   697 

Pratt,  J.  H.,  and  Sterrett,  D.  B.,  tin  deposits.  687 

Pratt,  N.  A.,  phosphate  rock 527 

Precht,  H.,  cited,  on  Stassfurt  salts 221 

on  langbeinite 223 

Precht,  H.,  and  Wittjen,  B.,  kieserite 227 

Precht,  J. , heat  of  radium 314 

See  also  Runge  and  Precht. 

Predazzite 570 

Prehnite 601 

Prehniterock 624 

Preiswerk,  H.,  sodalite  trachyte 375 

Pressure  and  chemical  change 291 

Prestwich,  J.,  water  in  volcanism 284 

Pretoria  salt  lake,  analysis  of  water 173, 176 

Price,  T.,  water  analysis  cited 83, 199 

Priceite 248 

Priestley,  J.,  gases  in  rocks 274 

Primero,  Rio,  analysis  of  water 92 

Pring,  J.  N.,  ozone  in  atmosphere 43 

Pring,  J.  N.,  and  Hutton,  R.  S.,  synthetic 

hydrocarbons 724 

See  also  Hayhurst  and  Pring. 

Prior,  G.  T.,  dundasite 679 

riebeckite  rocks 389 

teallite,  etc 684 

See  also  Hussak  and  Prior. 

Prior,  G.  T.,  and  Spencer,  L.  J.,  cerargyrite 

group 655 

Prismatine 381,393 

Priwoznik,  E.,  native  iron 331 

Prochlorite 397,600 

Prost,  E.  See  Spring,  W. 


Page. 

Proustite 653,654 

Prowersose 442 

Przibylla,  C.,  formation  of  carnallite 225 

Pseudoboleite 680 

Pseudobrookite 349 

Pseudogay  lussit  e 158 

Pseudoleucite 371 

Pseudonephelite 372 

Pseudowollastonite 378 

Psilomelane 533,534 

Psittacinite 682 

Pteropod  ooze 131,512 

Ptilolite 416 

Pucherite 706 

Puiggari,  M.,  cited 91 

Pulaskose 439,450 

Pulgar,  P.  del.  See  Calderon,  C.  S.,  etc. 

Pumpelly,  R.,  native  copper 656 

loess 509 

sedimentation 511 

Purdue,  A.  H.,  phosphate  rock 526 

Purington,  C.  W.,  Uralian  platinum 702 

Pyramid  Lake,  analysis  of  water 158, 176 

Pyrargyrite 653,654 

Pyrite 332-335,741 

Pyrocatechin 765 

Pyrochroite 533 

Pyrolusite 533,534 

Pyromorphite 682 

Pyrope 400 

Pyrophanite 348 

Pyrophyllite 415, 493, 605, 611 

Pyrostilpnite 653 

Pyroxene 376-383 

Pyroxenite 464 

Pyrrhotite 332-335 

Q. 

Quadrat,  B.,  analysis  of  spinel 342 

Quantitative  classification  of  rocks 425-433 

Quartz 357-363 

gaseous  inclusions  in 274 

melting  point 293 

volatility  of 273 

Quartz-alunite  rock 497 

Quartz  basalt 458 

Quartz-diaspore  rock 497 

Quartz  diorite 453 

Quartz  monzonite 452 

Quartz  porphyry 434,436 

Quartz  trachyte 434 

Quartzine 357 

Quartzite 606-608 

Quayle,  W.  O.  See  Mabery  and  Quayle. 

Quensel,  P.  D.,  formation  of  quartz  and 

tridymite 293,359 

Quercigh,  E.  See  Pellini  and  Quercigh. 

Quercylite 523 

Quincy  mine,  water  from 185 

Quinton,  R.,  ocean  water 119 

Quisqueite 706,746 

R. 


Raben,  E.,  nitrogen  and  silica  in  sea  water. . 120 

Radioactivity 313-320,709 

Radiolarian  ooze 131, 512, 513 


INDEX. 


807 


Page. 

Radiothorium 12,315 

Radium 19,314 

emanation 18,315 

in  coal 741 

in  sea  water 122 

in  springs 215 

Radominsky,  F.,  synthesis  of  monazite  and 

xenotime 355 

Ragsky,  F.,  analysis  by 193 

Rainfall 49-52 

Raken,  M.  See  Cohen,  E. 

Rakusin,  M.,  petroleum 735 

Ramage,  H.  See  Hartley,  W.  N. 

Ramirite 706 

Rammelsberg,  C.,  composition  of  tourmaline.  413 

Rammelsbergite 692 

Ramsay,  Sir  W.,  composition  of  the  atmos- 
phere  41 

sedimentation 506 

See  also  Rayleigh  and  Ramsay. 

Ramsay,  W.,  and  Travers,  M.  W.,  argon  and 

helium  in  minerals 274, 275 

Ramsay,  W.  (of  Helsingfors),  and  Illiacus, 

A.,  monazite  in  pegmatite 356 

Ramsay,  W.,  and  Nyholm,  E.  T.,  cancrinite 

syenite 375 

Ramsay  and  Hunter,  sintering  of  silica 363 

Ramseyer,  L.  See  Pictet  and  Ramseyer. 

Rangeley  Lake,  analysis  of  water 71 

Rankin,  G.  A.  See  Shepherd  and  Rankin. 

Ransome,  F.  L.,  alunite  and  diaspore 259,497 

chert 543 

enrichment  of  sulphides 639 

glaucophane  schist 591 

lawsonite 411 

See  also  Hillebrand  and  Ransome. 

Ransome,  F.  L.,  and  Palache,  C.,  lawsonite. . 411 

Raritan  River,  analysis  of  water 71 

Rastall,  R.  H.  See  Hatch  and  Rastall. 

Rath,  G.  vom,  anorthite in  marble 622 

cristobalite 357 

sublimed  silicates 273 

sulphur  deposits 578 

Rathite 678 

Ray,  J.  C.,  Butte  ores 662 

Rayleigh,  Lord,  argon  in  springs 180 

hydrogen  in  atmosphere 44 

Rayleigh,  Lord,  and  Ramsay,  W.,  argon  in 

springs 180 

Raymond,  R . W. , uintaite 720 

Read,  T . T . , copper  sulphide 660 

phase  rule 304 

platinum 704 

Read,  W.  T.,  analysis  by 73 

Reade,  T.  M.,  chemical  denudation 112, 114, 117 

Realgar 270,688,689 

Recknagel , R . , origin  of  tin  deposits 686 

Rectorite 611 

Red  clay,  oceanic 131,512-514,629 

Red  Lake,  analysis  of  water 169, 174 

Red  River  (Louisiana),  analysis  of  water 81 

Red  River  of  the  N orth , analyses  of  water 87 

Red  Sea,  analyses  of  water 125 

Redingtonite 696 

Redlich,  K.  A.,  and  Cornu,  F.,  talc  deposits. . . 605 

Redwood,  B . , formation  of  petroleum 725, 732 


Page. 

Reese, C.  L.,  solubility  of  calcium  phosphate..  519 


Refdanskite 695 

Regen,  River,  analysis  of  water 101 

Regnault,  V.,  oxygen  of  the  atmosphere 42 

Reich , A . , synthesis  of  sillimanite 410 

of  topaz 408 

See  also  Stutzer,  A. 

Reich,  F . , electrical  activity  in  ore  bodies 640 

Reichardt,  E . , analysis  of  bittern 233 

Reichardtite 223 

Reichert,  F. , Argentine  borates 250 

Reid , C . , and  Scrivenor , J . B . , cassiterite 684 

Reid,  J.  A.,  mine  water 631 

Reid , W . F . , Argentine  nitrates 256 

Reinders,  G.,  bog  iron  ore 530,532 

Reiner,  P.,  tourmaline 413 

Reindl,  J.,  cited 90 

Reinitzer,  B.,  trona 240 

Reiset,  J.,  carbon  dioxide  in  air 45 

Reiter,  H . H . , fusion  of  mineral  mixtures 306 

Reitinger,  J.  See  Hussak  and  Reitinger. 

Remingtonite 694 

Renard,  A.  F.,  phthanite 542 

phyllites 614 

See  also  Murray,  J. 

Renard,  A.  F.,  and  Cornet,  J.,  phosphorite 525 

Renault,  B . , cannel  coal 751 

peat 744 

micro-organisms  in  coal 763 

See  also  Bertrand  and  Renault. 

Renner,  O.,  baeumlerite 225 

Rennie,  E . H . , vanadium  in  clay 705 

Resins 741 

Republican  River,  analysis  of  water 80 

Retgers,  J.  W.,  constitution  of  pyroxenes 383 

minerals  in  sand 503 

Reuter,  M . See  Treadwell,  F.  P . 

Reyer , E . , volcanism 285 

Reyes,  Rio  de  los , analysis  of  water 92 

Rezbanyite 678 

Rheineck,  H.,  composition  of  tourmaline 413 

Rhine,  River,  analyses  of  silt 505 

analyses  of  water 97, 107 

Rhodium 19,700-704 

Rhodium  gold 700 

Rhodoehrosite 571 

Rhodonite 379 

Rhodose 468 

Rhodusite 388 

Rhoenite 388 

Rhone,  River,  analysis  of  water 94 

Rhyolite 433-438 

fusibility 299 

Riban,  J.,  synthesis  of  cerusite 679 

Ricciardi , L . , vanadium  in  lava 705 

Richards,  Ellen  S.,  chlorine  maps 51 

Richards,  R.  H.  See  Day  and  Richards. 

Richards,  R.  W.  See  Gale  and  Richards. 

Richardson,  C.,  asphalt 721,722 

grahamite 722 

Richardson,  C.,  and  Wallace,  E.  C.,  Texas 

petroleum 717 

Richardson,  G . B . , natural  gas 714 

sulphur  deposits 578 

tin  deposits 686 

waters  of  Utah 155 


808 


INDEX. 


Page. 

Richardson,  T.,  barytic  deposit 579 

Richmond,  H.  D.  See  Pappe,  A. 

Richterite 384 

Richthofen,  F.,  loess 509 

Rickard,  E . , tin  deposits 686 

Rickard,  F.,  tungsten  ores 699 

Rickard,  T . A . , precipitation  of  silver 649 

solution  and  deposition  of  gold 647, 648 

Rickardite 658 

Ricketts,  L.  C. , cited 163 

Riebeckite 388,389 

Riedel,  O.,  cited 221 

Rieke,  R.,  melting  points  of  silicates 292 

See  also  Endell  and  Rieke. 

Riemann,  C.,  Stassfurt  salts 221 

Ries,  H.,  alteration  of  pyroxenes 383 

clays 492,508 

limestones 557 

peat 745 

zincite 672 

Riess,  E.  R.,  eclogite 598 

Rigaud,  F.,  origin  of  coal  and  petroleum 727 

Riggs,  R.  B.,  analyses  by 453, 

507, 508, 510, 573, 596, 608, 619 

Riley,  E.,  titanium  in  clays 500 

Rimann,  E.,  magmatic  sphalerite 671 

Rinne,  F.,  koenenite 225 

reactivity  of  quartz 363 

Rinne,  F.,  and  Kolb,  R.,  Stassfurt  salts 225 

Rinneite 225 

Rio  Grande,  analysis  of  water 82 

Rising,  W.  B.  See. Le  Conte  and  Rising. 

Risler  and  Walter,  Lac  Ldman 94 

Ritom,  Lac,  analysis  of  water 95 

Ritter,  A.,  nature  of  earth’s  interior 57 

Rivas,  S.,  cited 91 

Roanoke  River,  analysis  of  water 72 

Roberts,  J.  See  Anderson  and  Roberts. 

Roberts,  M.  G.,  analyses  by 69, 70, 71, 72, 73, 78 

Roberts- Austen,  W.  C.,  melting  points  of 

minerals 292,293 

Robertson,  J.  D.,  heavy  metals  in  rocks. . . 628, 674 

precipitated  zinc  sulphide 671 

zinc  deposits 674, 675 

Robinson,  A.  C.,  and  Mabery,  0.  F.,  analysis 

by 185 

Robinson,  F.  C.,  analyses  of  water 71 

phosphoric  acid  in  beryl 414 

Rockbridge  Alum  Spring,  analysis 198 

Rock  River  (Illinois),  analysis  of  water 77 

Rock  River  (Minnesota),  analysis  of  water. . 76 

Rodzyanko,  A.,  cited 108 

Roeblingite 683 

Roepperite 389 

Roesler,  H.,  kaolinization 492 

ltoessler,  F.,  synthesis  of  argentite 650 

of  matildite 654 

of  galena  and  clausthalite 677 

Rossler,  H.,  platinum  in  silver  bullion 704 

Rottisite 695 

Rofe,  J.,  cannel  coal 751 

Rogers,  A.  F.,  alterations  of  copper 657 

corundum  syenite 339 

dahllite,  etc 523 

riebeckite  rocks 389 


Page. 

Rogers,  A.  F.,  secondary  enrichment 662 

synthesis  of  covellite 659 

Rogers,  W.  B.,  and  R.  E.,  solubility  of  min- 
erals..  478 

Rogue  River,  analysis  of  water 86 

Rohland,  P.,  plasticity  of  clays 502 

Roloff,  M.,  cited 301 

Romburgh,  P.  van,  analysis  by 197 

Romeite .-. 691 

Romer,  E.  von,  cited 149 

Roncegno,  analysis  of  water  from 188 

Rondet,  J.,  sulphosalts  of  lead 678 

Roozeboom,  H.  W.  B.,  phase  rule 304 

Roscoe,  H.  E.,  mottramite 706 

Roscoelite 391,707 

Rose,  G.,  fusion  of  limestone 556 

synthesis  of  tridymite 359 

uralitization 590 

Rose,  T.  K.,  alloys  of  gold  and  tellurium 645 

Roselite 694 

R oseland  ose 468 

Rosen,  F.,  alteration  of  dolomite 571 

Rosenbach,  O.,  volcanic  nitrogen 272 

Rosenbusch,  II.,  chloritic  substance 600 

classification  of  igneous  rocks 425, 472 

epidotization . 597 

garnet  and  prehnite  rock 624 

glaucophane  rocks 388 

gneiss 618 

order  of  deposition  of  minerals 307 

succession  of  minerals  in  igneous  rocks . . 472 

venanzite 459 

See  also  Hunter  and  Rosenbusch. 

Rosenbuschite 383 

Rosenlecher,  R.,  mercury  deposits 669 

Rosiwal,  A.,  physical  analysis  of  rocks 475 

Ross,  O.  C.  D.,  origin  of  petroleum 728 

Ross,  W.  S.,  nitrates 254 

Rdsza,  M.,  Stassfurt  salts 221 

Rossel,  H.,  carbide  theory  of  volcanisra 281 

Roth,  J.,  predazzite 570 

Rothpletz,  A.,  oolitic  sand 550 

Roumania,  salt  lakes  of 172 

Rousseau,  G.,  artificial  diamond 324 

Roux,  B.,  water  analysis 168 

Rowland  ite 712 

Rubidium,  distribution 19,28 

in  feldspar 365 

in  sea  water 121 

Ruer,  R.  See  Levin  and  Ruer. 

Ruff,  O.,  iron  hydroxides 531 

Rumbold,  W.  R.,  tin  deposits 685, 687 

Rumpfite 397 

Runge,  C.,  and  Precht,  J.,  heat  of  radium . . . 314 

Ruppin,  E.,  ocean  water 139, 145 

Russ,  F.,  aluminum  hydroxides 498 

Russell,  I.  C.,  adobe  soil 509 

calcareous  tufa 549 

disintegration  of  rocks 490 

gypsum 228 

Lake  Lahontan 158 

playa  lakes 237 

residual  clays 50S,559 

Russian  River  (California),  analysis  of  water.  83 
Rust.  See  Fischer  and  Rust. 


INDEX, 


809 


Page. 

Ruszanda,  Lake,  analysis  of  water 172,177 

Ruthenium 19,700-704 

Rutherford,  E.,  age  of  minerals 318 

radioactivity 317 

See  also  Joly  and  Rutherford. 

Rutherford,  E.,  and  Barnes,  E.  T.,  heat  of 

radium 314 

Rutile 350-352 

Rutile-nelsonite 468 

Rutley,  F.,  novaculite 542 

Ryba,  F.,  chromite  deposit 697 

Rzehak,  A.,  mercury  deposits 669 

S. 

Saale,  River,  analysis  of  water 99 

Sabatier,  P.,  and  Senderens,  J.  B.,  synthetic 

hydrocarbons 724 

Sacc,  F.,  niter  in  Bolivia 256 

Sachs,  A.,  kleinite 665 

Sachsse,  R.,  water  analysis 168 

Sacramento  River,  analysis  of  water 83 

Sadtler,  S.  P.,  distillation  of  linseed  oil 725 

natural  gas 715 

Saemann,  L.,  and  Pisani,  F.,  alteration  of 

cancrinite 375 

Safflorite * 692 

Safford,  J.  M.,  phosphorite 526 

Sahlbom,  N.,  analysis  by 445 

Saint-Gilles,  L.  P.  de.  See  Hautefeuille  and 
Saint-Giiles. 

St.  Clair,  S.,  Sudbury  ores 693 

St.  Lawrence  River,  analyses  of  water 69 

flow  of 71 

Saladillo,  Rio,  analysis  of  water 92, 164, 173 

Salic  minerals 426 

Salinas  River,  analysis  of  water 83 

Saline  River,  analysis  oi  water 80 

Salisbury,  J.  H.,  the  Dead  Sea 169 

Salisbury,  R.  D.,  mineral  matter  in  the  sea. . 127 

See  also  Chamberlin  and  Salisbury. 

Salite 379 

Salomon,  W.,  occurrence  of  spinel 342 

scapolite 404 

Salsomaggiore,  water  of,  analysis 184 

Salt 224,228-231,249,274 

Salt  beds,  origin 217-221 

Saltet,  R.  H.,  and  Stockvis,  C.  S.,  cited Ill 

Saltpeter 256 

Salt  River,  analysis  of  water 82 

Saluda  River,  analysis  of  water 73 

Salvadori,  R.,  synthetic  hydrocarbons 723 

See  also  Nasini,  R. 

Samarium 19,711 

Samarskite 707,710 

Sambhar  Salt  Lake 150, 173 

Samsonite 653 

Sand 502-504 

Sandberger,  F.,  analyses  by 196 

lateral  secretion 627 

platinum  in  limonite 703 

serpentine 602 

Sandstone 537-542 

average  composition 28 

Sandstone  reefs 538 

Sanford,  S.,  precipitated  calcium  carbonate. . 549 

San  Gabriel  River,  analysis  of  water 83 


Page. 

San  Joaquin  River,  analysis  of  water 83 

San  Rom&n,  F.  J.,  water  analysis 164 

Santa  Ana  River,  analysis  of  water 83 

Santa  Clara  River,  analysis  of  water,  cited. . . 83 

Santa  Maria  River,  analysis  of  water 83 

Santa  Ynez  River,  analysis  of  water 83 

Saponite 415 

Sapper,  K.,  volcanoes  of  Java 283 

Sapropel 734,740 

Sarasin,  E.  See  Friedel  and  Sarasin. 

Saratoga  waters,  analyses 186 

Sardeson,  F.  W.  See  Hall  and  Sardeson. 

Sarkinite 691 

Sartorite 678 

Sartorius  von  Waltershausen,  and  Lasaulx, 

A.  von,  Etna 265 

Saskatchewan  River  system 87 

Sassolite 243 

Sauer,  A.,  alteration  of  leucite  to  analcite 371 

graphitoid 754 

kryptotile 393,611 

Saussurite 407,595 

Savage,  T.  E.,  peat 745 

Savannah  River,  analysis  of  water 73 

Savu-Savu  Spring,  analysis  of 185 

Saxonite 463,465 

Saytzefl,  A.,  Uralian  platinum 702 

Scacchi,  A.,  fluorite  on  lavas 335 

leucite  pseudomorphs 371 

sublimed  silicates 273 

Vesuvian  sublimates 261, 271 

Scandium 19,711 

Scapolite 403-405,596 

Scapolite  rocks 596, 597 

Scarpa,  O.,  radioactivity  of  lava 315 

Schafarzik,  F.,  the  Medve  Lake 172 

Scbafhautl,  P.,  snythesis  of  quartz 357 

Schaller,  W.  T.,  analyses  by 614 

barbierite 364 

bisbeeite  and  shattuckite 663 

bismuth  ocher 690 

dahllite  and  podolite 355 

dumortierite 412 

hulsite  and  paigeite 684 

molybdic  ocher 698 

nephelite 372 

tourmaline 413 

tremolite 387 

vanadium  minerals 707 

warrenite 678 

Schaller,  W.  T.,  and  Hillebrand,  W.  F., 

lawsonite 411 

See  also  Hillebrand  and  Schaller;  Hess 
and  Schaller. 

Schapbachite 653,678 

Schardt,  H.,  subterranean  erosion 210 

Scharizer,  R.,  composition  of  tourmaline 413 

constitution  of  hornblende 386 

Scheelite 699 

Scheerer,  T.,  formation  of  dolomite 561 

of  magnesian  carbonates 565 

Scheererite 719 

Scheflerite 378 

Schenck,  A.,  chloritization 600 

copper  ores 659 

epidotization 407, 597, 598, 599 


810 


INDEX. 


Page. 

Schering,  H.  G.,  loess 509 

Schertel,  A.,  melting  points  of  minerals 291 

See  also  Stelzner  and  Schertel. 

Schertel,  A.,  and  Erhard,  T.,  cited 291 

Schertelite 520 

Schick endantz,  Fr,  cited 236 

Schiebe,  O.,  gold  in  olivine  rock 642 

Schilling,  J.,  distribution  of  thorium 711 

Schinnerer,  L.,  and  Morawsky,  T.,  pyroca- 

techin  from  lignite 765 

Schirmerite 653,678 

Schlaepffer,  M.,  and  Niggli,  P.,  hydrothermal 

syntheses 586 

Schlagintweit,  H.  von,  Tibetan  borax 250 

Schleimer , H . , silicate  fusions 306 

Schliersee,  analysis  of  water 96 

Schlosing,  C.,  sedimentation 506 

Schloesing,  T.,  ammonia  in  atmosphere 51 

ammonia  in  sea  water 120 

analyses  of  sea  water 123, 124 

oceanic  carbonic  acid 143 

plasticity  of  clays 502 

solubility  of  calcium  carbonate 128 

solubility  of  calcium  phosphate 519 

tropical  soils 499 

Schlundt,  H.,  radioactivity  of  waters 215 

Schlundt,  EL,  and  Moore,  It.  B.,  radioactivity 

of  waters 215 

Schmelck,  L.,  analyses  by 124,442 

calcareous  organisms 566 

marine  clays 139 

marine  muds 515 

Schmidt,  C.,  chamosite 575 

sericitic  rocks 593 

Schmidt,  C.  (Dorpat),  water  analyses 104, 

123, 124, 125, 166, 169, 171, 244 

fumaroles  of  Monte  Cerboli 244 

Schmidt,  R.  E.  See  Lunge,  G. 

Schmidt,  W.  B.,  action  of  sulphurous  acid  on 

rocks 483 

Schmitz,  E.  J.,  copper  in  fossil  wood 657 

Schmutz,  K.  B.,  artificial  scapolite  rock 404 

formation  of  tridymite 358 

fusion  of  mineral  mixtures 306 

Schnarrenberger,  C.,  analysis  by 624 

Schneeberger,  P.  See  Gilpin  and  Schnee- 
berger. 

Schneebergite 691 

Schneider,  E.  A.,  analyses  by 207, 

464, 487, 541, 544, 608 

augite-andesite 487 

See  also  Barus,  C.;  Clarke  and  Schneider. 

Schneider,  J.,  water  analysis 172 

Schneider,  K.,  origin  of  perofskite 350 

Schneider,  O.,  rinneite 225 

Schneider,  R.,  cubanite 658 

precipitation  of  silver  sulphide 651 

synthesis  of  emplectite 661 

of  wittichenite 661 

of  greenoclcite 670 

of  matildite 654 

Schodler.  See  Petersen  and  Schodler. 

Schoeller,  water  analyses 91 

Schoenite 223 

Schorlomite 401 

Schrauf,  A.,  kelyphite 402 

mercury  ores 668, 669 


Page. 

Schrauf,  A.,  mine  waters 631 

serpentine  from  garnet 603 

Schreibersite 329 

Schreiner,  O.,  and  Failyer,  G.  H.,  absorbent 

power  of  soils 501 

See  also  Kahlenberg,  L. 

Schreiner,  O.,  and  Shorey,  E.  C.,  organic  mat- 
ter of  soils 108 

Schroter.  See  Friih  and  Schroter. 

Schrotterite 611 

Schucht,  F.,  cited 98,505 

Schuler,  E.,  synthesis  of  greenockite 670 

Schuler,  G.,  chromium  in  a phosphate 523, 524 

Schurmann,  E.,  corundum  in  basalt 338 

Schiirmann,  E.,  precipitation  of  sulphides. . . 639 

Schutzenberger,  P.,  volatility  of  silica 273 

Schulten,  A.  de,  synthesis  of  analcite 369 

synthesis  of  gibbsite 497,498 

of  lanarkite 780 

oflaurionite 680 

of  malachite 663 

of  molybdenite 698 

of  northupite  and  tychite 247 

of  phosgenite 679 

See  also  Lacroix  and  De  Schulten. 

Schultz,  A.  R.,  cited 163 

Schultze,  H.,  synthesis  of  wulfenite 681 

Schulze,  EL,  and  Stelzner,  A.,  artificial  tridy- 
mite  359 

artificial  willemite 673 

Schunett,  Lake,  analysis  of  water 170, 175 

Schungite 754 

Schuster,  M.,  fichtelite 745 

Schwager,  A.,  analyses  by 96, 98, 99, 100, 518 

Bavarian  waters 96 

loess 509 

river  silt 505 

Schwantke,  A.,  artificial  tridymite 359 

chemical  system  of  eruptive  rocks 425 

iron  in  basalt 328 

osteolite  and  staff  elite 520 

Schwarz,  E.  H.  L.,  African  hot  springs 213 

interior  of  earth 40 

primitive  atmosphere 56 

Schwartzembergite 680 

Schwarz,  R.,  forms  of  silica 363 

Schwarzenbach, , the  Dead  Sea 169 

Schweidler,  E.  von,  and  Hess,  V.  F.,  heat  of 

radium 314 

Schweig,  M.,  magnetic  differentiation 312 

Schweinfurth,  G.,  and  Lewin,  L.,  origin  of 

alkaline  carbonates 242 

Schweitzer,  P.,  analyses  by 183, 188, 191, 193 

Schwertschlager,  J. , water  in  volcanic  gases . . 284 

Scolecite 416 

Scorodite 208,689 

as  a spring  deposit 208 

Scott,  A.,  classification  of  rocks 422 

Scrivenor,  J.  B.,  topaz-bearing  rocks 408 

See  also  Reid  and  Scrivenor. 

Scrope,  P.,  volcanoes 312 

Seal,  A.  N.,  ozokerite 719 

Seamon,  W.  H.,  analyses  by 644 

tallow  clays 675 

Searlesite ..  247 

Secondary  enrichment 639-641 


INDEX, 


811 


Page. 

Sedimentary  rocks 537-582 

average  composition 28 

volume  of 30,31 

Sedimentation 505,506 

Seebach,  M.t  native  iron 328 

Seidell,  A.,  water  analysis 83,156 

See  also  Cameron  and  Seidell. 

Seine,  River,  analysis  of  water 94 

Selenite.  See  Gypsum. 

Selenium,  distribution 19 

in  mineral  springs 184 

Selen  sulphur 270 

Sella,  A.,  nickel  iron 330 

Sellards,  E.  H.,  phosphate  rock 527 

Selle,  V.,  origin  of  kaolin 492 

Semper,  E.,  and  Blanckenhorn,  M.,  origin  of 

nitrates 257 

Semper  and  Michels,  Chilean  nitrates 254 

Semseyite 678 

Senarmont,  H.  de,  precipitation  of  silver 649 

reduction  of  copper 657 

synthesis  of  ch  alcopyrite 659 

of  pyrargyrite  and  proustite 653 

ofpyrite 333 

of  quartz 357 

of  realgar,  stibnite,  and  bismuthinite . 688 

of  sphalerite 669 

sulphides  of  cobalt  and  nickel 692 

Senarmontite 690 

Senderens,  J.  B.  See  Sabatier  and  Senderens. 

Serajoe  River,  analysis  of  water 105 

Sericite 391,593,594 

Serpentine 376,398,414,415,602-606 

Sestini,  F.,  solubility  of  minerals 478 

Severin,  E.  See  Engler  and  Severin. 

Sevier  Lake,  analysis  of  water 156,174 

deposits  from 235 

Seybertite 393 

Seyfert,  F.,  water  analysis 102 

Shale 545-548,608,609 

average  composition 28 

Shaler,  N.  S.,  bog  iron  ore 530 

peat 742 

phosphorite 526 

soils 508 

Shales,  metamorphosed 608,609 

Shand,  S.  J.,  classification  of  igneous  rocks  . . 422 

Sharpies,  S.  P.,  coral 555 

phosphate  rock 519,521 

solubility  of  calcium  phosphate 519 

Sharpless,  F F.  See  Lane  and  Sharpless. 

Sharwood,  W.  J.,  mine  waters 631 

telluride  gold  ores 645 

Shattuckite 663 

Sheep  Creek,  analysis  of  water 88 

Shelton,  H.  S.,  age  of  earth,  etc 153 

Shenandoah  River,  analysis  of  water 72 

Shepard,  C.  U.,  jr.,  phosphate  rock 521,522 

Shepherd,  E.  S.  See  Day  and  Shepherd. 

Shepherd,  E.  S.,  and  Rankin,  G.  A.,  binary 

systems  of  alumina,  etc 292 

gehlenite 399 

synthesis  of  corundum 337 

of  garnet 402 

ofmeionite 404 

of  sillimanite 410 

of  spinel 342 


Page. 

Shepherd,  E.  S.,  Rankin,  G.  A.,  and  Wright, 


F E.,  cristobalite 360 

Sherzer,  W.  H.,  celestite 578 

sand 504 

Shiraz,  salt  lake  near,  analysis  of  water 169, 173 

Shoal  Creek,  analysis  of  water 188 

Shonkinite 442 

Shonkinose 442 

Shorey,  E . C.  See  Schreiner  and  Shorey. 

Shoshonose 452,455,456,457 

Shutt,  F.  T.,  nitrogen  in  rain 50 

Shutt,  F.  T .,  and  Spencer,  A.  G., water  analy- 
sis   70 

Sibertzew,  N.,  soils 508 

Siberian  Ocean,  analyses  of  water 124 

Sicha,  A.,  action  of  carbonated  water  on  min- 
erals   480 

Sickenberger,  E.,  formation  of  petroleum 731 

origin  of  alkaline  carbonates 241 

Sidener,  C.  F.,  analyses  of  water 75,76,182 

Siderite 417,529,530,571-573 

Siderophyllite 392 

Sidot,  T.,  synthesis  of  galena 676 

synthesis  of  greenockite  and  wurtzite 670 

of  magnetite 345 

oftroilite 333 

of  zincite 672 

Siebenthal,  C.  E.  limestone 557 

marl 551 

Siedentopf,  H.,  color  of  salt 231 

Siemens,  E.  W.  von,  volcanic  explosions 289 

Siepmann,  P.,  constitution  of  coal 764 

Siewert,  M.,  water  analysis 92 

Silber,  P.  G.,  synthesis  ofnephelite 373 

Silica,  in  river  waters 108 

in  sea  water 120 

volatility  of 273 

Silicates,  hydrolysis  of 194 

solubility  of 132,478-480 

Siliceous  sinter 205-209 

Silico-azo-humic  acid 108 

Silicon,  distribution 20 

Silliamn,  B.,  jr.,  the  Dead  Sea 169 

Sillimanite 409-410,612 

Sillimanite  schist 614 

Silt 504-506 

Silva,  A.  F.  de,  and  d ’Aguiar,  A.,  fluorine  in 

spring  waters 192 

Silver,  distribution 20 

in  native  copper 649 

in  sea  water 121 

in  volcanic  ash 271 

occlusion  0 f oxygen  by 288 

ores  of 648,655 

Silver  Islet,  analysis  of  water  from 185 

Silver  Lake,  analysis  of  water 162, 176 

Silver,  L.  P.,  nickel  deposits 693 

Silvestri,  O.,  fluid  inclusion  in  sulphur 578 

hydrocarbons  in  lava 281, 727 

iron  nitride 272 

volcanic  gases 265 

Silvialite 404 

Silvies  River,  analysis  o f water 162 

Simek,  A.  See  Jaeger  and  Simek. 

Simmersbach,  B.,  and  Mary,  F.,  nitrate  de- 
posits  254 

Simpson,  E.  S.,  laterite 494 

native  tin 684 


812 


INDEX. 


Page. 

Singer,  F.,  zeolites 417 

Singer,  L.,  origin  of  petroleum 731 

Singer,  M.,  constituents  o f wood 739 

Singerwald,  J.  T.,  titaniferous  iron  ores 469 

Sinter,  barytic 204 

Sinter,  calcareous 203 

Sinter , ferruginous 572 

Sinter,  siliceous 205-209 

Sipocz,  L.,  analysis  by 518 

krennerite 645 

See  also  Loebisch  and  Sipocz. 

Sippy  W.  L.,  analysis  by 80 

Siserskite 700 

Sitaparite 534 

Sjogren,  H.,  bog  iron  ore 530 

fluid  inclusion  in  sulphur 578 

Scandinavian  iron  ores 469 

vesuvianite 403 

Sjollema,  B.,  perchlorates  in  soda  niter 256 

Skagit  River,  analysis  of  water 86 

Skeats,  E.  M.,  acid  water  from  sulphur  beds.  578 

Skeats,  E.  W.,  coralline  limestone 555 

magnesia  in  coral  reef. 567 

phosphate  rock 528 

Skey , W. , analyses  by 183, 191, 196, 200 

awaruite 330 

electrical  activity  in  ore  bodies 640 

gold  sulphide 643 

ocean  water 122 

precipitation  of  gold 648 

of  silver  sulphide 651 

solvents  of  gold 646 

Skinner,  W.  W.,  mineral  springs 197 

underground  waters  of  Arizona 197 

See  also  Forbes,  R.  H. 

Skutterudite 692 

Slate 545-548 

Slichter , C.  S. , volume  of  ground  water 33 

Sloan,  E . , clays 508 

Slosson,  E.  F.,  water  analyses 79, 163 

Smaltite 692,694 

Smart,  C. , water  anal  vses 155 

Smith,  A.  W.  See  Mabery  and  Smith. 

Smith,  B.  H.  See  Haywood,  J.  K. 

Smith,  E.  A.,  phosphate  rock 528 

Smith,  F.  P. , tungsten  ores 699 

Smith,  G.  O.,  molybdenite 698 

Smith,  G.  O.,  and  Willis,  B.,  iron  ores 531 

Smith,  J.,  river  waters 93 

Smith,  J.  G.,  cited 162 

See  also  Failyer  and  Smith. 

Smith,  J.  L. , analysis  by 186 

native  iron 329 

Smith,  J.  P.,eclogite 599 

glaucephane  rocks 388,591 

lawsonite  rocks 411 

Smith,  N.  R.  See  Kellerman  and  Smith. 

Smith,  R.  A.,  oxygen  of  the  atmosphere 42 

peat 742 

Smith,  Watson,  resins  in  lignite 748 

Smith,  W.  S.  T.,  zinc  deposits 675 

See  also  Ulrich  and  Smith. 

Smithite 653 

Smithsonite 672 

Smits,  A. , and  Endell,  K. , cristobalite 360 

Smoky  Hill  River,  analysis  of  water 80 


Page. 

Smolensky,  G.,  synthesis  of  titanite 350 

Smoot,  L.  E . , analysis  by 198 

Smyth,  C.  H.,  jr.,  alkaline  rocks 446 

alteration  of  pyroxene 377, 378 

Clinton  iron  ores 531 

corrosion  of  quartz 363 

limestone 623 

losses  of  atmospheric  oxygen 55 

melilite  rocks 400 

metamorphosed  gabbro 597 

solubility  of  rocks 480, 481 

talc 415,604,605 

Smyth,  H.  L.,  iron  ores 346 

Snake  River,  analysis  of  water 84 

Snider,  L.  C.,  zinc  ores 675 

Soap  Lake,  analysis  of  water 162, 177 

Soapstone 605 

Soda  Lake,  soda  from 238 

Soda  Lakes,  analyses  of  water 159, 177 

Sodalite 282,373-375 

Sodalite  syenite 375, 448, 450 

Sodalite  trachyte 375 

Soda  niter 247, 249, 254-259 

Soddy,  F.,  origin  of  helium 317 

Sodium,  distribution 20 

metallic,  in  salt 231 

sulphate  deposits 233-235 

Sodium  chloride,  in  rainfall 51-53 

See  also  Salt. 

Soellner,  J.,  rhoenite 388 

Soils 491,499,508 

SokolofT,  N.  V. , origin  of  petroleum 727 

Sollas,  W.  J.,  chert  and  flint 543 

geologic  time 149, 152 

order  of  deposition  of  minerals 307 

quartzite 607 

Solomon  River,  analysis  of  water 80 

Soltmann,  R.,  melanite 401 

Solubility  of  minerals 478-483, 630 

Sommerfeldt,  E.,  classification  of  igneous 

rocks 425 

Sommerlad,  H.,  synthesis  of  chalcostibite 661 

syntheses  of  sulphosalts 654 

sulphosalts  of  lead 678 

Sommermeier,  E.  E.,  coal  analyses 746, 747 

Sonden,  K.,  cited 49, 142 

Sonnenschein,  F.  L.,  amalgam 644 

Sonstadt,  E.,  caesium  and  rubidium  in  sea 

water 121 

gold  in  sea  water 121 

iodine  in  sea  water. . : 119 

Sorby,  H.  C.,  calcite  and  aragonite 552 

enlargement  of  quartz  grains 538 

formation  of  magnesium  carbonate 560, 561 

of  siderite  and  limonite 571 

magnesium  sulphate  in  gypsum 560 

shale 547 

Soret’s  principle 309 

Sosman,  R.  B.  See  Day  and  Sosman. 

Souesite 330,331 

Sowetow,  S.,  Sea  of  Aral 166 

Spaeth,  E.,  water  analyses 97, 101 

Spalding,  E.  P.,  Terlingua  mines 665 

Spangenberg,  K.,  synthesis  of  dolomite 560 

tests  for  dolomite 564 


Spaulding,  H.  S.,  analyses  by.  75, 76, 77, 78, 79, 80, 82 


INDEX. 


Page. 

Spencer,  A.  C.,  Franklin  zinc  ores 676 

iron  ores 531 

magmatic  waters 213, 634 

secondary  enrichment 660 

Spencer,  A.  G.  See  Shutt  and  Spencer. 

Spencer,  Herbert,  nature  of  earth’s  interior. . 57 

Spencer,  J.  W.,  bauxite 497 

Spencer,  L.  J.,  jamesonite 678 

tellurides 644 

See  also  Prior  and  Spencer. 

Sperry,  F.  L.  See  Penfield  and  Sperry. 

Sperrylite 19,700,704 

Spessartite 401 

Spezia,  G.,  effects  of  pressure 585 

formation  of  quartz  and  opal 363 

metallic  sodium  in  salt 231 

solubility  of  quartz 363, 481 

sulphur  deposits 577 

Sphserite 520. 

Sphaerocobaltite 694 

Sphalerite 669-671, 675, 741 

Sphene 350 

Spica,  M.,  and  Halagian,  G.,  Italian  waters..  96 

Spiegel,  L.,  fichtelite 745 

Spielmann,  P.,  jet 746 

Spilker,  A.  See  Kramer  and  Spilker. 

Spinel 341-343,398 

Spirek,  V.,  mercury  ores 669 

Spodumene 379,380,687 

Spokane  River,  analysis  of  water 85 

Spreustein 375 

Spring,  R.,  platinum  ores 702 

Spring,  W. , argentite  formed  by  pressure  — 650 

colorati  on  of  clay 508 

compression  of  chalk 556 

of  peat 760 

humus  and  iron  in  waters 505, 531 

precipitation  of  organic  matter  by  iron. . . 506 

sedimentation 506 

Spring,  W.,  and  Prost,  E.,  water  of  the 

Meuse 94,114,118 

Spring  River,  zinc  in 188 

Springs,  potable,  analyses  of 64 

Spurr,  J.  E . , alaskite  and  tordrillite 434 

borates 246 

dolomitization 569 

glauconite 573 

iron  ores 572 

magmatic  quartz  veins 643 

ore  deposits 634 

primary  pyrrhotite 335 

succession  of  igneous  rocks 311 

Srebenica,  spring,  analysis 188 

Stabler,  H . , interpretation  of  water  analyses . . 62 

river  waters 68 

See  also  Dole  and  Stabler. 

Stackmann,  A.,  Lake  Durun 165 

Stafifelite 520 

Stahl,  A.  F.,  origin  of  petroleum 733 

Stahl,  W.,  on  Karaboghaz 165 

zinc  sulphide 669 

Stanley,  F.  C.  See  Penfield  and  Stanley. 

Stannite 683 

Stapff,  F.  M.,  bog-iron  ore 530 

Starnbergersee,  analysis  of  water 96 

Stassfurt  salts 221-228, 250 

Staurolite 411,612 


813 


Page. 

Steamboat  Springs,  analysis  of 186 

sinter  from 206 

Steatite 415,605,606 

Stecher,  E.,  carbide  theory  of  volcanism 281 

Steenstrup,  K.  J.  V.,  graphite  in  basalt 328 

Steidtmann,  E . , alteration  of  rocks 483- 

dolomite  563 

Steiger,  G.,  analyses  by 86, 

123, 161, 162, 163, 185, 193, 232, 445, 453, 
462, 468, 480, 504, 508, 514, 527, 528, 546, 
558,  570,  573,  574,  596,  606,  614,  615 

copper  in  lava 629 

Mississippi  silt 505,629 

solubility  of  minerals 480 

synthetic  hydrocarbons 723 

See  also  Clarke  and  Steiger. 

Stein,  G.,  formation  of  quartz 360 

fusion  of  quartz  and  silicates 294 

Stein,  S . , artificial  coal 762 

Steinmann,  G.,  precipitation  of  calcium  car- 
bonate  551 

Stelzner,  A.,  artificial  gahnite 673 

associates  of  perofskite 349 

Bolivian  tin  ores 683, 687 

melilite  rocks 409 

See  also  Schulze  and  Stelzner. 

Stelzner,  A.,  and  Bergeat,  A.,  ore  deposits. . . 626 

Stelzner,  A.,  and  Schertel,  A.,  tin  in  blende. . 684 

Stelzner,  A.,  and  Schulze,  H.,  fayalite  in 

slags 390 

Stelzner,  A . W . , lateral  secretion 627 

RioSaladillo 164 

ore  deposits 626 

St8p,  J.,  and  Becke,  F.,  uranium  ores 707 

Stepanow, , analysis  of  water 166 

Stephanite 653,654 

Stercorite 521 

Sternbergite 653 

Sterrett,  D.  B.  See  Pratt  and  Sterrett. 

Stevenson,  J.,  primitive  atmosphere 55 

Stibiconite 690 

Stibnite 688 

Stieglitz,  J.,  carbon  dioxide  of  the  atmos- 
phere  145 

Stilbite 416 

Stilpnomelane 397 

Stockvis,  C.  S.  See  Saltet,  R.  H. 

Stober,  F.,  synthesis  of  cotunnite 679 

Stokes,  H.  N.,  analyses  by 28,64, 189, 435, 439, 

440,  442, 444, 447, 450,  452, 458, 461, 462, 
473,  541,  546, 558, 592, 610, 615, 619, 632 

formation  of  copper  sulphides 660 

of  sphalerite 675 

precipitation  of  copper 656, 657 

of  lead  sulphide 677 

pyrite  and  marcasite 334 

solution  and  deposition  of  silver 649, 651 

solution  of  gold 646 

tallow  clay 675 

Stoklasa,  J.,  volcanic  nitrogen 272 

Stolba,  F.,  on  the  Moldau 98 

River  Radbuza 98 

synthesis  of  galena 676 

Stolzite 681,699 

Stone,  C.  H.,  analyses  of  water 75, 160 

Mississippi  silt 505 

Stone,  G.  H.,  asphalt 720 


814 


INDEX. 


Page. 

Stone,  R.  W.,  gold  in  coal 646 

Storer,  F.  H.  See  Warren  and  Storer. 

Storms,  W.  H.,  borate  deposits 248 

Stose,  G.  W.,  wavellite 520 

Strecker,  A.  and  H.,  marine  mud 515 

Stremme,  H.,  allophane,  halloysite,  etc 500 

coal 740 

decomposition  of  basalt 483 

humus  substances 484 

kaolinization 492 

polymerization  of  hydrocarbons 733 

See  also  Gagel  and  Stremme. 

Streng,  A.,  bauxite 496 

Strengite 520 

Strigovite 397 

Strombeck,  A.  von,  electrical  activity  in  ore 

bodies 640 

Stromeyer,  C.  E.,  fusibility  and  pressure 291 

Stromeyerite 653 

Strong,  W.  W.,  radioactivity 314,317 

Strontium,  distribution  of 20 

in  sea  water 121 

Strutt,  R.  J.,  age  of  minerals 318 

gases  in  rocks 281 

helium  and  geologic  time 317 

helium  in  beryl 319 

helium  in  saline  minerals 223, 317 

radioactivity  of  rocks 19, 314, 316 

radium  in  ocean  water 122 

Struvite 521 

Stubbs,  W.  C.,  phosphate  rock 528 

Stutzer,  A.,  and  Hartleb,  R.,  bacterial  decom- 
position of  cement 485 

Stutzer,  A.,  and  Reich,  A.,  water  analysis. . . 168 

Stutzer,  O.,  cobalt  ores 691 

graphite 328 

juvenile  springs 213 

kaolinite 492 

magmatic  bomite 335 

magnetite  ores 346 

origin  of  sulphur 577 

primary  calcite 418 

sulphides  in  coal 741 

water  of  pitchstone 284 

Stutzite 652 

Stylotypite 661 

Suess,  E.,  vadose  and  juvenile  waters 213 

volcanic  additions  to  oceanic  salts 141 

Siissenguth,  H.,  cited 98,505 

Suez  Canal,  analysis  of  water 125 

Sullivan,  E.  C.,  copper  sulphides 660 

deposition  of  copper 664 

Sullivan,  G.  See  Kastle,  J.  H.,  etc. 

Sulphates,  reduction  by  micro-organisms. . 148, 515 

Sulphates  in  sea  water 138, 139 

Sulphides,  solubility  of 630 

Sulphoborite 225,250 

Sulphohalite 247 

Sulphur,  distribution 29 

in  atmosphere 45 

in  petroleum 718 

native 247,270,576-578 

Sulphur  Bank,  analyses  of  waters  from 197 

Sulvanite 706 

Summer  Lake,  analysis  of  water 161, 176 

Sundell,  J.  G.,  cancrinito  syenite 375 


Page. 

Sungi  Pait,  Brook,  analysis  of  water 199 

Superior,  Lake,  analysis  of  water 69 

Susquehanna  River,  analysis  of  water 71 

Sutton,  J.  R.,  diamond 325 

Svanberg, , analyses  by 702 

Svanbergite 682 

Svedmark,  E.,  uralitization 590 

See  also  Tornebohm  and  Svedmark. 

Svendsen,  S.,  analyses  of  dissolved  air 142 

Sweden,  rivers  of 103 

Swinton,  A.  A.  C.,  occlusion  of  gases  by 

glass 276 

Switzerland,  lakes  of. 95 

Syenite 439-441 

Syepoorite.  See  Jaipurite. 

Sylvanite 644,645 

Sylvinite 224 

Sylvite 224,228 

Syngenite 227 

Syntagmatite 387 

Syracuse,  N.  Y.,  brine,  analyses  of 182 

Szabo,  J.,  primary  iolite 406 

Szadeczky,  J.  von,  bauxite 496 

Szajnocha, , origin  of  petroleum 730, 736 

Szathmary,  L.  von,  wollastonite 378 

T. 

Taal  Volcano,  analyses  of  water  from 200 

Tabbyite 719 

Taber,  S.  See  Watson  and  Taber. 

Taboury,  F.,  selenium  in  spring  waters 184 

Tachhydrite 224 

Tacke,  B.  See  Minssen  and  Tacke. 

Tagar  Lake,  analysis  of  water 170, 174 

Tahoe,  Lake,  analysis  of  water 158 

Takano,  S.  See  Mabery  and  Takano. 

Talbot,  J.  H.  See  Binney  and  Talbot. 

Talc 415,602-606 

Tallow  clay 675 

Talmage,  J.  F.,  water  analyses 155 

Tamentica,  Lagoon,  analysis  of  water 164, 174 

Tanatar,  S.,  origin  of  alkaline  carbonates 241 

Taney,  Lac 95 

Tantalite 710 

Tantalum,  distribution  of 20 

native ✓ 711 

sources  of 710-711 

Tapajos,  River,  analysis  of  water 91,107 

Tapalpite 653 

Tappeiner,  H.,  formation  of  marsh  gas 729 

Tarassenko,  W.,  constitution  of  feldspar 364 

Tasmanite 746 

Tate,  N.,  analysis  of  water 69 

Taylor,  F.  W.,  analysis  by 231 

Taylor,  H.,  analysis  of  cannel 751 

Taylor,  R.  A.,  cited 140 

Taylor,  W.  H.,  analysis  of  water  cited 72 

Teall,  J.  J.  H.,  classification  of  igneous  rocks..  425 

dedolomitization 623 

differentiation 312 

eutectic  mixtures  in  rocks 423, 425 

origin  of  serpentine 414 

phosphate  rock 522,528 

phosphatized  trachyte 521 

the  Scourie  dike 590 

Teallite 678,683 


INDEX, 


815 


Page. 

Tegemsee,  analysis  of  water 96 

Tehamose 435 

Teisseyre,  W.  See  Mrazec  and  Teisseyre. 

Tekir-Ghiol,  Lake,  analysis  of  water 172, 173 

Tellurides 644, 645, 648, 652, 653, 658, 688 

Tellurium,  distribution 20 

in  copper 658 

in  sulphur 270 

Temiskamite 692 

Tengerite 712 

Tennantite 653,661 

Tennessee  River,  analysis  of  water 78 

Tenorite 265,271,662 

Tephroite 389 

Terbium 20,711 

Terlinguaite 664 

Termier,  P.,  alunite 259 

lawsonite 411 

leverrierite 611 

optical  variations  in  zoisite 406 

riebeckite  rocks 389 

Terreil,  A.,  artificial  dolomite 561 

native  platinum 701 

water  analyses 167 

Tesch,  P.,  solubility  of  fossils 552 

T etlow,  W . E . , wat  er  analysis 93 

Tetradymite 688 

Tetrahedrite 653,661 

Thailium,  distribution 20, 28 

Thames,  River,  analysis  of  water 93, 107 

Than,  C.  von,  ionic  statement  of  water  anal- 
yses  59 

Thenard,  P.,  silico-azo-humic  acid 108 

Thenardite 234, 247, 249, 255 

Theralite 445 

Thermonatr  it  e 239 

Tidy,  C.  M.,  cited 93 

Thiele,  F.  C.,  Texas  petroleum 717 

Thiene,  H.,  nature  of  earth’s  interior 40, 57 

Thiessen,  R.,  See  White  and  Thiessen. 

Thinolite 158 

Thiophanes 718 

Thiosulphates  in  spring  waters 195 

Thoma, , gases  in  iron - 287 

Thomas,  J.  W.,  gases  in  coal 757-760 

Thomas,  P.,  phosphorite 525 

Thompson,  A.  B .,  formation  of  bitumens 734 

Thomsen,  J.,  thermochemistry  of  sulphides . . 651 

Thomson,  J.  A.,  matrix  of  diamond 325 

Thomson,  R.  D.,  cited 93 

Thomsonite 416 

Thorianite 711 

Thorite 711 

Thorium,  distribution 20 

sources  of 711 

Thorkelsson,  T.,  hot  springs  of  Iceland 261 

Thornton,  W.  M.,  jr.,  analyses  by 468 

Thorogummite 712 

Thorpe,  T.  E.,  analyses  by 184, 186, 187 

Thorpe,  T.  E.,  and  Morton,  E.  H.,  analysis  of 

seawater 123 

Thoulet,  J.,  chert 543 

desert  sand 508 

lakes  of  the  V osges 94 


Page. 

Thoulet,  J„  sedimentation 506 

solubility  of  calcium  carbonate 128 

of  silicates 132 

Thresh,  M.,  manganese  nodules 533 

Thiirach,  H.,  occurrence  of  zircon  and  tita- 
nium minerals 354 

Thugutt,  S.  J.,  allophane,  halloysite,  etc 500 

alteration  of  corundum 340, 481 

alteration  of  wollastonite 378 

cancrinite 374 

composition  of  sodalite 374, 375 

gibbsite  and  diaspore 498 

leucite  and  analcite 368,369 

nephelite 372 

reactions  of  calcite  and  aragonite 552 

Thulium 21,711 

Thuringite 397,575 

Tidy,  C.  M.,  water  analyses  cited 93 

Tiemannite 664 

Tietze,  E.,  atmospheric  transport  of  salt 52 

Tietze,  O.,  phosphorite 525 

Tilden,  W.  A.,  gases  in  rocks 275 

Tillo,  A.  von,  areas  of  igneous  and  sedimen- 
tary rocks 117 

Tilson,  B.  S.,  cited 82 

See  also  Fraps  and  Tilson. 

Tin,  distribution 21 

in  sinter 206,684 

ores 683-687 

Tinetzky  Lake,  analysis  of  water 166, 175 

Tinguaite 444,447,449 

Tinstone.  See  Cassiterite. 

Titanite 350 

Titanolivine 389 

Titanium,  distribution 21 

Tomebohm,  A.  E.,  melilite  rocks 400 

Tomebohm,  A.  E.,  and  Svedmark,  E.,  scap- 

olite  rocks 596 

Tomebohm,  A.  S.,  enlargement  of  quartz 

grains 538 

Tolman,  C.  F.,  jr.,  oceanic  carbonic  acid 145 

secondary  enrichment 639 

Tolman,  C.  F.,  jr.,  and  Clark,  J.  D.,  electro- 
lytic behavior  of  copper 657 

Tolomei,  G.,  iron  bacteria 530 

Tombigbee  River,  analysis  of  water 74 

Tonalite 456 

Tonalose 453,461 

Tookey,  C.,  analyses  by 743, 746, 747 

Topaz 408,409,410,601 

Torbanite 733 

Tordrillite 434 

Tornoe,  H.,  density  of  sea  water 126 

analyses  of  dissolved  air 142,144 

Torrico  y Meca,  vanadium  in  coal 706 

Torrey,  J.  See  Barbour  and  Torrey. 

Toscanose 436,437,452,473 

Tourmaline 412-413 

Tourmaline  hornstone 615 

Tower,  W.  S.,  Chile  nitrates 254 

Trachyte 439 

Track  Lake,  analysis  of  water 163 

Transition  temperatures 282 

Transvaalite 694 


816 


INDEX. 


Page. 

Traphagen,  W. , cited 79 

Traube,  H. , sublimation  of  minerals 273 

synthesis  of  beryl 414 

of  rutile 351 

wurtzite  as  furnace  product 669 

zincite 672 

See  also  Bourgeois  and  Traube. 

Traunsee,  analysis  of  water 96 

Travaglia,  R.,  formation  of  sulphur  deposits.  579 

Travers,  M.  W.,  gases  from  meteorites 287 

gases  from  minerals  and  rocks 275 

Travertine 203,550 

Treadwell,  F.  P.,  and  Reuter,  M.,  solubility  of 

calcium  bicarbonate 128,129 

Trechmann,  0.  O.,  pseudogaylussite 158 

Tremolite 383,387 

Trener,  G.  B.,  genesis  of  barite 581 

Tridymite 357-363 

Trinkerite 746 

Triphylite 686 

Tripuhyite 691 

Trobridge,  F.  G.,  gases  in  coal 760 

Troilite 332-335 

Trona 1 238,239,240,247 

Troost,  L.  See  Deville  and  Troost. 

Troost,  L.,  and  Hautefeuille,  P.,  gases  in  iron.  287 

Troostite 672 

Truchot , P. , monazite,  thorite,  and  zircon ...  356 

Truckee  River,  analysis  of  water 158 

Trueman,  J.  D.,  diagnostic  criteria 624 

Tschermak,  G.,  alteration  of  atacamite 662 

carbon  in  meteorite 288, 728 

constitution  of  pyroxenes 383 

composition  of  tourmaline 413 

gaseous  occlusions 287 

scapolite  group 404,597 

serpentine 602 

theory  of  chlorites 397, 398 

of  micas 393 

Tschirwinsky , W . , phosphorite 528 

podolite 355 

Tsuneto,  K. , phosphorite 528 

Tucan,  F . , bauxite 499 

dolomitization 563 

Tucker,  G.  P.  See  Pemberton,  H. 

Tufa,  barytic 204 

Tufa,  calcareous 203 

Tulare  Lake,  analyses  of  water 160, 177 

Tungsten,  distribution 21 

ores 699 

Tungstic  ocher 699 

Tuolumnose 439 

Turgite 529 

Turner,  H.  W.,  California  diamonds 326 

quartz-alunite  rock 259, 497 

Turner,  H.  W.,  and  Rogers,  A.  F.,  primary 

sulphides 660 

Turquoise 520 

Turrentine,  J.  W.,  brines  and  bitterns 181, 233 

Tuscarora  sour  spring,  analysis 198 

Tyrolite 662 

Tychite 247,662 

Tyrrell,  G.  W.,  analcite  rocks 371 

quantitative  classification  of  igneous  rocks  433 
Tyrrell,  J.  B.,  native  iron 331 


Page. 

Tysonite 336 

Tyuyamunite 709 

U. 

Ubbelohde,  L. , optical  activity  of  petroleum . 735 

U dden,  J.  A . , aerial  denudation 138 

Uglow,  "W.  L. , secondary  silicates  in  limestone  622 

Uhlig,  J. , garnet 401 

komerupine 381 

kryptotile  and  prismatine 393,611 

Uintaite 719,720 

Ule,  W.,  the  Mansfelder  lakes 95, 102 

Ulexite 246,248,249,250,251,255 

Ulke,  T.,  tin  deposits 686 

Ullik,  F.,  on  the  Elbe 98, 118 

Ullmannite 692 

Ulrich,  E.  O.  See  Hayes  and  Ulrich. 

Ulrich,  E.  O.,  and  Smith,  W.  S.  T.,  fluorite . 582 

Ulrich,  G.  H.  F.,  awaruite 330 

Umangite 658 

Umatilla  River,  analysis  of  water 85 

U mlauff , A . F . , mercury  deposits 668 

Umpqua  River,  analysis  of  water 86 

Umptekose 445 

Unakite 326,598,599 

Uralifce 384,590 

Uralitization 589-591 

Uralose 467 

Uraninite 707,708 

Uranium,  distribution 21 

ores  of 705-710 

See  also  under  Radioactivity. 

Urao.  See  Trona. 

Urbain,  G.,  rare  earths  in  fluorite 335 

rare  metals  in  blende 669 

ytterbium 21 

Urbainite 348,469 

Urbas,  M.,  silicate  fusions 306 

Urmi,  Lake,  analysis  of  water 169, 173 

Urtite 445 

Urtose 445 

Uruguay  River,  analysis  of  water 91, 107 

silica  in 108 

Usiglio,  J.,  concentration  of  sea  water 218-220 

Ussing,  N.  V.,  alteration  of  arfvedsonite 389 

Utah  Hot  Springs,  analysis 183 

Utah  Lake,  analysis  of  water 156 

Uvaldose 459 

Uvanite 710 

Uvarovite 401 

V. 

Vaalose 462 

Vadose  waters 213 

Valentin,  J.,  fluorite 582 

Valentine,  W.,  analysis  by 473 

Valentiner,  S.,  cited 223 

Valentinite 690 

Van,  Lake,  analysis  of  water 169, 177 

Vanadic  ocher 706 

Vanadinite 682 

V anadium , distribution 21 

in  bauxite 705 

in  bitumen 706 

in  salt  clay 222,705 

ores  of 705-710 


INDEX, 


817 


Page. 


Van  Hise,  C.  R.,  actinolite  magnetite  schist. . 384 

alterations  of  corundum 341 

of  hematite 348 

amount  of  carbon  dioxide  in  atmosphere.  46 

average  composition  of  clays,  schist,  etc.  619, 620 

chert 544 

ferruginous  schists 609 

fineness  of  sand  particles 515 

formation  of  iron  ores 572 

magmatic  quartz  veins 643 

magmatic  waters 634 

mica  schist 615 

ore  deposits 626 

origin  of  magnetite 346 

porosity  of  sand 538 

quartzite 607 

relative  proportions  of  sedimentary  rocks.  32 

volume  changesin  alteration  of  minerals.  585,589 

volume  of  ground  water 33 

zinc  deposits 675 

zones  in  lithosphere 584 

See  also  Irving  and  Van  Hise. 

Van  Hise,  C.  R.,  and  Leith,  C.  K.,  mine  waters  631 

Van  Horn,  F.  R.,  alkali-hornblende 387 

Van  Niiys,  T.  C.,  and  Adams,  B.  F.,  cited 45 

Van  Riesen, , analysis  by 606 

Van’t  Hoff,  J.  H.,  geological  thermometer. . . 228 

on  Stassfurt  salts 224, 228 

syntheses  of  borates 248 

Vant  Hoff,  I.  H.,  and  Barschall,  H.,  on 

glaserite 223 

Van’t  Hoff,  J.  H.,  and  Farup,  P.,  marine 

anhydrite 226 

Van’t  Hoff,  J.  H.  Kenrick,  F.  B.,  and  Daw- 
son, H.  M.,  tachhydrite 225 

Van’t  Hoff,  J.  H.,  and  Meyerhoffer,  W.,  on 

langbeinite 224 

Van’t  Hoff,  J.  H.,  and  Weigert,  F.,  formation 

of  anhydrite 226 

Vanthoffite 223,228 

Van  Wagenen,  T.,  soda  niter 259 

Van  Winkle,  W.,  analyses  by 74, 75, 

76,77,78,79,81,82,83, 
84,  85, 86, 160, 161, 162 

Van  Winkle,  W.,  and  Eaton,  F.  M.,  waters  of 

California 83 

Variscite 520,522 

Varon,  G.  See  Henriot  and  Varon. 

Varvicite 534 

Vasculose 761 

Vater,  H.,  alkaline  carbonates 241 

anhydrite 226 

artificial  hematite 347 

calcite  and  aragonite 551, 552 

forms  of  calcium  carbonate 552 

Vater  ite 552 

Vaubel,  W.,  aragonite 551 

Meigen’s  reaction 552 

Vaughan,  T.  W.,  fuller’s  earth 508 

precipitation  of  calcium  carbonate 549 

Vauquelinite 681 

Vaux,  F.,  coal  analyses 751, 753 

Veatch,  J.  A.,  boron  in  sea  water 120 

Veatch,  O.,  bauxite 497 

V egetation,  as  agent  of  rock  decomposition . 483 , 484 

97270°— Bull.  616—16 52 


Page. 

Veins,  metalliferous 634-638 

Velain,  C.,  artificial  tridymite 359 

volcanic  gases 268 

Venable,  F.  P.,  on  periodic  law 37 

Venanzite 459 

Venanzose 459 

Verde-antique 603,622 

Vermiculite 396,397 

Vermilion 665 

Vernadsky  ,W.,  andalusite,  kyanite,  siiliman- 

ite '. 409,612 

artificial  corundum 340 

calcination  of  dumor  tier  ite 412 

of  topaz 409 

formation  of  sillimanite 409, 611 

of  spinel 343 

fusion  of  muscovite 340, 396 

occurrence  of  native  elements 28 

rare  elements  in  rocks 28 

rubidium  in  feldspar 365 

Vernadsky,  W.,  and  Popo: ',  S.  P.,  borax 250 

Vernon- Harcourt,L.  V.,  sedimentation 506 

Versailles  alum  well,  analysis 188 

Vesterberg,  A.,  dolomite  and  magnesite 564 

Vesuvianite 403,601 

Veszelyite 672 

Vetter,  F.  See  Cornu  and  Vetter. 

Vichy,  spring  deposits 204,205 

Vichy  waters,  analyses 191, 192 

VictoriaNyanza,  analysis  of  water 106 

Vierthaler,  A. , cited 122 

Viezzenose 445 

Vignon,  L.,  experiments  on  coal 764 

Villarello,  J.  D.,  mercury  ores 664 

Ville,  L. , River  Chelif 66 

Villiaumite 373 

Vils,  River,  analysis  of  water 101 

Vinagre,  Rio,  analysis  of  water 199 

Viola,  C.,  occurrence  of  lawsonite 411 

Violette, , charcoal 760,761 

Virginia  Hot  Springs,  analysis  of  water 193 

Virginose 468 

Viridite 600 

Viry  phosphatic  water,  analysis 197 

V istula  River , analysis  of  silt 505 

analysis  of  water 102 

Vivianite 520 

Voelcker,  J.  A.,  composition  of  apatite 354 

Voelckerite 523 

V ogel,  H. , platinum  in  metallic  ores 704 

Vogelsang,  H.,  viridite 600 

Vogt,  J.  H.  L.,  anorthite  in  slags 365 

apatite  in  slag 355 

augite  in  slags 382 

bog  iron  ore 530 

cassiterite  as  a furnace  product 353,684 

chromite  deposits 344, 697 

distribution  of  the  elements 27,39 

of  vanadium 705 

6utectic  mixtures  in  rocks 302-304 

eutectics  in  classification  of  rocks 423 

formation  of  hematite 347 

of  magnetite 345 

of  pyroxene 379 

fusibility  and  pressure 291 


818 


INDEX. 


Page. 

Vogt,  J.  H.  L.,  fusion  of  garnet 401 

gehlenite  group . 399 

ionization  in  magmas 306 

magmatic  iron  ore 312,346 

magmatic  pyrrhotite 335, 693 

magmatic  waters 634 

manganese  ores 535 

melting  points  of  minerals 292, 293 

mica  in  slag 394 

native  silver 649 

olivine  in  slags 390 

on  assimilation  theory 310 

ore  deposits 626 

platinum  in  pyrrhotite 704 

solubility  of  sulphides  in  magmas 305,335 

synthetic  enstatite 376 

tin  deposits 686 

wollastonite  in  slags 377 

V ohl , H .,  water  analysis 97 

Voit , F . W .,  nickel  deposits 693 

origin  of  diamond 325 

Volborthite 706 

Volcanic  dust  and  climate 48 

Volcanic  gases 269-290 

Volcanic  explosions 285-289 

Volcanic  mud  and  sand 512 

Volcanism,  ascribed  to  radioactivity 316 

hot  springs  and 214 

Voltzite 669 

V ouga, , origin  of  petroleum 732 

Vrbaite 20 

Vredenburgite 534 

Vucnik,  M.,  formation  of  augite 383 

formation  of  hercynite 343 

of  magnetite 345 

fusion  of  acmite 380 

of  mineral  mixtures 300,306 

Vukits,  B. , formation  of  augite 383 

formation  of  magnetite 345 

of  spinal 343 

fusion  of  mineral  mixtures 300, 306 

W. 

Wabash  River,  analysis  of  water 78 

Wad 533,534 

Wade,  H.  R.  See  Failyer,  G.  H. 

Wadsworth,  M.  E.,  chromite 343 

native  copper 656 

Waggaman,  W.  H.  See  Patten  and  Wagga- 
man. 

Wagner,  P.  A.,  diamond 325 

Wagoner,  L.,  gold  and  silver  in  deep-sea 

dredgings 122,642 

gold  and  silver  in  rocks 642 

gold  in  sea  water 122 

Wahl,  A.,  experiments  on  coal 764 

Wahl,  W.  H.,  composition  of  meteorites 40 

Waidner,  C.  W.,  and  Burgess,  G.  K.,  tem- 
perature of  electric  arc 273 

Waini  River,  analysis  of  water 90 

Wait,  C.  E.,  antimony  deposits 690 

Wait,  F.  G.,  analyses  by 88, 162, 185, 191 

Wakarusa  River,  analysis  of  water 80 

Walchensee,  analysis  of  water 96 

Walden,  P,  origin  of  petroleum 735 

Walker,  P.  H.,  analysis  by 534 


Page. 

Walker,  T.  L.,  magmatic  differentiation 311 

nickel  deposits 692,693 

primary  calcite 418 

temiskamite 692 

Walker  Lake,  analysis  of  water 158, 177 

W alker  River,  analysis  of  water 158 

Wallace,  E.  C.  See  Richardson  and  Wallace. 

Wallace,  R.  C.,  dolomite 565,569 

gypsum  and  anhydrite 232,576 

silicate  fusions 300 

Wallace,  W.,  sandstones 541 

Waller,  E.,  analyses  by 155,344 

Waller,  S.  A.,  and  Twelvetrees,  W.  H.,  tin 

deposits 685 

Wallerant,  F.,  chalcedony 357 

Wallich,  G.  C.,  flint 543 

Walter,  H.  See  Wegscheider  and  Walter. 

Walther,  J.,  calcareous  algae 555 

criticism  of  Ochsenius 220,226 

desert  salts 235 

origin  of  graphite 327 

laterite 493 

Walther,  P.,  native  tantalum 711 

Wanklyn,  J,  A.,  free  iodine  in  spring  water. . 183 

Ward,  L.  K.,  tin  deposits 685 

Ward,  W.  J.,  analysis  by 746 

Wardite 520 

Waring,  G.  A.,  springs  of  California 216 

Warington,  R.,  absorbent  power  of  hydrox- 
ides   501 

ammonia  in  rainfall 50 

chlorides  in  rain 52 

decomposition  of  calcium  phosphate 520 

origin  of  boric  acid 245 

sulphur  in  the  atmosphere 65 

Warren,  C.  H.,  anorthite  in  limestone 367 

iron-anthophyllite 383 

minerals  in  sand 504 

urbainite 348,469 

See  also  Hidden  and  Warren ; Johnson  and 
Warren. 

Warren,  C.  M.,  and  Storer,  F.  EL,  artificial 

petroleum 724 

Rangoon  oil 718 

Warrenite 678 

Warsaw,  N.  Y.,  brine,  analysis  of 182 

Warth,  EL,  calcium  carbonate 551 

classification  of  igneous  rocks 421 

gibbsite 495 

Warth,  H.  and  F.  J.,  laterite  and  bauxite 495 

Washington,  H.  S.,  alteration  of  biotite 395 

analcite  basalt 370, 371 

analcite  in  tinguaite 370 

analyses  by 447, 450, 592 

average  composition  of  igneous  rocks <25 

distribution  of  the  elements 35 

glaucophane  rocks 388,591 

kaersutite  and  linosite 389 

leucite  in  igneous  rocks 448 

quantitative  classification 432, 433 

relative  abundance  of  minerals 419 

Washington,  H.  S.,  and  Larsen,  E.  S.,  mag- 
netite basalt 346, 468 

Washington,  H.  S.,  and  Wright,  F.  E.,  car- 

negieite 364 

See  also  Kunz  and  Washington. 


INDEX. 


819 


Page. 


Water,  influence  of,  on  magmas . . .’ 297 

Water  analyses,  statement  of 59 

Water ee  River,  analysis  of  water 73 

Water  glass 297 

Waters,  classification  of 180, 181,201 

Waters,  J.  W.,  radioactive  minerals 315 

Watson,  H.  E.,  helium  and  neon  in  air 41 

Watson,  T.  L.,  barite 581 

bauxite 496,497 

decomposition  of  diabase 488 

gold  in  sillimanite 642 

kragerite 469 

manganese  ores 535 

nelsonite 468 

Virginia  rutile 352 

zinc  deposits 675 

Watson,  T.  L.,  and  Hess,  F.  L.,  zirconiferous 

sandstone 354 

Watson,  T.  L.,  and  Taber,  S.,  nelsonite 352 

Watts,  W.  L.,  waters  accompanying  petro- 
leum   732 

Wavellite 520 

Way,  J.  T.,  absorption  of  potassium  by  soils..  501 

Wayne,  E.  S.,  analysis  by 183 

Weathering,  belt  of 584 

Weber  River,  analysis  of  water 156 

Websky,  J.,  analyses  of  peat 742 

gas  from  peat 757 

Websky  ite 415 

Websterite 463,464 

Websterose 464 

Webb,  C.  B.,  barytic  sandstones 539 

Webb,  C.  B.,  and  Drabble,  G.  C.,  fluorspar. . 582 

Wedding,  H.,  and  Fischer,  T.,  gases  in  iron..  287 

Weed,  W.  H.,  copper  ores 659 

gold  in  igneous  rocks 332 

iron  sinter 572 

on  siliceous  sinters 206, 207 

ore  deposits 626,634 

secondary  enrichment 639 

tin  deposits 686 

travertine 550 

Weed,  W.  H.,  and  Pirsson,  L.  V.,  alteration 

of  leucite  to  analcite 371 

origin  of  corundum 340 

orpimen  t and  rea  lgar 689 

Weed,  W.  H.,  and  Spurr,  J.  E.,  ore  deposits.  626 

Weeks,  F.  B.,  tungsten  ores 699 

Weeks,  F.  B.,  and  Ferrier,  W.  F.,  phosphate 

rock 527 

Weeks,  J.  D.,  manganese  deposits 535 

W eems , J.  B . , lead  and  zinc  i n 1 imestones 674 

Wegener,  A.,  composition  of  atmosphere 41 

Wegscheider,  R.,  and  Walter,  H.,  gaylussite 

and  pirssonite 247 

Wehrlite 463,464,688 

Wehrlose 464 

Weibull,  M.,  formula  of  iolite 405 

manganese  in  spring  water 205 

vesuvianite 403 

Weidman,  S.,  clays 507 

iron  ores 572 

Weigand,  B.,  serpentine 602 

Weigel,  O.,  solubility  of  sulphides 631 

Weigert,  F.  See  Van’t  Hoff  and  Weigert. 


Page. 

Weingarten,  P.  See  Jannasch  and  Wein- 


garten. 

Weinschenk,  E.,  constitution  of  pyrite 334 

garnet  group 401 

nickel  ores 692 

_ nontronite 491-492 

origin  of  graphite 327 

serpentine 602 

synthesis  of  apatite 355 

ofargentite 650 

oi  chalcoc.ite  and  covellite 659 

of  cinnabar 666 

of  galena 677 

of  orpiment  and  stibnite 688 

sulphides  of  cobalt  and  nickel 694 

talc  pseudomorphs 605 

Weiss,  F.,  origin  of  kaolin 492 

Weiss,  K.  E.,  chromite  deposit 697 

Weisswasser,  analysis  of  water 99 

Weith,  A.  J.,  analyses  by 80 

Weld,  C.  M.,  iron  ores 531 

Wellcome,  H.  S.,  analysis  of  salt 231 

Weller,  A.,  nitrogen  in  petroleum 718 

Wells,  G.  M.,  phosphate  rock 527 

Wells,  H.  L.,  sperrylite 704 

Wells,  H.  L.,  and  Penfield,  S.  L.,  sperrylite. . 704 

Wells,  J.  W.,  arsenic  mine 690 

molybdenite 698 

Wells,  R.  C.,  copper  in  basalt 629 

electrical  potential  of  ores 640 

mine  waters 631,632 

palladium  in  plumbojarosite 704 

precipitation  of  sulphides 640 

relative  solubility  of  carbonates 641 

vanadium  in  asphalt 706 

Wellsite 416 

Welsbach,  Auer  von,  ytterbium 21 

Wendebom, , mercury  deposits 668 

Wendt,  A.  F.,  tin  deposits 687 

Werling,  P.,  loess 509 

Werner  and  Fraatz,  samsonite 653 

Wemerite 404 

Werveke,  L.  van,  occurrence  of  chloritoid 395 

iron  ores 575 

Weser  River,  analysis  of  water 102 

Westgate,  L.  G.,  epidote-quartz  rock 598 

metamorphosed  limestone 623 

Westphal,  J.,  cited,  on  Stassfurt  salts 221 

West  Baden  Spring,  analysis 189 

Wethered,  E.  B.,  oolite 550 

Weyberg,  Z. , synthesis  of  acmite 380 

ofsodalite 374,375 

the  silicate  K2  Al2  Si06 387 

Wheeler,  A.  S.,  analyses  of  sea  water 123 

Wheeler,  H.  A.,  blende  in  lignite 671 

clays 508 

lead  silicate 683 

See  also  Luedeking  and  Wheeler. 

Wheeler,  W.  C.  See  Clarke  and  Wheeler. 

Wherry,  E.  T.,  camotite 709 

Whewellite 741 

Whipple,  G.  C.,  and  Jackson,  D.  D.,  chlorine 

maps 51 

Whitby  well,  analysis 185 

White,  A.  F.,  chemical  denudation 113 


820 


INDEX, 


Page. 

White,  C.J.,  ocean  water 122 

White,  D.,  petroleum 737 

White,  D . , and  Thiessen,  R.,  origin  of  coal . . . 740, 

741,748,763 

White,  I . C. , grahamite. . . 720 

White,  J.,  barium  in  artesian  water 200, 204 

White,  W.  P.  See  Allen  and  White. 

Whitehead,  W.  L.  See  Lindgren  and  White- 
head. 

White  Island  hot  lake,  analyses  of  water 200 

White  River,  analysis  of  water 78 

White  Sea,  analysis  of  water 124 

Whitfield,  J.  E . , analyses  by 79, 

203, 205, 207, 208, 435, 453, 464, 572 

Whitman,  A . R. , origin  of  pyrite 334 

Whitney,  J.  D.,  zinc  deposits 675 

Whitneyite 658 

Whittle,  C . L . , ottrelite  schist 613 

Wibel,  E.,  cited 122 

W ichmann,  A . , alteration  of  iolite 406 

glaucophane  rock 591 

minerals  in  sand 503 

sericitic  rocks 593 

Wiegand,  E.  See  Beilstein  and  Wiegand. 

Wieland,  G.  R.,  siliceous  oolite 544 

Wiesbaden,  analysis  of  water 184 

Wiesler,  A.,  gold  in  sea  water 122 

W iesner , G . H . , nitrogen  and  chlorine  in  rain . 50 

Wilder,  F.  A.,  gypsum 232 

W ilke,  E . , rubidium  in  potash  salts 222 

Wilkinson,  C.,  precipitation  of  gold 648 

Will,  W.,  and  Pinnow,  J.,  diamonds  in 

meteorite 324 

Willamette  River,  analysis  of  water 85 

Willemite 671,673,676 

Williams,  A.,  gold  sulphide 643 

Williams,  C.  P.,  zinc  in  waters 189,632 

Williams,  F.  H.,  hydrocarbons  in  iron 722 

Williams,  G.  F.,  matrix  of  diamond,  .s- 325 

Williams,  G.  H.,  allanite  and  epidote 408 

chloritization 600 

corundum,  emery,  and  spinel 340 

epidotization 407,597,598 

occurrence  of  magnetite 346 

ofperofskite 349 

of  pyroxenes 383 

of  spinel 343 

piedmontite  in  rhyolite 407 

saussurite  rocks 595 

sericitization 594 

serpentine  from  peridotite 414 

uralitization 589 

W illiams , I . A . , clays 508 

micrometric  analysis  of  rocks 475 

Williams,  J.,  cited 50, 52 

Williams,  J.  F.,  bauxite 498 

pseudoleucite 371 

See  also  Brackett  and  Williams. 

Williams,  K.  See  Ebaugh  and  Williams. 

Willis,  B.,  cited 75 

Willm,  E.,  analyses  by 173, 195 

See  also  Jacquot  and  Willm. 

Willyamite 692 

Wilm, , palladium  gold 644 

Wilmington  Lake,  analysis  of  water 163, 177 


Page. 

Wilsmore,  N.  T.  M.  See  Craig,  A.  W. 

Wiluite 403 

W inchell,  A. , cosmical  atmosphere 54 

Winchell,  A.  N. , chalcopyrite  and  bornite ...  658 

classification  of  igneous  rocks 422 

origin  of  graphite 328 

Winchell,  H.  V.,  chalcocite 660 

W inchell,  N . H . , silicated  iron  ores 573 

Winchell,  N.  H.  and  H.  V.,  iron  ores 572 

Winkler,  C.,  origin  of  nickel-iron 330 

trona 240 

uranium  in  coal 710 

Winnemucca  Lake,  analyses  of  water 158, 176 

W inslow , A . , zinc  ores 674 

W isconsin  River , analysis  of  water 76 

Witt,  H.  M.,  river  water 93 

Witter,  F.  M.,  gas  well 729 

W ittich,  E . , cassiterite 685 

Wittichenite 661,662 

Wittjen,  B.  See  Precht  and  Wittjen. 

Wittstein,  G.,  water  analysis 101 

Woehler,  F.,  carbon  in  meteorites 728 

gases  from  meteorites 288 

synthesis  of  pyrite 333 

See  also  Deville  and  Wohler. 

W oehler,  L. , and  Kasamowski,  color  of  salt. . 231 

Wohlerite 383 

W oemitz,  River,  analysis  of  water 101 

Wolf , T . , volcanic  gases 266 

Wolfachite 692 

Wolfbauer,  J.  F.,  water  of  the  Danube.  101, 102, 505 
Wolff,  F.  von,  volcanism  and  radioactivity. . 317 

W olff , J. , artificial  diamond 323 

waters  of  Mecklenburg 102 

Wolff,  J.  E.,  Franklin  zinc  ores 676 

ottrelite 613 

Wolframite 699 

Wollastonite 377,378 

Wollastonite  gneiss 624 

W olle,  C.  A. , analysis  of  spinel 342 

Wologdine,  S.  See  Le  Chatelier  and,  Wolog- 
dine. 

Wood 739 

W ood,  A.  See  Campbell  and  W ood. 

Woodward,  R.  S.,  geodetic  data 22 

Woodward,  R.  W.,  analyses  by 157, 

203,206,236,237,544 
W ooten.  See  Magnenat  and  W ooten. 

Workman,  R.,  primary  calcite 418 

Woyno,  T.  J.,  glaucophane  schists 591 

Wright,  A.  W.,  gases  from  meteorites 287 

gases  in  rocks 275 

See  also  Hawes  and  Wright. 


Wright,  F.  E .,  crystallized  copper  and  silver . 657 

See  also  Allen,  E.  T.;  Hillebrand,  W.  F.; 
Shepherd,  E.  S. 

Wright,  F.  E.,  and  Larsen,  E.  S.,  quartz  as 


geological  thermometer 360 

Wroezynski,  A.  See  Briner  and  Wroezynski. 
Wiilfing,  E.  A.,  composition  of  tourmaline. . . 413 

Wurmsee,  analysis  of  water 96 

Wiist,  E.,  kaolin 492 

Wulf,  H.,  scapolite  rock 597 

Wulf,  J.,  wollastonite  rock 377 

Wulfenite 681,698 


INDEX. 


821 


Page. 

Wurtz,  EL,  analysis  of  water  cited 71 

huntilite  and  animikite 650 

solvent  of  gold 646 

Wurtzilite 720 

Wurtzite 669-671 

Wyatt,  F.,  phosphates 526 

Wyomingite 447 

Wyomingose 447 

Wyrouboff,  G.,  Meigen’s  reaction 552 

X. 

Xanthitane 350,500 

Xanthoconite 653 

Xanthophyllite 393 

Xanthosiderite 529 

Xenon 21,41,180 

Xenotime 355-366,712 

Xingu,  River,  analysis  of  water 91, 107 

Y. 

Yakima  River,  analysis  of  water 85 

Yamasaki,  W.,  piedmontite 407 

Yamashita,  Y.,  and  Majima,  M.,  melting 

points  of  minerals 292 

Yeates,  W.  S.,  copper  pseudomorphs 656 

Yellowstone  National  Park,  analyses  of  wa- 
ters  79,193,194,196 

spring  deposits 203, 205, 206, 207, 208 

\ Yellowstonose 453 

Yeneseisk,  Siberia,  saline  lakes 170 

Yogoite 452 

Young,  A.  A.,  enlargement  of  quartz  grains..  538 

Young,  B.  R.,  analcite  diabase 371 

Young,  G.  J.,  salines  of  Great  Basin 236 

Young,  G.  See  Irvine,  R. 

Ytterbium 21,711 

Yttrialite 712 

Yttrium,  distribution 21, 711 

sources  of 712 

Yttrocerite 336 

Yttrocrasite 712 

Yukon  River,  analysis  of  water 86 

Z. 

Zaleski,  S.  S.,  cited 104 

Zalinski,  E . R.,  thuringite  and  chamosite 575 


Page. 

Zaloziecki,  R.,  formation  of  petroleum 731, 735 

mirabilite 227 

Zaloziecki,  R.,  and  Hausmann,  J.,  Rouma- 
nian petroleum 717 

Zaloziecki,  R.,  and  Klarfold,  II.,  optical  ac- 
tivity of  petroleum 735 

Zambonini,  F.,  age  of  earth 318 

Akermanite 398 

gehlenite  group 399 

molybdosodalite 373 

pseudonephelite 372 

sublimed  galena 271 

Zaracristi, , Colombian  nitrates 256 

Zaratite 694 

Zeiller,  R.,  compression  of  peat 760 

paper  coal 748 

Zelinsky,  N.,  cited Ill 

Zemduzny,  S.,  eutectics 423 

Zemjatschensky,  P.  A.,  hydrogoethite 529 

Zem-zem,  analysis  of  water 197 

Zeolites 210,211,416 

Zepharovichite 520 

Zietrisikite 719 

Zillaruello,  A.,  Chilean  nitrates 255 

Zilliacus,  A. , analysis  by 445 

Zinc,  distribution 21 

in  river  water 189 

in  sea  water 121 

ores  of 669-676 

Zincaluminite 672 

Zincite 672,676 

Zinkenite 678 

Zinnwaldite 392 

Zircon 274,352-354,711 

Zircon  pyroxenes 383,711 

Zirconiferous  sandstone 354 

Zirconium,  distribution 22 

sources  of 711 

Zitowitsch, , gases  in  coal 757 

Zoisite 406-408, 595, 601 

Zoisite  rocks 596 

Zorgite 676 

Zschimmer,  E .,  alteration  of  micas 396 

Zuber,  R.,  origin  of  petroleum 730 

Zulkowski,  K.,  andalusite  group 409 

Zurich,  Lake  of,  analysis  of  water 97 


O 


. RTMENT  OF  THE  INTERIOR 

Franklin  K.  Lane,  Secretary 


United  States  Geological  Survey 

George  Otis  Smith,  Director 

— --  

■ . — 


BULLETIN  616 


’c. 


m 


THE 


DATA  OF  GEOCHEMISTRY 


THIRD  EDITION 


W3 


BY 


FRANK  WIGGLESWORTH  CLARKE 


■■ 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 

1916 


